Climate Change Effects on Natural Resources · cm to 59 cm. Even if the greenhouse gas...

Projected number of snow-covered days(Image: Union of Concerned Scientists)

Climate Change Effectson Natural ResourcesFOR 797, Fall 2007John Stella, [email protected]

Muir Glacier, Alaska, 1941 and 2004 (Images: William Field, Bruce Molnia, USGS)

This seminar examined the evidence of global climate change, integrating scientific analyses and their perceptions in the media. Weekly class discussions focused on different physical, biological, and social facets of the climate change story. Readings were drawn from primary climate change research (Nature, Science), global and regional analyses (IPCC 4th Assessment Report, New England Regional Assessment), news accounts, and the popular science literature (e.g. Tim Flannery’s The Weather Makers).

For the final ‘White Paper’, students summarized the state of knowledge about a particular area, the perception of the issue in the media and popular literature, and the implications for policymakers.

(Image: IPCC 2007)

FOR 797 Climate Change Effects on Natural Resources, Fall 2007 Final White Papers

Table of Contents

Chapter Subject Area Author Page

1 Overview: the physical science basis Katherina Searing 3

2 Paleoclimate and physical changes to the atmosphere

Matt Distler 10

3 Changes to the oceans Kacie Gehl 15

4 Changes to the cryosphere (snow, ice and frozen ground)

Brandon Murphy 19

5 Global and regional climate models Anna Lumsden 26

6 Impacts to freshwater resources Nidhi Pasi 31

7 Carbon sinks and sequestration Ken Hubbard 34

8 Impacts to coastal regions Juliette Smith 38

9 Effects on biodiversity and species ranges Lisa Giencke 43

10 Effects on species’ phenology Laura Heath 47

11 Human health, crop yields and food production Judy Crawford 52

12 Media perceptions of climate change: the Northeast case study

Kristin Cleveland 57

13 Mitigation measures Tony Eallonardo 62

Overview: the physical science basis and expected impacts

Katherina Searing

EXECUTIVE SUMMARY The fourth assessment report (AR4) of

the Intergovernmental Panel on Climate Change (IPCC) is the most comprehensive report of climate change science to date. This report states that there is clear evidence that global temperatures have increased 0.74°C and sea levels have increased 17 cm in the 20th century. By the end of the 21st century, global temperatures are predicted to increase between 1.8 to 4.0°C and sea levels are expected to rise between 18 and 59 cm. Most importantly, this latest synthesis of climate change science reports, with 90% confidence, that human activities have caused a warming of the planet.

This new report also highlights some of the likely impacts of increased temperatures and sea level rise on six different sectors: freshwater resources and their management; ecosystems, their properties, goods and services; food, fiber and forest products; coastal systems and low lying areas; industry, settlement and society; and human health. Additionally, some regions of the world are identified as more vulnerable to the effects of climate change, based on their geographical location and adaptation capacity.

The media plays an important role in the climate change arena by bringing the issue to people’s attention and by helping to shape public opinion. The release of the components of the AR4 earlier in 2007 and the publication of final version in November 2007, received a great deal of media attention.

Some scientists have expressed concerns about the findings of the IPCC due to the exclusion of some recent scientific data pertaining to the melting of glaciers and the ice sheets. The IPCC has been criticized for not communicating these limitations clearly in the highly influential “Summary for Policymakers” documents that are utilized by decision makers. Aside from what is included in the AR4, policymakers should consider the following when constructing policies concerning climate change: the spatial and temporal scale of climate change and its impacts, the economics of the prospective policies, and the security issues regarding the effects of climate change.

INTRODUCTION Climate change is an extremely

complex issue. Due to this complexity, policymakers required an objective and comprehensive source of information regarding this topic. The Intergovernmental Panel on Climate Change (IPCC) was established by the World Meteorological Organization (WMO) and the United Nations Environmental Programme (UNEP) in 1988. The stated goal of the IPCC is to assess the scientific, technical and socio-economic information pertaining to the understanding of the risks associated with anthropogenic climate change, its potential impacts and the mitigation strategies available. This international organization does not conduct research nor does it collect climate related data. They rely on peer reviewed scientific and technical literature that has been published. The IPCC also does not prescribe policy.

The IPCC published their fourth assessment report (AR4) in 2007. Contributions to this report were made by 1250 lead and contributing authors from more than 130 countries and the report was reviewed by more than 2500 scientific experts.1 This latest report includes several advancements over the previous reports (most recently the third assessment report [TAR] in 2001)2, such as tighter estimates and a better understanding of uncertainties provided by substantial new data collection and research. 3 The IPCC is currently divided it to three working groups. Working Group I (WG I) reports on “The Physical Basis of Climate Change,” Working Group II (WG II) focuses on “Climate Change: Impacts, Adaptation and Vulnerability,” and Working Group III deals with the “Mitigation of Climate Change.” The findings of WGs I and II will be discussed here.

1 Chairman Pauchuri, Chairman of the IPCC Presentation: “IPCC Fourth Assessment Report: Synthesis Report” Valencia, Spain. November 17, 2007. 2 IPCC, 2001: Summary for Policymakers. In: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change [Houghton, J.T.,Y. Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, X. Dai, K. Maskell, and C.A. Johnson (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. 3 Chairman Pauchuri, Chairman of the IPCC Presentation: “Introduction to AR4” Bonn, Germany. May 12, 2007.

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STATE OF THE SCIENCE

Working Group I: The Physical Science Basis

Perhaps the most important statement in the recent report of WG I is that “warming of the climate system is unequivocal.” 4 , This declaration is based on direct observations of increased global air and ocean temperatures, rising global sea level and reductions in snow and ice in the Northern hemisphere. The 100-year trend of increasing global average air temperature was approximately 0.74°C, up from 0.60°C, given in the TAR. This report also stated that the average ocean temperatures have increase to depths up to 3000 m. This heating leads to seawater expansion and consequently sea level rise. Global average sea level rose on average 1.8 mm per year from 1861 to 2003 and there is some evidence that the rates of sea level rise are increasing.5 Sea levels increased a total of 17 cm during the 20th century. Reasons for the increased sea level include the melting of the glaciers, ice caps and polar ice sheets.

Warming trends have not been uniform across the globe. Temperatures in the Arctic have increased at almost twice the global average rate over the past century and the sea ice extent in the Arctic has shrunk by 2.7% per decade. The last time the Polar Regions were warmer than at present, for an extended period of time (125,000 years ago), the melting of polar ice led to 4 to 6 m of sea level rise. Information gained from examining the paleoclimatic record informs us that the warming that has occurred in the past 50 years is unusual in the past 1,300 years.

This observed warming is due to both natural and anthropogenic forces. Only climate models that incorporate both natural and anthropogenic factors can explain the changes in surface temperatures over the past 100 years. Foremost among these anthropogenic factors is the increased concentration of greenhouses gases,

4 IPCC, 2007: Summary for Policymakers. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. 5 The rate of sea level rise was higher between 1993 and 2003, with the sea level increasing by 3.1 mm per year. However it is not known whether this reflects a true increase or if it is simply decadal variation. Ibid. pp 5-7.

especially CO2 and CH4. A number of models have been constructed to predict how surface temperatures would change with a continued increase in greenhouse gases. These models project increases of about 0.2°C are over the next two decades for a range of greenhouse gas emission scenarios. Projections for the year 2100 range from increases of 1.8 to 4.0°C, depending upon the concentration of greenhouse gases released into the atmosphere. Sea level is projected to increase by 18 to 59 cm by the end of the 21st century. 6 The upper sea level projection has decreased since the TAR from 88 cm to 59 cm. Even if the greenhouse gas concentrations could be stabilized, further warming and sea level rise would continue for centuries due to the effects of the greenhouse gases already present in the atmosphere.

Working Group II: Impacts, Adaptation and Vulnerability

The major findings of WG II in the AR47, are that the impacts of climate change are already occurring and they are now detectable at a global scale. 8 Potential impacts of climate change were identified in six sectors:

1) Freshwater resources and their management

Changes in average river runoff and water availability

Drought affected areas will expand

Increased frequency of heavy precipitation events

Increased flood risk

2) Ecosystems, their properties, goods and services

Net carbon uptake will peak prior to 2050 and then weaken or reverse

6 The predicted sea level rise is for the years 2090-2099 relative to 1980-1999. Ibid. p 13. 7 IPCC, 2007: Summary for Policymakers. In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK. 8 In the third assessment report (2001), only impacts at the regional scale could be detected. Presentation of WGII 2007: “Climate Change 2007: Impacts, Adaptation and Vulnerability” Brussels. April 6, 2007.


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Around 20 – 30% of animal and plant species are likely to be at an increased risk of extinction

Major changes in ecosystem structure and function

Coral reefs and marine shelled organisms are particularly vulnerable

3) Food, fiber and forest products

Crop productivity will increase slightly at mid- to high latitudes for temperature increases of 1-3°C increases and will decrease beyond that

Crop productivity at low latitudes will decline for even small temperature increases (1-2°C)

Commercial timber productivity may increase slightly with increased temperatures, with large regional variability

Changes in the distribution and production of fish species are expected with negative effects on aquaculture and fisheries

4) Coastal systems and low lying areas

Increased coastal erosion due to higher sea levels

More frequent coral bleaching events

Negative effects on coastal wetlands (salt marshes and mangroves) due to sea level rise

Low lying areas are extremely vulnerable to flooding

5) Industry, settlement and society

Those in coastal and river flood plains are the most vulnerable

Poor communities are also extremely vulnerable (limited adaptive capacity)

6) Human health

Increases in malnutrition and diarrhoreal diseases

Increases in death and injury from heat waves, floods, storms, fires, and droughts

Changes in the distribution of infectious disease vectors.

Given these potential impacts, it is possible

to identify regions of world that are the most vulnerable. The regions in the world that are most at risk are the Arctic, Africa (particularly Sub-Saharan Africa), small islands and the Asian mega-deltas. Some adaptation to the effects of climate change is occurring now but more will be required in order to contend with the future impacts of climate change. These responses may include a variety of adaptation mechanisms, such as technological, behavioral, managerial and policy changes.

PERSPECTIVES IN THE MEDIA AND PUBLIC POLICY

The media has a very important role in the climate change arena. The media affects the public by bringing the issue to the attention of the public and by influencing public opinion on climate change through issue framing.

Many articles were written in response to the release of the report by WG I in early February 2007. 9 These articles focused on the IPCC’s conclusions that climate change is “unequivocal” and that it is “very likely” caused by human activities.10 After the report of WG II was released in April 2007, many articles appeared in national newspapers as well. 11 These reports focused on the potential impacts of the proposed temperature increases, such as droughts, flooding, rising sea level and food shortages. Extremely vulnerable regions, both globally (mentioned in the previous section) and nationally, such as the Southwestern U.S., were discussed in several reports.

Criticisms of the IPCC Several climate experts have expressed

concerns about the lessened worst-case scenario for sea level rise in the new IPCC report (down from 88 cm in the TAR to 59 cm in the AR4).12 The panel did not consider or include new evidence on the rate of melting of glaciers and the Greenland and West Antarctic ice sheets because there was a set deadline of December

9 See Appendix I for a list of selected newspaper articles published around the release of the report from WG I. 10 greater than 90% certainty 11 See Appendix II for a list of selected newspaper articles published around the release of the report from WG II. 12 Cornelia Dean, Andrew C. Revkin contributed reporting.. Even Before Its Release, World Climate Report Is Criticized as Too Optimistic. New York Times (Late Edition (east Coast)) [serial online]. February 2, 2007:A.11.


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2005 for the submission of scientific information. However, limitations such as this are often not discussed in the highly consulted and cited “Summary for Policymakers” of the Working Groups. This demonstrates the difficulty of making scientific statements and predictions in a rapidly progressing field and reporting them in a condensed summary report. This highlights one of the difficulties of an international panel involving many participants and a rigorous and lengthy review process. To remedy this problem, it has been suggested that smaller groups be formed to focus on particular aspects of climate change and create special reports on a more frequent basis.13

CONSIDERATIONS FOR POLICYMAKERS Considerations for Policymakers are

vast and complex. Aside from the information included within the AR4, policymakers should consider the following aspects of climate change.

Spatial and Temporal Scale Climate change is a global phenomenon

that should be addressed in a global context with international cooperation. Although the regional impacts of climate change vary, an international effort must be made to supply information and technical expertise to developing nations to assist them with reducing their emissions or adapting to the impacts of climate change.

Particular attention should be given to the fact that warming will occur over the next century due to the greenhouse gases already in the atmosphere. Therefore, adaptation and mitigation strategies are necessary to cope with inevitable warming and sea level rise. Measures to reduce greenhouse gas emissions are also necessary to reduce future impacts of climate change.

Economics Efforts to reduce greenhouse emissions

are often viewed to be perilous to the economy. While the Bush administration accepts the recent findings of the IPCC, they oppose mandatory reductions in greenhouse gas emissions because of the potential damage to the U.S. economy. The administration warns of industries moving abroad, possibly to developing countries, to avoid stringent reductions in the U.S., again

13 Oppenheimer, M., O’Neill, B.C., Webster, M., and Agrawala, S. 2007. The Limits of Consensus. Science. 317: p1505-1506.

demonstrating the need for a comprehensive global plan.14

Security Climate change is now being considered

a security threat. A military panel of retired generals and admirals released a report in April that said, “projected climate change poses a serious threat to America’s national security.”15 This report describes climate change as a “threat multiplier,” that may exacerbate instability throughout the world. The United Nations Security Council also held a debate about the impacts of climate change on peace and security in April 2007.

APPENDIX I

Newspaper articles published around the release of WG I in February 2007. 1) Beth Daley Climate report faults humans

for warming; Panel voices more certainty than in 2001 :[3 Edition]. Boston Globe [serial online]. February 2, 2007:A.3.

2) Beth Daley UN study spurs call to fight warming; Panel says rise is `unequivocal' :[3 Edition]. Boston Globe [serial online]. February 3, 2007:A.1.

3) ERIC BERGER Severe heat, drought predicted for life in 22nd-century Texas / Global warming report also warns of more flooding :[3 STAR , 0 Edition]. Houston Chronicle [serial online]. February 3, 2007:A.1.

4) Gautam Naik and Jeffrey Ball U.N. Report Adds Pressure to Global-Warming Fight. Wall Street Journal (Eastern Edition) [serial online]. February 2, 2007:A.4.

5) Ian Sample, Science correspondent National: IPCC report: Why the news about warming is worse than we thought: feedback: Oceans, soil and trees will become worse at absorbing carbon dioxide

14 Zachary Coile Report spurs calls for aggressive action / White House accepts findings but rejects mandatory cuts :[FINAL Edition]. San Francisco Chronicle [serial online]. February 3, 2007:A.6. 15 The Center Naval Analyses Corporation. 2007. National Security and the Threat of Climate Change, available at http://SecurityAndClimate.cna.org/


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as temperatures rise: Evidence for warming: what the scientists found. The Guardian [serial online]. February 3, 2007:12.

6) James Bronzan Ever-Firmer Statements on Global Warming. New York Times (Late Edition (east Coast)) [serial online]. February 4, 2007:2.

7) Jane Kay A WARMING WORLD / Climate Change Report / Grim global warming prognosis for Western U.S. / International group says quick action can mitigate some effects :[FINAL Edition]. San Francisco Chronicle [serial online]. February 3, 2007:A.1.

8) John J. Fialka Politics & Economics: Global-Warming Report Gets U.S. Emphasis. Wall Street Journal (Eastern Edition) [serial online]. February 3, 2007:A.4.

9) Katy Human Denver Post Staff Writer .N. climate-change panel's projections for '01 borne out The earlier estimates were called alarmist at the time, but updated data indicate they were conservative :[Final Edition]. Denver Post [serial online]. February 2, 2007:A.4.

10) MIKE TONER 'We're creating a different planet': Scientists warn climate changes might worsen :[Main Edition]. The Atlanta Journal - Constitution [serial online]. February 3, 2007:A.5.

11) Patrick O'Driscoll Report says warming 'very likely' caused by people, will last centuries :[FINAL Edition]. USA TODAY [serial online]. February 2, 2007:A.6.

12) Peter N. Spotts Staff writer of The Christian Science Monitor A clearer global climate forecast ; A report coming Friday will offer the strongest consensus yet on how the Earth will change :[ALL Edition]. The Christian Science Monitor [serial online]. February 1, 2007:01.

13) Peter N. Spotts Staff writer of The Christian Science Monitor In wake of latest climate report, calls mount for global response ; UN findings name human activity as 'very likely' cause of 'unequivocal' climate change :[ALL Edition]. The Christian Science

Monitor [serial online]. February 5, 2007:02.

14) Peter N. Spotts Staff writer of The Christian Science Monitor Reports on global warming lag behind the science ; The newest UN-sponsored assessment left out research that suggests more dire climate change :[ALL Edition]. The Christian Science Monitor [serial online]. February 7, 2007:03.

15) SETH BORENSTEIN Report: Global warming to last for centuries / Scientists say it's `very likely' caused by people :[3 STAR , 0 Edition]. Houston Chronicle [serial online]. February 2, 2007:1.

16) Seth Borenstein, Associated Press Report steps up warning on global warming threat ; In strongest wording yet, humans get blame :[Chicago Final Edition]. Chicago Tribune [serial online]. February 2, 2007:9.

17) Thomas H. Maugh II and Karen Kaplan Deal with warming, don't debate it, scientists warn; The U.N.'s stark report puts policymakers on notice, though there is no consensus on action :[HOME EDITION]. Los Angeles Times [serial online]. February 3, 2007:A.1.

18) Zachary Coile Report spurs calls for aggressive action / White House accepts findings but rejects mandatory cuts :[FINAL Edition]. San Francisco Chronicle [serial online]. February 3, 2007:A.6.

19) Cornelia Dean, Andrew C. Revkin contributed reporting.. Even Before Its Release, World Climate Report Is Criticized as Too Optimistic. New York Times (Late Edition (east Coast)) [serial online]. February 2, 2007:A.11.

20) ELISABETH ROSENTHAL and ANDREW C. REVKIN, Elisabeth Rosenthal reported from Paris, and Andrew C. Revkin from New York. Felicity Barringer contributed reporting from Washington.. Science Panel Says Global Warming Is 'Unequivocal'. New York Times (Late Edition (east Coast)) [serial online]. February 3, 2007:A.1.

21) Global Warning; The world's scientists agree, again, that climate change is a big


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problem :[FINAL Edition]. The Washington Post [serial online]. February 5, 2007:A.14.

22) John Leicester, the Associated Press. Climate change report's forecast is bleak :[First Edition]. St. Louis Post Dispatch [serial online]. February 4, 2007:A.5.

23) Key players react to the IPCC global warming report :[ALL Edition]. The Christian Science Monitor [serial online]. February 8, 2007:25.

24) Melting doubts / The latest United Nations assessment of the human role in global warming should spur a U.S. search for solutions :[3 STAR , 0 Edition]. Houston Chronicle [serial online]. February 3, 2007:B.6.

25) Political climate shifts as verdict on warming arrives :[FINAL Edition]. USA TODAY [serial online]. February 2, 2007:A.8.

26) Seth Borenstein, THE ASSOCIATED PRESS. Global warming is here to stay That's the message in a climate report by the world's leading experts :[Third Edition]. St. Louis Post - Dispatch [serial online]. February 3, 2007:A.22.

27) Seth Borenstein, the associated press. Finger pointed at us all Climate panel agrees on most powerful warning yet, saying human activities are "very likely" causing rising seas and stronger hurricanes :[Third Edition]. St. Louis Post Dispatch [serial online]. February 2, 2007:A.1.

APPENDIX II

Newspaper articles published around the release of WG II in April 2007. 1) ANDREW C. REVKIN and TIMOTHY

WILLIAMS Global Warming Called Security Threat. New York Times (Late Edition (east Coast)) [serial online]. April 15, 2007:1.25.

2) Andrew C. Revkin Wealth and Poverty, Drought and Flood: Reports From 4 Fronts In the War on Warming. New York Times (Late Edition (east Coast)) [serial online]. April 3, 2007:F.4.

3) Beth Daley A CLIMATE CHANGE WARNING; Panel says humans are probably causing shifts around world :[3 Edition]. Boston Globe [serial online]. April 7, 2007:A.1.

4) Beth Daley US lags on plans for climate change :[3 Edition]. Boston Globe [serial online]. April 5, 2007:A.1.

5) Brad Knickerbocker White House expected to feel the heat from Supreme Court's ruling on global warming :[ALL Edition]. The Christian Science Monitor [serial online]. April 5, 2007:10.

6) Dan Vergano Study forecasts new 'Dust Bowl' :[FINAL Edition]. USA TODAY [serial online]. April 6, 2007:A.8.

7) David Adam, Environment correspondent Climate change will hit poorest hardest, say UN scientists. The Guardian [serial online]. April 6, 2007:6.

8) David Adam, Environment correspondent Environment: UN: we have the money and know-how to stop global warming: Report obtained by the Guardian spells out strategy to reverse climate change. The Guardian [serial online]. April 28, 2007:6.

9) Ed Pilkington, New York UK to raise climate talks as security council issue. The Guardian [serial online]. April 16, 2007:24.

10) Jane Kay Report predicts climate calamity / All continents face drought, starvation, rising seas, panel says :[FINAL Edition]. San Francisco Chronicle [serial online]. April 7, 2007:A.1.

11) Joseph Schuman The Morning Brief: A Climate Report Brings Dire Warnings, and Frustration :Online edition. Wall Street Journal (Eastern Edition) [serial online]. April 6, 2007:

12) Juliet Eilperin - Washington Post Staff Writer Climate Panel Confident Warming Is Underway; Report to Detail the Role of humans :[FINAL Edition]. The Washington Post [serial online]. April 5, 2007:A.1.

13) Juliet Eilperin - Washington Post Staff Writer Military Sharpens Focus on Climate Change; A Decline in Resources Is Projected to Cause Increasing Instability Overseas :[FINAL Edition]. The


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Washington Post [serial online]. April 15, 2007:A.6.

14) Juliet Eilperin - Washington Post Staff Writer Warming Predicted to Take Severe Toll on U.S :[FINAL Edition]. The Washington Post [serial online]. April 17, 2007:A.12.

15) Katy Human Denver Post Staff Writer Flame-plagued summers part of climate forecast The next chapter of a report on global warming predicts a dried-out West battling more and more fires at a cost of billions :[Final Edition]. Denver Post [serial online]. April 3, 2007:B.4.

16) Maggie Farley The World; U.N. discusses climate change; Some Security Council members say the issue isn't germane; others argue that it threatens peace and security :[HOME EDITION]. Los Angeles Times [serial online]. April 18, 2007:A.8.

17) Marc Kaufman - Washington Post Staff Writer Southwest May Get Even Hotter, Drier; Report on Warming Warns of Droughts :[FINAL Edition]. The Washington Post [serial online]. April 6, 2007:A.3.

18) Mark Magnier THE WORLD; U.N. report raises pressure on China to cut pollution; Economic growth has brought environmental disaster, but fixing it is complicated by politics, poverty and tradition :[HOME EDITION]. Los Angeles Times [serial online]. April 8, 2007:A.3.

19) Mark Martin Legislature flooded with bills about climate crisis / Poll-driven politicians see need to tackle global warming :[FINAL Edition]. San Francisco Chronicle [serial online]. April 2, 2007:A.1.

20) Peter N Spotts Surviving a warmer world: Global forecast is 'mostly dry' :[ALL Edition]. The Christian Science Monitor [serial online]. April 5, 2007:1.

21) A Consensus on Crisis; A U.N. panel details the distress that global climate change might cause human societies :[FINAL Edition]. The Washington Post [serial online]. April 8, 2007:B.6.

22) Alan Zarembo, Bettina Boxall. The Nation; A permanent drought seen for Southwest; A study says global warming threatens to

create another Dust Bowl. Water politics could also get heated :[HOME EDITION]. Los Angeles Times [serial online]. April 6, 2007:A.1.

23) Alan Zarembo, Thomas H. Maugh II. Dire warming report too soft, scientists say; Some nations lobbied for changes that blunt the study, contributors charge. The U.N. forecast is still bleak :[HOME EDITION]. Los Angeles Times [serial online]. April 7, 2007:A.1.

24) JAMES KANTER and ANDREW C. REVKIN, James Kanter reported fromBrussels, and Andrew C. Revkin from New York.. Scientists Detail Climate Changes, Poles to Tropics. New York Times (Late Edition (east Coast) [serial online]. April 7, 2007:A.1.

25) Many species feel impact of global warming, panel finds :[Fourth Edition]. St. Louis Post-Dispatch [serial online]. April 1, 2007:A.6.

26) Andrew C. Revkin. "U.N. Draft Cites Humans in Current Effects of Climate Shift. " New York Times [New York, N.Y.] 5 Apr. 2007, Late Edition (East Coast): A.6.

27) Karen Kaplan, Thomas H. Maugh II. "The Nation; Military panel calls global warming a security threat; Food shortages, melting ice and natural disasters pose danger, report says :[HOME EDITION]. " Los Angeles Times [Los Angeles, Calif.] 17 Apr. 2007,A.16.

Paleoclimate overview report Matt Distler

EXECUTIVE SUMMARY Earth’s climate over the last 1 million years

has changed on a 100,000 year (100 ka) cycle, driven by parameters related to earth’s orbit. Ice core data now covers the last 8 cycles, revealing a repeated pattern of gradual cooling into 100 ka glacial periods followed by rapid warming to 8 ka to 28 ka interglacial conditions like those ex-perienced today. New ice core evidence shows the interglacial of 410 ka, like our current inter-glacial, was particularly long (~28 ka), suggest-ing that orbital parameters do not necessarily predict an imminent return to glacial conditions.

Paleoclimate research in the last several decades has better characterized rapid climate change events superimposed upon the long-term orbital-driven cycle. Ice core data from Greenland reveals that these events, including the Little Ice Age (LIA) in the last 200 years, are characterized by significant changes in tempera-ture and climate over continental or global scale and may initiate within decades. These events are often triggered by changes in ocean circula-tion, including changes to the strength of the Atlantic thermohaline circulation system. In ad-dition, Greenland ice core data show that the circulation patterns characteristic of the LIA have not ended, despite increased global tem-peratures, implying possible anthropogenic, not orbital, causes of warming.

INTRODUCTION The degree and timing of Earth’s tilt on

it’s axis as it circles the sun and the shape of its orbit are the major drivers of earth’s climate on a multi-millenial timescale. The eccentricity (variation from circular) of earths orbit around the sun produces a 100,000 year (100 ka) cycle of greater and lesser insolation, the obliquity (tilt) of the orbit drives a 41 ka cycle, and the preces-sion (timing of seasons relative to orbital dis-tance from sun ) driving a 22 ka cycle of varying seasonality. Together these parameters produce an approximately 100 ka cycle of glacial and interglacial periods that have characterized the earth’s climate for much of the last million years. The changing position of continents, which dra-matically affect ocean and heat circulation around the globe may have played a crucial part in modulating the effects of these orbital cycles

on the climate over time periods longer than 1 million years.

Other factors affect the earth’s climate on smaller temporal scales, however, including changes in ocean circulation, atmospheric green-house gas concentrations, terrestrial albedo con-ditions, vulcanism, asteroid impacts, and many others. There is accumulating evidence that the climate is currently warming, and that increases in anthropogenically produced greenhouse gases, especially carbon dioxide (CO2), may be a pri-mary driver of this change (Mayewski and White, 2002).

Paleoclimatic reconstructions provide im-portant clues as to the past interactions between these factors, orbital parameters, and past climate change, allowing us to better predict the trajec-tory of the modern climate. Ice cores in particu-lar are important data sources for paleoclimatic reconstructions, due to their high temporal reso-lution and the direct inclusion of atmospheric components, including CO2, in the ice. Other characteristics of ice and included impurities, such as dust or ice density, serve as climate prox-ies, telling us more about weather conditions in the past. This report endeavors to give an over-view of the recent advances in our knowledge of paleoclimates based on ice core data, and dis-cusses the implications of this research for future climate change.

STATE OF THE SCIENCE Recent ice cores in the Antarctic have ex-

tended the length of our high resolution ice core records to approximately 800 ka (EPICA, 2004), improving our understanding of the very long-term changes in the orbital climate cycles of earth. The new records corroborate the general pattern of temperature and greenhouse gas con-centration changes seen in previous records of recent glaciations; glacial periods are character-ized by slowly decreasing temperatures and CO2 concentrations culminating in a period of cold but variable climate lasting approximately 100 ka. Glacial periods then transition more abruptly to a warmer interglacial similar to our current Holocene period.

The recent long Antarctic cores extend back to four glacial cycles not yet observed in ice cores, and show that the oldest of these glacial periods seem increasingly driven by the two shorter (41ka, 22ka) orbital cycles, and that in-terglacials were cooler during this period. This change in the orbital cycles toward beginning of

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the last 1 million years is in keeping with sedi-ment core results, but is not yet completely un-derstood. Another new finding is the extended length of the interglacial period that occurred 410 ka ago, the first cycle beyond the reach of earlier ice cores. The three more recent intergla-cials we’ve studied up until these new data have all been approximately 8 ka in length, which suggested that the current 10 ka length of our own Holocene might require a non-orbital-driven explanation, such as early agricultural CO2/methane emissions. The recently revealed 410 ka interglacial, however, was approximately 28 ka in duration (before agriculture and without an accompanying rise in CO2), showing that or-bital parameters may be able to explain our long Holocene (EPICA, 2004; White, 2004).

High resolution ice cores from Greenland (GISP2 project) are informative about recent climatic changes, particularly the speed with which major climate change can occur. Johnsen and others (1992) compare the results of four Greenland ice cores, and show conclusively that short (0.5 to 2 ka) periods of warm interstadial conditions occurred irregularly and repeatedly during the latter part of the last glaciation. From the raised δ18O values (signifying increased tem-peratures) these interstadials appear to be charac-terized by temperatures ~7ºC warmer than the cold glacial conditions, only 5-6 ºC cooler than modern Greenland temperatures. Perhaps more importantly, annual resolution records confirm earlier speculation that these warm periods initi-ate abruptly, within a few decades. Subsequent cooling to glacial conditions was a more gradual process. These RCCEs and later ones during the recent interglacial have been linked to changes in Atlantic Ocean circulation, which may be slowed or stopped by increased freshwater input from melting glaciers during periods of warming (Mayewski and White 2002). The speed of these changes suggests that the climate systems is more dynamic and variable at a shorter temporal scale than previously thought.

Greenland ice cores, coupled with long-term observational data on weather across the North Atlantic, have also shed light on relatively recent (historical) climate change, helping to sort out the influences of human civilization on the climate versus the suite of orbital, solar, and other “natural” influences on climate. Dawson and others (2003) compared temperature records from Greenland and Northern Europe dating back to the 1880s, confirming earlier observa-tions that cold Greenland winters are associated

with warmer northern European winters. This effect is due to a “seesaw” of high pressure sys-tems affecting the paths of cold air across the north Atlantic. Ice core data from Dawson’s team in Greenland match historical temperature records well and show that colder years in Greenland are also associated with greater so-dium (Na+) deposition from sea salts, a marker of increased storminess. Furthermore, the period from 1400 A.D. to 1900 A.D., a widespread cold period known as the Little Ice Age (LIA) is char-acterized by more frequent storms in Greenland (despite the inverse year-by-year correlation be-tween temperatures in Greenland and Europe). This study shows that the degree of storminess in Greenland is a good indicator of RCCE cooling in Europe and possibly other parts of the world. Interestingly, the return to a warmer post-LIA climate ~1900 A.D. is not accompanied by a resumption of the storm circulation patterns from the previous warm period. Rather, LIA patterns in the ice core continue to the present (Dawson et al. 2003; Mayewski and White, 2002.), despite the global warming of approximately 1 degree C since the turn of the 19th century. These data provide some evidence that the LIA atmospheric conditions continue, but that anthropogenic ef-fects on climate have cancelled out the LIA cool-ing (Mayewski and White 2002).


Compared to news of current changes in weather, temperature, organisms’ reaction to weather, or even output from predictive climate models, paleoecological research is less often presented in the popular press. This may be due to the indirect connection between paleoecologi-cal findings and our predictive capabilities for future climate as well as the highly technical nature of paleoclimatic techniques and results. Nonetheless, there are a number of sources that have brought paleoecological data to the public eye. Examples include The Weathermakers (Flannery, 2005), portions of Al Gore’s (2006) An Inconvenient Truth, the IPCC summary for policymakers, and a few popular books specifi-cally about paleoclimate.

Flannery’s book uses paleoecological sources to place current climate in perspective and highlights some paleo-events as analogs for future change, including the massive release of methane at the Paleocene-Eocene boundary, 55 million years ago. An Inconvenient Truth pro-vides greenhouse gas data from ice cores, but,


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like many popular sources, simplifies the results to make a more forceful point. Gore shows that modern CO2 levels are well above past Pleisto-cene levels, but fails to explain complex feed-backs between CO2 levels and global tempera-ture, leading to confusion about cause and effect. The IPCC summary for policymakers (2007) focuses on paleoecological estimates of sea level rise in past interglacials, past variability in CO2 and other greenhouse gas levels from ice cores, and past estimates of temperature. A few popular books are directed entirely toward paleoecologi-cal findings, including The Ice Chronicles (Mayewski and Frank, 2002) and The two-mile time machine (Alley, 2000), allowing more com-prehensive discussion and summary of this com-plex field.

CONSIDERATIONS FOR POLICYMAKERS The science outlined above is part of a

growing body of paleoecological literature that aims to better describe the history of earth’s past climate changes in order to better understand future change. Some of the most important les-sons from these studies are these:

1) Earth’s climate is continuously variable,

undergoing change at all temporal scales (gradual and rapid, short and long-term). Our civilization needs to strengthen its abil-ity to adapt to oncoming climate change.

2) Major climate change, particularly warming, may happen very quickly, within a century or even decades. Certain periods (for in-stance, the last glacial period) may be more prone to these major, rapid changes, but there is evidence that they re-occur ap-proximately every 1400 years (Mayewski and White, 2002). This instability of our climate system on short timescales should cause us to work on improving our adapta-bility to such changes, but also caution us to avoid any anthropogenic impacts that might set off feedbacks that bring on RCCEs (such as causing significant melting of polar/arctic freshwater into the North At-lantic).

3) Human impact on climate may already be observable in paleoecological records. Al-though new Antarctic cores suggest our current interglacial may be long due to or-bital forcing, not anthropogenic influences beginning ~10 ka, Greenland cores suggest our impact since ~1900 A.D. may have al-

ready offset Little Ice Age conditions. This research adds to the vast and growing body of evidence for anthropogenic effects on the climate, all of which represents a seri-ous argument for reducing greenhouse gas emissions, improving our ability as a civili-zation to adapt to changing climate and pursuing possible technologies to remediate greenhouse gas effects.

REFERENCES Alley, R.B. 2000. The Two-mile Time Machine:

Ice Cores, Abrupt Climate Change, and Our Future. Princeton University Press.

An inconvenient Truth. 2006. (Film) Dir. D.

Guggenheim. Perf. A. Gore. Lawrence Bender Productions.

Dawson, A.G. L.Elliott, P. Mayewski, P. Lockett,

S. Noone, K. Hickey, T. Holt, P. Wadhams, and I. Foster. 2003. Late-Holocene North Atlantic climate ‘seesaws’, storminess changes and Greenland ice sheet (GISP2) palaeoclimates. The Holocene, 4 (13): 381 - 392. Abstract: The oxygen-isotope record of pa-laeotemperature from Greenland ice cores has for many years been the kingpin of cli-mate reconstructions for the North Atlantic region and northern Europe, An air tempera-ture, 'seesaw' between Greenland and north-ern Europe. first described in AD 1765, is also well known and is related to the North Atlantic Oscillation (NAO). Whereas the NAO index series is based on instrumental records of air pressure, the North Atlantic climate 'seesaw' has conventionally been based on air-temperature records, Here we describe relationships between this 'seesaw' mechanism and the Greenland (GISP2) oxy-gen-isotope chronology of air-temperature variations, as well as relationships between GISP2 Na+ (sea-salt) variations and instru-mental records of North Atlantic storminess. The GISP2 proxy air-temperature record is calibrated for the last 130 years with instru-mental weather records for West Greenland, while the Na+ series is compared with in-strumental records of North Atlantic stormi-ness change. Reconstruction of an annual se-ries of these climate parameters for the last 1000 years shows that during the 'Mediaeval Warm Period' there were no years character-ized by high Na+ extremes (high North At-


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lantic storminess) but there were many years when there were extremes of temperature. Remarkably, there A ere no years of excep-tionally low air temperature and high Na+ precipitation at GISP2 between AD 1650 and 1710. a period of time that in northern Europe incorporates the period of maximum 'Little Ice Age' cooling. It would appear also that for the last thousand years the most ex-treme 'seesaw' winters when GISP2 tem-peratures were very low and Na+ concentra-tions were high occurred in discrete clusters and pairs of years.

EPICA community members*. 2004. Eight gla-

cial cycles from an Antarctic ice core. Na-ture 429: 623-628. Abstract: The Antarctic Vostok ice core provided compelling evidence of the nature of climate, and of climate feedbacks, over the past 420,000 years. Marine records sug-gest that the amplitude of climate variability was smaller before that time, but such re-cords are often poorly resolved. Moreover, it is not possible to infer the abundance of greenhouse gases in the atmosphere from marine records. Here we report the recovery of a deep ice core from Dome C, Antarctica, that provides a climate record for the past 740,000 years. For the four most recent gla-cial cycles, the data agree well with the re-cord from Vostok. The earlier period, be-tween 740,000 and 430,000 years ago, was characterized by less pronounced warmth in interglacial periods in Antarctica, but a higher proportion of each cycle was spent in the warm mode. The transition from glacial to interglacial conditions about 430,000 years ago (Termination V) resembles the transition into the present interglacial period in terms of the magnitude of change in tem-peratures and greenhouse gases, but there are significant differences in the patterns of change. The interglacial stage following Termination V was exceptionally long - 28,000 years compared to, for example, the 12,000 years recorded so far in the present interglacial period. Given the similarities be-tween this earlier warm period and today, our results may imply that without human intervention, a climate similar to the present one would extend well into the future.

IPCC, 2007: Summary for Policymakers. In: Climate

Change 2007: The Physical Science Basis. Contri-bution of Working Group I to the Fourth Assessment

Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, US.

Flannery, Tim. 2005. The Weathermakers. At-

lantic Monthly Press, New York. Johnsen, S.J., H.B. Clausen, W. Dansgaard, K.

Fuhrer, N. Gunderstrup, C.U. Hammer, P. Iversen, J. Jouzel, B. Stauffer, and J.P, Steffensen. 1992. Irregular glacial intersta-dials recorded in a new Greenland ice core. Nature 359: 311-313. Abstract: The Greenland ice sheet offers the most favourable conditions in the Northern Hemisphere for obtaining high-resolution continuous time series of climate-related pa-rameters. Profiles of 18O/16O ratio along three previous deep Greenland ice cores1–3 seemed to reveal irregular but well-defined episodes of relatively mild climate condi-tions (interstadials) during the mid and late parts of the last glaciation, but there has been some doubt as to whether the shifts in oxygen isotope ratio were genuine represen-tations of changes in climate, rather than ar-tefacts due to disturbed stratification. Here we present results from a new deep ice core drilled at the summit of the Greenland ice sheet, where the depositional environ-ment and the flow pattern of the ice are close to ideal for core recovery and analysis. The re-sults reproduce the previous findings to such a degree that the existence of the interstadial episodes can no longer be in doubt. Accord-ing to a preliminary timescale based on stratigraphic studies, the interstadials lasted from 500 to 2,000 years, and their irregular occurrence suggests complexity in the be-haviour of the North Atlantic ocean circula-tion.

Mayewski, P. and F. White. 2002. The Ice chronicles. University Press of New Eng-land.

White, J.W.C. 2004. Do I hear a million? Sci-

ence 304: 1609-1610. *Laurent Augustin1, Carlo Barbante2, Piers R. F. Barnes3, Jean Marc Barnola1, Matthias Bigler4, Emiliano Castellano5, Olivier Cattani6, Jerome Chappellaz1, Dorthe Dahl-Jensen7, Barbara Del-monte1,8, Gabrielle Dreyfus6, Gael Durand1, Sonia Falourd6, Hubertus Fischer9, Jacqueline Flu¨ ckiger4, Margareta E. Hansson10, Philippe


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Huybrechts9, Ge´ rard Jugie11, Sigfus J. Johnsen7, Jean Jouzel6, Patrik Kaufmann4, Josef Kipfstuhl9, Fabrice Lambert4, Vladimir Y. Lipenkov12, Genevie` ve C. Littot3, Antonio Longinelli13, Reginald Lorrain14, Valter Maggi8, Valerie Mas-son-Delmotte6, Heinz Miller9, Robert Mulvaney3, Johannes Oerlemans15, Hans Oerter9, Giuseppe Orombelli8, Frederic Parrenin1,6, David A. Peel3, Jean-Robert Petit1, Dominique Raynaud1, Cath-erine Ritz1, Urs Ruth9, Jakob Schwander4, Urs Siegenthaler4, Roland Souchez14, Bernhard Stauffer4, Jorgen Peder Steffensen7,

Ocean Acidification Effects of Anthropogenic CO2 on Marine Calcifying Organisms, Ocean Water Chem-istry and What the Future has in Store…

Kacie Gehl

EXECUTIVE SUMMARY: Anthropogenic release of carbon diox-

ide into the atmosphere is affecting the oceans profoundly. The oceans are the main source of carbon sequestration on the planet and without this storage; the planet may be currently unin-habitable. As the oceans take up carbon dioxide, it combines with calcium ions to produce car-bonic acid (Orr, et. al., 2005). This, in effect, decreases the alkalinity of the oceans. With ris-ing levels of undersaturation, there is a move to more acidic ocean waters (Orr, et. al., 2005), (Feely, et. al., 2004). The slight change creates an environment that is devastating for marine calcifying organisms. Because there is a de-pleted amount of calcium in the ocean water, calcifying organisms such as pteropods and cor-als are no longer able to maintain or produce shells or skeletons (Orr, et. al., 2005), (Hughes, et. al., 2003). This disrupts the basis of the food chain in many ecosystems. As the oceans can only sequester a specific amount of carbon diox-ide of which the value is unknown, it is of the utmost importance to understand as completely as possible, the effects of acidification of the oceans on calcifying organisms and the thresh-olds that exist concerning where and when the most abrupt changes in calcium saturation will occur.

INTRODUCTION: Changes in ocean water chemistry occur

from the deposition of atmospheric carbon diox-ide into the oceans. This process enables life on land to exist more comfortably as we would have a much warmer and less pleasant climate without this sequestration. When the critical threshold is reached, in which the oceans will be a net source of carbon, the climate will warm at a greater ex-tent. However, already, effects in the oceans are evident. Marine calcifying organisms, which form the basis of many food chains, are strug-gling to survive. As CO2 depletes the free cal-cium ions in the water and becomes carbonic acid, calcifying organisms are no longer able to build new shells or maintain the ones they cur-rently have, because their source of calcium is

depleted (Orr, et. al., 2005). Research is cur-rently needed in many areas to gain a better un-derstanding of how much time we have to possi-bly mitigate current damage and prevent future damage to oceans and calcifying organisms.

Although there is much we do not know concerning the process, we do know that the net source of carbon to the oceans is of an anthropo-genic nature. As the IPCC defines, even at a zero emissions standstill in CO2 pollution, the oceans will continue to take up carbon dioxide because this system is lagging behind. Also, we do know that we can not reverse what we have already released into the oceans; we can only look to the future. With this in mind, without knowing anymore than we do about ocean acidi-fication, it seems the answer is to bring emis-sions down and as close to zero as possible (Orr, et. al., 2005).

STATE OF SCIENCE: The saturation state of calcium carbonate in

the “business as usual” scenario of the IPCC is undersaturated. Undersaturation of seawater, which is the decrease in calcium saturation and thus more acidic water, though still at pH levels greater than 7.0, will likely occur within fifty years in some polar and sub polar surface waters (Orr, et. al., 2005). It is predicted that this change in chemistry will occur most drastically in the higher latitude oceans due to the presence of seasonality in these areas as opposed to equa-torial regions. In winter, the waters are cooled and there is a higher amount of dissolved CO2. Due to these factors, undersaturation of calcium will occur in these waters first during winter. As calcium binds with CO2, carbonic acid forms thus making the water more acidic. However, this process uses up the calcium in the water that would be used to form and maintain the shells and skeletons of marine calcifying organisms such as pteropods and corals (Orr, et. al., 2005). These species are critical to food webs and have a difficult time migrating because in many cases, they can survive only in specific habitats and the availability of these habitats is lessening each day.

Supporting research shows that through analyzing aragonite and calcite saturation values and quantifying calcium carbonate dissolution, saturation horizons are migrating (Feely, et. al., 2004). Results showed that in the southeastern and northeastern Atlantic Ocean, the saturation horizon for aragonite moved up between 80 and

GEHL OCEAN ACIDIFICATION FOR 797 CLIMATE CHANGE EFFECTS ON NATURAL RESOURCES FALL 2007

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150 meters. In the Pacific Ocean, the horizon is between 30 and 80 meters south of 38 degrees south and between 30 and 100 meters north of 3 degrees north latitude (Feely, et. al., 2004). Again, we see that the saturation horizon is be-coming shallower in the higher latitude oceans. This leaves much narrower spaces for species to thrive and survive (Feely, et. al., 2004).

Climate change has caused three major threats to the health of coral reefs. These include ocean uptake of atmospheric carbon dioxide, increased amount of hurricanes and warming waters. Ocean uptake of CO2 leads to more acidic waters which impede the ability of corals to maintain and form their shells. Hurricanes destroy corals with damaging currents. Warming waters enable bleaching and disease among cor-als (Hughes, et. al., 2003).

One model assumes corals respond the same to similar stresses and that corals can not adapt to changes in temperature. This has been questioned by noting that bleaching of corals is patchy indicating that not all corals respond the same to temperature or chemistry stressors (Hughes, et. al., 2003).

In addition, bleaching has been thought to be “adaptive”. However, it has been shown that bleaching in corals is a response to environ-mental stressors such as warming, pH differences, and chemistry differences rather than an adaptive measure (Hughes, et. al., 2003).

Although it is unknown whether corals can evolve to adapt to warming climates and changes in ocean water chemistry, it may be possible and further research must be conducted. Even if evo-lution can occur at such a quick rate, it is uncer-tain whether genetic traits will be inherited that will enable corals to survive. Perhaps, if corals evolve to be more tolerant of warmer tempera-tures, they will be less tolerant of higher pH val-ues. These are considered life history tradeoffs. It is impossible to know more about these trade-offs without more studies and even then, the fu-ture is uncertain (Hughes, et. al., 2003).

PERSPECTIVES IN MEDIA AND PUBLIC POLICY:

Elizabeth Kolbert’s, The Darkening Sea, highlights the deteriorating shells of pteropods while explaining sea water chemistry as the cul-prit for the disintegration. Kolbert relates that anthropogenic emissions are the cause of the trend toward more acidic ocean waters. She

shows how each of the IPCC emissions scenarios lead ultimately to more acidic oceans because we cannot reverse the process of carbon sequestra-tion; we can only slow it down. She acknowl-edges that if the oceans did not sequester the majority of the carbon dioxide that we emit, then the earth would be at a heightened state of warm-ing currently. This sequestration leaves us an opportunity to reduce or aim for zero emissions and create a lag to disrupt the rate of acidifica-tion. This will give us more time to research the issue.

However, Kolbert does not address the frightening reality that the oceans will only se-quester a certain amount of carbon dioxide be-fore they become saturated and are no longer to buffer our emissions. At this point, which is unidentified, the oceans will become a net source of carbon (Kolbert, 2006). This occurs as the oceans reach their capacity with how much car-bon they can hold and begin to release carbon to compensate. This release, coupled with our high emissions, will increase the rate of warming and climate change.

Perhaps the general media opinion was aimed at giving people hope that with a zero emissions policy, we may be able to counter the damage we have created.

CONSIDERATIONS FOR POLICYMAKERS: With all of this information, policymakers

should produce emissions management plans with an end product of low-zero emissions. Ef-forts currently underway by governments include laws and incentives for green lifestyles. Treaties and voluntary carbon reduction programs are beginning to show the world’s interest in reduc-ing emissions. However, many of these efforts are treating the symptom, not the problem. To begin to give ourselves enough time, we must implement a low emissions target. This notion is justified by the IPCC in their IPCC S650 stable rate emissions model versus their business as usual model IPCC IS92a (IPCC, 2007).

Also, to help sustain corals, better man-agement practices need to be implemented con-cerning no-take areas. The main threats to corals are not mitigated by small no-take areas. Al-though no-take zones can not protect corals from warming waters and ocean acidification, they can protect them from direct human intervention. These areas must encompass the majority of the reefs they are meant to protect if they are to be successful. However, without limiting emissions


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and giving corals an opportunity to evolve, mi-grate or adjust, there is little hope that no-take areas alone will do the job (Hughes, et. al., 2003).

In addition to lowering emissions, funding research to further the breadth of knowledge concerning ocean water chemistry and impacts on calcifying organisms is critical. Understand-ing the thresholds that exist in the ocean chemis-try and within ecosystems will give us clues as to how much time we have to make changes before the oceans are only inhabitable by jellyfish and the main buffer of our carbon emissions becomes a source.

There are many social conflicts and techni-cal uncertainties associated with reducing emis-sions. Will our society crash without fossil fuel usage? If we plan accordingly to use our deplet-ing natural resources to define a new society of “green technology” in which emissions are dras-tically reduced, there is hope that the pace of climate change will slow and the quality and health of our environment will improve. In the mean time, the delicate ecosystems of our oceans are fighting to survive.

CITED REFERENCES WITH ABSTRACTS: Feely, R. A., C. L. Sabine, et al. (2004).

"Impact of anthropogenic CO2 on the CaCO3 system in the oceans." Science 305(5682): 362-366.

Abstract: Rising atmospheric carbon diox-ide (CO2) concentrations over the past two cen-turies have led to greater CO2 uptake by the oceans. This acidification process has changed the saturation state of the oceans with respect to calcium carbonate (CaCO3) particles. Here we estimate the in situ CaCO3 dissolution rates for the global oceans from total alkalinity and chlorofluorocarbon data, and we also discuss the future impacts of anthropogenic CO2 on CaCO3 shell forming species. CaCO3 dissolution rates, ranging from 0.003 to 1.2 micromoles per kilo-gram per year, are observed beginning near the aragonite saturation horizon. The total water column CaCO3 dissolution rate for the global oceans is approximately 0.5 +/- 0.2 petagrams of CaCO3-C per year, which is approximately 45 to 65% of the export production of CaCO3.

Hughes, T. P., A. H. Baird, et al. (2003). "Climate change, human impacts, and the resil-ience of coral reefs." Science 301(5635): 929-933.

Abstract: The diversity, frequency, and scale of human impacts on coral reefs are in-creasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. How-ever, reefs will change rather than disappear en-tirely, with some species already showing far greater tolerance to climate change and coral bleaching than others. International integration of management strategies that support reef resil-ience need to be vigorously implemented, and complemented by strong policy decisions to re-duce the rate of global warming.

IPCC, 2007: Summary for Policymakers. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovern-mental Panel on Climate Change [Solomon, S., D. Qin, M. Manning,

Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Kolbert, E. (2006). "The Darkening Sea." The New Yorker 82(38).

Orr, J. C., V. J. Fabry, et al. (2005). "An-thropogenic ocean acidification over the twenty-first century and its impact on calcifying organ-isms." Nature 437(7059): 681-686.

Abstract: Today's surface ocean is satu-rated with respect to calcium carbonate, but in-creasing atmospheric carbon dioxide concentra-tions are reducing ocean pH and carbonate ion concentrations, and thus the level of calcium carbonate saturation. Experimental evidence suggests that if these trends continue, key marine organisms - such as corals and some plankton - will have difficulty maintaining their external calcium carbonate skeletons. Here we use 13 models of the ocean - carbon cycle to assess cal-cium carbonate saturation under the IS92a 'busi-ness-as-usual' scenario for future emissions of anthropogenic carbon dioxide. In our projections, Southern Ocean surface waters will begin to be-come undersaturated with respect to aragonite, a metastable form of calcium carbonate, by the year 2050. By 2100, this undersaturation could extend throughout the entire Southern Ocean and into the subarctic Pacific Ocean. When live pter-opods were exposed to our predicted level of undersaturation during a two-day shipboard ex-


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periment, their aragonite shells showed notable dissolution. Our findings indicate that conditions detrimental to high-latitude ecosystems could develop within decades, not centuries as sug-gested previously.

Changes to the Cryosphere Brandon Murphy

EXECUTIVE SUMMARY Changes to the frozen surfaces of the

earth provide some of the most visible evidence of a shifting climate. Glaciers are shrinking throughout the world, and the two largest ice sheets, Greenland and Antarctica, are experienc-ing a negative mass balance of ice. This loss of continental ice is contributing to the rise of sea level. The loss of mass from inland glaciers is occurring more rapidly than from the ice sheets, and threatens both communities that depend of them for sources of water and communities that depend on them for sources of income.

Sea ice is steadily decreasing in extant during summer at a rate of 4% per decade, which will have a negative impact on those animals that are adapted to living on it. The opening of Arc-tic waters also creates new opportunities for hu-man economic gain through fishing, resource extraction, and new trade routes. However, there is the possibility that access and rights to these waters may be a source of conflict in the future.

The loss of permafrost will affect hu-man infrastructure as the ground subsides. The loss of permafrost in peatlands may have posi-tive and negative effects on the rate to climate change. Peatlands are large storage pools of carbon and many are located in permafrost re-gions. Depending on shifting climate patterns, at least some areas may become carbon and radia-tive forcing sinks as they become more produc-tive. However, there may be a lag in this effect during which the peatland becomes a radiative forcing source because of increased methane production. If some of these thawing peatlands also become drier because of changing climate, then they will likely become sources of carbon.

INTRODUCTION The cryosphere consists of all the fro-

zen parts of the earth, such as glaciers, ice caps, ice sheets, sea ice, and areas of land underlain by permafrost. Recent warming trends associated with anthropogenic climate charge are reducing the extent of these frozen areas. There are many implications associated with changes in the cryosphere. The melting of large bodies of con-tinental ice contributes to the rise of sea level. In some areas, glacial melt is an important source of water, and the potential loss of glaciers could

have dire consequences for the surrounding populations. Changes in sea ice may have some positive effects, such as opening new trade routes, but also negative consequences for the animals that live and depend on the ice. The loss of permafrost can wreak human infrastructure as the ground begins to subside, but may also cause a shift in vegetation which can create a carbon sink.

The melting of glaciers and ice caps is a topic very commonly associated with global cli-mate change. The recession of glacial terminal ends, and the thinning of snow and ice pack are a favorite visualization of the warming climate in the media. The rise of sea level associated with the glacial melt water to the is also a common topic in the popular media, although in reality it is a much smaller contributor to sea level rise than the thermal expansion of water. Before delving into any discussion on the cryosphere it is helpful to clarify a few common (and often interchanged) terms. The American Meteoro-logical Society Glossary of Meteorology defines a glacier as “a mass of land ice, formed by the further recrystalization of firn (compacted, meta-morphosed old snow), flowing continuously from higher to lower elevations.” AMS defines an ice cap as, “a dome-shaped perennial cover of ice and snow over an extensive portion of the earth’s surface.” AMS defines an ice sheet as, “a continuous sheet of land ice that covers a very large area and moves outward in many direc-tions,” which is so thick that it will, “mask the land surface contours.” In general, both ice caps and ice sheets refer to bodies of ice so large that they can cover mountains, and therefore flow radially. The distinction is sometimes drawn at 50,000 km2 (19,300 mi2) between the smaller ice cap and the larger ice sheet.

Permafrost consists of all the ground that is frozen year round for at least two years. Permafrost underlies about 24% of the Northern Hemisphere’s land surface (Turetsky et al. 2007). These northern climates also support substantial peatlands. These northern peatlands are a sub-stantial carbon pool, estimated to range from 42 to 489 Pg C (Turetsky et al. 2007), which repre-sents 20-30% of all global soil C (Johansson et al. 2006). Concerns have been raised that as some of these peatlands that have been frozen begin to thaw, they will turn into carbon sources as the peat decays. However, there is new evidence that suggests that some of these peatlands will not dry out when they thaw but instead increase in productivity creating more carbon sinks

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(Camill et al. 2001; Johansson et al. 2006; Turet-sky et al. 2007).

STATE OF THE SCIENCE It is estimated that there may be as

many as 170,000 glaciers in the world, and of them only about 300 have been studied for changes in mass balance for any length of time (Barry 2006). Only 50 or so of the 300 glaciers have records going back more than 20 years. There are a number of ways in which glaciers are monitored. The most common has been changes in the location of the glacial terminus. However, the glacial terminus is not necessarily the best representation of true changes in mass and vol-ume of a glacier because glaciers may thin more rapidly than they recede (Barry 2006).

There are three main techniques used to calculate a mass balance (Rignot & Thomas 2002). The mass budget method is calculated from estimates of all inputs and outputs to a gla-cier or ice sheet. Outputs include melt, sublima-tion, flow, calving, which are all dynamic proc-esses. The uncertainties with all the estimations of the inputs and outputs can lead to error in the mass budget calculation, particularly on larger areas of ice. The second method for mass bal-ance is measurements of elevation change over time. The changes in elevation can then be con-verted into estimates of changes in volume. The changes in elevation are measured by laser al-timetry from either satellites or aircraft, and must first be corrected to account for isostatic rebound of the earth’s surface. The third method of cal-

culating a mass balance involves measuring the changes in weight of a body of ice by measuring changes in the earth’s field of gravity using NASA’s Gravity Recovery and Climate Experi-ment (GRACE) satellites. The premise behind the gravimetric technique is that the greater the mass at any point on the earth, the stronger its field of gravity. The measurements made by the GRACE satellites need to be corrected for isostatic rebound, atmospheric mass, and exter-nal signals from continental hydrology outside the area being measured and ocean mass vari-ability (Velicogna & Wahr 2006). The gravimet-ric technique, which only began in 2002, is par-ticularly useful for calculating mass budget on very large areas such as the Greenland ice sheet, and the Antarctic ice sheet.

The calculation of mass budget for the three main ice sheets from GRACE satellites’ data generally shows a net loss of ice in recent years. The Greenland ice sheet had a total loss of 82 + 28 km3 ice per year from 2002-2004 (Veli-cogna & Wahr 2005). The West Antarctic ice sheet had a loss of 148 + 21 km3 per year, and the East Antarctic ice sheet had a change of 0 + 56 km3 per year from 2002-2005 (Velicogna & Wahr 2006). There is a general consensus among different mass balance techniques that both Greenland and Antarctica are currently ex-periencing a net loss of ice (table 1)

Table 1. Summary of mass balance studies of the East Antarctic ice sheet (EAIS), West Ant-arctic ice sheet (WAIS), total Antarctic ice sheets (AIS), and the Greenland ice sheet (GIS) (Shepherd & Wingham 2007).

While Greenland and Antarctica account for the vast majority of the worlds ice, it is the smaller continental glaciers that are melting faster. Approximately 60% of the ice being lost each year comes from small glaciers as opposed to the ice sheets (Meier et al. 2007). These smaller glaciers lack the thermal inertia of the ice sheets.

The Artic sea ice is in a decline, primarily in its extent during the summer months. Since around 1960, the extent of summer ice has been decreasing at about 4% per decade (Deser et al. 2000). While sea ice loss does not affect sea level, it has important implications for animals that are adapted to living on the ice.

There has been a concern that the loss of permafrost in peatlands will cause the peat to dry out and decompose in a warming climate, which would contribute to large releases of CO2. How-ever, Johansson et al. (2006) calculated a net increase of 16% in the CO2 sink following thaw-ing in a peatland. Despite the reduction in CO2, it was estimated that the peatland would have a net 47% greater radiative forcing on the atmos-phere over a 100 year because of increased methane production. Another study by Turetsky et al. (2007), which looked at various stages of thawing peatlands, found that the increase in methane production would decrease over time, such that the radiative forcing from the increase methane might offset gains from CO2 sequestra-tion for as much as 70 years, but eventually the peatland becomes a net radiative forcing sink.

The new evidence that thawing peat-lands may help offset anthropogenic increases in radiative forcing is encouraging, but more re-search is necessary because there have been so few studies experimentally looking at the ques-tion. With a changing climate it is unknown if the effects will be consistent everywhere. It is possible that in some areas, the warming may also coincide with less precipitation and thawing peatlands may dry out and decompose in these areas thus contributing to greenhouse gas emis-sions.


The loss of sea ice and glaciers has been a hot topic in the media for making the case of global warming. Pictures of glaciers now versus 50 years ago make for dramatic evidence of a warming climate. However, the implications for people who depend on some of those glaciers for

water seems to be less commonly discussed. However, it is this aspect that requires the great-est attention from policy makers, not just in ad-dressing global warming, but also in planning for the lack of water. It is unlikely that changes made now to reduce greenhouse gas emissions will be able to prevent many of these glaciers from melting completely, so other plans must be made now on how to keep the populations in these regions supplied with water in order to avoid a humanitarian crisis.

A somewhat less severe, but still prob-lematic effect of the loss of glaciers will be the collapse of local economies that depend upon glaciers for tourism and recreation. The effects may ripple through into the larger winter sports industry as a whole as well.

The loss of sea ice is another poster child for global climate change, particularly be-cause of the wildlife associated it (Amos 2007; Stuck 2007). Despite the negative implications for wildlife, the loss of sea ice is also viewed to have some positive consequences such as open-ing up new areas for fishing, exploration for oil and gas, and new shipping routes (Stuck 2007). However, the opening up of new water may lead to further international conflict as countries de-bate who controls and has rights to these various areas. Since most of the benefits from these new open areas of have economic consequences, they are all the more likely to result in conflicts.

IMPLICATIONS FOR POLICYMAKERS The biggest implication for policymak-

ers is to address the potential water shortages that will occur as the glaciers recede and vanish, while water is still available. This may involve establishing some other water storage system, enacting policies to enforce water use efficiency, and limiting continued population growth in these areas. It will be much easier to set up a new system now and be prepared, than waiting until the water runs out.

In regards to implications of the arctic waters opening up, new international treaties should be created regarding its access and use to the areas to avoid future conflicts.

The implications of all the changes in glaciers and sea ice enforce the point that new policies are required to curb the continued an-thropogenic contribution to global climate change. Due to the visible nature of the losses of ice, changes to the cryosphere has been a strong


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arguing point for change, however the cause would be further helped by emphasizing the negative impacts it may have on humans.

WORKS CITED WITH ABSTRACTS American Meteorological Society. 2000.

Glossary of Meteorology, 2nd Edition. http://amsglossary.allenpress.com.

Amos, J. 2006. Arctic sea ice 'faces rapid melt'. in. BBC News.

Barry, R. G. 2006. The status of research on glaciers and global glacier recession: a review. Progress in Physical Geography 30:285-306. Abstract: Mountain glaciers are key indicators of climate change, although the climatic vari-ables involved differ regionally and temporally. Nevertheless, there has been substantial glacier retreat since the Little Ice Age and this has ac-celerated over the last two to three decades. Documenting these changes is hampered by the paucity of observational data. This review out-lines the measurements that are available, new techniques that incorporate remotely sensed data, and major findings around the world. The focus is on changes in glacier area, rather than esti-mates of mass balance and volume changes that address the role of glacier melt in global sea-level rise. The glacier observations needed for global climate monitoring are also outlined.

Camill, P., J. A. Lynch, J. S. Clark, J. B. Adams, and B. Jordan. 2001. Changes in bio-mass, aboveground net primary production, and peat accumulation following permafrost thaw in the boreal peatlands of Manitoba, Canada. Eco-systems 4:461-478. Abstract: Permafrost thaw resulting from climate warming may dra-matically change the succession and carbon dy-namics of northern ecosystems. To examine the joint effects of regional temperature and local species changes on peat accumulation following thaw, we studied peat accumulation across a re-gional gradient of mean annual temperature (MAT). We measured aboveground net primary production (AGNPP) and decomposition over 2 years for major functional groups and used these data to calculate a simple index of net annual aboveground peat accumulation. In addition, we collected cores from six adjacent frozen and thawed bog sites to document peat accumulation changes following thaw over the past 200 years. Aboveground biomass and decomposition were more strongly controlled by local succession than regional climate. AGNPP for some species differed between collapse scars and associated

permafrost plateaus and was influenced by re-gional MAT. A few species, such as Picea mariana trees on frozen bogs and Sphagnum mosses in thawed bogs, sequestered a dispropor-tionate amount of peat; in addition, changes in their abundance following thaw changed peat accumulation. Pb-210-dated cores indicated that peat accumulation doubles following thaw and that the accumulation rate is affected by histori-cal changes in species during succession. Peat accumulation in boreal peatlands following thaw was controlled by a complex mix of local vegeta-tion changes, regional climate, and history. These results suggest that northern ecosystems may show responses more complex than large releases of carbon during transient warming.

Deser, C., J. E. Walsh, and M. S. Timlin. 2000. Arctic sea ice variability in the context of recent atmospheric circulation trends. Journal of Climate 13:617-633.

Abstract: Forty years (1958-97) of reanalysis products and corresponding sea ice concentration data are used to document Arctic sea ice variabil-ity and its association with surface air tempera-ture (SAT) and sea level pressure (SLP) throughout the Northern Hemisphere extratropics. The dominant mode of winter (January-March) sea ice variability exhibits out-of-phase fluctua-tions between the western and eastern North At-lantic, together with a weaker dipole in the North Pacific. The time series of this mode has a high winter-to-winter autocorrelation (0.69) and is dominated by decadal-scale variations and a longer-term trend of diminishing ice cover east of Greenland and increasing ice cover west of Greenland. Associated with the dominant pattern of winter sea ice variability are large-scale changes in SAT and SLP that closely resemble the North Atlantic oscillation. The associated SAT and surface sensible and latent heat flux anomalies are largest over the portions of the marginal sea ice zone in which the trends of ice coverage have been greatest, although the well-documented warming of the northern continental regions is also apparent. The temporal and spa-tial relationships between the SLP and ice anom-aly fields are consistent with the notion that at-mospheric circulation anomalies force the sea ice variations. However, there appears to be a local response of the atmospheric circulation to the changing sea ice cover east of Greenland. Spe-cifically, cyclone frequencies have increased and mean SLPs have decreased over the retracted ice margin in the Greenland Sea, and these changes differ from those associated directly with the


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North Atlantic oscillation. The dominant mode of sea ice variability in summer (July-September) is more spatially uniform than that in winter. Summer ice extent for the Arctic as a whole has exhibited a nearly monotonic decline (-4% dec-ade(-1)) during the past 40 yr. Summer sea ice variations appear to be initiated by atmospheric circulation anomalies over the high Arctic in late spring. Positive ice-albedo feedback may ac-count for the relatively long delay (2-3 months) between the time of atmospheric forcing and the maximum ice response, and it may have served to amplify the summer ice retreat.

Johansson, T., N. Malmer, P. M. Crill, T. Friborg, J. H. Akerman, M. Mastepanov, and T. R. Christensen. 2006. Decadal vegetation changes in a northern peatland, greenhouse gas fluxes and net radiative forcing. Global Change Biology 12:2352-2369. Abstract: Thawing permafrost in the sub-Arctic has implications for the physical stability and biological dynamics of peatland ecosystems. This study provides an analysis of how permafrost thawing and subse-quent vegetation changes in a sub-Arctic Swed-ish mire have changed the net exchange of greenhouse gases, carbon dioxide (CO2) and CH4 over the past three decades. Images of the mire (ca. 17 ha) and surroundings taken with film sensitive in the visible and the near infrared portion of the spectrum, [i.e. colour infrared (CIR) aerial photographs from 1970 and 2000] were used. The results show that during this pe-riod the area covered by hummock vegetation decreased by more than 11% and became re-placed by wet-growing plant communities. The overall net uptake of C in the vegetation and the release of C by heterotrophic respiration might have increased resulting in increases in both the growing season atmospheric CO2 sink function with about 16% and the CH4 emissions with 22%. Calculating the flux as CO2 equivalents show that the mire in 2000 has a 47% greater radiative forcing on the atmosphere using a 100-year time horizon. Northern peatlands in areas with thawing sporadic or discontinuous perma-frost are likely to act as larger greenhouse gas sources over the growing season today than a few decades ago because of increased CH4 emis-sions.

Meier, M. F., M. B. Dyurgerov, U. K. Rick, S. O'Neel, W. T. Pfeffer, R. S. Anderson, S. P. Anderson, and A. F. Glazovsky. 2007. Glaciers dominate Eustatic sea-level rise in the 21st cen-tury. Science 317:1064-1067. Abstract: Ice loss to the sea currently accounts for virtually all

of the sea-level rise that is not to ocean warming, and about 60% of the ice loss is from glaciers and ice caps rather than from two ice sheets. The contribution of these smaller glaciers has accel-erated over the past decade, in part due to marked thinning and retreat of marine-terminating glaciers associated with a dynamic instability that is generally not considered in mass-balance and climate modeling. This accel-eration of glacier melt may cause 0.1 to 0.25 meter of additional sea-level rise by 2100.

Rignot, E., and R. H. Thomas. 2002. Mass balance of polar ice sheets. Science 297:1502-1506. Abstract: Recent advances in the de-termination of the mass balance of polar ice sheets show that the Greenland Ice Sheet is los-ing mass by near-coastal thinning, and that the West Antarctic Ice Sheet, with thickening in the west and thinning in the north, is probably thin-ning overall. The mass imbalance of the East Antarctic Ice Sheet is likely to be small, but even its sign cannot yet be determined. Large sectors of ice in southeast Greenland, the Amundsen Sea Embayment of West Antarctica, and the Antarc-tic Peninsula are changing quite rapidly as a re-sult of processes not yet understood.

Shepherd, A., and D. Wingham. 2007. Re-cent sea-level contributions of the Antarctic and Greenland ice sheets. Science 315:1529-1532. Abstract: After a century of polar exploration, the past decade of satellite measurements has painted an altogether new picture of how Earth's ice sheets are changing. As global temperatures have risen, so have rates of snowfall, ice melting, and glacier flow. Although the balance between these opposing processes has varied considerably on a regional scale, data show that Antarctica and Greenland are each losing mass overall. Our best estimate of their combined imbalance is about 125 gigatons per year of ice, enough to raise sea level by 0.35 millimeters per year. This is only a modest contribution to the present rate of sea-level rise of 3.0 millimeters per year. However, much of the loss from Antarctica and Greenland is the result of the flow of ice to the ocean from ice streams and glaciers, which has accelerated over the past decade. In both conti-nents, there are suspected triggers for the accel-erated ice discharge-surface and ocean warming, respectively- and, over the course of the 21st century, these processes could rapidly counteract the snowfall gains predicted by present coupled climate models.


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Struck, D. 2007. NOAA scientists say Arc-tic ice is melting faster than expected. Pages A06 in Washington Post.

Turetsky, M. R., R. K. Wieder, D. H. Vitt, R. J. Evans, and K. D. Scott. 2007. The disap-pearance of relict permafrost in boreal north America: Effects on peatland carbon storage and fluxes. Global Change Biology 13:1922-1934. Abstract: Boreal peatlands in Canada have har-bored relict permafrost since the Little Ice Age due to the strong insulating properties of peat. Ongoing climate change has triggered wide-spread degradation of localized permafrost in peatlands across continental Canada. Here, we explore the influence of differing permafrost regimes (bogs with no surface permafrost, local-ized permafrost features with surface permafrost, and internal lawns representing areas of perma-frost degradation) on rates of peat accumulation at the southernmost limit of permafrost in conti-nental Canada. Net organic matter accumulation generally was greater in unfrozen bogs and inter-nal lawns than in the permafrost landforms, sug-gesting that surface permafrost inhibits peat ac-cumulation and that degradation of surface per-mafrost stimulates net carbon storage in peat-lands. To determine whether differences in sub-strate quality across permafrost regimes control trace gas emissions to the atmosphere, we used a reciprocal transplant study to experimentally evaluate environmental versus substrate controls on carbon emissions from bog, internal lawn, and permafrost peat. Emissions of CO2 were highest from peat incubated in the localized per-mafrost feature, suggesting that slow organic matter accumulation rates are due, at least in part, to rapid decomposition in surface permafrost peat. Emissions of CH4 were greatest from peat incubated in the internal lawn, regardless of peat type. Localized permafrost features in peatlands represent relict surface permafrost in disequilib-rium with the current climate of boreal North America, and therefore are extremely sensitive to ongoing and future climate change. Our results suggest that the loss of surface permafrost in peatlands increases net carbon storage as peat, though in terms of radiative forcing, increased CH4 emissions to the atmosphere will partially or even completely offset this enhanced peatland carbon sink for at least 70 years following per-mafrost degradation.

Velicogna, I., and J. Wahr. 2005. Greenland mass balance from GRACE. Geo-physical Research Letters 32. Abstract: We use 22 monthly GRACE (Gravity Recovery and

Climate Experiment) gravity fields to estimate the linear trend in Greenland ice mass during 2002-2004. We recover a decrease in total ice mass of 82 +/- 28 km(3) of ice per year, consis-tent with estimates from other techniques. Our uncertainty estimate is dominated by the effects of GRACE measurement errors and errors in our post glacial rebound (PG) correction. The main advantages of GRACE are that it is sensitive to the entire ice sheet, and that it provides mass estimates with only minimal use of supporting physical assumptions or ancillary data.

Velicogna, I., and J. Wahr. 2006. Meas-urements of time-variable gravity show mass loss in Antarctica. Science 311:1754-1756. Abstract: Using measurements of time-variable gravity from the Gravity Recovery and Climate Experiment satellites, we determined mass varia-tions of the Antarctic ice sheet during 2002-2005. We found that the mass of the ice sheet de-creased significantly, at a rate of 152 +/- 80 cu-bic kilometers of ice per year, which is equiva-lent to 0.4 +/- 0.2 millimeters of global sea-level rise per year. Most of this mass loss came from the West Antarctic Ice Sheet.

Zwally, H. J., M. B. Giovinetto, J. Li, H. G. Cornejo, M. A. Beckley, A. C. Brenner, J. L. Saba, and D. H. Yi. 2005. Mass changes of the Greenland and Antarctic ice sheets and shelves and contributions to sea-level rise: 1992-2002. Journal of Glaciology 51:509-527. Abstract: Changes in ice mass are estimated from elevation changes derived from 10.5 years (Greenland) and 9 years (Antarctica) of satellite radar altimetry data from the European Remote-sensing Satel-lites ERS-1 and -2. For the first time, the dH/dt values are adjusted for changes in surface eleva-tion resulting from temperature-driven variations in the rate of firn compaction. The Greenland ice sheet is thinning at the margins (-42 +/- 2 Gt a(-1) below the equilibrium-line altitude (ELA)) and growing inland (+53 +/- 2 Gt a(-1) above the ELA) with a small overall mass gain (+11 +/- 3 Gt a(-1); -0.03 mm a(-1) SLE (sea-level equiva-lent)). The ice sheet in West Antarctica (WA) is losing mass (-47 +/- 4 Gt a(-1)) and the ice sheet in East Antarctica (EA) shows a small mass gain (+16 +/- 11 Gt a(-1)) for a combined net change of -31 +/- 12 Gt a(-1) (+0.08 mm a(-1) SLE). The contribution of the three ice sheets to sea level is +0.05 +/- 0.03 mm a(-1). The Antarctic ice shelves show corresponding mass changes of -95 +/- 11 Gt a(-1) in WA and +142 +/- 10 Gt a(-1) in EA. Thinning at the margins of the Greenland ice sheet and growth at higher eleva-


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tions is an expected response to increasing tem-peratures and precipitation in a warming climate. The marked thinnings in the Pine Island and Thwaites Glacier basins of WA and the Totten Glacier basin in EA are probably ice-dynamic responses to long-term climate change and per-haps past removal of their adjacent ice shelves. The ice growth in the southern Antarctic Penin-sula and parts of EA may be due to increasing precipitation during the last century.

Global Circulation Models Anna Lumsden

EXECUTIVE SUMMARY Global circulation models are computer

model representations of the earth’s climate system. They are used to estimate the impacts of anthropogenic influences on future climate, most commonly global mean temperatures. As these models have become more sophisticated the results they generate are subject to greater uncertainty because the number of parameters which are estimated has increased. Although there is agreement among models that global temperature will rise in the next three decades regardless of emission policies, the complexity of these models and the uncertainties inherent in them have led to a generally apathetic view of climate models in the media, and equivocating on the part of some governments to commit to radical changes in policy to deal with the causes of global warming.

INTRODUCTION “Model experiments show that

even if all radiative forcing agents1 are held constant at year 2000 levels, a further warming trend would occur in the next two decades at a rate of about 0.1oC per decade, due mainly to the slow response of the oceans. About twice as much warming (0.2oC per decade) would be expected if emissions are within the rage of the SRES scenarios. Best-estimate projections from models indicate that decadal-average warming over each inhabited continent by 2030 is insensitive to the choice among SRES scenarios and is very likely to be at least twice as large as the corresponding model-estimated natural variability during the 20th century” (IPCC 2007)

The predictions of warming made by the Inter-governmental Panel on Climate Change (IPCC) are based on global circulation models (GCMs). GCMs, which have their origins in weather forecasting, are a combination of

1 Radiative forcing is a measure of the influence that a climatic factor, such as cloud cover, has on the balance of incoming and outgoing energy. Positive forcing warms the earth’s surface, and negative forcing cools it (IPCC 2007)

atmospheric, ocean, and terrestrial models; coupled together to create a computer model representation of the earth’s climate (Houghton 2004). In the above quotation, the IPCC climate scientists have used GCMs to predict the effects of different Special Report on Emission Scenarios 2 (SRES) to determine a range of warming possibilities over the next two decades. In this paper I will briefly outline the composition of a climate model, review the current scientific literature, the perspectives of GCMs in the media, and how climate model results are implemented by policy makers. The focus here will not be on the predictions that climate models make, but the uncertainties inherent in those predictions and how these are perceived by the public and policy makers, it at all.

The first climate model3 was a simulation of the circulation patterns of the atmosphere in 1949 (Flannery 2005). Since then, GCMs have increased in complexity, and also model the terrestrial and oceanic components of the climate system, and the interactions and feedbacks within and between these systems, and the atmosphere. These interactions and feedbacks are modeled based on what scientists know about the physical processes, such as the conservation of energy, and parameters within the climate system. Models can have hundreds of parameters which could include: horizontal and vertical movement of air or water, the amount of incoming solar radiation or the concentration of a certain atmospheric gas. To model these physical processes and parameters, the atmosphere and the ocean are divided into three-dimensional grids. In addition to correct parameterization of processes, the cloud-radiation, water vapor, ocean-circulation, and ice-albedo feedbacks within the system must be modeled as well.

Decades of research and data accumulation have evolved into three uses for GCMs. One, to model past climatic change; second, to model the current climate and weather patterns; and third, to model the future climate. The ability of a climate model to accurately depict past and current climate, to predict the effects of natural disasters on the system (e.g. a volcanic eruption), and to accurately depict the physical processes

2 The SRES scenarios represent four different combinations of global population and economic growth, and energy types and consumption. 3 In this paper GCMs and climate model are used interchangeably.

LUMSDEN GLOBAL CIRCULATION MODELS FOR 797 CLIMATE CHANGE EFFECTS ON NATURAL RESOURCES FALL 2007

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within the climate system are an indication of its credibility (Flannery 2005, Houghton 2004). This in turn leads to greater confidence in the predictions of GCMs.

Over time, as the processing power of computers has increased and uncertainties in computer programming have reduced, the uncertainty from the inclusion of real world parameters has increased, as the number of parameters has increased. A good example of this is the recent inclusion of seal level pressure into model parameters (Flannery 2005). These uncertainties arise because each parameter is estimated and averaged for each grid cell, and are dependent upon the particulars of the GCM used. This means that each climate model will produce different outputs for combinations of parameters. As GCMs are used mainly to forecast how anthropogenic effects on the climate system will lead to atmospheric warming, the range in possible outputs which can be produced has lead to debate in the scientific literature and within the media and public as to which results are important.

STATE OF THE SCIENCE Uncertainty arises from at least four

sources. One, is that the range of parameters which are used for each model are different; two, the choice of emission scenario; three, structural uncertainty, where models do not necessarily depict climate processes accurately e.g. feedbacks or non-linear change; and four, inherent climate variability (Zwiers 2002; Dettinger 2005, Stainforth et al. 2005). The uncertainties inherent in the generation of climate models are evident in the trend of recent scientific publications, which have focused on how to quantify these model uncertainties, and relative importance of the range of predictions produced.

Acknowledging the variability in results which occur due to using different climate models, the consensus of the scientific community has been to run a number of simulations on different models, by perturbing model parameters, and then comparing the results. These ensembles 4 produce a range of responses for a number of different models,

4 “An ensemble is a collection of predictions; each prediction is different from the others due to some prescribed change in the model condition, such as model: constructions, initial conditions or future emissions of greenhouse gasses into the global atmosphere” (Dettinger 2005)

therefore they give a more representative idea of possible impacts and outcomes for the particular scenario being investigated (Murphy et al. 2004, Dettinger 2005, Stainforth et al. 2005). Some authors have suggested that even the most sophisticated GCM will provide only limited knowledge on the possible impacts of warming, therefore only large ensembles of climate models should be used to determine a range of impacts and estimate uncertainty (Murphy et al. 2004, Dettinger 2005).

Work by Stainforth et al. (2005), which used the novel approach of running over 2000 different simulations using the downtime on personal computers, aimed to estimate uncertainty by changing groups of parameters in the GCMs. Each of these parameter groups created an ensemble, which were then combined to create a grand ensemble to estimate model sensitivity, or the response of global mean temperature to doubled levels of atmospheric CO2 (Stainforth et al. 2005). The conclusions of the work were that this grand ensemble produced a wide range of sensitivities, with uncertainty increasing with the number of parameters perturbed (Stianforth et al. 2005).

This work determined that extreme sensitivity values cannot be ignored because they are indicators of model shortcomings, and therefore where research resources should be allocatedm in order to improve parameter values (Stainforth et al. 2005). A study by Zhang et al. (2007) focusing on the difference between modeled estimates versus observed changes in precipitation indicated that ensemble simulations tended to underestimate regional precipitation changes, and with wide ranges in uncertainties which varied with latitude. These results suggest that more research resources need to be allocated towards fine tuning model parameters.


It is clear that GCMs are the main information source for planners about future warming trends; therefore their relative forecasting abilities are important to the climate change debate (Murphy et al 2004). However, the science behind GCMs is so complex that I would venture to say that the lay person would not be able to interpret the statistical analyses that go into determining not only what are the important parameters driving temperature increases, but also the range of temperatures,


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sensitivities and uncertainties produced. It is therefore up to climate scientists to interpret these values for the public, and policy makers.

A good example of scientific interpretation for the media and public are the IPCC Assessment Reports. These reports are readily available, and are geared towards guiding policy makers in the decisions they have to make about country s’ climate change and energy usage policies. The IPCC reports tend to remove the technical details and focus on the trends which the climate models display. The IPCC references the climate models which generate their results in a fairly cursory manner (see opening quote), without going into detail about the science behind the GCMs used.

Similarly the complexity of the issue does not lend itself to discussion in the popular media. For example US Today, the most widely read newspaper in the US, has a readership of 5.4 million, 2.5 print (Marketwatch.com, 2007). A search on their website of keywords “climate models” returned 59 search results from 1987 to the present, 32 of which occurred since December 20th 2005 (usatoday.com 2007). Compare these results with a search of “Paris Hilton” for the same time period and 305 results are returned. This, I believe is an indication of a combination of possibilities. Either, that the scientific community has not expressed the importance of climate models to the public, therefore enabling an apathetic attitude; or the topic is simply too complex for reporters to interpret and engage with the public; or the media is responding to a low desire by the public to engage with the issue.

According to a BBC.com poll (September 2007), 80% of the public believes that climate change is as the result of anthropogenic forcing. If this is the common public opinion, then perhaps it is not necessary to have a discourse about GCMs in the public sphere. What may be more important is that the trends which have been observed in these data and agreed upon by the scientific community are translated into public policy.

CONSIDERATIONS FOR POLICY MAKERS Despite the uncertainties inherent in climate

science, all GCMs agree that warming will continue, and for the range of the next 20 to 30 years. Climate models agree on the amplitude of change, because the effects of this CO2 which is already in the atmosphere will not be felt until

2050. Therefore if all emissions of greenhouse gases were to cease now, it would take until 2050 for the climate to stabilize (Zwiers 2002, Flannery 2005). One problem is that warming is often predicted to the 2100’s; this is far beyond the range of typical policy development and possible mitigation strategies (Zwiers 2002). Although these temporal ranges are useful for looking at the differences in predictions between models, it tends to obscure the general agreement about the certain warming of the next few decades (Zwiers 2002).

Globally, many countries ratified the Kyoto Protocol in 2005, with the exception of the US and Australia. This law was to bind the 146 countries that signed to cut their combined emissions to 5% below 1990 levels by 2008 to 2012 (bbc.oc.uk. 2005) In the United States in July 2007, President Bush put forward a “post-Kyoto framework on energy security and climate change by 2008” (state.gov 2007). This framework is designed to implement near term domestic policies to reduce green house gas emissions by 18% by 2012. This would include programs such as Energy Star, domestic methane programs, and increasing the fuel economy of vehicles by using alternative and renewable fuels. These domestic policies are in addition to the billions of dollars in research and design which have been invested into reducing green house gases.

Despite this seeming commitment to addressing climate change, in response to the IPCC’s final assessment report issued on November 17th 2007, the NY Times had this analysis of the administration’s response:

“Despite the report’s added emphasis on a list of “reasons for concern” about the continuing growth of long-lived emissions that trap heat, senior White House officials said Friday and Saturday that it remained impossible to define a “dangerous” threshold in the concentration of greenhouse gases or resulting warming.” (NY Times 2007)

Although it is probably not necessary to define “dangerous threshold in the concentration of greenhouse gases or resulting warming”, some might say that the uncertainty inherent in GCMs has been used to equivocate about a serious commitment to the implementation of drastic policy changes to reduce the concentrations of greenhouse gases expelled into the atmosphere.


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In short, U.S. policy makers seem yet to be convinced that although there are a range of possibilities in results from GCMs, the agreement in the scientific community and the public is that climate warming is not uncertain, and that policy needs to be implemented to curtail its effects.

REFERENCES Bbc.co.uk. Man causing climate change.

September 25, 2005. http://search.bbc.co.uk/cgibin/search/results.pl?q=climate+change+poll&go.x=0&go.y=0&go=go&edition=i. Accessed November 19th 2007.

Bbc.co.uk. Q&A the Kyoto protocol. 16 February 2005. http://news.bbc.co.uk/2/hi/science/nature/4269921.stm Accessed November 19th 2007.

Dettinger, M.D. 2005. From climate-change spaghetti to climate-change distributions for 21st century California. San Francisco Estuary and Watershed Science 3 (1) Article 4, 1 – 14

The uncertainties associated with climate-change projections for California are unlikely to disappear any time soon, and yet important long-term decisions will be needed to accommodate those potential changes. Projection uncertainties have typically been addressed by analysis of a few scenarios, chosen based on availability or to capture the extreme cases among available projections. However, by focusing on more common projections rather than the most extreme projections (using a new resampling method), new insights into current projections emerge: (1) uncertainties associated with future greenhouse-gas emissions are comparable with the differences among climate models, so that neither source of uncertainties should be neglected or underrepresented; (2) twenty-first century temperature projections spread more, overall, than do precipitation scenarios; (3) projections of extremely wet futures for California are true outliers among current projections; and (4) current projections that are warmest tend, overall, to yield a moderately drier California, while the cooler projections yield a somewhat wetter future. The resampling approach applied in this paper also provides a natural opportunity to objectively incorporate measures of model skill and the likelihoods of various emission scenarios into future assessments.

Flannery, T. 2005. The weather makers: how man is changing the climate and what it means for life on earth. Atlantic Monthly Press New York, NY

Houghton, John. 2004. Global warming the complete briefing. Cambridge University Press. 3rd Edition.

IPCC Summary for Policy Makers. 2007. In Climate Change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change Solomon, S., Qin, D., Manning M., Chen, Z., Marquis, M., Avery, K.B., Tignor, M., Miller, H.L. (eds.). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Marketwatch.com November 15, 2007. USA TODAY remains the most widely read newspaper in the United States. http://www.marketwatch.com/news/story/usa-today-remains-most-widely/story.aspx?guid=%7B52FE1518-B2D8-4AD4-BBCF-FAC3A73EA43B%7D Accessed November 19th 2007

Murphy, J.M., Sexton, D.H.M., Barnett, D.N., Jones, G.S., Webb, M.J., Collins, M., Stainforth, D.A. 2004. Quantification of modeling uncertainties in a large ensemble of climate change simulations. Nature 430, 768 – 772

Abstract: Comprehensive global climate models1 are the only tools that account for the complex set of processes which will determine future climate change at both a global and regional level. Planners are typically faced with a wide range of predicted changes from different models of unknown relative quality2,3, owing to large but unquantified uncertainties in the modelling process4. Here we report a systematic attempt to determine the range of climate changes consistent with these uncertainties, based on a 53-member ensemble of model versions constructed by varying model parameters. We estimate a probability density function for the sensitivity of climate to a doubling of atmospheric carbon dioxide levels, and obtain a 5–95 per cent probability range of 2.4–5.4 8C. Our probability density function is constrained by objective estimates of the relative reliability of different model versions, the choice of model parameters that are varied and their uncertainty ranges, specified on the basis of


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expert advice. Our ensemble produces a range of regional changes much wider than indicated by traditional methods based on scaling the response patterns of an individual simulation5,6

Stainforth, D. A., Aina, T., Christensen, C., Collins, M., Faull, N., Frame, D. J., Kettleborough, J. A., Knight, S., Martin, A., Murphy, J. M, Piani, C., Sexton, D., Smith, L. A., Spicer, R. A., Thorpe, A. J., Allen, M. R. 2005. Uncertainty in predictions of the climate response to rising levels of greenhouse gases. Nature 433, 403 – 406

The range of possibilities for future climate evolution1–3 needs to be taken into account when planning climate change mitigation and adaptation strategies. This requires ensembles of multidecadal simulations to assess both chaotic climate variability and model response uncertainty4–9. Statistical estimates of model response uncertainty, based on observations of recent climate change10–13, admit climate sensitivities—defined as the equilibrium response of global mean temperature to doubling levels of atmospheric carbon dioxide—substantially greater than 5K. But such strong responses are not used in ranges for future climate change14 because they have not been seen in general circulation models. Here we present results from the ‘climateprediction.net’ experiment, the first multi-thousand-member grand ensemble of simulations using a general circulation model and thereby explicitly resolving regional details15–21. We find model versions as realistic as other state-of-the-art climate models but with climate sensitivities ranging from less than 2K to more than 11 K. Models with such extreme sensitivities are critical for the study of the full range of possible responses of the climate system to rising greenhouse gas levels, and for assessing the risks associated with specific targets for stabilizing these levels.

U.S. Department of State 2007. USA: Energy needs, clean development and climate change. http://www.state.gov/documents/organization/90174.pdf. Accessed November 19th 2007

Zhang, X., Zwiers, F.W., Gegerl, G.C., Lambert, F.H., Gillett, N.P., Solomon, S., Stott, P.A., Nozawa, T. 2007. Detection of human influence on twentieth-century precipitation trends. Nature 448, 461 – 465

Human influence on climate has been detected in surface air temperature1–5, sea level pressure6, free atmospheric temperature7, tropopause height8 and ocean heat content9. Human-induced changes have not, however, previously been detected in precipitation at the global scale10–12, partly because changes in precipitation in different regions cancel each other out and thereby reduce the strength of the global average signal13–19. Models suggest that anthropogenic forcing should have caused a small increase in global mean precipitation and a latitudinal redistribution of precipitation, increasing precipitation at high latitudes, decreasing precipitation at sub-tropical latitudes15,18,19, and possibly changing the distribution of precipitation within the tropics by shifting the position of the Intertropical Convergence Zone20. Here we compare observed changes in land precipitation during the twentieth century averaged over latitudinal bands with changes simulated by fourteen climate models. We show that anthropogenic forcing has had a detectable influence on observed changes in average precipitation within latitudinal bands, and that these changes cannot be explained by internal climate variability or natural forcing. We estimate that anthropogenic forcing contributed significantly to observed increases in precipitation in the Northern Hemisphere mid-latitudes, drying in the Northern Hemisphere subtropics and tropics, and moistening in the Southern Hemisphere subtropics and deep tropics. The observed changes, which are larger than estimated from model simulations, may have already had significant effects on ecosystems, agriculture and human health in regions that are sensitive to changes in precipitation, such as the Sahel.

Zwiers, Francis W. 2002. The 20-year forecast. Nature 416, 690 – 691

Policy-makers need short-term climate predictions to develop strategies for coping with climate change over the typical two-decade planning horizon. Two new studies increase our confidence in these predictions.

Impact on freshwater resources Nidhi Pasi

EXECUTIVE SUMMARY Water is indispensable to all life and to

human activities. The impacts of the climate change on freshwater resources are mainly due to observed increases in temperature (land and sea surface), sea level and precipitation variability. These impacts will be compounded by factors like population growth and current management practices. A significant percentage of population already exists in water stress regions. The adap-tive practices, management and planning will determine the impacts of global warming on freshwater resources and their sustainable use/ development.

INTRODUCTION: Water is indispensable to all forms of life

and is needed for almost all human activities. Historically, civilizations have flourished along or around the sources of water. Rivers have sup-ported life and have been a source of communi-cation. History is replete with examples of civili-zations that have withered and vanished when water became scarce. The global freshwater availability is finite. However, with pressure of ever increasing human population, demand for direct human consumption, for food production and consequent development and industrial proc-esses on water resources are ever increasing. The UN Comprehensive Assessment of freshwater resources estimated that about one third of the world’s population withdrawing more than 20% of the their available water resources are deemed to be suffering with water stress (Kundzewicz, Z.W et all 2007). Moreover, it has been esti-mated that people living in conditions of acute water shortage will increase from present figure of 470 million to around 3000 million in 2025 (Vombatkere, Sudhir 2004) representing two-thirds of world population. Human activities affect freshwater resources in terms of both qual-ity and quantity. Due to complex interconnec-tions between climate and freshwater ecosystems, any change affects both mean states and variabil-ity. In addition, spatial variations in the distribu-tion of this prime natural resource have led to formation of “water surplus” and “water deficit” regions. Water scarcity leads to regional imbal-ances in terms of socio-economic development and such imbalances are detrimental to sustain-

able development and adversely affect human rights.

STATE OF THE SCIENCE Flannery (2006) mentions that for every

degree increase in global temperature, the world experiences one percent increase in rainfall. However, this increase is not evenly distributed in time and space leading to unusual patterns. World rainfall in increasing over large parts and more rain is falling at high altitudes in winter leading to disastrous consequences. Also in-creases in winter rains in the southern part of the hemisphere is affecting agriculture and increas-ing extreme weather events (like flooding, ava-lanches etc.). At the same time certain regions are being tipped into a perpetual rain deficit po-tentially developing new Saharas. He talks about the evidence of the shift to a newer drier climate in Africa’s Sahel region, where models have showed that rising sea temperature over the In-dian Ocean due to accumulation of greenhouse gases resulted in rainfall decline.

Arnell (2004) further talks about the rela-tive effects of climate change and population growth on the future global water resources stresses using the special report on emission sce-narios (SRES). The author estimates population at risk by determining annual runoff (surplus/ deficit) using a macro-scale hydrological model, monthly precipitation data downscaled to water-shed and population estimates. It has been esti-mated that in absence of climate change the number of people living in water stressed regions will depend upon the population scenarios and about 40% of world population in 2025 will be water stressed. However, with climate change, decreased runoff increases water stress in some parts of the world like Mediterranean, central and southern Africa, America and parts of Europe. At the same time, increases in runoff in wet seasons in certain parts of the world like Southern and eastern Asia, may not be beneficial as this leads to flood. The analysis also shows that the impacts of the changes (in terms of population and emission scenarios) will also de-pend on how water resources are managed in the future.


Climate change effects on freshwater sys-tems are often termed as the “other” water prob-lem in the media (Gertner, Jin 2007) because

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global warming has been more commonly linked with rise in the sea level and submergence of the coastal cities. However, steady melts of the mountain snow packs and the loss of the deep accumulated high latitude snow is a reality which may just lead to lead to many challenges and uncertainties.

The working group II third assessment re-port summarizes apparent trends (both increase and decrease) in stream water volume, with peak flows likely to move to winter from spring due to early snowmelt. The glacier retreat will continue. Moreover the magnitude and frequency of floods is likely to increase and at the same time vol-umes of low flows will decrease in many regions (NOAA- GDLF 2007).

The water quality degradation is likely to be degraded due to high temperatures. With the higher temperatures, increased intensity of pre-cipitation and shifts in time of peak flow will further worsen many forms of water pollution. The pollutants may include sediments, nutrients, dissolved organics, pathogens, pesticides, salt and thermal pollution. This will impact the eco-systems, human health and operation costs of current water treatment and infrastructure sys-tems.

CONSIDERATIONS FOR POLICYMAKERS Many current rivers originate in the glacier

regions (particularly in the Hindu Kush Hi-malalyan region and sustaining the highly popu-lated countries of India and China) and are sus-tained by the summer season glacier melt. Global warming will lead to glacier retreat with in-creased river flows (floods) in short terms and gradual decline (water scarcity, stress and drought) in flow over the next decades.

The decision makers within the countries need to realize that the current water manage-ment practices are very likely going to be inade-quate to reduce the negative impacts of climate change on water supply reliability, flood risk and health concerns. There need to be a continuous evolution of management systems, as the un-managed ones are likely to be most vulnerable. The impacts will also depend upon a particular freshwater system characteristic. The adverse effects of climate on freshwater systems may be further increased by the intensity of other stresses like population growth. Hence there is a need to incorporate the climate change variabil-ity into the water management and planning which could help in better adaptation (Mall, R.K.

et all 2006) and long term potential sustainable development of freshwater resources..

REFERENCES 1) Flannery, Tim (2005). Liquid Gold:

changes in rainfall. Chapter 13: The weather makers: how man is changing the climate and what it means for life on earth. Atlantic Monthly Press : New York

2) NOAA- GDLF (2007). National Oceanic and Atmospheric Administration -Geophysical Fluid Dynamics Laboratory Climate modeling research highlights. Will the wet get wetter and the dry drier? Vol 1, No.5, February 2007. http://www.gfdl.noaa.gov/research/climate/high-lights/PDF/GFDLhighlight_Vol1N5.pdf

3) Kundzewicz, Z.W., L.J. Mata, N.W. Arnell, P. Döll, P. Kabat, B. Jiménez, K.A. Miller, T. Oki, Z. Sen and I.A. Shiklomanov (2007). Freshwater resources and their management. Climate Change 2007: Im-pacts, Adaptation and Vulnerability. Con-tribution of Working Group II to the Fourth Assessment Report of the Intergovernmen-tal Panel on Climate Change. M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge.

4) Gertner, Jin. (2007) The future is drying up. New York Times. October 21 2007. http://query.nytimes.com/gst/fullpage.html?res=9C0CEFDA103CF932A15753C1A9619C8B63

5) Vombatkere, Sudhir (2004). Interlinking National Rivers: to link or not to link? In: Patekar, Medha, River Linking: a Millen-nium Folly?: Maharashtra, National Alli-ance of People’s Movement.

6) Arnell, Nigel W. (2004). Climate change and global water resources: SRES emis-sions and socio-economic scenarios. Global Economic Change. Vol.14:31-55 In 1995, nearly 1400 million people lived in water-stressed watersheds (runoff less than 1000m3/capita/year), mostly in south west Asia, the Middle East and around the Medi-terranean. This paper describes an assess-ment of the relative effect of climate change and population growth on future global and regional water resources stresses,

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using SRES socio-economic scenarios and climate projections made using six climate models driven by SRES emissions scenar-ios. River runoff was simulated at a spatial resolution of 0.5_0.5_ under current and fu-ture climates using a macro-scale hydro-logical model, and aggregated to the water-shed scale to estimate current and future water resource availability for 1300 water-sheds and small islands under the SRES population projections. The A2 storyline has the largest population, followed by B2, then A1 and B1 (which have the same population). In the absence of climate change, the future population in water-stressed watersheds depends on population scenario and by 2025 ranges from 2.9 to 3.3 billion people (36–40% of the world’s population). By 2055 5.6 billion people would live in water-stressed watersheds under the A2 population future, and ‘‘only’’ 3.4 billion under A1/B1. Climate change increases water resources stresses in some parts of the world where runoff de-creases, including around the Mediterra-nean, in parts of Europe, central and south-ern America, and southern Africa. In other water-stressed parts of the world— particu-larly in southern and eastern Asia—climate change increases runoff, but this may not be very beneficial in practice because the increases tend to come during the wet sea-son and the extra water may not be avail-able during the dry season. The broad geo-graphic pattern of change is consistent be-tween the six climate models, although there are differences of magnitude and di-rection of change in southern Asia. By the 2020s there is little clear difference in the magnitude of impact between population or emissions scenarios, but a large difference between different climate models: between 374 and 1661 million people are projected to experience an increase in water stress. By the 2050s there is still little difference between the emissions scenarios, but the different population assumptions have a clear effect. Under the A2 population be-tween 1092 and 2761 million people have an increase in stress; under the B2 popula-tion the range is 670–1538 million, respec-tively. The range in estimates is due to the slightly different patterns of change pro-jected by the different climate models. Sen-sitivity analysis showed that a 10% varia-tion in the population totals under a story-

line could lead to variations in the numbers of people with an increase or decrease in stress of between 15% and 20%. The im-pact of these changes on actual water stresses will depend on how water re-sources are managed in the future.

7) Mall, R.K., Akhilesh Gupta, Ranjeet Singh, R. S. Singh and L. S. Rathore (2006) Water resources and climate change: An Indian perspective. Current Science, Vol. 90, No. 12: 1610- 1626 In recent times, several studies around the globe show that climatic change is likely to impact significantly upon freshwater resources availability. In India, demand for water has already in-creased manifold over the years due to ur-banization, agriculture expansion, increas-ing population, rapid industrialization and economic development. At present, changes in cropping pattern and land-use pattern, over-exploitation of water storage and changes in irrigation and drainage are modifying the hydrological cycle in many climate regions and river basins of India. An assessment of the availability of water resources in the context of future national requirements and expected impacts of cli-mate change and its variability is critical for relevant national and regional long-term development strategies and sustainable de-velopment. This article examines the poten-tial for sustainable development of surface water and groundwater resources within the constraints imposed by climate change and future research needs in India..

Carbon Sinks and Sequestration Ken Hubbard

EXECUTIVE SUMMARY Quantification of carbon sources and sinks

is an essential part of determining long term an-thropogenic impacts to global climate change. Carbon is continually emitted to the atmosphere in the form of carbon dioxide (CO2) as a byprod-uct of many processes such as combustion of fossil fuels, biomass burning and land use changes. Increased concentration of CO2 in the atmosphere contributes to the “Greenhouse Ef-fect”. The use of terrestrial carbon sinks as a means of sequestering atmospheric CO2 has been studied recently. Carbon can be removed from the atmosphere by terrestrial vegetation, captured and stored in geologic formations and captured and transported for geologic storage. The uncer-tainties surrounding these different forms of ter-restrial carbon sequestration warrant further in-vestigation. Experiments have been conducted in order to model plant response to increased CO2 concentration. The length of time these reservoirs can store the carbon, the efficiency of carbon capture and storage, saturation limits of the reservoirs and response to changes in cli-matic variables are all issues requiring further research to determine the feasibility of terrestrial sequestration.

INTRODUCTION Carbon compounds are a major con-

stituent of all living and non-living components of the Earth. All life forms on the planet are built around carbon based structures. In addition to living organisms, substantial amounts of car-bon are allocated to non-living things such as rocks, sediments, oceans and dead and decaying organic matter. Carbon, in the form or carbon dioxide (CO2), is emitted naturally to the atmos-phere as a byproduct of aerobic respiration, fires, rotting of wood and decaying of other organic matter in soils (Houghton, 2004). Carbon emit-ted to the atmosphere by natural means is offset by the process of photosynthesis, in which plants uptake CO2 in the air and emit oxygen as a by-product. It has been thought that these natural processes of carbon cycling were quite stable prior to human induce disturbances (Houghton, 2004).

Since the dawn of industrialized times, hu-man activities have caused measurable changes

in the composition of the atmosphere. Anthro-pogenic carbon compounds emitted to the at-mosphere have long been known to have delete-rious effects. Since the Industrial Revolution (circa 1700), the carbon cycle has been imbal-anced due to increasing anthropogenic carbon inputs to the atmosphere. Atmospheric CO2 concentrations have increased approximately 30% from a pre-industrial level of 280 parts per million (ppm) to present day level of 370 ppm (Houghton, 2004). As CO2 accumulates in the atmosphere, the “Greenhouse Effect” is magni-fied. Compounds in the atmosphere create a layer above the Earth that let light and heat en-ergy pass through, but do not allow the infrared radiation (heat) escape as readily.

Terrestrial carbon sequestration can be de-fined as capture of CO2 and long term storage out of the atmosphere. Atmospheric carbon can be removed and pumped into geologic reservoirs, transported via pipeline to further geologic stor-age if no local reservoirs are present or seques-tered in the biomass of terrestrial vegetation. Although these seem like viable options to miti-gate the ongoing carbon emission problem, each of these mitigation measures are not without potential limitations.


Recent patterns and mechanisms of carbon exchange by terrestrial ecosystems

This paper written by Schimel et al. was published in Nature in 2001 and attempts to quantify exchange of CO2 between the atmos-phere and terrestrial and marine environments in three different latitudinal zones. This study uses inverse model calculations to estimate carbon flux, calculating sources and sinks of carbon based on CO2 distribution in the atmosphere. Inverse modeling (the top down approach) is one of two primary methods of estimating carbon fluxes between the atmosphere and terrestrial environments. The primary goals are to identify the mechanisms controlling atmosphere-terrestrial fluxes, analyze spatial patterns of car-bon fluxes and develop explanations for interan-nual variability in flux estimates.

The paper estimates net sinks in terrestrial and marine environments in the 1980’s and 1990’s. It is suggested that the major mecha-nisms contributing to the net carbon sink in ter-restrial environments is land use change (i.e. reforestation from former agricultural lands) in North America and land use, land management

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and increased forest growth due to CO2 fertiliza-tion and nitrogen deposition in Europe. The au-thors suggest that the variability in carbon fluxes between years is likely due to changes in cli-matic factors, indicating that there appears to be a net release of carbon to the atmosphere during warm and dry years and a net uptake from the atmosphere during cooler years.

It seems that the authors could have ex-panded the scope of the paper slightly to include a comparison of land-based estimation to their atmosphere-based estimates. This could give some indication as to the validity of the estimates if both approaches yielded similar results. These results address the objectives stated in the paper quite well. The authors also included a section of issues needed to be addressed for future re-search. The carbon cycle is quite a dynamic sys-tem, especially when human impacts are added into the equation. The need for more models with increasing complexity speaks to the multi-faceted nature of the field of global climate change.

Consistent Land- and Atmosphere-Based U.S. Carbon Sink Estimates

This paper written by Pacala et al. was pub-lished in Science in 2001. The authors attempt to compare model results of atmosphere-land carbon fluxes using two different approaches. The goal of the study was to determine sources and sinks in the coterminous United States. The first method is the land-based approach (the bot-tom up method) in which the authors use data from direct inventory measurements of carbon, reconstructions of land use changes and ecosys-tem models. The second method is the atmos-phere-based approach (the top down method) in which global CO2 concentration data is input into atmospheric transport models.

The land-based estimates of atmosphere to ground carbon flux (carbon sink) yielded a much smaller range of values than did the atmosphere-based estimates. However, using seasonal inver-sion monthly data, the two methods agreed quite well. These results are quite impressive, when taking into account the extreme diversity in input data into the two modeling methods. Both the land-based and atmosphere-based estimates indi-cated a large net carbon sink in the United States. Their analysis also indicated a steady atmosphere to ground carbon flux for the study period of 1980-1994.

This study is quite well designed in that both methods used served as a check of sorts to the other method. When both the land-based and atmosphere-based estimates of carbon flux are in general agreement, this serves as verification of the utility of the each approach.

The Not-So-Big U.S. Carbon Sink This paper written by Field and Fung was

published in Science in 1999. The primary focus of the paper is to review two methods of quanti-fying carbon sinks, the bottom up and the top down approach. As discussed above, the bottom up, or land-based approach includes inventory measurements of carbon and the top down, or atmosphere-based approach inputs global CO2 data into atmospheric transport models. This paper is a synthesis of data used in previous work in order to analyze the two methods of car-bon flux estimation and to determine the major drivers in terrestrial carbon sequestration.

The authors state that changes in historical land use have emerged as major factors influenc-ing carbon sequestration in addition to factors such as rising temperatures, increases in atmos-pheric CO2 and nitrogen deposition. The authors state that latitudinal estimates are becoming in-creasingly more reliable for analyzing terrestrial processes due to a global network of atmospheric monitoring stations.

The overlying conclusion of the paper seems to be that changes in historical land use are quite important when attempting to quantify terrestrial carbon sources and sinks. They sug-gest that future research should focus as much on history of land use practices as on ecosystem changes and atmospheric composition. However, it does not seem that the authors put forth a very exhaustive review of the bottom up and top down approaches to estimating carbon sinks. The text is slightly difficult to comprehend and could use more justification for their conclusions. The synthesis paper is only based on nine sources. The paper would be more useful if it were broken into sections addressing each of the approaches and then a section for comparison between the two methods.


Carbon sequestration has received much publicity in the mainstream media as of late. It becomes big news when a large oil company such as BP invests money in a technology to


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capture CO2 produced during combustion of coal at electricity generating plants. BP, for instance, has entered into an agreement with Powerspan to develop a cost effective technology to capture CO2 from power plant emissions (Powerspan, 2007).

Similary, a large scale sequestration project in Germany, funded by the European Union, is in the planning stages. The proposed design will include a facility to inject CO2 into the ground to a depth of approximately 1880 meters. The ini-tial stages of this project include feasibility test-ing of the technology and monitoring to deter-mine the long term stability of the stored gas with a goal of full implementation by 2020 (AgReport, 2007).

CONSIDERATIONS FOR POLICYMAKERS Although the science behind quantifying

carbon sources, sinks and means of sequestering atmospheric CO2 are continually improving, policymakers should not rely on carbon seques-tration solely to address the effects of carbon emissions on global climate change. Although sequestration projects may help to mitigate ef-fects of increased carbon emissions, the only method to properly address the problem is to mandate decreases in emissions of carbon. There are vast uncertainties concerning the effec-tiveness of sequestration including but certainly not limited to: the efficiency of capture and transport of CO2, long term stability of seques-tration projects such as geologic storage, satura-tion limits of sinks and the unknown response of terrestrial environments to climate change. At-tempts to reduce carbon emissions by means such as “Carbon Credits” and international trea-ties like the Kyoto Protocol are steps in the right direction. The next step will have to include incentives in order for developing nations to be able to work to reduce emissions without com-promising economic and social well being.

CITED REFERENCES WITH ABSTRACTS Field, C.B. and Fung, I.Y (1999). The Not-

So-Big U.S. Carbon Sink. Science, 285, 544-545. Atmospheric carbon emitted through human ac-tivities is stored in carbon sinks in oceans and terrestrial ecosystems. Two methods of quantify-ing the sinks are analyzed.

Houghton, J. (2004). Global Warming: The Complete Briefing, The greenhouse gases (pp. 28-42). New York, NY: Cambridge University Press.

Pacala, S.W. et al. (2001). Consistent Land- and Atmosphere-Based U.S. Carbon Sink Estimates. Science, 292, 2316-2320.

For the period 1980-89, we estimate a carbon sink in the coterminous United States between 0.30 and 0.58 petagrams of carbon per year (petagrams of carbon = 1015 grams of carbon). The net carbon flux from the atmosphere to the land was higher, 0.37 to 0.71 petagrams of car-bon per year, because a net flux of 0.07 to 0.13 petagrams of carbon per year was exported by rivers and commerce and returned to the atmos-phere elsewhere. These land-based estimates are larger than those from previous studies (0.08 to 0.35 petagrams of carbon per year) because of the inclusion of additional processes and revised estimates of some component fluxes. Although component estimates are uncertain, about one-half of the total is outside the forest sector. We also estimated the sink using atmospheric models and the atmospheric concentration of carbon dioxide (the tracer-transport inversion method). The range of results from the atmosphere-based inversions contains the land-based estimates. Atmosphere- and land-based estimates are thus consistent, within the large ranges of uncertainty for both methods. Atmosphere-based results for 1980-89 are similar to those for 1985-89 and 1990-94, indicating a relatively stable U.S. sink throughout the period.

Schimel, D.S. et al. (2001). Recent pat-terns and mechanisms of carbon exchange by terrestrial ecosystems. Nature, 414, 169-172.

Knowledge of carbon exchange between the at-mosphere, land and the oceans is important, given that the terrestrial and marine environ-ments are currently absorbing about half of the carbon dioxide that is emitted by fossil-fuel combustion. This carbon uptake is therefore lim-iting the extent of atmospheric and climatic change, but its long-term nature remains uncer-tain. Here we provide an overview of the current state of knowledge of global and regional pat-terns of carbon exchange by terrestrial ecosys-tems. Atmospheric carbon dioxide and oxygen data con®rm that the terrestrial biosphere was largely neutral with respect to net carbon ex-change during the 1980s, but became a net car-bon sink in the 1990s. This recent sink can be largely attributed to northern extratropical areas, and is roughly split between North America and Eurasia. Tropical land areas, however, were ap-proximately in balance with respect to carbon exchange, implying a carbon sink that offset


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emissions due to tropical deforestation. The evo-lution of the terrestrial carbon sink is largely the result of changes in land use over time, such as regrowth on abandoned agricultural land and fire prevention, in addition to responses to environ-mental changes, such as longer growing seasons, and fertilization by carbon dioxide and nitrogen. Nevertheless, there remain considerable uncer-tainties as to the magnitude of the sink in differ-ent regions and the contribution of different processes.

Powerspan Corp. “BP and Powerspan Col-laborate to Demonstrate and Commercialize CO2 Capture Technology for Power Plants” [Online] 19 November 2007. <http://www.earthtimes.org/articles/show/news_press_release,155722.shtml>.

AgReport. “Underground CO2 Storage Plant in Germany” [Online] 19 November 2007. <http://www.agreport.com/open/259550.phtml>.

The effects of climate change on coastal regions - with a focus on

the US Juliette L. Smith

EXECUTIVE SUMMARY Coastal regions, including shorelines,

estuaries, wetlands, coastal margins, and coral reefs, are vulnerable to climate change drivers such as warming oceanic temperatures, sea-level rise, and precipitation fluctuations. These re-gions house over ½ of the US population while providing valuable resources and services such as aquaculture, freshwater aquifers, and storm surge protection.

INTRODUCTION Climate change is predicted to act upon the

world’s coastal regions through three main forces: an increase in ocean temperature, sea-level rise, and changes in precipitation and river flow (Scavia et al. 2002, and references therein). These forces spin a web of direct and indirect effects on the weather, physical and biogeo-chemical parameters, ecosystems, culture, and socioeconomics of coastal regions, including shorelines, estuaries, coral reefs, coastal wet-lands, and ocean margins. Indirect, negative effects are also predicted for the larger continents that rely on these fertile regions for numerous products and services.

Increase in ocean temperature Warming ocean temperatures are expected

to cause an increase in tropical cyclone strength and duration (i.e., hurricane, coastal storms), an increase in coral bleaching, and a northward shift in coastal region biota. More controversial pre-dictions include an increase in the frequency of tropical cyclones, the shutdown or speeding up of ocean circulation, and the switch of estuaries to act as a nitrogen source instead of sink. The mean temperature of the upper 300 m of ocean has increased by 0.31°C over the past 45 yr and warming has been recorded to depths as low as 3,000 m. The occurrence of widespread, deeper warmer waters has the potential to increase tropical cyclone strength and duration as (1) strength is dependent upon the difference in tem-perature between the upper, colder troposphere and the warmer, sea surface temperatures and (2) storm duration is determined by the geographical range of warm surface and sub-surface waters

that are necessary to fuel the storm moisture and postpone negative feedback (i.e., rising cold wa-ter beneath the storm’s eye, see Willoughby 1999). Emanuel (2005) showed empirical evi-dence that tropical cyclone intensity (wind speed and duration of storm) has significantly in-creased over the past thirty years, suggesting that if the predicted rise in sea surface temperature occurs (1 - 3°C over this century) so will coastal storm intensity. Socioeconomic hardship is likely to follow this alarming trend if landfall occurs, as storm wind speed has been directly correlated with the cost of a storm. Cyclone fre-quency, however, is not as predictable, most likely due to other drivers of cyclones including vertical and horizontal windsheer and/or internal dynamics of the storm itself. It is unknown how climate change will affect windsheer and tropical storm formation.

Emanuel (2005) suggested that an increase in cyclone intensity may, in turn, lead to a speed-ing-up of ocean circulation with more cold, denser water being brought to the surface at the equator during a storm making it more easily sunk when it reaches the poles. This suggestion is opposite that of the general scientific commu-nity which hypothesizes that polar melting and increased freshwater runoff will increase stratifi-cation and hinder vertical mixing, slowing down the conveyor belt. The Intergovernmental Panel on Climate Change (IPCC) reports that it is very likely that there will be a 25% reduction in circu-lation flow by the end of the century (Scavia et al. 2002). Either way, alteration to ocean circula-tion is likely to have vast impacts on the location and intensity of nutrient rich upwelling events, global climate, and geographic distribution of coastal biota.

Warmer ocean temperatures are also pre-dicted to increase the frequency and geographic distribution of coral bleaching events as these ecosystems already live near their upper thermal tolerance limits. Warmer temperature periods have been correlated with zooxanthellae (symbi-otic algae) expulsion, slowing or halting of growth or reproduction, or an increase in patho-gen vulnerability. Other anthropogenic effects such as eutrophication, sedimentation, pollution, and coastline development will most likely hin-der the ecosystems ability to migrate or recolo-nize at the same location. Similarly, estuarine, wetland and shoreline biota will most likely have to migrate northwards or adapt when thermal tolerances are exceeded.

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In the last two years, scientists have re-corded an alarming shift in US estuaries as these bodies of water have suddenly become a source, instead of sink, for nitrogen (Lane 2007). Scien-tists argue that the switch is due to a community shift towards nitrogen-fixing bacteria or cyano-bacteria as a result of oceanic warming; however, the empirical data are sparce and rely on a com-parison of only four years: 1979, 1986, 2005, and 2006 (Fulweiler et al. 2007). If true, how-ever, this net influx of nitrogen into the system may put the coastal ocean at risk for acidification (i.e., nitrate is acidic) or the occurrence of harm-ful algal blooms and fish/shellfish kills as am-monia or nitrate levels rise. More research is needed to confirm this trend and determine the mechanism(s) behind the shift.

Sea-level rise Sea-level rise has been a continuous threat

to wetlands, shorelines, and human development over the last 100 years, rising at an average of 10 – 20 cm. This threat has been bearable with ad-aptation, migration, or constructive barriers. Over the next 100 years, however, sea level is predicted to rise another 9 – 88 cm according to the IPCC (Scavia et al. 2002). The final level will be determined by the actual amount and duration of greenhouse gas emissions, rise in atmospheric and oceanic temperatures, and the amount of glacial and ice cap melt.

Coastal regions are very sensitive to a rise in sea level (Scavia et al. 2002, and references therein). A rapid or substantial rise will likely prevent wetlands from accumulating peat or sediment, and therefore, cause wetland submer-sion or erosion. If migration inland is obstructed, then wetlands and shoreline will be lost. Human development is also subjected to this threat, as over ½ of the US population already lives on the 17% of land considered coastal and another 18 million Americans are predicted to move to the coast (i.e., CA, FL, TX, and WA). Shoreline flooding, the inundation of freshwater aquifers, and the subsequent motility of toxic chemicals and water-borne pathogens are predicted to have large monetary implications, with a 50-cm sea-level rise estimated to cost between $20 and $200 billion by the end of this century. Protec-tion from storm surges will also decrease as wet-lands are lost to inundation.

Changes in precipitation and river flow Although prediction models contradict in

regards to whether the US will experience more

or less precipitation with climate change, they converge to state that there will be more extreme rainfall events, floods, and droughts (Scavia et al. 2002, and references therein). Precipitation run-off supplies the coastal embayments with fresh-water, nutrients, and sediment. Without the de-livery of sediment, the erosion of shoreline and loss of wetlands are to be expected; however, a sudden influx of sediments, nutrients, or fresh-water (e.g., flooding or high rainfall event) can cause a wetland to be buried and the physical and biogeochemical status of the receiving water body to be altered. Alterations to freshwater input can also affect localized salinity levels in the estuaries and wetlands, thereby indirectly controlling the biotic community. For example, a period of decreased runoff or drought would likely result in an increase in salinity, conditions under which mangroves, a diverse nursery for fish, mammals and invertebrates, would perish.


Emanuel (2005): In this modeling paper the author plots

smoothed mean sea-surface temperatures (SST) of the Atlantic in September, the western North Pacific from July – November, and the Atlantic + western North Pacific, as an annual mean, against storm intensity from 1950 – 2005. In all three cases, a significant positive relationship is derived, giving evidence for an increasing trend in cyclone intensity over the last 30 years. Storm intensity is described as an index of power dissi-pation (PDI), a measure based mostly on the wind speed and duration of the storms that oc-curred.

Willoughby (1999): This work provides an explanation on how

tropical cyclones are formed and sustained. Tropical cyclones are created through the colli-sion and organization of already occurring thun-derstorms that converged around a low-surface pressure zone. Overall, the storm relies upon the transfer of energy between the ocean surface and the upper troposphere. As warm surface air passes over the warm ocean, evaporation occurs. As the warm moist air mass rises in altitude the surrounding cooler temperatures and increased pressure of the troposphere causes condensation and cloud formation. Condensation releases heat which is mostly dissipated through precipitation. The cooled, dry air mass moves outward due to the coriolis effect and high pressure center at the top of the storm, and consequently, sinks. As the


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air mass sinks it warms as a result of compres-sion due the surrounding atmosphere, and is again moved across the sea surface towards the low pressure eye while accumulating water va-por. As the storm continues, more energy trans-ferred, resulting in greater winds, and more evaporation - the high and low pressure centers strengthen and even more energy is brought into the system.

Climate change affects tropical cy-clones because the ocean’s surface is warming at a greater rate than the upper troposphere making the temperature difference greater. The storm intensifies because a greater differential equates to a greater power exchange between the water surface and upper troposphere through evapora-tion/condensation. Additionally, the warming of the subsurface waters (3,000m) allows a storm to last longer as it then takes longer for colder warmers to upwell under the storm’s eye and cause a negative feedback.

Fulweiler et al. (2007): In this research paper, sediment samples

collected from Narragansett Bay, RI in 2006 switched to being a net source of nitrogen in-stead of a net sink. Four studies, consisting of different years, were compiled, showing a sud-den increase in nitrogen fixation in 2006 as com-pared to 1979, 1986 and 2005 which instead were years with high rates of denitrification. The second point of the article was that phytoplank-ton biomass has decreased as a result of global warming. The data presented to support this theory was a scatter plot of years against mean summer chlorophyll a concentrations. A trend of decreasing chlorophyll a concentrations over time occurred; however, sea surface or atmos-pheric temperatures were not plotted on the fig-ure. I felt this work was representative of a pre-liminary study instead of a conclusive work and should be followed up with future annual meas-urements. In addition, I think future studies should include more spatial distribution across the estuary as different regions of the water body are acting differently and sediments are inher-ently patchy.

Scavia et al. (2002): Scavia et al. (2002) provides a compre-

hensive review of predicted climate change im-pacts on US coastal and marine ecosystems and possible adaptation and coping strategies. Major forces of climate change identified by the authors include changes to sea-level, coastal storms,

freshwater inflow, ocean temperature and ice extent, and ocean circulation. Impacts are pre-dicted against the weather, organisms, ecosys-tems, culture, socioeconomics, and health of coastal regions.


Lane (2007): Disappointingly, this news feature in

Nature did not provide a satisfactory synthesis of studies, and instead barraged the reader with numerous speculations and hypotheses in a man-ner that was hard to follow or evaluate. The main points of the article were that (1) estuaries are switching from being a nitrogen sink to now a nitrogen source and (2) that the switch is recent and a result of global warming. No direct evi-dence was provided and the reader was forced to read the original articles to gain an understanding of the arguments (see Fulweiler et al. 2007). And worse, the reader is left feeling skeptical of global warming and the science behind its possi-ble impacts.

Kerr (2007): Interestingly, this news focus article in Sci-

ence began with an image of five devastated Louisianans wading their way down a flooded street with a caption that read “ungentle reminder. Katrina's destruction brought global warming to mind.” Kerr points out that the public’s aware-ness of global warming is largely linked to “cli-mate science and weird weather:” Ice-melting of the Arctic, daffodil blooms in Washington, D.C in January, and most recently, the raging hurri-cane, Katrina. It was this last association that drew my attention; Katrina being used as a poster child for global warming. Although I see the value in this association, I feel it may be a bit premature as the science is not sufficient to sup-port the claim. As discussed earlier, a positive, significant relationship exists between warming sea surface temperatures (SST) and tropical cy-clone wind speed and duration (Emanuel 2005); however, not enough data yet exists to determine if there is also a relationship between SST and the frequency of cyclone development or the landfall of storms. Based on current data, Katrina was an example of poor land manage-ment, but its direct connection to global warming is still to be confirmed.


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CONSIDERATIONS FOR POLICYMAKERS I am unaware of any US policy specifically

in place to protect coastal regions from possible future impacts associated with climate change, such as dramatic sea-level rise, warming ocean temperatures, or changes in precipitation or river runoff. Instead, policies exist to protect coastal regions from threats that have already been iden-tified by governments. Such policies focus on pollution and nutrient abatement, marine ecosys-tem preserves, fishery closures, and wetland pro-tection and mitigation. Additionally, local gov-ernment has taken action to protect personal property against beach/shoreline erosion, coastal flooding, and storm surges; however, I believe these regulations do not take into account the expected rise in sea level, local predictions for precipitation change, or increased ocean tem-peratures over the next few decades. Before new policy can be made, global warming impacts must be (1) further studied, independent, from other environmental threats (e.g., eutrophication, sedimentation, pollution, shoreline development, hydrology alteration, etc.) and (2) studied in con-junction with these threats to look for compensa-tory, additive, or synergistic effects.

CITED REFERENCES WITH ABSTRACTS Emanuel, K. 2005 Increasing destructive-

ness of tropical cyclones over the past 30 years. Nature 436; 686-688.

Theory and modeling predict that hurricane in-tensity should increase with increasing global mean temperatures, but work on the detection of trends in hurricane activity has focused mostly on their frequency and shows no trend. Here I define an index of the potential destructiveness of hurricanes based on the total dissipation of power, integrated over the lifetime of the cyclone, and show that this index has increased markedly since the mid-1970s. This trend is due to both longer storm lifetimes and greater storm intensi-ties. I find that the record of net hurricane power dissipation is highly correlated with tropical sea surface temperature, reflecting well-documented climate signals, including multi-decadal oscilla-tions in the North Atlantic and North Pacific, and global warming. My results suggest that future warming may lead to an upward trend in tropical cyclone destructive potential, and—taking into account an increasing coastal population—a sub-stantial increase in hurricane-related losses in the twenty-first century.

Fulweiler, R.W., Nixon, S.W., Buckley, B.A., Granger, S.L. 2007 Reversal of the net dinitrogen gas flux in coastal marine sediments. Nature 448; 180-182.

The flux of nitrogen from land and atmosphere to estuaries and the coastal ocean has increased substantially in recent decades. The observed increase in nitrogen loading is caused by popula-tion growth, urbanization, expanding water and sewer infrastructure, fossil fuel combustion and synthetic fertilizer consumption. Most of the nitrogen is removed by denitrification in the sediments of estuaries and the continental shelf, leading to a reduction in both cultural eutrophi-cation and nitrogen pollution of the open ocean Nitrogen fixation, however, is thought to be a negligible process in sub-tidal heterotrophic ma-rine systems. Here we report sediment core data from Narragansett Bay, USA, which demonstrate that heterotrophic marine sediments can switch from being a net sink to being a net source of nitrogen. Mesocosm and core incubation ex-periments, together with a historic data set of mean annual chlorophyll production support the idea that a climate-induced decrease in primary production has led to a decrease in organic mat-ter deposition to the benthos and the observed reversal of the net sediment nitrogen flux. Our results suggest that some estuaries may no longer remove nitrogen from the water column. Instead, nitrogen could be exported to the continental shelf and the open ocean and could shift the ef-fect of anthropogenic nitrogen loading beyond the immediate coastal zone.

Kerr, R.A. 2007 U.S. Policy: A Permanent Sea Change? Science 315 (5813); 756 – 757.

Lane, N. 2007 Climate change: What's in the rising tide? Nature 449; 778-780.

Scavia, D., Field, J.C., Boesch, F., Budde-meier, R.W., Burkett, V., Cayan, D., Fogarty, M., Harwells, M.A., Howarth, R.W., Mason, C., Reed, D.J., Royer, T.C. Sallenger, A.H., Titus, J.G. 2002 Climate Change Impacts on U.S. Coastal and Marine Ecosystems. Estuaries 25 (2); 149–164.

Increases in concentrations of greenhouse gases projected for the 21st century are expected to lead to increased mean global air and ocean tem-peratures. The National Assessment of Potential Consequences of Climate Variability and Change (NAST 2001) was based on a series of regional and sector assessments. This paper is a summary of the coastal and marine resources


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sector review of potential impacts on shorelines, estuaries, coastal wetlands, coral reefs, and ocean margin ecosystems. The assessment considered the impacts of several key drivers of climate change: sea level change; alterations in precipita-tion patterns and subsequent delivery of freshwa-ter, nutrients, and sediment; increased ocean temperature; alterations in circulation patterns; changes in frequency and intensity of coastal storms; and increased levels of atmospheric CO2. Increasing rates of sea-level rise and intensity and frequency of coastal storms and hurricanes over the next decades will increase threats to shorelines, wetlands, and coastal development. Estuarine productivity will change in response to alteration in the timing and amount of freshwater, nutrients, and sediment delivery. Higher water temperatures and changes in freshwater delivery will alter estuarine stratification, residence time, and eutrophication. Increased ocean temperatures are expected to increase coral bleaching and higher CO2 levels may reduce coral calcification, making it more difficult for corals to recover from other disturbances, and inhibiting poleward shifts. Ocean warming is expected to cause poleward shifts in the ranges of many other or-ganisms, including commercial species, and these shifts may have secondary effects on their predators and prey. Although these potential impacts of climate change and variability will vary from system to system, it is important to recognize that they will be superimposed upon, and in many cases intensify, other ecosystem stresses (pollution, harvesting, habitat destruc-tion, invasive species, land and resource use, extreme natural events), which may lead to more significant consequences.

Willoughby, H.E. 1999 Hurricane heat en-gines. Nature 401; 649-650.

Climate Change Effects on Biodiversity and Species Ranges

Lisa Giencke

EXECUTIVE SUMMARY Climate envelope modeling is one of the

key methods that scientists have been utilizing in order to predict how future climate change will affect species ranges. However, there has been some dispute within the scientific community as to the accuracy and usefulness of these models. The main criticisms are that these models do not account for biotic interactions, genetic adaptation or dispersal. As our knowledge about these subjects improves, it will be increasingly important to include them into species range models. For now, however, these bioclimate models, if environmental variables are used in the appropriate context and if the inherent limitations of these models are presented in full, are a means to investigate the magnitude of range changes.

Many studies have been conducted throughout the world showing the changes that have already occurred due to a moderately small change (compared at least to what is possible in the future) in global climate. One study shows that on average, across a variety of taxonomic groups, range changes are approximately 6.1 km or m poleward or upward in elevation per decade (Parmesan and Yohe 2003). Other studies take a broader look at some of the ecological responses that can be attributed to climate change. Still other studies look at extinction rates and predict that somewhere between 15-37% of species will be “committed to extinction” by 2050, if the mid-range prediction in climate change and emission standards are accurate (Thomas et al 2004).

INTRODUCTION According to the Synthesis Report of

the Fourth Assessment Report of the Intergovernmental Panel on Climate Change there has been an increase in global surface temperature of 0.74º C in the last 100 years. The report goes on to say, “In terrestrial ecosystems, earlier timing of spring events and poleward and upward shifts in plant and animal ranges are with very high confidence linked to recent warming” (IPCC 2007). Therefore, it is becoming increasingly important that we investigate the consequences of further climate change that will

be manifested in species distributions and biodiversity.

STATE OF THE SCIENCE In order to understand how scientists make

predictions about the future range of a given species, we should first examine the models behind the science. One of the key ways of predicting such changes is through the use of bioclimate envelope models. The article by Pearson and Dawson (2003) provides an informative overview, and it also provides some of the main criticisms (and counter-criticisms) in the design of these models.

Two of the main approaches of bioclimate envelope models are to either correlate current species distributions with environmental conditions or to examine physiological responses of a given species to its environment. In either case, it is assumed that species will show the same response to the environment in the future as they do today, and so climate change scenarios are used to simulate future distribution.

There are three major criticisms often directed toward the bioclimate envelope approach, which are: it does not accurately take into account biotic interactions, evolution or genetic adaptation or dispersal ability. In each case, the authors provide either a counter-criticism or show how models could be improved in the future with a better understanding of the complexity of each issue.

In answering the question posed by the article (are bioclimate envelopes useful?), it is clear that the authors would agree that they are. They conclude the article by providing a hierarchical framework within which future models should be designed. They assert that this framework is not perfect and may be over simplistic, but that it at least provides some guidelines as to what environmental variables should be considered when modeling at various scales. As with any predictions of the future, there are inherent limitations to the accurate simulation of species ranges into the future. These are due in large part to our as-yet imperfect understanding of the complexity of natural systems. The authors conclude that bioclimate envelopes models are a good first pass toward understanding the magnitude of the changes to be expected. Even so, they stress the importance knowing the limitations of these models

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Many studies have been conducted using bioclimate envelope models and other methods to determine if there is already a detectable influence of climate change on species ranges, biodiversity and extinction. One of these concluded, as they termed it, that a “globally coherent climate fingerprint” does indeed exist (Parmesan & Yohe 2003). Their research used a probabilistic model to determine how likely it is that climate is the major force behind observed range and phenological changes. The results show that 74-91% of documented changes occur in the direction expected based on climate change predictions and that these changes amount to a shift of 6.1 km toward the poles or m upward in elevation.

Another study (Walther et al. 2002) reviewed the various ecological changes that are being in observed in various ecosystems, spanning from species- to community-level effects. The paper focuses on changes in phenology, species ranges, invasive species, community composition and biotic interactions. Changes have been observed in the spring timing of many biological activities including flowering, bird migration and calling or singing in amphibians and birds. Species ranges, as noted above, are moving poleward or upward in accordance with climate changes. Species invasions are expected to increase as non-native organisms are more likely to survive in regions that were previously inhospitable. Community composition is expected to change since climate change will cause individual species to react in different ways. This has the potential to change dynamics between trophic levels. Despite lingering uncertainties, it is clear that climate is playing a role in each of the above cases.

Other studies have focused on the risk of species extinctions. One study used a bioclimate envelope approach, and specifically took into account dispersal ability by using two dispersal scenarios: one of no dispersal and one of high (universal) dispersal. The authors claim that species will likely fall somewhere in-between these scenarios – that is, these two scenarios form the upper and lower bounds of likely extinction values. Looking only at endemic species of various taxonomic groups across the world, the study predicts that 15-37% of species will be “committed to extinction” by 2050, given a mid-range climate change scenario (Thomas et al. 2004). A more recent study found that “For ectothermic animals with relatively short generation times, at least, climate change

already appears to have joined habitat loss, invasive species and overexploitation as a major driving force of population- and species-level extinctions” (Thomas et al. 2006).


As part of a year-long effort in conjunction with National Geographic, National Public Radio is producing a special series called “Climate Connections” with the objective to examine “how climate changes people and how people change climate.” One recent installment (October 29, 2007) examined the effect that climate is having on sugar maples in New England. The sugar maple is crucial for its production of syrup and is very sensitive to changes in climate. Many maple syrup producers are having a hard time extracting the same quantity of sap from the trees that they have gotten in the past.

As the example above shows, the species that are going to garner the most attention as climate change continues to unfold are the relatively few charismatic plant and animal species that people know and pay attention to. Changes in butterfly, wildflower and bird distributions or abundance will surely be noticed before all the millions of more mundane creatures, including insects, invertebrates and bacteria, whose contribution to ecosystems may not yet be fully realized, and that may not ever be known to science before they become extinct. Even species of great scientific importance, such as two species of gastric brooding frog that possessed a previously unknown method of reproduction, are at risk – both frogs have ceased to be seen in the wild, one just months after it was first discovered (Flannery 2005).

CONSIDERATIONS FOR POLICYMAKERS Besides knowing how climate change is

going to effect species ranges and extinction rates, it will be ever more important for policymakers to consider the importance of the interplay between climate change and habitat fragmentation. Even species with high dispersal abilities may have a hard time migrating through the human-modified environment. One solution to this problem might be the creation and implementation of conservation corridors which would hopefully allow at least some species to migrate unimpeded by development.


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Changes in ranges and extinctions of charismatic organisms may spark some policy initiatives limiting greenhouses gases, as the policymakers and general public start to observe for themselves the consequences of climate change.

LITERATURE CITED In New England, Concern Grows for Sugar

Maple (Climate Connections). Ketzel Levine. NPR, Washington, D.C. 29 Oct. 2007.

Summary for Policymakers of the Synthesis Report of the IPCC Fourth Assessment Report. Intergovernmental Panel on Climate Change. 2007.

Flannery, Tim. The Weather Makers. Text Publishing Company: Melbourne, Australia. 2005.

Parmesan, C. & Yohe, G. A globally coherent fingerprint of climate change impacts across natural systems. Nature 421, 37–42 (2003).

Pearson, R. G. & Dawson, T. P. Predicting the impacts of climate change on the distribution of species: are bioclimate envelope models useful? Global Ecol. Biogeog. 12, 361–371 (2003).

Thomas, C. D. et al., Extinction risk from climate change. Nature 427, 145 (2004).

Thomas, C.D., Franco, A.M.A. & Hill J.K. Range retractions and extinction in the face of climate warming. Trends Ecol.. Evol 21, 415-416 (2006).

Walther, G.R., Post, E., Convey, P., Menze, 1, A., Parmesan, C., Beebee, T.J.C., Fromentin, J.M., Hoegh-Guldberg, O.&Bairlein, F. Ecological responses to recent climate change. Nature 416, 389–395 (2002).

ABSTRACTS FROM CITED REFERENCES 1. Predicting the impacts of climate change

on the distribution of species: are bioclimate envelope models useful?

2. A globally coherent fingerprint of climate change impacts across natural systems.

3. Ecological responses to recent climate change.

4. Extinction risk from climate change.

Pearson, R. G. & Dawson, T. P. Predicting the impacts of climate change on the distribution of species: are bioclimate envelope models useful? Global Ecol. Biogeog. 12, 361–371 (2003).

Modelling strategies for predicting the potential impacts of climate change on the natural distribution of species have often focused on the characterization of a species' bioclimate envelope. A number of recent critiques have questioned the validity of this approach by pointing to the many factors other than climate that play an important part in determining species distributions and the dynamics of distribution changes. Such factors include biotic interactions, evolutionary change and dispersal ability. This paper reviews and evaluates criticisms of bioclimate envelope models and discusses the implications of these criticisms for the different modelling strategies employed. It is proposed that, although the complexity of the natural system presents fundamental limits to predictive modelling, the bioclimate envelope approach can provide a useful first approximation as to the potentially dramatic impact of climate change on biodiversity. However, it is stressed that the spatial scale at which these models are applied is of fundamental importance, and that model results should not be interpreted without due consideration of the limitations involved. A hierarchical modelling framework is proposed through which some of these limitations can be addressed within a broader, scale-dependent context.

Parmesan, C. & Yohe, G. A globally coherent fingerprint of climate change impacts across natural systems. Nature 421, 37–42 (2003).

Causal attribution of recent biological trends to climate change is complicated because non-climatic influences dominate local, short-term biological changes. Any underlying signal from climate change is likely to be revealed by analyses that seek systematic trends across diverse species and geographic regions; however, debates within the Intergovernmental Panel on Climate Change (IPCC) reveal several definitions of a 'systematic trend'. Here, we explore these differences, apply diverse analyses to more than 1,700 species, and show that recent biological trends match climate change predictions. Global meta-analyses documented significant range shifts averaging 6.1 km per decade towards the poles (or metres per decade


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upward), and significant mean advancement of spring events by 2.3 days per decade. We define a diagnostic fingerprint of temporal and spatial 'sign-switching' responses uniquely predicted by twentieth century climate trends. Among appropriate long-term/large-scale/multi-species data sets, this diagnostic fingerprint was found for 279 species. This suite of analyses generates 'very high confidence' (as laid down by the IPCC) that climate change is already affecting living systems.

Walther, G.R., Post, E., Convey, P., Menze, 1, A., Parmesan, C., Beebee, T.J.C., Fromentin, J.M., Hoegh-Guldberg, O.&Bairlein, F. Ecological responses to recent climate change. Nature 416, 389–395 (2002).

There is now ample evidence of the ecological impacts of recent climate change, from polar terrestrial to tropical marine environments. The responses of both flora and fauna span an array of ecosystems and organizational hierarchies, from the species to the community levels. Despite continued uncertainty as to community and ecosystem trajectories under global change, our review exposes a coherent pattern of ecological change across systems. Although we are only at an early stage in the projected trends of global warming, ecological responses to recent climate change are already clearly visible.

C. D. Thomas et al., Extinction risk from Climate Change. Nature 427, 145 (2004).

Climate change over the past ~30 years has produced numerous shifts in the distributions and abundances of species1,2 and has been implicated in one species-level extinction3. Using projections of species’ distributions for future climate scenarios, we assess extinction risks for sample regions that cover some 20% of the Earth’s terrestrial surface. Exploring three approaches in which the estimated probability of extinction shows a powerlaw relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15–37% of species in our sample of regions and taxa will be ‘committed to extinction’. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction (~18%) than mid-range (~24%) and maximum change (~35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease

greenhouse gas emissions and strategies for carbon sequestration.

Thomas, C.D., Franco, A.M.A. & Hill J.K. Range retractions and extinction in the face of climate warming. Trends Ecol.. Evol 21, 415-416 (2006).

Until recently, published evidence for the responses of species to climate change had revealed more examples of species expanding than retracting their distributions. However, recent papers on butterflies and frogs now show that population-level and species-level extinctions are occurring. The relative lack of previous information about range retractions and extinctions appears to stem, at least partly, from a failure to survey the distributions of species at sufficiently fine resolution to detect declines, and from a failure to attribute such declines to climate change. The new evidence suggests that climate-driven extinctions and range retractions are already widespread.

The Effect of Climate Change on Species’ Phenology

Laura Heath

EXECUTIVE SUMMARY Phenology is the timing of development

from one point in an organism’s life cycle to another. Phenological events can include timing of flowering, leaf out, migration, and reproduction, amongst others. Due to the dependence of many phenological events on temperature, species’ phenology is thought to be one of the easiest ways to document the occurrence of global climate change. In addition, changes in species’ phenologies have the potential to impact ecological processes, agriculture, forestry, economics and human health.

Current scientific research indicates that many geographic areas within the mid-latitudes of the northern hemisphere have shown increases in the onset of spring and delays in the onset of fall. Research has determined that globally, and across multiple trophic levels, phenologies are occurring an average of 2.3 days earlier per decade (Parmesan and Yohe 2003). Research has documented earlier onset of tree bud burst (Badeck et al. 2004), plant flowering (Fitter and Fitter 2002), frog calling (Gibbs and Breisch 2001), bird migration (Cotton 2003) and bird egg-laying (Dunn and Winkler 1999). Although changes in species’ phenologies are not always detrimental to ecosystem functioning, they can be in situations where one organism is highly dependent on the timing of a life cycle event of another organism. One such example is the recent observation that cold winters and warm springs are causing unequal rates of advancement of winter moth (Operophtera brumata) egg hatching and English oak (Quercus robur) bud burst, causing moths to hatch before their food source (oak) has developed (Visser and Holleman 2001).

Change in species’ phenologies is a subject easily understood by the public and therefore used in the mass media as a way to demonstrate the validity of global warming. Although earlier onset of spring and later onset of fall could be perceived as positive consequences of global climate change, the media still recognizes these changes as abnormal, which is essential in conveying the serious nature of global climate change. It is therefore

necessary that policymakers use phenology data as strong evidence that global warming is a serious threat and impetus to take action.

INTRODUCTION Phenology is defined in biology as the

timing of life history events. Such events include breeding, migration, hibernation, metamorphosis, leaf out, bud burst, flowering and leaf senescence, amongst others. It has been well documented that many life history events vary from year to year based on climate conditions, and as a result, it is thought that phenology will be one of the earliest and most easily recognizable traits that change in response to global climate change. In addition, phenology is a subject easily identifiable with the general public, as the public’s connection to the natural world is often associated with elements such as flowering time, bird migration and leaves changing color.

Changes in plant phenology have the potential to have many ecological, social and economic impacts. Agricultural and forestry industries can be affected by changes in plant productivity, length of growing season and zoning that can ultimately result from changes in plant phenology. Changes in phenology can also alter ecological systems by altering interspecific competition, disrupting highly coupled associations amongst organisms at different trophic levels and altering the terrestrial carbon balance. Finally, changes in plant phenology can impact human health, such as changes in the timing and abundance of pollen release, which affects the seriousness and treatment of allergies. This paper will explore the current knowledge on the impacts of global climate change on species’ phenologies.

STATE OF THE SCIENCE Long-term phenological data has

historically been collected by amateur naturalists with a connection to the agricultural industry. Today, many countries of Europe, North America and Asia have developed national phonological networks to aid in long-term data collection and compilation. The phenology network of the United States began in 2007 and aims to get citizens involved in phenology data collection (such as bud burst, flowering time and first site of migratory birds) in order to build a dataset that is as large as possible and geographically extensive. The phenological network of Britain currently has 50,000 citizens

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submitting phenology data every year. In addition to “on the ground” data collected by citizens and scientists around the world, new technology has recently allowed for large-scale data collection using satellite technology. The Normalized Difference Vegetation Index (NDVI) is a remote-sensing technique using NASA satellites that measure the amount of light reflecting off the earth at varying wavelengths. This technology is based on the principle that green plants absorb visible light (at wavelengths 0.4-0.7 µm) and reflect near infrared light (at wavelengths 0.7-1.1µm). As a result, measurements of visible and infrared light reflectance by the earth can serve as a way to quantify how green the earth is over time, and therefore how the onset of spring and fall is changing.

Many studies encompassing large geographical areas and habitat types now report that plant and animal species’ phenologies are changing as of late, which have been shown to be correlated to increasing temperatures. Fitter and Fitter (2002) presented data, collected by a single observer, concerning the first flowering dates of 385 plant species in Britain from 1954 to 2000. The authors determined that the plants flowered an average of 4.5 days earlier in the 1990’s than the previous decades. First flowering date of plants blooming in February, March and April were correlated with temperatures of the previous month (January, February and March, respectively). In addition, annual plants exhibited earlier average flowering date in the 1990’s by 7.8 days than perennials, with an average of 3.2 days earlier. Finally, insect-pollinated plants had an earlier first flowering date (by 4.8 days) than wind-pollinated plants (3.5 days earlier) and insect-pollinated plants flowering in the spring appeared to be most sensitive to warming. The fact that spring-flowering, insect-pollinated plants flowered earlier in the 1990’s than all other plant types could have drastic consequences on those insect-plant systems, especially if synchrony of insect development and plant flowering is lost. The work discussed in this paper is particularly important not only because it has a long timeframe (1954-2000), but also because it is the only phenology study that uses data collected by a single observer.

Phenologies of animals have also been shown to be affected by global warming. Gibbs and Breisch (2001) found that many frogs of central New York, especially early spring

breeders, exhibited earlier first calling dates, up to 13 days earlier, in the 1990’s as compared to the period from 1900 to 1912. In addition, average daily temperatures increased over the last century during 5 of the 8 months important for frog development, indicating that earlier first calling dates could be a biotic response to increased temperatures. Changes in time of reproduction have also been documented for tree swallows in North America. Dunn and Winkler (1999) found that tree swallows exhibited advancement in egg-laying by an average of 9 days from 1959 to 1991. In addition, egg-laying date was highly correlated to mean May air temperatures. Finally, Cotton (2004) found that birds in England migrate from sub-Saharan Africa an average of 8 days earlier than they did 30 years ago.

Although changes in species’ phenologies due to global climate change will not always be detrimental to organisms, some highly specialized systems are threatened by global warming. One such system is that of the winter moth (Operophtera brumata) and English oak (Quercus robur). Winter moth egg hatching is timed to coincide with oak bud burst such that moth larvae can feed on young, easily digestible oak leaves. Visser and Holleman (2001), using descriptive modeling techniques, found that between 1975 and 2000, there has been an increase in the mis-timing of moth egg hatching and oak bud burst. The authors attributed this result to recent increases in spring temperatures, which cause advancement of both moth egg hatching and oak bud burst, but no subsequent changes in the number of winter frost days, which delays oak development. Therefore, warm springs and cold winters lead to egg hatching up to three weeks before bud burst, which can result in large-scale mortality of moths. This example of loss of synchrony across trophic levels is particularly important because it demonstrates that organisms highly dependent on one another can become threatened by global climate change.


Change in species’ phenologies over time is a subject that is easily understood by the general public. Many media outlets, including magazines and local newspapers, have used phenological data to demonstrate the validity of global warming. An article published in the New York Times entitled “March may be


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coming in like a lamb” summarizes, in a simple but accurate way, current knowledge on phenological changes that have been attributed to global warming (Stevens 1999). Although this article could easily spin the concept of earlier spring onset as a positive consequence of global climate change, it recognizes that these observed changes are not consistent with historical trends. As a result, changes in phenology hold the potential to be a poster child for the public to demonstrate that global warming is indeed occurring, as demonstrated by the assertion in the article that “all the recent studies indicate that a warming and greening of the planet is indeed under way” (Stevens 1999). However, some media outlets, especially those without a strong base in science, generally focus on consequences of phenology changes that have a direct impact on peoples’ daily lives rather than broad ecological functioning. Such topics include the effects of climate change on gardening, winter and spring recreation, and the maple syrup industry. Although the human aspect of the problem is important, it gives an incomplete perspective on the issue.

CONSIDERATIONS FOR POLICYMAKERS The effects of climate change on

species’ phenology have been strongly documented. However, in only a few cases has research shown that these changes cause a breakdown of ecological systems. Therefore, it is unlikely, with the current level of scientific knowledge on changes in phenology, that government officials will institute policy aimed at maintaining species’ phenology in the wake of climate change.

Although changes in species’ phenology are some of the strongest and most accessible evidence for global climate change, there are inherent drawbacks to the data. Trends in this field rely primarily on correlations between changes in phenology and changes in temperature. However, causation cannot be inferred from correlations. As a result, one cannot state without a doubt that recent increases in spring temperature are causing the observed changes in species’ phenology, although the probability of causation is high.

REFERENCES Badeck, F.W, A. Bandeau, K. Bottcher, D.

Doktor, W. Lucht, J. Schaber and S. Sitch. 2004. Responses of spring phenology to climate change. New Phytologist 162: 295-309.

Climate change effects on seasonal activity in terrestrial ecosystems are significant and well documented, especially in the middle and higher latitudes. Temperature is a main driver of many plant developmental processes, and in many cases higher temperatures have been shown to speed up plant development and lead to earlier switching to the next ontogenetic stage. Qualitatively consistent advancement of vegetation activity in spring has been documented using three independent methods, based on ground observations, remote sensing, and analysis of the atmospheric CO2 signal. However, estimates of the trends for advancement obtained using the same method differ substantially. We propose that a high fraction of this uncertainty is related to the time frame analysed and changes in trends at decadal time scales. Furthermore, the correlation between estimates of the initiation of spring activity derived from ground observations and remote sensing at interannual time scales is often weak. We propose that this is caused by qualitative differences in the traits observed using the two methods, as well as the mixture of different ecosystems and species within the satellite scenes.

Cotton, P.A. 2003. Avian migration phenology and global climate change. Proceedings of the National Academy of Sciences 100: 12219-12222.

There is mounting evidence that global climate change has extended growing seasons, changed distribution patterns, and altered the phenology of flowering, breeding, and migration. For migratory birds, the timing of arrival on breeding territories and over-wintering grounds is a key determinant of reproductive success, survivorship, and fitness. But we know little of the factors controlling earlier passage in long-distance migrants. Over the past 30 years in Oxfordshire, U.K., the average arrival and departure dates of 20 migrant bird species have both advanced by 8 days; consequently, the overall residence time in Oxfordshire has remained unchanged. The timing of arrival has advanced in relation to increasing winter temperatures in sub-Saharan Africa, whereas the timing of departure has advanced after elevated summer temperatures in Oxfordshire. This finding demonstrates that migratory phenology is quite likely to be affected by global climate change and links events in tropical winter quarters with those in temperate breeding areas.


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Dunn, P.O. and D.W. Winkler. Climate change has affected the breeding date of tree swallows throughout North America. Proceedings of the Royal Society of Biological Sciences 266: 2487-2490.

Increasing evidence suggests that climate change has affected the breeding and distribution of wildlife. If such changes are due to global warming, then we should expect to see large-scale effects. To explore for such effects on avian reproduction, we examined 3450 nest records of tree swallows from across North America. The egg-laying date in tree swallows advanced by up to nine days during 1959 to 1991. This advance in phenology was associated with increasing surface air temperatures at the time of breeding. Our analysis controlled for several potentially confounding variables such as latitude, longitude, breeding density and elevation.We conclude that tree swallows across North America are breeding earlier and that the most likely cause is a long-term increase in spring temperature.

Fitter, A.H. and R.S.R Fitter. 2002. Rapid changes in flowering time in British plants. Science 296: 1689-1691.

The average first flowering date of 385 British plant species has advanced by 4.5 days during the past decade compared with the previous four decades: 16% of species flowered significantly

earlier in the 1990s than previously, with an average advancement of 15 days in a decade. Ten species (3%) flowered significantly later in the 1990s than previously. These data reveal the strongest biological signal yet of climatic change. Flowering is especially sensitive to the temperature in the previous month, and spring-flowering species are most responsive. However, large interspecific differences in this response will affect both the structure of plant communities and gene flow between species as climate warms. Annuals are more likely to flower early than congeneric perennials, and insect-pollinated species more than wind-pollinated ones.

Gibbs, J.P. and A.R. Breisch. Climate warming and calling phenology of frogs near Ithaca, New York, 1900–1999. Conservation Biology 15: 1175-1178.

Because ambient temperature strongly influences reproduction in frogs, the seasonal timing of frog calling provides a sensitive index of biotic response to climate change. Over the last century,

daily temperatures increased during 5 of the 8 months key to gametogenesis in frogs and toads near Ithaca, New York ( U.S.A.). Earliest dates of calling frogs recorded by Albert Hazen Wright between 1900 and 1912 near Ithaca were compared to those from the New York State Amphibian and Reptile Atlas Project for 1990–1999 for the three counties surrounding Ithaca. Four species are now calling 10–13 days earlier, two are unchanged, and none is calling later. The data suggest that climate has warmed in central New York State during this century and has resulted in earlier breeding in some amphibians—a possible first indication of biotic response to climate change in eastern North America.

Parmesan, C. and G. Yohe. 2003. A globally coherent fingerprint of climate change impacts across natural systems. Nature 421: 37-42.

Causal attribution of recent biological trends to climate change is complicated because non-climatic influences dominate local, short-term biological changes. Any underlying signal from climate change is likely to be revealed by analyses that seek systematic trends across diverse species and geographic regions; however, debates within the Intergovernmental Panel on Climate Change (IPCC) reveal several definitions of a 'systematic trend'. Here, we explore these differences, apply diverse analyses to more than 1,700 species, and show that recent biological trends match climate change predictions. Global meta-analyses documented significant range shifts averaging 6.1 km per decade towards the poles (or metres per decade upward), and significant mean advancement of spring events by 2.3 days per decade. We define a diagnostic fingerprint of temporal and spatial 'sign-switching' responses uniquely predicted by twentieth century climate trends. Among appropriate long-term/large-scale/multi-species data sets, this diagnostic fingerprint was found for 279 species. This suite of analyses generates 'very high confidence' (as laid down by the IPCC) that climate change is already affecting living systems.

Stevens, W.K. 1999. March may be coming in like a lamb. NY Times: New York, New York.

Visser, M.E. and L.J.M. Holleman. 2001. Warmer springs disrupt the synchrony of oak and winter moth phenology. Proceedings of the Royal Society of Biological Sciences 268: 289-294.


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Spring temperatures have increased over the past 25 years, to which a wide variety of organisms have responded. The outstanding question is whether these responses match the temperature-induced shift of the selection pressures acting on these organisms. Organisms have evolved response mechanisms that are only adaptive given the existing relationship between the cues organisms use and the selection pressures acting on them. Global warming may disrupt ecosystem interactions because it alters these relationships and micro-evolution may be slow in tracking these changes. In particular, such shifts have serious consequences for ecosystem functioning for the tight multitrophic interactions involved in the timing of reproduction and growth. We determined the response of winter moth (Operophtera brumata) egg hatching and oak (Quercus robur) bud burst to temperature, a system with strong selection on synchronization. We show that there has been poor synchrony in recent warm springs, which is due to an increase in spring temperatures without a decrease in the incidence of freezing spells in winter. This is a clear warning that such changes in temperature patterns may affect ecosystem interactions more strongly than changes in mean temperature.

Crop yields, food production and human health Judy Crawford

EXECUTIVE SUMMARY There is increasingly clear evidence that

climate change is affecting crops, food produc-tion and human health. Warming temperatures have led to earlier crop planting and earlier fruit tree flowering. An unusually severe heat wave during the summer of 2003 destroyed European food crops and caused an estimated 35,000 deaths. Disease vectors have shifted their ranges northward, as has allergenic pollen. Although relatively small right now, for both health and agriculture, impacts in the future are potentially huge. Greater health risks are expected through extreme weather, floods and storms. Fatal heat waves will be more frequent. Infectious disease dynamics will change and water sources for drinking and sanitation will be reduced. Overall, the spread of disease will be enhanced in a warming and variable climate. Models show that at high latitudes, modest increases in tempera-tures, from 1 – 3 °C, are expected to increase crop yields and food production. At low lati-tudes, even slight warming of 1-2 °C is projected to decrease crop yields. At any latitude, more than 3 °C decreases crop yields. Agriculture is tremendously adaptable and effective policies can help to limit the effects of climate change by promoting adaptive capacity. Changes in plant variety, improved water and fertilizer manage-ment, changes in timing and location of crops can all work to minimize negative impacts. Negative impacts on health are most effectively met through strengthening of basic public health infrastructures. This is especially important for people in low latitude and tropical developing countries who will suffer most from climate change even though they have contributed least to greenhouse gas emissions.

INTRODUCTION Crop yields, food production and human

health impacts are closely linked issues in cli-mate change. Human survival is dependent upon an adequate food supply and food production is dependent upon climate. This paper briefly ex-amines key aspects of the state of the science underlying these topics. Media perspectives are explored with examples from contrasting sources

and some considerations for policymakers are presented.


Agriculture and Crops Agricultural production will most certainly

be impacted by climate change. Whether those impacts are harmful or beneficial depend largely upon location. Changes in global temperature, precipitation and carbon dioxide concentration are major determinants of agricultural production. In middle and higher latitudes, warming tem-peratures may enhance production through lengthened growing seasons, earlier crop matura-tion, earlier harvesting, and potentially two crop-ping cycles. Earlier fruit tree flowering and ear-lier planting dates for some crops have already been observed in Europe. [1] With warmer temperatures, crops may be planted further north, although there are many uncertainties related to a northward shift of crops. Along with the plants, pests, weeds and plant diseases are expected to expand their northern ranges, and soil fertility may be an issue. Increased precipitation at high latitudes is projected, while reduced precipitation is expected at lower and mid-latitudes. Also at lower latitudes, increased temperatures may cause drier soils and heat stress on plants. These conditions, especially for crops that are already near their maximum temperatures, translate into reduced plant growth, crop production and food supply. [2]

The carbon dioxide effect or ‘fertilization’ refers to the stimulation of photosynthesis at increased concentrations of CO2. The response varies according to a plant’s photosynthetic pathway. Experiments with C3 plants, which include the majority of plants and crops such as wheat, rice, soybeans and barley, show yield increases of 10 – 20% at CO2 concentrations of 550 ppm. [1] C4 plants, including corn, sugar-cane, sorghum and millet are less responsive, with increased yields of less than 10%. Precipi-tation and temperature changes modify or limit the CO2 effect, so that under actual field condi-tions, yields are uncertain. The impact of ex-treme weather events on crops is another area of uncertainty. Increased frequency and intensity of storms, heavy rainfall and heat waves are ex-pected, however their impacts are difficult to project. The European heat wave during the summer of 2003 illustrates the substantial effect of extreme temperatures, in this case 6 °C above average. In France and Italy, many crops were

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reduced by 30% or more and total losses were estimated at 19 billion dollars. [1] Crop losses from extreme weather may outweigh positive effects from warming and CO2. Results from over 69 studies modeling the response of cereal yields to climate change produced the following key conclusions and projections: In mid to high latitudes, a warming of 1 – 3 °C, along with a CO2 increase and rainfall changes, benefits crop yields. However, even slight warming of 1 -2 °C decreases yields for all major cereals in season-ally dry and low latitude areas. Further warming at any latitude is more negative. Overall global food production then is projected to increase with temperatures 1-3 °C, but decreases beyond that. [1] Models of climate and global crop yields are highly complex, yet Lobell developed a simple relationship between growing season temperatures, precipitation and crop yields. [3] The study reports a negative global yield for wheat, maize and barley with increased tempera-tures. It also estimates the costs of the negative impact on yields for these crops from 1980 – 2000 at roughly $5 billion per year.

Historically, agricultural has been highly adaptable and productive. Changes in plant va-rieties, fertilization, water management, planting times and pest and pathogen management have brought steady increases in world crop yields. Adaptation to climate change will be necessary. Adaptive capacity is greatest in developed coun-tries where resources are available. Developing countries and subsistence farmers will be highly challenged.

Human Health Climate change can impact human health

through direct and indirect pathways. Changes in temperature, precipitation, sea-level rise and extreme events are capable of causing direct ad-verse effects such as heat-related illness, drown-ing from floods, and traumatic injury during storms. Indirect effects can occur through cli-mate-related changes in air quality, water quality, food availability, ecosystems, industry and econ-omy. Currently, human health impacts are be-lieved to be in the early stages, with observations and evidence of change limited to three key areas:

1) Warming temperatures are believed to be related to altered distributions of disease vectors, including changes in tick distribu-tion and tick-borne infections in Europe.

2) An earlier onset of the spring allergenic pollen season has been noted in the North-

ern Hemisphere with length of the pollen season increased also.

3) An increase in heat wave related deaths has been documented. [4]

The same 2003 European heat wave that destroyed crops was responsible for an estimated 35, 000 deaths. [5] Important risk factors for heat-related deaths include age (elderly and chil-dren), urban location, poverty, and social isola-tion. [6] Although European health care sys-tems are sophisticated, public health response to the heat wave was inadequate and few preventive measures were taken to reduce heat-related mor-tality. With warming temperatures, more heat waves are projected, along with continued range expansions for disease vectors and pollen. [7]

Ground level ozone, a ‘summertime’ pol-lutant, is formed by the reaction of nitrogen ox-ides, volatile organic compounds, sunlight and heat. Ozone is an irritant gas associated with adverse health effects such as pneumonia, asthma, other respiratory diseases and premature death. Warming temperatures are expected to increase airborne ozone concentrations. [4]

Food insecurity arises from changes in ag-ricultural systems as outlined above. Drought and malnutrition are projected for lower latitude areas already water-stressed including those in sub-Saharan Africa, south Asia, and tropical ar-eas of Latin America. In the same locations, water scarcity is expected to cause decreased efficiency of sewers and contamination of water supplies resulting in increased diarrheal diseases, especially among children. [7] On the other hand, too much water, from flooding and storms, is associated with water-borne and other disease outbreaks. Heavy rainfall can transport micro-bial and toxic agents and mobilize rodent popula-tions. After rains or floods, mosquito populations may increase explosively with a resulting in-crease in mosquito borne diseases.

Some health benefits are expected from climate change. Fewer cold-related deaths should result from warming temperatures. Infec-tious disease vectors, including malarial mosqui-toes, will likely have some contraction in ranges and transmission seasons. These positive effects are small however, and the overall balance of health impacts is overwhelmingly negative. [4]


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Mainstream media perspectives on climate change appear to be shifting even as of this writ-ing. The Nobel prize awarded to the IPCC committee and Al Gore likely adds greater au-thority and credibility to the committee’s work. The Draft Synthesis Report of the IPCC Fourth Assessment has been out for three days now and most media reports appear to accept and promote the IPCC as the undisputed authority on climate change. Articles covering the Draft Synthesis report in the New York Times and Washington Post did not even mention alternate views on climate change. With the increasing authority of the IPCC, it is possible we will see less main-stream media coverage of climate skeptics.

Alternate views do exist however, for ex-ample, the newspaper “Environment and Climate News” published by the Heartland Institute. According to their website, the organization’s mission is to promote free-market solutions to social and economic problems, including market-based approaches to environmental protection. An October, 2007 article, “Health Fears About Global Warming Are Unfounded”, argued that warmer temperatures are healthier because of fewer cold-related deaths. [8] The article ne-glects to mention that cold benefits will not off-set all of the negative effects from heat and fo-cuses only on developed countries. Supporting studies are discussed, but citations are not given, so they cannot be identified. In all, this is an opinion piece containing selective information, but with the appearance and flow of a science-based article. Because it looks and sounds like science, it may influence some readers, espe-cially those who do not understand peer-reviewed literature.

CONSIDERATIONS FOR POLICYMAKERS In the human health area, policies that serve

to strengthen public health infrastructures are critically important. A comprehensive strategy to support public health internationally will be most effective in preparing for and responding to climate-related health impacts. Because health impacts are only just emerging, there is time to develop public health capacity. This is particu-larly important for developing nations, who are most vulnerable. Strong public health organiza-tions are actively involved in disease surveil-lance, sanitation programs, emergency prepared-ness and response, water and air pollution con-

trol, immunization programs, training of health professionals and community health education. These are the most important and cost-effective measures available, especially for developing countries. There is really no downside to public health investment: life expectancy improves, maternal, infant and child mortalities declines, quality of living improves, infectious disease rates decline along with many other benefits. Climate change adds further urgency to the need to develop basic preventive public health pro-grams. Developed countries also need policies that will rebuild existing public health programs. Inadequate public health response to extreme weather events such as hurricane Katrina in the US and the European heat wave demonstrate that these organizations were clearly not prepared. In addition, policies should promote research and development of technologies that will protect people. Improvements in housing, air condi-tioning, water purification and pest control will all be useful for responding to climate based health impacts. With anticipated water scarcity, it is important to have policies and a solid regu-latory framework for protection of water re-sources and water quality.

In the agricultural area, policies that pro-mote adaptive capabilities are essential. In order to maintain crop yields during climate change, farmers will need to respond rapidly with changes in plant variety, water and fertilization practices, and timing and location of crops. Such adjustments are most difficult for small farmers; policies should support farmers in vulnerable locations where food shortages are expected. Investment in agricultural research and training is important as is access to credit for capital im-provements. Financial incentives, subsidies, and crop insurance are other measures that may be part of an overall strategy to support adaptation in agriculture. Regulatory structures that protect and preserve land and water resources are also important.

Finally, policymakers must be aware of a basic inequity related to climate change; coun-tries that have generated the least greenhouse gas emissions will bear most of the negative impacts in health and agriculture. A strategy for com-pensation and support should be considered.

REFERENCES 1. Easterling, W.E., et al., Food, fibre and

forest products, in Climate Change 2007: Im-pacts, Adaptation and Vulnerability. Contribu-


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tion of Working Group II to the Fourth Assess-ment Report of the Intergovernmental Panel on Climate Change. 2007, Cambridge University Press: Cambridge. p. 273-313.

2. Rosenzweig, C. (2003) Climate Change and Agriculture: Mitigation and Adaptation. Senate Committee on Environment and Public Works Subcommittee on Clean Air, Climate Change, and Nuclear Safety, Available at: http://epw.senate.gov/108th/Rosenzweig_070803.htm

3. Lobell, D.B. and C.B. Field (2007) Global scale climate-crop yield relationships and the impacts of recent warming. Environ Res. Lett 2, DOI: 10.1088/1748-9326/2/1/014002

Abstract - Changes in the global production of major crops are important drivers of food prices, food security and land use deci-sions. Average global yields for these commodi-ties are determined by the performance of crops in millions of fields distributed across a range of management, soil and climate regimes. Despite the complexity of global food supply, here we show that simple measures of growing season temperatures and precipitation—spatial averages based on the locations of each crop—explain ~30% or more of year-to-year variations in global average yields for the world's six most widely grown crops. For wheat, maize and barley, there is a clearly negative response of global yields to increased temperatures. Based on these sensitivities and observed climate trends, we estimate that warming since 1981 has resulted in annual combined losses of these three crops rep-resenting roughly 40 Mt or $5 billion per year, as of 2002. While these impacts are small relative to the technological yield gains over the same period, the results demonstrate already occurring negative impacts of climate trends on crop yields at the global scale Changes in the global produc-tion of major crops are important drivers of food prices, food security and land use decisions. Av-erage global yields for these commodities are determined by the performance of crops in mil-lions of fields distributed across a range of man-agement, soil and climate regimes. Despite the complexity of global food supply, here we show that simple measures of growing season tempera-tures and precipitation—spatial averages based on the locations of each crop—explain ~30% or more of year-to-year variations in global average yields for the world's six most widely grown crops. For wheat, maize and barley, there is a clearly negative response of global yields to in-

creased temperatures. Based on these sensitivi-ties and observed climate trends, we estimate that warming since 1981 has resulted in annual combined losses of these three crops represent-ing roughly 40 Mt or $5 billion per year, as of 2002. While these impacts are small relative to the technological yield gains over the same pe-riod, the results demonstrate already occurring negative impacts of climate trends on crop yields at the global scale

4. Confalonieri, U., et al., Human health. Climate Change 2007: Impacts, Adaptation and Vulnerability. , in Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, et al., Editors. 2007, Cambridge University Press: Cambridge. p. 391-431.

5. Vandentorren, S., et al., Mortality in 13 French cities during the August 2003 heat wave. Am J Public Health, 2004. 94(9): p. 1518-20.

Abstract - We observed the daily trend in mortality rates during the 2003 heat wave in 13 of France's largest cities. Mortality data were collected from July 25 to September 15 each year from 1999 through 2003. The con-junction of a maximum temperature of 35 de-grees C and a minimum temperature of 20 de-grees C was exceptional in 7 cities. An excess mortality rate was observed in the 13 towns, with disparities from +4% (Lille) to +142% (Paris)

6. McGeehin, M.A. and M. Mirabelli, The potential impacts of climate variability and change on temperature-related morbidity and mortality in the United States. Environ Health Perspect, 2001. 109 Suppl 2: p. 185-9.

Abstract - Heat and heat waves are pro-jected to increase in severity and frequency with increasing global mean temperatures. Studies in urban areas show an association between in-creases in mortality and increases in heat, meas-ured by maximum or minimum temperature, heat index, and sometimes, other weather conditions. Health effects associated with exposure to ex-treme and prolonged heat appear to be related to environmental temperatures above those to which the population is accustomed. Models of weather-mortality relationships indicate that populations in northeastern and midwestern U.S. cities are likely to experience the greatest num-ber of illnesses and deaths in response to changes in summer temperature. Physiologic and behav-ioral adaptations may reduce morbidity and mor-tality. Within heat-sensitive regions, urban popu-


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lations are the most vulnerable to adverse heat-related health outcomes. The elderly, young children, the poor, and people who are bedridden or are on certain medications are at particular risk. Heat-related illnesses and deaths are largely preventable through behavioral adaptations, in-cluding the use of air conditioning and increased fluid intake. Overall death rates are higher in winter than in summer, and it is possible that milder winters could reduce deaths in winter months. However, the relationship between win-ter weather and mortality is difficult to interpret. Other adaptation measures include heat emer-gency plans, warning systems, and illness man-agement plans. Research is needed to identify critical weather parameters, the associations be-tween heat and nonfatal illnesses, the evaluation of implemented heat response plans, and the ef-fectiveness of urban design in reducing heat re-tention.

7. Patz, J.A. and R.S. Kovats, Hotspots in climate change and human health. BMJ, 2002. 325(7372): p. 1094-8.

8. Singer, S.F. and D.T. Avery, Health Fears About Global Warming are Unfounded, in Environment and Climate News. October 2007. p.10.

Observations and Predictions for the Northeast Kristin Cleveland

EXECUTIVE SUMMARY In recent years, New York and other

northeastern states (Pennsylvania, New Jersey, and the New England states) have been experiencing a variety of "… changes [that] are consistent with those expected to be caused by global warming," (UCS, 2000, p. ix). This paper identifies several of these current natural resource changes and highlights some potential future changes, focusing on changes that in turn will likely affect public health, alter economic traditions and regional identity, and have an impact on water resources in New England and in New York's Catskill Mountain region. In addition, the ways in which information about changes to the Northeast's natural resources is presented in the media and to public decision makers are analyzed in light of suggestions from several communication and public education scholars.

INTRODUCTION A 2007 Gallup Panel poll reveals that

while the majority of Americans are aware of and somewhat concerned about global warming, "only a small fraction of the public names global warming in unaided measures of perceived problems facing the nation or as a top government priority," (Saad). The Gallup Panel found this relatively low ranking of the climate change issue to be due at least in part to the fact that Americans perceive global warming effects to be distant, rather than likely to occur within the next few decades. Numerous other factors are also likely to contribute to this low ranking, including variations in political affiliations (Saad, 2007) and other interpretive communities (Leiserowitz, 2005), the manner in which climate change is portrayed in the media (Nisbet, 2007), and a sense that the potential effects of climate change will be geographically remote (Leiserowitz, 2005). Therefore, as a step towards learning how to improve communication of scientific information to better help Americans relate to the issues of climate change, this paper will focus on climate change impacts in the northeastern United States, examining two scientific studies concerning water resources in New York and New England and two sections of

a Union of Concerned Scientists report related to the Northeast. In addition, these reports and articles will be discussed in terms of communication theory's "framing" and the "two-step flow of popularization" model (Nisbet & Mooney, 2007; Nisbet, 2007).

STATE OF THE SCIENCE In 2007 the Northeast Climate Impacts

Assessment (NECIA) team reported on current and predicted impacts of climate change for the northeastern region of the United States (UCS NY, 2007; UCS Summary, 2007). Some changes already observed are as follows:

- More frequent days with temperatures above 90ºF

- A longer growing season

- Less winter precipitation falling as snow and more as rain

- Reduced snowpack and increased snow density

- Earlier breakup of winter ice on lakes and rivers

- Earlier spring snowmelt resulting in earlier peak river flows

- Rising sea-surface temperatures and sea levels (UCS Summary, 2007, ix)

The NECIA reports also identify changes predicted to occur to the region's natural resources by mid- or late-century as a result of changes in climate regimes, based on lower- and higher-emissions scenarios. These changes are likely to alter, and in some cases threaten, the region's social identity, its traditional economic base, and the health of the region and its inhabitants.

Noting, "[t]he character and economy of the Northeast have been profoundly shaped over the centuries by its varied and changeable climate," the NECIA report observes that changes to the region's climate are likely to alter both this character, which is closely tied to regional identity, and to alter the economy that is based upon features of that character (USC Summary, 2007, ix). For instance, based on the higher-emissions scenario, reductions of snowfall and shortening of winter temperatures will most likely eliminate downhill ski operations from all parts of the region except western Maine (x). Even the lower-emissions scenario will "shorten the average ski and

CLEVELAND NORTHEAST PERSPECTIVES FOR 797 CLIMATE CHANGE EFFECTS ON NATURAL RESOURCES FALL 2007

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snowboard seasons, increase snowmaking requirements, and drive up operating costs" (xi). In New York State, recent decades have seen a rise in average annual temperatures of over 1.5ºF, with winter average temperatures rising 4ºF (UCS NY, 2007, 1). Predictions for additional winter temperature increases by the end of this century are 8ºF-12ºF under the higher emissions scenario, and 4ºF-6ºF under the lower scenario (1-2). Such increases would lead to more of New York's winter precipitation falling as rain rather than snow, and more winter precipitation overall (approximately 20-30% increase under the lower scenario, and slightly more under the higher scenario) (2). This will reduce winter ski and snowmobile seasons in New York's Adirondack Mountain region. Skiing, snowmobiling, and other snow-related tourism is an important component of the Adirondack region's winter economy (5).

Another character-economy alteration relates to New England fall-foliage tourism, as "climate conditions suitable for maple/beech/birch forests would shift" either out of the southern parts of the region, if future greenhouse gas emissions were closer to the lower-emissions scenario, or would move even further northward, if the future emissions are closer to the higher-emissions scenario (USC Summary, 2007, x-xi). The shift from the dramatic palette of maple/beech/birch's reds, oranges and yellows to the more monotone yellows and browns of the likely successors, the oak/hickory forests, may reduce the numbers of people traveling to the Northeast for scenic tourism, and will certainly alter the identity of the region.

Regional character and economics will also be affected by changes to marine and aquatic habitat, which provides the conditions for the current fishing industry. The NECIA team reports that under the higher-emissions scenario, the predicted "increasing water temperatures may make the storied fishing grounds of Georges Bank unfavorable for cod" (UCS Summary, 2007, x). Even under the lower-emissions scenario, Georges Bank will be less inhabitable for young cod, and under both scenarios, the Long Island lobster industry will also decline to the point where it will likely be gone by mid-century (xi; UCS NY, 2007, 5). In rivers throughout New England, future climate changes could potentially lead to reduced river flows, affecting habitat for the endangered

Atlantic Salmon and other valued northern species (Huntington, 2003).

In addition to potential changes to the Northeast's traditional economy and regional identity, climate change may also be detrimental to residents' health. Under either emissions scenario, conditions promoting the growth of mosquitoes and ticks may lead to increases in the spread of diseases carried by these animals. Also, "[t]he number of days over 90ºF is expected to triple in many of the region's cities, including Boston, Buffalo, and Concord, NH" (xi). Under the higher emissions scenario, many Northeast cities could have at least 14 days over 100ºF during the average late-century summer (x). Summer temperatures in New York City are likely to exceed 100ºF for over 25 days by the end of the century under the higher scenario (UCS NY, 2007, 1-2). Such high temperatures in regions where people are unaccustomed to these extremes can increase the number of heat-related deaths, especially to fragile populations such as the poor, the elderly, and the sick (McGeehin & Mirabelli, 2001, p. 186). Also, by late-century, ground-level ozone pollution, which contributes to respiratory ailments, is expected to rise by 50% under the lower-emissions scenario, and by 200% under the higher-emissions scenario (UCS Summary, 2007, x-xi). Finally, predicted sea level rises of at least 1 – 2 feet (lower scenario) and increasing frequencies of severe flooding for coastal cities (either scenario) will likely cause both health and economic problems, at least until communities adapt to such changes (xi).

Changing temperature patterns and precipitation regimes in the Northeast may also affect regional drinking water supplies (Burns, 2006) and water availability for agriculture and forests, as well as for aquatic species (Huntington, 2003). In New York's Catskill region, such changes may alter potential evapotranspiration rates so that, even with predicted increases in regional runoff amounts, the net yield to New York City's water supply will be reduced (Burns, 2006). New York farms may have to spend more money on irrigation, as short-term droughts are likely to occur more often (UCS NY, 2007, 5). Overall average runoff rates in New England could drop, although numerous factors affecting these estimates, "…the site-specific combination of precipitation, vegetation, soils, geology, aquifer characteristics, and microclimate," make it difficult to predict specific impacts to particular river basins (Huntington, 2003, 199).


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PERSPECTIVES IN MEDIA AND PUBLIC POLICY

Matthew Nisbet, a specialist in communication of scientific information, observes that the growing number and accessibility of choices in modern media make readers increasingly likely to select media content based on interest preferences and to select media sources based on political, religious, or other ideologies. This "fragmented media system" can lead to "…selective acceptance of like-minded arguments and opinions," making it increasingly difficult for readers to attend to a diversity of information (Nisbet, 2007). Nisbet recommends three techniques to manage this information situation in order to get scientific information to the public. First, explaining that, "…citizens do not use the news media as scientists assume," Nisbet and Mooney (2007) argue, "Without misrepresenting scientific information on highly contested issues, scientists must learn to actively 'frame' information to make it relevant to different audiences."

Framing is a way of making an issue personally relevant, defining it through "[organizing] central ideas [and]… giving some aspects greater emphasis [in order to] …allow citizens to rapidly identify why an issue matters, who might be responsible, and what should be done" (Nisbet & Mooney, 2007). Noting the prevalence of "science-intensive" messages provided by researchers, Nisbet and Mooney explain that "much of the public likely tunes out these technical messages" and instead attend to messages that are framed in ways that they can connect to issues they better understand, such as "economic development" or "social progress" (2007). In addition, emphasizing only the technical details of a study opens up these details to be interpreted by politicians, business and industry leaders, and others who have a particular agenda. Some of the frames that have been applied to the climate change issue are "unfair economic burden" and "scientific uncertainty," which have been countered by the "catastrophe" frame of drowning polar bears and destructive hurricanes, which in turn "have evoked charges of 'alarmism' and further battles" (Nisbet & Mooney, 2007). Nisbet and Mooney explain that providing technical information along with a frame such as "public accountability" can help media readers to understand a perspective that suggests their role and the role of government in dealing with the implications of that technical information. Nisbet

also recommends branching out from the news to other genres of popular culture, such as the entertainment media and "celebrity culture." Politicians are learning this trick, recognizing that they can get a wider audience on "The Daily Show" than on the "MacNeil/Lehrer NewsHour." Finally, Nisbet explains the "importance of 'opinion-leaders' in … [diffusing]… messages within local communities." Nisbet recommends:

When "surges" in communication and public attention are needed – such as surrounding the release of a future section of the IPCC report or a major study by the National Academies of Science – opinion leaders can be activated with talking points to share in conversations with friends and co-workers, in emails, in blog posts, or letters to the editor. These "scientific citizens" would not formally speak on behalf of or represent the scientific organization, but instead their effectiveness would stem from their ability as co-workers and friends to communicate climate change in a way that makes it personally and politically relevant. (Nisbet, 2007)

Some additional alternative methods of communicating information about climate change include holding community workshops and other forms of public information sessions (Taylor, Gray, & Schiefer, 2006). Such techniques can be particularly effective in helping community residents understand and adapt to the changes that will occur in their local environment.

CONSIDERATIONS FOR POLICYMAKERS For policymakers to devise plans to, at a

minimum, manage the effects of climate change for their constituencies, and perhaps to reduce some of the potential harmful effects, they need to have as much information as is practical for them to work with, and they need to understand the relevance of various levels of uncertainty and of variations between studies. The New England Regional Assessment addresses this issue of uncertainty and predictive model variation by recommending "an assessment approach … [that] allows individual regions or sectors to consider 'what if' cases that reflect educated guesses based on the nature and importance of specific regional and sector vulnerabilities." Huntington reflects this advice in his caution to readers that, "The value of the empirical relationships [examined in this study] is in understanding likely average runoff response for a region rather than prediction for a specific river basin" (2003,199).


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Policymakers must recognize the value of "educated guesses," and understandings of general regional impacts rather than specific certainties, considering the danger of ignoring these likelihoods while awaiting certainties and specifics. For this to happen, scientists must be willing to explain such values to policymakers.

REFERENCES Burns, D.A., Klaus, J., & McHale, M.R.

(2007). Recent climate trends and implications for water resources in the Catskill Mountain region, New York, USA. Journal of Hydrology, 336(1-2), 155-170.

Abstract: Climate scientists have concluded that the earth's surface air temperature warmed by 0.6ºC during the 20th century, and that warming induced by increasing concentrations of greenhouse gases is most likely to continue in the 21st century, accompanied by changes in the hydrologic cycle. Climate change has important implications in the Catskill region of southeastern New York State, because the region is a source of water supply for New York City. We used the non-parametric Mann-Kendall test to evaluate annual, monthly, and multi-month trends in air temperature, precipitation amount, stream runoff, and potential evapotranspiration (PET) in the region during 1952-2005 based on data from 9 temperature sites, 12 precipitation sites, and 8 stream gages. A general pattern of warming temperatures and increased precipitation, runoff, and PET is evident in the region. Regional annual mean air temperature increased significantly by 0.6ºC per 50 years during the period; the greatest increases and largest number of significant upward trends were in daily minimum air temperature. Daily maximum air temperature showed the greatest increase during May through September. Regional mean precipitation increased significantly by 136 mm per 50 years, nearly double that of the regional mean increase in runoff, which was not significant. Regional mean PET increased significantly by 19 mm per 50 years, about one-seventh that of the increase in precipitation amount, and broadly consistent with increased runoff during 1952-2005, despite the lack of significance in the mean regional runoff trend. Peak snowmelt as approximated by the winter-spring center of volume of stream runoff generally shifted from early April at the beginning of the record to late March at the end of the record, consistent with a decreasing trend in April runoff and an increasing trend in

maximum March air temperature. This change indicates an increased supply of water to reservoirs earlier in the year. Additionally, the supply of water to reservoirs at the beginning of winter is greater as indicated by the timing of the greatest increases in precipitation and runoff – both occurred during the summer and fall. The future balance between changes in air temperature and changes in the timing and amount of precipitation in the region will have important implications for the available water supply in the region.

Huntington, T.G. (2003). Climate warming could reduce runoff significantly in New England, USA. Agricultural and Forest Meteorology, 117(3-4), 193-201.

Abstract: The relation between mean annual temperature (MAT), mean annual precipitation (MAP) and evapotranspiration (ET) for 38 forested watersheds was determined to evaluate the potential increase in ET and resulting decrease in stream runoff that could occur following climate change and lengthening of the growing season. The watersheds were all predominantly forested and were located in eastern North America, along a gradient in MAP from 3.4ºC in New Brunswick, CA to 19.8ºC in northern Florida. Regression analysis for MAT versus ET indicated that along this gradient ET increased at a rate of 2.85 cmº-1 increase in MAT (±0.96 cmºC-1, 95% confidence limits). General circulation models (CGM) using current mid-range emission scenarios project global MAT to increase by about 3ºC during the 21st century. The inferred, potential, reduction in annual runoff associated with a 3ºC increase in MAT for a representative small coastal basin and an inland mountainous basin in New England would be 11-13%. Percentage reductions in average daily runoff could be substantially larger during the months of lowest flows (July – September). The largest absolute reductions in runoff are likely to be during April and May with smaller reduction in the fall. This seasonal pattern of reduction in runoff is consistent with lengthening of the growing season and an increase in the ratio of rain to snow. Future increases in water use efficiency (WUE), precipitation, and cloudiness could mitigate part or all of this reduction in runoff but the full effects of changing climate on WUE remain quite uncertain as do future trends in precipitation and cloudiness.


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Leiserowitz, A.A. (2005). American risk perceptions: is climate change dangerous? Risk Analysis 25(6), 1433-1442.

McGeehin, M.A. & Mirabelli, M. (2001). The potential impacts of climate variability and change on temperature-related morbidity and mortality in the United States. Environmental Health Perspectives 109(2), 185-189.

New England Regional Assessment (1999). NERA Model White Paper. Retrieved from www.necci.sr.unh.edu/reports.html on November 12, 2007.

Nisbet, M. (2007). A "two-step flow of popularization" for climate change: recruiting opinion leaders for science. Retrieved October 24, 2004 from the Community for Skeptical Inquiry website: http://www.csicop.org/scienceandmedia/climate.

Saad, L. (2007, March). To Americans, the risks of global warming are not imminent. Retrieved 11/12/07 from www.gallup.com/poll/26842/Americans-Risks-Global-Warming

Taylor, M.E., Gray, P.A., & Schiefer, K. (2006). Helping Canadians adapt to climate change in the Great Lakes coastal zone. The Great Lakes Geographer, 13(1), 14-25.

Abstract: As global warming increases, Great Lakes coastal communities will be subjected to significant climate changes driven by increasing temperature, changing precipitation and wind patterns, and a potential increase in the frequency of severe events such as windstorms and ice storms. Climate change will impact all life in every ecosystem, and people who live and work in these systems will need to adapt in a variety of ways. In response, a number of agencies and organizations have partnered to assist Great Lakes coastal communities in their efforts to identify and assess adaptation options. To date, workshops have been completed in Belleville (Lake Ontario) and Parry Sound (Lake Huron). This paper reviews some of the known and potential impacts that will result in our near Presqu'ile Provincial Park, Lake Ontario and in Sturgeon Bay, Lake Huron, and proposes a checklist of actions that could provide the basis for an adaptation protocol.

Union of Concerned Scientists (2007). Northeast Climate Impacts Assessment Executive Summary. Retrieved September, 2007 from www.climatechoices.org.

A survey of climate change mitigation technologies in Pacala

and Socolow (2004) Tony Eallonardo

EXECUTIVE SUMMARY It is now widely known and well accepted

that anthropogenic green house gas emissions are modifying the global climate in a syndrome of ways described as The Greenhouse Effect or Climate Change. There is also broad based agreement that unless business-as-usual activities are radically changed over the next decades, significant alteration of the biosphere is likely (IPCC 2007a,b). The risk of inaction on climate change, which briefly stated amounts to increased stress to hundred of millions of humans (IPCC 2007b), outweighs the cost of action. The IPCC (2007c) states that the cost of stabilizing atmospheric CO2 at approximately double pre-industrial levels will range from 0.2-2.5% of global GDP. Under modeling scenarios where mitigation improves market efficiency, GDP gains are predicted (IPCC 2007c). Pacala and Socolow (2004) state that humanity has the technological know-how to limit CO2 emissions to approximately a doubling of pre-industrial levels over the next 50 years and they provide a list of potential mitigation solutions. This paper explores technologies itemized in Pacala and Socolow (2004), namely, carbon capture and storage, hydrogen fuels, biomass derived ethanol, and conservation tillage.

INTRODUCTION

Mitigation in the context of global environmental issues

Greenhouse gas (aka Carbon) mitigation is any activity that reduces green house gas emissions to the atmosphere. While a variety of carbon mitigation technologies are currently available and will be discussed further below, it is worth noting that ultimately most (if not all) environmental issues are driven by the increasing human population and that we are met at the outset with the following irony:

Since increasing human population is the ultimate driver of environmental issues, there is a need to reduce the global population growth rate. Human population growth rate is negatively correlated with GDP (the so-called ‘demographic transition,’ Goldstein 1999). Yet production of

GDP is positively correlated with fossil fuel use (Cleveland et al. 1984). Assuming that the relationship exemplified in the demographic transition is real, then the global standard of living (e.g. GWP, gross world product) must be increased in order to stabilize our environmental impacts (not to mention other ethical and sovereignty issues). Yet bringing the global standard of living up to levels enjoyed by developed nations would lead to massive increases in green house gas emissions. Therefore, another way of considering carbon mitigation is the decoupling of wealth production from fossil fuel use. Pacala and Socolow (2004) provide a framework for doing just that.

Pacala and Socolow (2004) state that humanity has the technological know-how to limit CO2 emissions to approximately a doubling of pre-industrial levels, but what needs to happen is a scaling up of a suite of these technologies. Stabilizing atmospheric concentrations of CO2 near 500 ppm requires that global emissions be held at about 7 Pg C/yr, while business as usual will put us at about 14 Pg C/yr emissions by 2054. The authors envision a “stabilization triangle” comprised of the difference between these two emission rates over a 50 year time span. They divide the stabilization triangle into seven potential mitigation solutions (e.g. wedges) that each represents “an activity that reduces emissions to the atmosphere that starts at zero today and increases linearly until it accounts for 1 Pg C/yr of reduced carbon emissions in 50 years.” Each wedge totals 25 Pg C to be mitigated over 50 years. Citing the fact that gross world production has increased by 3% while energy consumption has increased by only 2%, the authors indicate that the global economy has been on a trajectory of decarbonization since the time of Cleveland et al. (1984). This decreasing energy intensity (emissions/$GDP) has led to avoiding the need for three additional wedges.

The authors present what they call is a non-exhaustive list of 15 options for the seven wedges:

1) Increasing transportation fuel economy from 30 to 60 mpg

2) Reduce fuel use by halving the miles driven

3) Reduce building emissions by 20%

4) Increase coal plant efficiency from today’s 32% to 60%

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5) Replace coal with gas by increasing gas power production by 300%

6) Capture CO2 at power plant: apply carbon capture and storage (CCS) at 800 GW of coal or 1600 GW of natural gas

7) Capture CO2 at hydrogen plant: apply CCS to 250 Mt H2/yr from coal or 500 Mt H2/yr from natural gas

8) Capture CO2 at a coal to synfuels plant: apply CCS to the production of 30 million barrels/day of synfuels production

9) Increase nuclear capacity by 100%

10) Replace coal with wind: increase wind capacity by 4900%

11) Replace coal with photovoltaics (PV): increase PV by 69900%

12) Replace hybrid cars with wind derived H2 cars: increase wind capacity by 9900%

13) Convert 1/6th of earth’s cropland to biofuel production

14) Stop tropical deforestation and double the current rate of afforestation projects

15) Apply conservation tillage to all cropland

I will further explore key technologies associated with these potential wedges: CCS, hydrogen fuel, biofuels, and conservation tillage. These technologies were chosen for further study due to their broad applicability and/or potentially controversial issues. While Pacala and Socolow (2004) do not explicitly discuss interactions between wedges, I will aim to reveal potential synergies/controversies in the ‘State of the Science’ section.


Carbon capture and storage Carbon capture and storage (CCS) is the

collection, purification, liquification and placement of carbon dioxide emissions in geologic reservoirs or the oceans. Significant questions remain at all steps in this process. Since the heavy ecological toll of increasing oceanic carbon concentrations is well known, I will not consider the oceans as a potential reservoir. Given the high relative abundance and inexpensiveness of coal, Rau and Caldiera (2007) state that two coal-fired power plants are to be built every two weeks over the next 25 years. Therefore, CCS will likely be a central

component of wedge portfolio. For one wedge’s worth of CCS, approximately 120 million barrels of liquid CO2 would need to be buried every day (Shepard and Socolow 2007). While there is evidence that there is space for the several hundred years of CO2 emissions (Shepard and Socolow 2007, Damen et al. 2006), at least several hundred CCS systems would have to come on line in the next 50 years to stabilize emissions (IPCC 2005).

There are two relatively well-known methods by which carbon capture can occur: the so-called pulverized coal (PC) process where the carbon is removed post combustion and the integrated gasification combined cycle (IGCC) where the carbon is removed after the coal is gasified but before it is burned. In most current scenarios, the PC process uses the solvent monoenthanolamine (MEA) to capture CO2 in the gas, however significant heating is required to remove the captured CO2 from the MEA for compression and storage. Due to this inefficiency, many other carbon collection methods ranging from nano-technology biological catalysts are being tested (Kintisch 2007a), but in the mean time, IGCC process appears to be the favored technology (Kintisch 2007b).

Risks and management implications associated with transport, injection and storage of CO2 are as follows (Damen et al. 2006):

1) The main risk associated with transporting and injecting CO2 are leaks in transport and well head failures. However, given the positive track-record of existing CO2 pumping operations for oil recovery, the risk is quite low.

2) Risks in geological storage include: leaks, earthquakes and other ground movements, and damage to freshwater aquifers. Model results suggest that CO2 escaping from failed geological reservoirs located 700-1000 m below the earth’s surface would take at least 5,500 and possibly up to 500,000 yr to surface. While “cap rock” failures may occur in geological reservoirs, number of secondary processes (e.g. CO2 capture in liquids, fossil fuels, heavy soils). The strongest consideration for CCS activities should be given to sites with the greatest number and extent of these secondary capture mechanisms. While CO2 can damage the integrity of clay shales, the authors site other studies that have shown that mineral precipitation may decrease


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CO2 permeability, and variety of seismic issues can be avoided by keeping storage pressure below the geostatic pressure.

3) Potential “point sources” for CO2 leakage are abandoned wells that have been decommissioned improperly or that have deteriorated. Abandoned wells represent one of the more significant CCS risks, however at least this risk can be managed through knowing the location and conditions of all decommissioned wells on site, and site selection should factor out areas with excessive wells.

4) Considerable uncertainly remains in regards to polluting fresh water aquifers with brine displaced from CCS operations.

A potential natural analog for a worst case scenario was in 1986 when the hypolimneon of Lake Nyos, Cameroon became supersaturated with volcanic CO2 and rapidly overturned. This event released CO2 that settled into a nearby village and killed approximately 1700 people. Loss of human life on this scale would likely not occur from a failure from geological reservoir unless the CO2 leaked into a surface water body. Therefore site selection committees should also factor out any sites with surface water bodies that could receive gas leakage. The Lake Nyos example shows that type of the type of the release (in terms of rapidity and topography (In the Lake Nyos example the gas cloud was able to remain intact and settle in the village)) is likely more important than the volume of release when considering short term human health impacts (Damen et al. 2006).

Hydrogen fuel: attractive potential with a CCS requirement and logistical issues

Since the transport sector is responsible for a significant amount of the increase in world oil demand over the last 30 years (Difiglio and Gielen 2007), zero-carbon fuels could be an important mitigation tool. While hydrogen has well-known advantages such as zero carbon emissions and energy independence, it also has many current disadvantages. For example, low cost hydrogen production, storage and conversion technologies are currently unavailable (Dixon 2007). The most practical production of hydrogen is from fossil fuel sources where the conversion efficiency is less than one, and which would necessitate the development of CCS (Difiglio and Gielen 2007).

Outstanding issues needing resolution are associated with the following topics:

1) Distribution: At room temperature, hydrogen occupies 2000-3000 times the space per energy unit than gasoline does (Dixon 2007); therefore besides the energy needed to create hydrogen fuel, energy is needed to liquefy it.

2) Technology life span: The Proton Exchange Membrane (PEM) is largely the preferred fuel cell type, but it is expensive and needs replacement every 31,000 miles (Difiglio and Gielen 2007).

3) Overall cost: The life-cycle analysis of Difiglio and Gielen (2007) suggests that significant progress must be made in the production, transport and use of hydrogen fuel to reduce what are currently prohibitive costs.

Difiglio and Gielen (2007) report that the relative mitigation cost of utilizing fuel cell vehicles decreases as total driving time increases, and that passenger cars are, surprisingly, not used enough to realize mitigation benefits in terms of dollars. They suggest initiating hydrogen technologies in trucks, buses, trains, and airplanes—end uses that have a much greater annual use.

An alternative view is provided by Lovins and Cramer (2004). They have designed a fuel cell vehicle that reduces required propulsive energy by approximately 66%, which, in their view, moots any argument on the expense of fuel cells because the required engines and tanks can be smaller and more economical.

Biomass ethanol production as an alternative fuel option

One wedge worth of carbon may be accounted by the use of biofuels however bioenergy cropping systems require fossil fuel inputs, emit non-carbon greenhouse gases, and entail important ethical questions. Adler et al. (2007) provide a life cycle assessment of bioenergy cropping systems. The authors considered potential biofuel crops for North America: corn, soy, alfalfa, reed canarygrass, alfalfa, and hybrid poplar. They found that combined corn grain and stover harvest had the highest ethanol yield (8 MJ/m2/yr), with switchgrass and hybrid poplar tied for second at (7-8 MJ/m2/yr). When crop inputs and greenhouse gas emissions were considered,


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switchgrass and hybrid poplar displace the greatest amount of fossil fuels (150 to 160 g CO2 equivalents/m2/yr). Besides increased machinery emissions, traditional cropping systems (e.g. corn, soy) have 100 to 200% greater N2O emissions and 50% greater CO2 emissions from the soil than switchgrass and hybrid poplar systems. Across all cropping systems the greatest amount of CO2 emissions was associated with harvesting—up to 80-90% for switchgrass and hybrid poplar. Therefore, small increases in harvesting efficiency could have relatively large effects on the overall system carbon balance.

One wedge of biofuels is 250 x 106 hectares or about 1/6th of total cropland (Pacala and Socolow 2004). One is left wondering how a 40-50% bigger global population (U.S. Census Bureau 2006) will be fed on 16% less land by 2050.

Righelato and Spracklen (2007) collated a variety of life cycle analyses to show that, “In all cases, forestation of an equivalent area would sequester two to nine times more carbon over a 30-year period than emissions avoided by the use of biofuel.” They suggest that forest restoration should be favored over biofuel production for this reason. While this suggestion makes sense for lower latitude areas, it has been shown that reforestation in temperate zones has a net radiative forcing due to the relatively low albedo of forests (Myre and Myre 2003). One must also consider that forests periodically burn. Therefore the most logical solution may be to utilize land area for biofuel production where forest radiative forcing would outweigh carbon sequestration effects or where forests fires are relatively frequent; and during biofuel production utilize agricultural RMPs (described next) to facilitate carbon storage in the soil.

Recommended management practices (aka Conservation Tillage)

While approximately 300 Pg of C have been emitted by fossil fuel combustion over the last century an additional 150 GT has been from agricultural soil emissions (Rosenzweig and Tubiello 2007). The causes of agricultural CO2 emissions are well known: soil drainage, plowing, removal of crop residue, fire, inorganic amendments (e.g. lime), and erosion (Lal 2007). Agronomists have developed recommended management practices (RMPs) that increase soil quality and in doing so reduce net carbon emissions and increase crop yield. RMPs are: no-till farming, incorporation of forages into the

rotation cycle, and use of manure/biosolids for soil amendment instead of inorganic fertilizers. RMPs also reduce climate change stresses on crops by increasing soil quality.

Recommended management practices result in increased formation of stable soil aggregates, increased soil humification, increased eluviation of soil C to subsoils, and increased leaching of carbonates to groundwater (which is also considered a form of C sequestration (Raymond and Cole 2003)). The greatest C sequestration potential is in relatively cool and humid environments on relatively heavy textured soils that also have sufficient levels of humus building blocks (e.g. N, P, and S). On the other hand, structurally reduced soils (e.g. those dominated by kaolinite clays) that are nutrient-poor and in warm regions have the greatest capacity to volatilize carbon. The global mean rate of soil C sequestration for conversion of conventional to no-till cropping is 400-600 kg/ha/yr which equates to a 0.6 to 1.2 Pg C/yr across all crop land (Rosenzweig and Tubiello 2007). This sequestration rate is consistent with “one wedge” of carbon or 1 Pg C sequestered per year in Pacala and Socolow (2004).


Time magazine recently published a special section: Global Warming (Knauer 2007). The magazine is packed full of striking, highly effective images related to the sources, environmental impacts and mitigation solutions of climate change. There is a consistent theme across the magazine’s articles that climate change’s sources are anthropogenic, the environmental impacts are and have been coming into fruition, but that mitigation solutions are both practical, economical, and available to both average citizens and industry. The magazine features “FAQs” sections for the climate change neophytes and puts answers to complex climate questions in understandable, informative terms.

In regards to mitigation, the magazine is packed with examples of mitigation solutions across all sectors of the economy; incorporated with this effort are a series of profiles on progressive individuals, e.g. “Pioneers of Alternative Energy,” which makes real the sometimes illusive vision of how the world can adapt to and mitigate climate change. On the other hand, the magazine touts corn ethanol as a


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prospective mitigation solution, but the scientific evidence (e.g. Adler et al. 2007) does not support this position. The magazine lists 51 actions individuals can take and communicates the effectiveness and cost of each action in simple diagrammatic terms. Lacking from this magazine is more emphasis on forcing politicians to take up the climate change issue in large measure. Voting for leaders who will be active on climate issues is an important mitigation activity that individuals can perform.

CONSIDERATIONS FOR POLICYMAKERS The risk of inaction on climate change,

which briefly stated amounts to increased stress to hundred of millions of humans (IPCC 2007b) outweighs the cost of action. The IPCC (2007c) states that the cost of stabilizing atmospheric CO2 at approximately double pre-industrial levels will range from 0.2-2.5% of global GDP. Upfront costs of implementing infrastructural changes will be almost completely recouped over long term increases in efficiency. When economic models assume that current energy market conditions are non-optimal (e.g. that subsidies obscure real competitive interactions between commodities), GDP gains are predicted if models assume that mitigation solutions improve market efficiencies (IPCC 2007c). In other words, there is a good overall chance for money to be made on carbon mitigation if competitive markets are allowed to determine which mitigation technologies are best and that they result in increases in energy efficiency and productivity.

The biggest economic potentials exist in the building sector, followed by energy supply and tied for third are agriculture and industry (IPCC 2007c). In the building sector, 30% of projected carbon emissions can be avoided through simple, money-saving energy efficiency options e.g. more efficient lighting, heating and cooling systems; improved insulation; solar heating). The potential for profitable solutions for people, businesses and governments increases as oil price increases, and a multi-greenhouse gas mitigation approach tends to make conversion less costly (IPCC 2007c). In other words, focus on the low hanging fruit.

Hydrogen energy—where government intervention may be useful

Overall, the combined risks associated with production, distribution and end-use of hydrogen has lead to the so-called “chicken or the egg”

problem in which potential providers will not invest in hydrogen if potential consumers can not be identified and consumers will not purchase a fuel cell vehicle if the fuel is not reliable and widely available (Difiglio and Gielen 2007). Overcoming “chicken or the egg” type problems will be an ideal opportunity for government intervention. Government spurred hydrogen use for mass transit/shipping would establish the infrastructural framework that consumers expect. Difiglio and Gielen (2007) report that the relative mitigation cost of utilizing fuel cell vehicles decreases as total driving time increases, therefore the most effective initial use of hydrogen technologies would be in mass transit/shipping applications.

Carbon certification systems One of the key issues arising from the

biofuels, conservation tillage, and CCS components of Pacala and Socolow (2004) is that a certification system for carbon sequestration is needed to set standards, assess results, and provide an adaptive framework if standards are not being met. For example, three issues in regards to soil C sequestration are that:

1) Soil C eventually saturates

2) Increasing global temperatures may reduce soil carbon storage

3) As agriculture moves north in adapting to climate change, additional carbon may be volatilized from previously untilled grounds

Policy makers should also recognize that soil C sequestration is not immediate and occurs over a roughly 40 year window. However, that lag may be balanced by the fact that RMPs generally mean less energy intensive approaches which will also reduce C emissions through reduced machinery and labor time (Rosenzweig and Tubiello 2007).

CITED REFERENCES WITH ABSTRACTS

Adler, P.R., S.J. Del Grosso, W.J. Parton. 2007. Life-cycle assessment of net greenhouse-gas flux for bioenergy cropping systems. Ecological Applications 17: 675-691.

Abstract: Bioenergy cropping systems could help offset greenhouse gas emissions, but quantifying that offset is complex. Bioenergy crops offset carbon dioxide emissions by converting atmospheric CO2 to organic C in crop biomass


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and soil, but they also emit nitrous oxide and vary in their effects on soil oxidation of methane. Growing the crops requires energy (e.g., to operate farm machinery, produce inputs such as fertilizer) and so does converting the harvested product to usable fuels (feedstock conversion efficiency). The objective of this study was to quantify all these factors to determine the net effect of several bioenergy cropping systems on greenhouse-gas (GHG) emissions. We used the DAYCENT biogeochemistry model to assess soil GHG fluxes and biomass yields for corn, soybean, alfalfa, hybrid poplar, reed canarygrass, and switchgrass as bioenergy crops in Pennsylvania, USA. DAYCENT results were combined with estimates of fossil fuels used to provide farm inputs and operate agricultural machinery and fossil-fuel offsets from biomass yields to calculate net GHG fluxes for each cropping system considered. Displaced fossil fuel was the largest GHG sink, followed by soil carbon sequestration. N2O emissions were the largest GHG source. All cropping systems considered provided net GHG sinks, even when soil C was assumed to reach a new steady state and C sequestration in soil was not counted. Hybrid poplar and switchgrass provided the largest net GHG sinks, .200 g CO2e-C/m2/yr1 for biomass conversion to ethanol, and .400 g CO2e-C/m2/yr1 for biomass gasification for electricity generation. Compared with the life cycle of gasoline and diesel, ethanol and biodiesel from corn rotations reduced GHG emissions by 40%, reed canarygrass by ;85%, and switchgrass and hybrid poplar by 115%.

Cleveland, C.J., R. Costanza, C.A.S. Hall, and R. Kaufman. 1984. Energy and the U.S. economy: a biophysical perspective. Science 225: 890-897.

Damen, K., A. Faaij, and W. Turkenburg. 2006. Health, safety and environmental risks of underground CO2 storage—overview of mechanisms and current knowledge. Climate Change 74: 289-318.

Abstract: CO2 capture and storage (CCS) in geological reservoirs may be part of a strategy to reduce global anthropogenic CO2 emissions. Insight in the risks associated with underground CO2 storage is needed to ensure that it can be applied as safe and effective greenhouse mitigation option. This paper aims to give an overview of the current (gaps in) knowledge of risks associated with underground CO2 storage and research areas that need to be addressed to

increase our understanding in those risks. Risks caused by a failure in surface installations are understood and can be minimised by risk abatement technologies and safety measures. The risks caused by underground CO2 storage (CO2 and CH4 leakage, seismicity, ground movement and brine displacement) are less well understood. Main R&D objective is to determine the processes controlling leakage through/along wells, faults and fractures to assess leakage rates and to assess the effects on (marine) ecosystems. Although R&D activities currently being undertaken are working on these issues, it is expected that further demonstration projects and experimental work is needed to provide data for more thorough risk assessment.

Difiglio, C., and D. Gielen. 2007. Hydrogen and transportation: alternative scenarios. Mitigation and Adaptation Strategies for Global Change 12: 387-405.

Abstract: If hydrogen (H2) is to significantly reduce greenhouse gas emissions and oil use, it needs to displace conventional transport fuels and be produced in ways that do not generate significant greenhouse gas emissions. This paper analyses alternative ways H2 can be produced, transported and used to achieve these goals. Several H2 scenarios are developed and compared to each other. In addition, other technology options to achieve these goals are analyzed. A full fuel cycle analysis is used to compare the energy use and carbon (C) emissions of different fuel and vehicle strategies. Fuel and vehicle costs are presented as well as cost-effectiveness estimates. Lowest hydrogen fuel costs are achieved using fossil fuels with carbon capture and storage. The fuel supply cost for a H2 fuel cell car would be close to those for an advanced gasoline car, once a large-scale supply system has been established. Biomass, wind, nuclear and solar sources are estimated to be considerably more expensive. However fuel cells cost much more than combustion engines. When vehicle costs are considered, climate policy incentives are probably insufficient to achieve a switch to H2. The carbon dioxide (CO2) mitigation cost would amount to several hundred US$ per ton of CO2. Energy security goals and the eventual need to stabilize greenhouse gas concentrations could be sufficient. Nonetheless, substantial development of related technologies, such as C capture and storage will be needed. Significant H2 use will also require substantial market intervention during a transition period when there are too few


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vehicles to motivate widely available H2 refueling.

Dixon, R.K. 2007. Advancing towards a hydrogen energy economy: status, opportunities and barriers. Mitigation and Adaptation Strategies for Global Change 12: 325-341.

Goldstein, J. 1999. International relations. Longman: New York, NY. 672 pp.

IPCC. 2005. Carbon dioxide storage and capture. Bert Metz, Ogunlade Davidson,

Heleen de Coninck, Manuela Loos and Leo Meyer (Eds.) Cambridge University Press, UK. pp 431.

IPCC. 2007a. Summary for policymakers. In: cClimate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

IPCC. 2007b. Summary for policymakers. In: climate change 2007: impacts, adaptation and vulnerability. Contribution of working group II to the fourth assessment report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 7-22.

IPCC. 2007c. Summary for policymakers. In: climate change 2007: mitigation. Contribution of working group III to the fourth assessment report of the Intergovernmental Panel on Climate Change [B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)], Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Kintish, K. 2007a. Making dirty coal plants cleaner. Science 317: 184-186.

Kintish, K. 2007b. Report backs more projects to sequester CO2 from coal. Science 315:1481.

Lal, R. 2007. Carbon management in agricultural soils. Mitigation and Adaptation Strategies for Global Change 12: 303-322.

Abstract: World soils have been a major source of enrichment of atmospheric concentration of CO2 ever since the dawn of settled agriculture,

about 10,000 years ago. Historic emission of soil C is estimated at 78 ± 12 Pg out of the total terrestrial emission of 136 ± 55 Pg, and post-industrial fossil fuel emission of 270 ± 30 Pg. Most soils in agricultural ecosystems have lost 50 to 75% of their antecedent soil C pool, with the magnitude of loss ranging from 30 to 60 Mg C/ha. The depletion of soil organic carbon (SOC) pool is exacerbated by soil drainage, plowing, removal of crop residue, biomass burning, subsistence or low-input agriculture, and soil degradation by erosion and other processes. The magnitude of soil C depletion is high in coarse-textured soils (e.g., sandy texture, excessive internal drainage, low activity clays and poor aggregation), prone to soil erosion and other degradative processes. Thus, most agricultural soils contain soil C pool below their ecological potential. Adoption of recommend management practices (e.g., no-till farming with crop residue mulch, incorporation of forages in the rotation cycle, maintaining a positive nutrient balance, use of manure and other biosolids), conversion of agriculturally marginal soils to a perennial land use, and restoration of degraded soils and wetlands can enhance the SOC pool. Cultivation of peatlands and harvesting of peatland moss must be strongly discouraged, and restoration of degraded soils and ecosystems encouraged especially in developing countries. The rate of SOC sequestration is 300 to 500 Kg C/ha/yr under intensive agricultural practices, and 0.8 to 1.0 Mg/ha/yr through restoration of wetlands. In soils with severe depletion of SOC pool, the rate of SOC sequestration with adoption of restorative measures which add a considerable amount of biomass to the soil, and irrigated farming may be 1.0 to 1.5 Mg/ha/yr. Principal mechanisms of soil C sequestration include aggregation, high humification rate of biosolids applied to soil, deep transfer into the sub-soil horizons, formation of secondary carbonates and leaching of bicarbonates into the ground water. The rate of formation of secondary carbonates may be 10 to 15 Kg/ha/yr, and the rate of leaching of bicarbonates with good quality irrigation water may be 0.25 to 1.0 Mg C/ha/yr. The global potential of soil C sequestration is 0.6 to 1.2 Pg C/yr which can off-set about 15% of the fossil fuel emissions.

Myhre, G., and A. Myhre. 2003. Uncertainties in radiative forcing due to surface albedo changes caused by land-use changes. Journal of Climate 16: 1511–1524.


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Pacala, S., and R. Socolow. 2004. Stabilization wedges: solving the climate problem for the next 50 years with current technologies. Science 305: 968-972.

Abstract: Humanity already possesses the fundamental scientific, technical, and industrial know-how to solve the carbon and climate problem for the next half-century. A portfolio of technologies now exists to meet the world's energy needs over the next 50 years and limit atmospheric CO2 to a trajectory that avoids a doubling of the preindustrial concentration. Every element in this portfolio has passed beyond the laboratory bench and demonstration project; many are already implemented somewhere at full industrial scale. Although no element is a credible candidate for doing the entire job (or even half the job) by itself, the portfolio as a whole is large enough that not every element has to be used.

Rau, G.H., and K. Caldiera. 2007. Coal’s Future: clearing the air. Science 316: 691.

Raymond, P.A., and J.J. Cole. 2003 Increase in the Export of Alkalinity from North America's Largest River. Science 301: 88-91.

Righelato, R., and D.V. Spracklen. 2007. Carbon mitigation by biofuels of by saving and restoring forests? Science 317: 902.

Rosenzweig, C., and F.N. Tubiello. 2007. Adaptation and mitigation strategies in agriculture: an analysis of potential synergies. Mitigation and Adaptation Strategies for Global Change 12: 855-873.

Sheppard, M.C., and R.H. Socolow. 2007. Sustaining fossil fuel use in a carbon-constrained world by rapid commercialization of carbon capture and sequestration. American Institute of Chemical Engineers 53: 3022-3028.

U.S. Census Bureau. 2006. World population information. http://www.census.gov/ ipc/www/idb/worldpopinfo.html. U.S. Census Bureau, Washington, DC.

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