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Climate Change

Greenhouse Warming Prediction

Major information sources:

Climate Change 2001: IPCC Synthesis Report, at http://www.grida.no/climate/ipcc_tar/vol4/english/

Vital Climate Graphics, at http://www.grida.no/climate/vital/

Climate Change Impacts on US, at http://www.gcrio.org/NationalAssessment/

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Energy Consumption and C emissions, 1990-2020(no climate policy intervention)

Region

Energy Consumption(Quadrillion Btu)

Carbon Dioxide Emissions(Million Metric Tons Carbon

Equivalent)

1990 1999 2010 2020 1990 1999 2010 2020

Industrialized 182.4 209.6 243.4 270.4 2,842 3,122 3,619 4,043

EE/FSU 76.3 50.5 60.3 72.3 1,337 810 940 1,094

Developing                

  Asia 51.0 70.9 113.4 162.2 1,053 1,361 2,137 3,013

  Middle East 13.1 19.3 26.9 37.2 231 330 451 627

  Africa 9.3 11.8 16.1 20.8 179 218 294 373

  Central and South America 13.7 19.8 29.6 44.1 178 249 394 611

    Total 87.2 121.8 186.1 264.4 1,641 2,158 3,276 4,624

Total World 346.0 381.8 489.7 607.1 5,821 6,091 7,835 9,762

Sources: History: Energy Information Administration (EIA), International Energy Annual 1999, DOE/EIA-0219(99) (Washington, DC, January 2001). Projections: EIA, World Energy Projection System (2001).

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Major Questions

Third Assessment Report, IPCC 2001

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Question 2What is the evidence for, causes of, and consequences of

changes in the Earth’s climate since the pre-industrial era?

(a) Has the Earth’s climate changed since the pre-industrial era at the regional and/or global scale? If so, what part, if any, of the observed changes can be

attributed to human influence and what part, if any, can be attributed to natural phenomena? What is the basis for that attribution?

(b) What is known about the environmental, social, and economic consequences of climate changes since the pre-industrial era with an

emphasis on the last 50 years?

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Question 3What is known about the regional and global climatic,

environmental, and socio-economic consequences in the next 25, 50, and 100 years associated with a range of greenhouse

gas emissions arising from scenarios used in the TAR (projections which involve no climate policy intervention)?

To the extent possible evaluate the:

• Projected changes in atmospheric concentrations, climate, and sea level • Impacts and economic costs and benefits of changes in climate and

atmospheric composition on human health, diversity and productivity of tecological systems, and socio-economic sectors (particularly agriculture and

water)• The range of options for adaptation, including the costs, benefits, and

challenges• Development, sustainability, and equity issues associated with impacts and

adaptation at a regional and global level

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Question 5What is known about the inertia and time scales associated with the changes in the climate system, ecological systems,

and socio-economic sectors and their interactions?

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Question 7What is known about the potential for, and costs and benefits of, and time frame for reducing greenhouse gas emissions?

• What would be the economic and social costs and benefits and equity implications of options for policies and measures, and the mechanisms of the Kyoto Protocol, that might be considered to address climate change regionally

and globally?

• What portfolios of options of research and development, investments, and other policies might be considered that would be most effective to enhance

the development and deployment of technologies that address climate change?

• What kind of economic and other policy options might be considered to remove existing and potential barriers and to stimulate private- and public-

sector technology transfer and deployment among countries, and what effect might these have on projected emissions?

• How does the timing of the options contained in the above affect associated economic costs and benefits, and the atmospheric concentrations of

greenhouse gases over the next century and beyond?

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Question 9What are the most robust findings and key uncertainties

regarding attribution of climate change and regarding model projections of:

• Future emissions of greenhouse gases and aerosols?• Future concentrations of greenhouse gases and aerosols?

• Future changes in regional and global climate?• Regional and global impacts of climate change?

• Costs and benefits of mitigation and adaptation options

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Integrated Framework of Climate Change

Schematic and simplified representation of an integrated assessment framework for considering anthropogenic climate change. The yellow arrows show the cycle of cause and effect among the four quadrants shown in the figure, while the blue arrow indicates the societal response to climate change impacts.

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Increase in Ambient Air Temperatures

Increase in Sea-surface Temperatures

Decrease inOcean CO2 Uptake

Increase in Atmospheric CO2

Feedbacks in the climate system occur when the output from one component is input into a second component, which then generates an output altering the first component.

Example:

Climate Feedbacks

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The Fundamentals of Global Climate

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Components of the global climate system (bold), their processes and interactions (thin arrows) and aspects that may change (bold arrows).Climate Change 2001: The Scientific Basis; IPCC 2001

The Climate System

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Hadley Cells

The excess heat received in the equatorial region causes air to rise and move towards higher latitudes. The outward motion at high latitudes near the equator has to be balanced by inward low altitude winds. This system is a huge twin-cell circulation pattern (one cell in each atmosphere), called Hadley Cells.

Because Earth rotates and has continental land masses, the actual prevailing winds do not directly blow from pole to equator, but curve around and form a multicellular circulation pattern. The curving form is called the "Coriolis effect“ and is so great as to split up each Hadley cell into three smaller cells.

from GC1:Physical Processes

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The direction of air flow and the ascent and descent of air masses in these convective (Hadley) cells determine Earth’s general climatic zones

Global air circulation and biomes

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Ocean Conveyer Belt

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Greenhouse Effect

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Main Greenhouse Gases

Global Warming Potential (GWP)• used to compare the abilities of different greenhouse gases to trap heat in the atmosphere

(heat-absorbing ability and decay rate)• provides a construct for converting emissions of various gases into a common measure

(relative toCO2)

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Greenhouse gas warming

Methane19%

Other Halocarbons

5%

CFC-126%

Nitrous Oxide6%

Carbon Dioxide

64%

J. T. Houghton et al., eds. Climate Change 1995: The Science of Climate Change, published for the IPCC, in collaboration with WMO and UNEP

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Cooling Factors

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Radiative Forcing: Cooling and Heating

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The Global Climate Record

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400,000 years climate record

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Earth’s recent surface temperature

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Multi-year measurements of carbon dioxide abundances from a single location in Hawaii, showing strong yearly signal (peak in winter months, minimum in summer months) together with overall increase due to anthropogenic effects.

Atmospheric CO2

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Human influence

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Modeling Climate Change

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Hi all Climate Change Impacts on the United States, NAST, 2000.

Modeling the Climate System

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Climate Models: How are they built? How are they applied?

• Major components of the climate system represented in sub-models (atmosphere, ocean, land surface, cryosphere and biosphere), along with processes within and between them

• General circulation models (GCMs) – e.g., Atmosphere GCMs and Ocean GCMs – equations that describe the large-scale evolution of momentum, heat and

moisture are solved in both cases– Model resolution:

• Atmosphere GCM: ~ 250 km in the horizontal and ~ km in the vertical above the boundary layer

• ocean GCM: ~ 125 - 250 km in the horizontal and ~ 200 to 400 m in the vertical

• many physical processes (e.g., clouds or ocean convection) take place on much smaller spatial scales than the model grid and therefore cannot be modeled and resolved explicitly

their average effects are approximately included in a simple way by taking advantage of physically based relationships with the larger-scale variables. This technique is known as parameterization.

• Regional circulation models (RCMs)– smaller spatial scales allow regional variations

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Climate Models, ctn’d

• Quantitative projections of future climate change require– models that simulate all the important processes governing the future

evolution of the climate• atmosphere, land, ocean and sea ice • developed separately and then gradually integrated

– considerable computing power to run comprehensive AOGCMs

• Simpler models (e.g., coarser resolution and simplified dynamics and physical processes) are widely used – to explore different scenarios of emissions of greenhouse gases

– to assess the effects of assumptions or approximations in model parameters

• Simple, intermediate and comprehensive models form a “hierarchy of climate models”, all of which are necessary to explore choices made in parameterizations and assess the robustness of climate change

Climate Change 2001: The Scientific Basis; IPCC 2001

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Climate Model

Short-term Climate Change from NCAR Global Circulation Model

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Comparison between Models and Observation

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Key FindingsThird Assessment Report,

Intergovernmental Panel on Climate Change (IPCC, 2001)

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Key Findings

The global average surface temperature has increased over the 20th century by about 0.6oC.

Temperatures have risen during the past four decades in the lowest 8 kilometers of the atmosphere.

Snow cover and ice extent have decreased.

Global average sea level has risen and ocean heat content has increased.

Concentrations of atmospheric greenhouse gases and their radiative forcing have continued to increase as a result of human activities.

Climate Change 2001: The Scientific Basis. Summary for Policymakers; IPCC 2001

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Key Findings, cnt’d

Natural factors have made small contributions to radiative forcing over the past century.

There is new and stronger evidence that most of the warming observed over the past 50 years is attributable to human activities.

Human influences will continue to change atmospheric composition throughout the 21st century.

Global average temperature and sea level are projected to rise under all IPCC SRES scenarios.

Anthropogenic climate change will persist for many centuries.

Climate Change 2001: The Scientific Basis. Summary for Policymakers; IPCC 2001

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Scenarios

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ScenariosWhat are they? Why use them?

• neither predictions nor forecasts

• alternative images of how the future might unfold

• an appropriate tool with which to analyze how driving forces may influence future emission outcomes and to assess the associated uncertainties

IPCC Special Report on Emission Scenarios

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A1 Storyline and Scenario Family

A world with:• very rapid economic growth• low population growth• rapid introduction of new and

more efficient technologies

Major Underlying Themes: convergence among regions capacity building increased cultural and social interactions substantial reduction in regional differences in per capita income

Alternative directions of technological change A1FI - high coal and high oil and gas A1B - balanced (even distribution among options) A1T - predominantly non-fossil fuel

IPCC Special Report on Emissions Scenarios

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A2 Storyline and Scenario Family

A highly heterogeneous world with: high population growth (due to slow convergence of fertility

patterns across regions) regionally-oriented economic development per capita economic growth more fragmented/slower technological change more fragmented/slower

Major underlying themes: self reliance preservation of local identities

IPCC Special Report on Emissions Scenarios

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B1 Storyline and Scenario Family

A convergent world with:• rapid changes in economic structures toward a service and

information economy• low population growth (same as A1)• reductions in material intensity

introduction of clean and resource-efficient technologies

Major Underlying Themes: global solutions to economic, social,

and environmental sustainability (without additional climate initiatives)

improved equity

IPCC Special Report on Emissions Scenarios

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B2 Storyline and Scenario Family

A world with:• intermediate levels of economic

development• moderate population growth• reductions in material intensity• less rapid and more diverse

technological change

Major Underlying Themes: local solutions to economic, social, and environmental

sustainability (without additional climate initiatives social equity (with local/regional focus) environmental protection (with local/regional focus)

IPCC Special Report on Emissions Scenarios

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Scenarios

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Projections for the 21st Century

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The Emission scenarios and their implications for atmospheric composition, climate, and sea level

Date

Global Population (billions)a

Global GDP (1012

US$/yr)b

Per Capita Income Ratioc

Ground- Level O3 (ppbv)d

CO2

(ppmv)e

Global Temperature

Change (C) f

Global Sea-Level Rise (cm)g

1990 5.3 21 16.1 --- 354 0 0

2000 6.1 – 6.2 5 – 28 12.3 – 14.2 40 367 0.2 2

2050 8.4 – 11.3 59 – 187 2.4 – 8.2 ~60 463 – 623 0.8 – 2.6 5 – 32

2100 7.0 – 15.1 197 - 550 1.4 – 6.3 >70 478 - 1099 1.4 – 5.8 9 - 88

Technical Summary Climate Change 2001: Impacts, Adaptation, and Vulnerability; IPCC 2001

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After CO2 emissions are reduced and atmospheric concentrations stabilize, surface air temperature continues to rise slowly for a century or more. Thermal expansion of the ocean continues long after CO2 emissions have been reduced, and melting of ice sheets continues to contribute to sea-level rise for many centuries. (Illustration for stabilization at level between 450 and 1,000 ppm.)

Climate Change 2001: Synthesis Report; IPCC 2001

Effect of Time Scale

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Stabilization

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Potential Impacts of Climate Change

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Climate Model

Short-term Climate Change from NCAR Global Circulation Model

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Climate Change Impacts

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Thinning of Arctic Sea Ice

Ice Melting:• glaciers and ice caps: .5m• Greenland ice sheet: 7m• Antarctic ice sheet: 70m

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Sea Level Rise

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Sea level rise: examples

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Extreme Weather

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Precipitationand Freshwater

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Health and Climate Change

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Dengue Fever and Temperature RiseCLINICAL FEATURES

Sudden onset of fever, severe headache, myalgias and arthralgias, leukopenia, thrombocytopenia and hemorrhagic manifestations

Occasionally produces shock and hemorrhage, leading to death

Globally, there are an estimated 50 to 100 million cases of dengue fever (DF) and several hundred thousand cases of dengue hemorrhagic fever (DHF) per year

Average case fatality rate of DHF is about 5%

http://www.cdc.gov/

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Regional Analysis

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Climate Change Impacts on the United States: The Potential Consequences of Climate Variability and Change

• to identify key climatic vulnerabilities of particular regions and sectors

-in the context of other changes in the nation’s environment,

resources, and economy

• to identify the highest priority uncertainties about which we must know more to understand climate impacts, vulnerabilities, and our ability to adapt

The objectives of the National Assessment:

• to synthesize, evaluate and report on what we presently know about the potential consequences of climate variability and change for the United States in the 21st century

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Climate Change Impacts on the United StatesRegional Evaluations and Sectors

Regions

NortheastSoutheastMidwestGreat PlainsWestPacific NorthwestAlaskaIslands

Sectors

Agriculture ForestsWater Coastal Areas and Marine ResourcesHuman Health

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The Analysis Process

• State-of-the-science climate models were used to generate climate change scenarios:– Hadley Center, United Kingdom– Canadian Centre for Climate

Modeling and Analysis– AND

• The National Center for Atmospheric Research, USA• NOAA Geophysical Fluid Dynamics Laboratory, USA• NASA Goddard Institute for Space Studies, USA

• Models used to study systems responses to the climate change scenarios:– Ecological systems– Hydrological systems– Socioeconomic systems

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The assessment considered high, medium, and low scenarios of future U.S. population and economic growth.

21st C growth in the US

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Temperature and Heat Predictions

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Agriculture and Forest Sectors

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Water, Coastal Areas and Marine Resources

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Health Sector

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66All

All the

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Source: Climate Change Impacts on the United States, NAST Overview, 2000.

Key Findings

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Key Findings, ctn’d

Source: Climate Change Impacts on the United States, NAST Overview, 2000.

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Today

• The earth is warming, unambiguously. Surface air temperature records, radiosonde data, and satellite observations all show this has been happening for several decades; there is disagreement over the magnitude of the warming.

• This warming is unprecedented in historical times. Warming in the NH (northern hemisphere) over last 100 yrs. has been greater than any over last thousand. 1998 was the warmest year of the millennium.

• There is evidence, independent of temperature recordings, that the planet is warming. Snow cover, glaciers, spring and summer sea ice are all decreasing and/or receding.

• There are a few opposing data points. For example, parts of Antarctica are not warmer.

• Other parts of the climate system have been affected. Precipitation and cloud cover have increased over the mid to high latitudes in the NH, and have decreased in NH subtropics. El Ninos are more frequent, and droughts are more common in Africa and Asia.

• Sea level has risen 10-20cm during 20th century. Half of this expansion is due to thermal expansion. The other half is from glacial melting.

• Anthropogenic effects are indeed increasing the levels of greenhouse gases. For example, CO2 has increased by 31% since 1750; ¾ of this increase is due to fossil fuels. Methane (CH4) has increased by 151%; ~1/2 of which is due to anthropogenic emissions.

• This has had a radiative effect. From 1750-2000, there has been a warming of 2.78 W/m2.

• Man has also produced some cooling influences, for example, -0.65W/M2 cooling has been observed, mostly from sulfate aerosols and stratospheric O3 reduction.

• Natural variability is probably a small factor here. More important locally than globally.

• Conclusion: Humanity is likely responsible for the warming.

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Tomorrow?• Greenhouse gases are projected to increase over the next century. Carbon cycle projections show an increase

of 50-170% for CO2 alone.

• Aerosol projections vary. Sulfate aerosols should decrease; natural and carbon aerosols most will increase.

• Radiative forcing will increase, primarily from CO2 emissions.

• Surface air temperature will increase an estimated 1.4 -5.8 degrees Celsius globally.

• Even the low estimate would be unprecedented for the last 10,000 yrs.

• Areas will not warm equally. Increased warming over land, particularly in high northern latitudes, in winter. Possibly 40% greater.

• Ocean circulation may change. El Niño events may increase in freq; North Atlantic circulation could change, mitigating warming of Western Europe.

• Water availability may change influenced by both heavier rainfall and severe droughts. Wetter at high latitudes, drier in mid latitudes during summer.

• Severe storms will probably increase.

• Snow cover, sea ice cover, glaciers, and ice caps should decrease.

• Sea level rise projections vary greatly. From 1990-2100, 10-90 cm is possible.

• The effects last an unknown amount of time. Even if greenhouse gas emissions were suddenly stabilized, higher levels of CO2 would persist for hundreds of years, and with that, continued increase in temp and sea level; most disconcerting is that ice sheet changes could last thousands of years with potential sea level rise of up to 10m.

• Steps necessary to stabilize CO2 levels depend on the level desired. To achieve 450 ppm CO2 levels, we would have to go below 1990 emissions; in order to stabilize CO2 levels at twice current levels, we would have to do nothing for one century.

• Confidence levels of the above projections vary, but it is certain that there will be continued warming, sea level rise, and amplification of the hydrologic cycle.