Agriculture and Climate Change

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS

Agriculture and Climate Change

Eugene S. TakleAgronomy Department

Geological and Atmospheric Science Department

Iowa State University

Ames, Iowa 50011

[email protected]

Underwriting/Marketing Seminar, 30 March 2005


Outline Evidence for global climate change Future atmospheric carbon dioxide concentrations Simulations of global climate and future climate

change Impacts of climate change for the US Midwest “Climate surprises” Social inequities and ethical issues

surrounding climate change Summary

Carbon Dioxide and Temperature


2005


2005

2040

(375 ppm)

(440 ppm)


Stabilization at 550 ppm


“Business as Usual”(fossil intensive)

2100


Associated Climate Changes

Global sea-level has increased 1-2 mm/yr Duration of ice cover of rivers and lakes decreased by 2 weeks in N.

Hemisphere Arctic ice has thinned substantially, decreased in extent by 10-15% Reduced permafrost in polar, sub-polar, mountainous regions Growing season lengthened by 1-4 days in N. Hemisphere Retreat of continental glaciers on all continents Poleward shift of animal and plant ranges Snow cover decreased by 10% Earlier flowering dates Coral reef bleaching

Source: Intergovernmental Panel on Climate Change, 2001 Report

Mann, M. E., R. S. Bailey, and M. K. Hughes, 1999: Geophysical Research Letters 26, 759.






Hansen, Scientific American, March 2004

Mt. Pinatubo (1991)

El Chichon (1982)Agung, 1963

Source: Jerry Meehl, National Center for Atmospheric Research

Source: National Center for Atmospheric Research

Source: National Center for Atmospheric Research

The planet is committed toa warming over the next 50 years regardless of political decisions


40% Probability

5% Probability


Climate Change Projected for 2100

Rapid Economic Growth

Slower Economic Growth

Source: IPCC, 2001: Climate Change 2001: The Scientific Basis


IPCC Summary for Policy Makers

An increasing body of observations gives a collective picture of a warming world and other changes in the climate system

IPCC Summary for Policy Makers

An increasing body of observations gives a collective picture of a warming world and other changes in the climate system

Emissions of greenhouse gases and aerosols due to human activities continue to alter the atmosphere in ways that are expected to affect the climate

IPCC Summary for Policy Makers, cont’d

Confidence in the ability of models to project future climate has increased


Confidence in the ability of models to project future climate has increased

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


Anthropogenic climate change will persist for many centuries


Anthropogenic climate change will persist for many centuries

Further action is required to address remaining gaps in information and understanding


Climate Surprises:Low Probability but High-Impact Events

Breakdown of the ocean thermohaline circulation (Greenland melt water)

Breakoff of the West Antarctic Ice Sheet

ClimateCold Warm

Ice V

olu

me

0

AntarcticaGreenland



Meltwater flows into a large moulin on Greenland and down to the bedrock to "lubricate" the sheet

BBC News: World Editionhttp://news.bbc.co.uk/2/hi/science/nature/2558319.stm

For the Midwest Warming will be greater for winter than summer Warming will be greater at night than during the

day A 3oF rise in summer daytime temperature triples

the probability of a heat wave Growing season will be longer (8-9 days longer

now than in 1950) More precipitation Likely more soil moisture in summer More rain will come in intense rainfall events Higher stream flow, more flooding

Sub-Basins of theSub-Basins of theUpper MississippiUpper MississippiRiver BasinRiver Basin

119 sub-basins

Outflow measuredat Grafton, IL

Approximately oneobserving stationper sub-basin

Approximately onemodel grid pointper sub-basin

RegCM2 Simulation DomainRegCM2 Simulation Domain

Red = global model grid point Green/blue = regional model grid points

Ten-Year Mean Monthly Stream Flow Generated by the Ten-Year Mean Monthly Stream Flow Generated by the RegCM2 Regional Climate Model Driven RegCM2 Regional Climate Model Driven

with HadCM2 Global Model Results for the with HadCM2 Global Model Results for the Contemporary and Future Scenario (2040s) ClimateContemporary and Future Scenario (2040s) Climate

Relation of Runoff to Precipitation Relation of Runoff to Precipitation for Various Climatesfor Various Climates

More precip goes to streamflow in a future climate

“Warming Hole”

TTmaxmax (JJA) (JJA)˚C



Social Inequities due to Climate Change

Agricultural production Freshwater availability Sea-water innundation Intergenerational equities





Impact on US Agriculture(my speculations)

The US is a large enough country at a high enough latitude that it will have regional winners and losers

Areas now marginal for agriculture may become less suitable Some areas now having abundant water but limited growing seasons may be

winners Areas with good soils and robust climate, like Iowa, may be impacted less The US Midwest may experience more variability from

year to year, which would make agricultural yields more variable (flooding, water-logging, drought)

Changes in consumption and agricultural production in other nations may affect US agriculture more than changes to US climate

Environmental refugees?




http://www.grida.no/climate/vital/37.htm

http://www.grida.no/climate/vital/38.htm






Sea-Water InnundationExample: The Maldives

Area: 115 square miles Population: 143,000 Highest point: 20 ft above sea level



Agricultural production Freshwater availability Sea-water innundation Intergenerational inequities


Intergenerational Inequities

Sustainable Development: “To meet the needs of the present without compromising the ability of future generations to meet their needs.”

Energy sources? Non-renewable earth resources? Agricultural productivity? Fresh water supplies? Heavy metal contamination of soil

and water?


Summary

Climate change is real and we need to be doing something about it

The longer we wait, the fewer our options Regional patterns of warming will be complicated Climate surprises can’t be discounted Climate change will create regional

agricultural winners and losers Climate change carries ethical

implications


For More Information

See my online Global Change course:

http://www.meteor.iastate.edu/gccourse

Contact me directly:

[email protected]

http://www.meteor.iastate.edu/faculty/takle/

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Agriculture and Climate Change

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