PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Agriculture and Climate Change Eugene S. Takle Agronomy Department Geological and Atmospheric Science Department Iowa State University Ames, Iowa Underwriting/Marketing Seminar, 30 March 2005

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 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

Carbon Dioxide and Temperature (375 ppm) (440 ppm)

Carbon Dioxide and Temperature Stabilization at 550 ppm

Carbon Dioxide and Temperature “Business as Usual” (fossil intensive) 2100

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 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.

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS

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

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

Source: Intergovernmental Panel on Climate Change, 2001 Report

40% Probability 5% Probability Source: Intergovernmental Panel on Climate Change, 2001 Report

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

IPCC Summary for Policy Makers, cont’d  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

IPCC Summary for Policy Makers, cont’d  Anthropogenic climate change will persist for many centuries

IPCC Summary for Policy Makers, cont’d  Anthropogenic climate change will persist for many centuries  Further action is required to address remaining gaps in information and understanding

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Climate Surprises: Low Probability but High-Impact Events  Breakdown of the ocean thermohaline circulation (Greenland melt water)  Breakoff of the West Antarctic Ice Sheet

Climate Cold Warm Ice Volume 0 Antarctica Greenland

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS

Meltwater flows into a large moulin on Greenland and down to the bedrock to "lubricate" the sheet BBC News: World Edition

For the Midwest  Warming will be greater for winter than summer  Warming will be greater at night than during the day  A 3 o F 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 the Upper Mississippi River Basin 119 sub-basins Outflow measured at Grafton, IL Approximately one observing station per sub-basin Approximately one model grid point per sub-basin

RegCM2 Simulation Domain Red = global model grid point Green/blue = regional model grid points

Ten-Year Mean Monthly Stream Flow Generated by the RegCM2 Regional Climate Model Driven with HadCM2 Global Model Results for the Contemporary and Future Scenario (2040s) Climate

Relation of Runoff to Precipitation for Various Climates More precip goes to streamflow in a future climate

“Warming Hole”  T max (JJA) ˚C

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

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Social Inequities due to Climate Change  Agricultural production  Freshwater availability  Sea-water innundation  Intergenerational equities

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Social Inequities due to Climate Change  Agricultural production  Freshwater availability  Sea-water innundation  Intergenerational equities

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 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?

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Social Inequities due to Climate Change  Agricultural production  Freshwater availability  Sea-water innundation  Intergenerational equities

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Social Inequities due to Climate Change  Agricultural production  Freshwater availability  Sea-water innundation  Intergenerational equities

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS

Sea-Water Innundation Example: The Maldives  Area: 115 square miles  Population: 143,000  Highest point: 20 ft above sea level

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Social Inequities due to Climate Change  Agricultural production  Freshwater availability  Sea-water innundation  Intergenerational inequities

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 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?

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 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

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS For More Information  See my online Global Change course:  Contact me directly: