PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Carbon Dioxide and Climate Change Eugene S. Takle Agronomy Department Geological and Atmospheric Science Department Iowa State University Ames, Iowa Lecture to Political Science Class on Science, Technology and Public Policy Iowa State University 7 February 2004

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  Implications for stream flow  Impact of 2004 election decisions  Summary

Carbon Dioxide and Temperature

2004

Carbon Dioxide and Temperature

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.

Source: Jerry Meehl, National Center for Atmospheric Research

Source: National Center for Atmospheric Research

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

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

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

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Soil Water Assessment Tool (SWAT)  Long-term, continuous watershed simulation model (Arnold et al,1998)  Assesses impacts of climate and management on yields of water, sediment, and agricultural chemicals  Physically based, including hydrology, soil temperature, plant growth, nutrients, pesticides and land management  Daily time steps

SWAT Output with Various Sources of Climate Input

Calibration of SWAT: Annual Stream Flow at Grafton, IL

Calibration of SWAT: Monthly Stream Flow at Grafton, IL

Validation of SWAT: Annual Stream Flow at Grafton, IL

Validation of SWAT: Monthly Stream Flow at Grafton, IL

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

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

Comparison of Simulated Stream Flow under Climate Change with Various Model Biases

Relation of Runoff to Precipitation for Various Climates

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Election 2004 Issues and Their Time Scales What are the election issues in 2004, and how long will decisions on these issues have an impact?

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 2004 Issues  Jobs  US Economy  National security, terrorism  War  Environment

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 2004 Issues: Jobs  The average American changes jobs about every ? 7 years?  Tenured position at a university ~ 35 years -> Time scale of jobs 7-35 years

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 2004 Issues: US Economy  Economic cycles last about 5 years  Home mortgage lasts about 20 years  Factory is productive ~50 years -> Time scale of economic decisions: 5-50 years

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 2004 Issues: National Security  Nazi Germany: 10 years (impact 50 years)  China ??  Rawanda ?? -> Time scale of terrorism: 5-50 years

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 2004 Issues: War  Wars last 2-5 years  Impact of WWII ~ years -> Time scale of war years

Decisions we make now Determine global warming For the next 200-2,000 years

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 2004 Issues: Environment (Global Warming) Time scale of environmental decisions on global warming: ,000 years !!

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS 2004 Issues  Jobs: 7-35 years  US Economy: 5-50 years  National security, terrorism: 5-50 years  War: years  Environment: 200-2,000 years

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