Regional Climate Modeling: A Tool for Decision-Makers

1. Regional Climate Modeling:A Tool for Decision-Makers Eugene S. Takle Agronomy Department Geological and Atmospheric Science Department Iowa State University Ames, Iowa 50011 gstakle@iastate.edu Institute for Science and Society Iowa State University 4 May 2004

2. Outline • Evidence for global climate change • Future atmospheric carbon dioxide concentrations • Simulations of global climate and future climate change • Implications for stream flow and nutrient loss • International collaboration for understanding water and energy cycles • Summary

3. Carbon Dioxide and Temperature

4. Carbon Dioxide and Temperature 2004

5. 2040 Carbon Dioxide and Temperature 2004

6. Carbon Dioxide and Temperature Stabilization at 550 ppm

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

9. 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

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

13. Source: Jerry Meehl, National Center for Atmospheric Research

14. Source: National Center for Atmospheric Research

15. Source: Intergovernmental Panel on Climate Change, 2001 Report

16. 40% Probability 5% Probability Source: Intergovernmental Panel on Climate Change, 2001 Report

17. Climate Change Projected for 2100 Rapid Economic Growth Slower Economic Growth

18. 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

19. 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

20. 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

21. 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

22. 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

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

26. Climate Surprises • Breakdown of the ocean thermohaline circulation (Greenland melt water) • Breakoff of the West Antarctic Ice Sheet

27. Antarctica Greenland Ice Volume 0 Warm Cold Climate

29. Regional Climate Change for the US Midwest • Observed and projected changes in climate • Impact on water quantity and water quality • Policy implications

30. 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

31. 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

32. 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

33. SWAT Output with Various Sources of Climate Input

34. Validation of SWAT: Annual Stream Flow at Grafton, IL

35. Validation of SWAT: Monthly Stream Flow at Grafton, IL

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

39. Annual Stream Flow Simulated by SWAT Driven by the RegCM2 Regional Climate Model with NNR Lateral Boundary Conditions

40. Mean Monthly Precipitation Simulated by the RegCM2 Regional Climate Model with NNR Lateral Boundary Conditions

41. Seasonal Stream Flow Simulated by SWAT Driven by the RegCM2 Regional Climate Model with NNR Lateral Boundary Conditions

42. “Warming Hole” ˚C DTmax (JJA)

43. 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

44. 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

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

46. Relation of Runoff to Precipitation for Various Climates

47. Regional Climate Modeling for Informing Policy on Water Quality • How does the combination of climate change and land use impact water quality? • Use nitrates and sediment as indicators • What alternative land management strategies will improve water quality? • What policies need to be implemented to achieve this water quality improvement?

48. Maquoketa Watershed

49. Scenario 1: all Agriculture Scenario 2: all Forest

50. Scenario 3: N. half Agric. and S. half Forest. Scenario 4: S. half Agric. and N. half Forest.