PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Global Climate Change: Recent Trends and Future Projections Eugene S. Takle, PhD, CCM Professor of Atmospheric Science Department of Geological and Atmospheric Sciences Professor of Agricultural Meteorology Department of Agronomy Faculty Director, University Honors Program Iowa State University Ames, Iowa Chemical Engineering 302 Iowa State University 11 October 2007

Image courtesy of NASA/GSFC

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Outline  Changes in atmospheric carbon dioxide  Radiative forcing  Simulations of global climate and future climate change  Four components for addressing climate change  Climate change for Iowa and the Midwest: adaptation strategy Except where noted as personal views or from the ISU Global Change course or the Iowa Environmental Mesonet, all materials presented herein are from peer-reviewed scientific reports

CO 2, CH 4 and temperature records from Antarctic ice core data Source: Vimeux, F., K.M. Cuffey, and Jouzel, J., 2002, "New insights into Southern Hemisphere temperature changes from Vostok ice cores using deuterium excess correction", Earth and Planetary Science Letters, 203,

CO 2, CH 4 and temperature records from Antarctic ice core data Source: Vimeux, F., K.M. Cuffey, and Jouzel, J., 2002, "New insights into Southern Hemisphere temperature changes from Vostok ice cores using deuterium excess correction", Earth and Planetary Science Letters, 203, Natural cycles Pattern repeats about every 100,000 years

IPCC Third Assessment Report

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS ppm Carbon Dioxide and Temperature

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS ppm Carbon Dioxide and Temperature

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS “Business as Usual” 950 ppm Carbon Dioxide and Temperature

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS “Business as Usual” 950 ppm ? Carbon Dioxide and Temperature

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

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

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS

Planet T e (K) T s (K) Earth Venus Mars e TsTs

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS IPCC Fourth Assessment Report Summary for Policy Makers

Hansen, Scientific American, March 2004 Mt. Pinatubo (1991) El Chichon (1982) Agung, 1963 At present trends the imbalance = 1 Watt/m 2 in 2018

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Source: Corell, R. W., 2004: Impacts of a warming Arctic. Arctic Climate Impact Assessment ( Cambridge University Press (

Areas subjected to Inundation with a 1 m (~3 ft) rise in sea level Kennedy Space Center Miami Impact of a 1-m rise in sea level on low-lying areas Source: Corell, R. W., 2004: Impacts of a warming Arctic. Arctic Climate Impact Assessment ( Cambridge University Press ( Projected sea-level rise In 21st century: 0.5 to 1.0 m

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS

Climate Cold Warm Ice Volume 0 Antarctica Greenland

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS

Hansen, Scientific American, March 2004

An exhibition of old and new photographs at the Swiss Alpine Museum in Bern documents the gradual disappearance of Switzerland's glaciers. The Rhone glacier with the Hotel Belvedere in the foreground and the Furka pass, Canton Valais circa 1906 and 2003 (Pictures: Gesellschaft fur okologische Forschung, Munich)

Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg Grey bands indicate 68% and 95% range derived from multiple simulations.

Natural cycles

Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg Grey bands indicate 68% and 95% range derived from multiple simulations. Not Natural

Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg Grey bands indicate 68% and 95% range derived from multiple simulations. Not Natural Highly Likely Not Natural

Source: Jerry Meehl, National Center for Atmospheric Research

IPCC Fourth Assessment Report Summary for Policy Makers

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS IPCC Fourth Assessment Report Summary for Policy Makers Reduced Consumption Energy intensive Energy conserving

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS IPCC Fourth Assessment Report Summary for Policy Makers The planet is committed to a warming over the next 50 years regardless of political decisions Energy intensive Energy conserving Reduced Consumption

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS IPCC Fourth Assessment Report Summary for Policy Makers Reduced Consumption Energy intensive Energy conserving Adaptation Necessary Mitigation Possible

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS IPCC Fourth Assessment Report Summary for Policy Makers

Tin and Seager

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Four-Component Approach for Addressing Climate Change  Mitigation policies: –Example: reduction in GHG emissions  Adaptation (long-term): –Example: Developing Iowa’s competitive economic advantage  Adaptation (short-term): –Example: redefining climate “normals” when needed and scientifically justified  Scenario planning for Iowa’s “Katrina”: –Example: Multi-year drought, recurrent floods, combination of both; drought and wildfire EST personal view

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS If a meteorological variable began departing from its long-term background near or after 1970 it may be related to the radiation imbalance and thereby has a better chance than not of continuing its new trend over the next 5-10 years. Climate Adaptation(Short-Term) EST personal view

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Projected Changes for the Climate of Iowa/Midwest (My tentative assessment)  Longer frost-free period (high)  Higher average winter temperatures (high)  Fewer extreme cold temperatures in winter (high)  More extreme high temperatures in summer (medium)  Higher nighttime temperatures both summer and winter (high)  More (~10%) precipitation (medium)  More variability of summer precipitation (high) –More intense rain events and hence more runoff (high) –Higher episodic streamflow (medium) –Longer periods without rain (medium)  Higher absolute humidity (high)  Stronger storm systems (medium)  Reduced annual mean wind speeds (medium) Follows trend of last 25 years and projected by models No current trend but model suggestion or current trend but models inconclusive

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Reasons Crop Yields Might Increase in the Midwest  Longer growing season  Warmer spring soil temperatures  Modest or no increase in summer daily maximum temperatures  Increase in nighttime temperatures  Reduced risk of late frost in spring or early frost in fall  More freeze-thaw cycles that will recharge soil moisture in winter

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Reasons Crop Yields Might Increase in the Midwest  More precipitation  More soil moisture  Higher dew-point temperatures reduces moisture stress  Higher CO 2 increased carbon uptake by crops  Higher CO 2 increases the water-use efficiency of crops

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Reasons Crop Yields Might Decrease in the Midwest  More precipitation extremes –More rain events bring heavy rain –More droughts –More floods  More over-wintering pests  More pathogens due to higher humidity  More vigorous weed growth

D. Herzmann, Iowa Environmental Mesonet

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS Summary  Climate change of the past 35 years is not consistent with natural variations over the last 400,000 years  Evidence clearly shows that radiative forcing due to anthropogenic greenhouse gases has contributed over half of the warming of the last 35 years  Mitigation efforts, although urgently needed, will have little effect on global warming until the latter half of the 21st century  Adaptation strategies should be developed for the next 50 years  Recent trends and model projections should be used to develop adaptation strategies for the next 10 years EST personal view

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS For More Information  For peer-reviewed evidence supporting everything you have seen in this presentation, see my online Global Change course:  Contact me directly:  Current research on regional climate and climate change is being conducted at Iowa State Unversity under the Regional Climate Modeling Laboratory  North American Regional Climate Change Assessment Program  For this and other climate change presentations see my personal website: Or just Google Eugene Takle