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 50011 gstakle@iastate.edu Chemical Engineering 302 Iowa State University 11 October 2007

Image courtesy of NASA/GSFC

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

CO2, CH4 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, 829-843.

CO2, CH4 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, 829-843. Pattern repeats about every 100,000 years Natural cycles

IPCC Third Assessment Report

Carbon Dioxide and Temperature 2007 380 ppm

Carbon Dioxide and Temperature 2050 550 ppm

Carbon Dioxide and Temperature “Business as Usual” 950 ppm

Carbon Dioxide and Temperature “Business as Usual” 950 ppm ?

http://www.ncdc.noaa.gov/img/climate/research/2006/ann/glob_jan-dec-error-bar_pg.gif

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

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

Planet Te(K) Ts(K) Earth 256 288 Venus 227 732 Mars 217 223

IPCC Fourth Assessment Report Summary for Policy Makers

At present trends the imbalance = 1 Watt/m2 in 2018 El Chichon (1982) Agung, 1963 Mt. Pinatubo (1991) At present trends the imbalance = 1 Watt/m2 in 2018 Hansen, Scientific American, March 2004

http://www.nytimes.com/interactive/2007/10/01/science/20071002_ARCTIC_GRAPHIC.html?ex=1191902400&en=c94928ddecd5ba57&ei=5070&emc=eta3

http://www.nytimes.com/interactive/2007/10/01/science/20071002_ARCTIC_GRAPHIC.html?ex=1191902400&en=c94928ddecd5ba57&ei=5070&emc=eta3

http://www.nytimes.com/interactive/2007/10/01/science/20071002_ARCTIC_GRAPHIC.html?ex=1191902400&en=c94928ddecd5ba57&ei=5070&emc=eta3

http://www.nytimes.com/interactive/2007/10/01/science/20071002_ARCTIC_GRAPHIC.html?ex=1191902400&en=c94928ddecd5ba57&ei=5070&emc=eta3

http://www.nytimes.com/interactive/2007/10/01/science/20071002_ARCTIC_GRAPHIC.html?ex=1191902400&en=c94928ddecd5ba57&ei=5070&emc=eta3

http://www.nytimes.com/interactive/2007/10/01/science/20071002_ARCTIC_GRAPHIC.html?ex=1191902400&en=c94928ddecd5ba57&ei=5070&emc=eta3

http://www.nytimes.com/interactive/2007/10/01/science/20071002_ARCTIC_GRAPHIC.html?ex=1191902400&en=c94928ddecd5ba57&ei=5070&emc=eta3

Source: Corell, R. W., 2004: Impacts of a warming Arctic. Arctic Climate Impact Assessment (www.acia.uaf.edu) Cambridge University Press (www.cambridge.org).

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

Antarctica Greenland Ice Volume Cold Warm Climate

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)

http://www.ncdc.noaa.gov/img/climate/research/2006/ann/glob_jan-dec-error-bar_pg.gif

Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg 2001. Grey bands indicate 68% and 95% range derived from multiple simulations.

Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg 2001. 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 2001. Grey bands indicate 68% and 95% range derived from multiple simulations. Not Natural

Highly Likely Not Natural Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg 2001. Grey bands indicate 68% and 95% range derived from multiple simulations. Highly Likely Not Natural Not Natural

Source: Jerry Meehl, National Center for Atmospheric Research From Jerry Meehl This slide shows the time evolution of globally averaged surface air temperature from multiple ensemble simulations of 20th century climate from the NCAR Parallel Climate Model (PCM) compared to observations. The simulations start in the late 19th century, and continue to the year 2000. The temperature scale at left is in degrees Centigrade, and temperature anomalies are calculated relative to a reference period averaged from 1890 to 1919. The black line shows the observed data, or the actual, recorded globally averaged surface air temperatures from the past century. The blue and red lines are the average of four simulations each from the computer model. The pink and light blue shaded areas depict the range of the four simulations for each experiment, giving an idea of the uncertainty of a given realization of 20th century climate from the climate model. The blue line shows the average from the four member ensemble of the simulated time evolution of globally average surface air temperature when only "natural" influences (solar variability and volcanic eruptions) are included in the model. Therefore, the blue line represents what the model says global average temperatures would have been if there had been no human influences. The red line shows the average of the four member ensemble experiment when natural forcings AND anthropogenic influences (greenhouse gases including carbon dioxide, sulfate aerosols from air pollution, and ozone changes) are included in the model. Note that this model can reproduce the actual, observed data very well only if the combined effects of natural and anthropogenic factors are included. The conclusion that can be drawn is that naturally occuring influences on climate contributed to most of the warming that occurred before WWII, but that the large observed temperature increases since the 1970s can only be simulated in the model if anthropogenic factors are included. This confirms the conclusion of the IPCC Third Assessment Report that most of the warming we have observed in the latter part of the 20th century has been due to human influences. Source: Jerry Meehl, National Center for Atmospheric Research

IPCC Fourth Assessment Report Summary for Policy Makers

Energy intensive Energy conserving Reduced Consumption IPCC Fourth Assessment Report Summary for Policy Makers

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

Energy intensive Energy conserving Mitigation Possible Adaptation Reduced Consumption Energy conserving Possible Mitigation Necessary Adaptation IPCC Fourth Assessment Report Summary for Policy Makers

IPCC Fourth Assessment Report Summary for Policy Makers

IPCC Fourth Assessment Report Summary for Policy Makers

Tin and Seager

Four-Component Approach for Addressing Climate Change Mitigation policies: 2050-2100 Example: reduction in GHG emissions Adaptation (long-term): 2015-2050 Example: Developing Iowa’s competitive economic advantage Adaptation (short-term): 2008-2015 Example: redefining climate “normals” when needed and scientifically justified Scenario planning for Iowa’s “Katrina”: 2007-2100 Example: Multi-year drought, recurrent floods, combination of both; drought and wildfire EST personal view

Climate Adaptation(Short-Term) 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. EST personal view

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

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

Reasons Crop Yields Might Increase in the Midwest More precipitation More soil moisture Higher dew-point temperatures reduces moisture stress Higher CO2 increased carbon uptake by crops Higher CO2 increases the water-use efficiency of crops

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

D. Herzmann, Iowa Environmental Mesonet

D. Herzmann, Iowa Environmental Mesonet

D. Herzmann, Iowa Environmental Mesonet

D. Herzmann, Iowa Environmental Mesonet

D. Herzmann, Iowa Environmental Mesonet

D. Herzmann, Iowa Environmental Mesonet

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

For More Information Or just Google Eugene Takle For peer-reviewed evidence supporting everything you have seen in this presentation, see my online Global Change course: http://www.meteor.iastate.edu/gccourse Contact me directly: gstakle@iastate.edu Current research on regional climate and climate change is being conducted at Iowa State Unversity under the Regional Climate Modeling Laboratory http://rcmlab.agron.iastate.edu/ North American Regional Climate Change Assessment Program http://www.narccap.ucar.edu/ For this and other climate change presentations see my personal website: http://www.meteor.iastate.edu/faculty/takle/ Or just Google Eugene Takle