Recent Observed and Projected Future Climate Trends for the Midwest: Agricultural Impacts Eugene S. Takle Director, Climate Science Initiative Professor of Atmospheric Science Department of Geological and Atmospheric Sciences Professor of Agricultural Meteorology Department of Agronomy Iowa State University Ames, Iowa Eugene S. Takle Director, Climate Science Initiative Professor of Atmospheric Science Department of Geological and Atmospheric Sciences Professor of Agricultural Meteorology Department of Agronomy Iowa State University Ames, Iowa Climate Change and Its Impacts on Food Production and Biofuels Ames, Iowa 2 March 2010

“I hear so many conflicting views on climate change, I don’t know what or who to believe” Soybean producer from NE Iowa

 Established on 3 March 1863 by Abraham Lincoln  Act of Incorporation: to "investigate, examine, experiment, and report upon any subject of science or art" whenever called upon to do so by any department of the government  June 2001: National Academy of Sciences Committee on the Science of Climate Change concludes that human-induced global warming is a serious issue [  Established on 3 March 1863 by Abraham Lincoln  Act of Incorporation: to "investigate, examine, experiment, and report upon any subject of science or art" whenever called upon to do so by any department of the government  June 2001: National Academy of Sciences Committee on the Science of Climate Change concludes that human-induced global warming is a serious issue [ US National Academy of Sciences

 "Human activities... are modifying the concentration of atmospheric constituents... that absorb or scatter radiant energy.... [M]ost of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations” (NAS, 2001: p. 21)  "The IPCC's conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue” (NAS, 2001: p. 3)  "Human activities... are modifying the concentration of atmospheric constituents... that absorb or scatter radiant energy.... [M]ost of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations” (NAS, 2001: p. 21)  "The IPCC's conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue” (NAS, 2001: p. 3) National Academy of Sciences Committee on the Science of Climate Change, 2001: Climate Change Science: An Analysis of Some Key Questions. National Academy Press, Washington, DC. US National Academy of Sciences

A critical examination of climate modeling as a basis for assessing climate change  Morning session:  The scientific basis underpinning climate change projections for the 21 st century  Recent trends in Midwest climate relating to agriculture and farmer adaptations  Afternoon sessions:  Limitations of climate models (Arritt)  Recent mild summers: What’s going on? (Anderson)  Emerging climate forecasting techniques (applications maybe you hadn’t thought about)(Gutowski)  Morning session:  The scientific basis underpinning climate change projections for the 21 st century  Recent trends in Midwest climate relating to agriculture and farmer adaptations  Afternoon sessions:  Limitations of climate models (Arritt)  Recent mild summers: What’s going on? (Anderson)  Emerging climate forecasting techniques (applications maybe you hadn’t thought about)(Gutowski) Presenters collectively have over 50 years of global and regional climate modeling research experience

In science, the prevailing theory is the one that explains the balance of evidence What is the evidence?

Global Mean Surface Temperature

Global Mean Surface Temperature

Global Mean Surface Temperature

NASA

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

Temperature Trends in Upper and Lower Atmosphere Upper Atmosphere (Stratosphere) Lower Atmosphere (Troposphere)

“One of the clearest trends in the United States observational record is an increasing frequency and intensity of heavy precipitation events… Over the last century there was a 50% increase in the frequency of days with precipitation over mm (four inches) in the upper midwestern U.S.; this trend is statistically significant “ Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

Arctic Sea-Ice Decline

Decline in Greenland Ice Mass Equivalent to about 5 ft of ice over the state of Iowa each year

Emanual, Kerry, 2005: Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436, Sea-surface temperature VV Tropical Atlantic Ocean Hurricane Power Dissipation Index (PDI) V

Ocean Heat Content 1 o C rise in top 3 m of global ocean is equivalent to a 1 o C rise in entire atmosphere

Where is this extra heat coming from? Possible mechanisms: More solar radiation Less reflection from clouds Less reflection from Earth’s surface More energy trapped and recycled by ozone and greenhouse gases

Earth’s Energy Balance: Incoming solar = outgoing infrared radiation But rapid changes in atmosphere and ocean temperatures and loss of land and sea ice indicate an imbalance

Earth’s Energy Balance: Incoming solar = outgoing infrared radiation But rapid changes in atmosphere and ocean temperatures and loss of land and sea ice indicate an imbalance ? ? ? ?

*Other solar cycles have periods of 22,000, 41,000, and 100,000 years with 0.1% variation. 0.1 %

Forcing Factors in the Global Climate Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp. More trapped (recycled) heat More cloud & land reflection See Arritt for details this afternoon

Increased Greenhouse Gases => Global Heating Increasing greenhouse gases increases heating of the Earth

Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009.

Global Carbon Emissions (Gt) Actual emissions are exceeding worst case scenarios projected in 1990

Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp. Warming of the Lower and Upper Atmosphere Produced by Natural and Human Causes

Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp. Warming of the Lower and Upper Atmosphere Produced by Natural and Human Causes Note that greenhouse gases have a unique temperature signature, with strong warming in the upper troposphere, cooling in the lower stratosphere and strong warming over the North Pole. No other warming factors have this signature.

Global Mean Surface Temperature

Attribution studies: See Anderson this afternoon for applications to the Midwest

Source: Jerry Meehl, National Center for Atmospheric Research

The balance of evidence for the magnitude and distribution of warming is explained by increases in atmospheric greenhouse gases

IPCC Fourth Assessment Report Summary for Policy Makers Balanced fuel sources Energy intensive More environmentally friendly If current emission trends continue, global temperature rise will exceed worst case scenarios projected in 2007 FI =fossil intensive

IPCC 2007

December- January- February Temperature Change A1B Emission Scenario minus o F 6.3 o F

IPCC 2007

June-July- August Temperature Change A1B Emission Scenario minus o F 5.4 o F

June-July- August Temperature Change A1B Emission Scenario minus o F 5.4 o F Not the direction of current trends (see Anderson this afternoon)

IPCC 2007

Low confidence in model projection of summer precipitation. See Arritt presentation this afternoon

IPCC 2007

Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

Low confidence: See Arritt this afternoon Emerging techniques for improvement: See Gutowski this afternoon

Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp. Trend of increase in occurrence of heavy precipitation over the 20 th C is consistent with increasing GHG concentrations. Frequency of intense precipitation events is likely to increase in the future.

Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp. Mitigation Possible Adaptation Necessary Adaptation Necessary The planet is committed to a warming over the next 50 years regardless of political decisions

Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp. Mitigation Possible Adaptation Necessary Adaptation Necessary The planet is committed to a warming over the next 50 years regardless of political decisions Farmers install more drainage tile

Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp. Adaptation Necessary Adaptation Necessary Mitigation Possible The planet is committed to a warming over the next 50 years regardless of political decisions

Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp. Adaptation Necessary Adaptation Necessary Mitigation Possible The planet is committed to a warming over the next 50 years regardless of political decisions Farmers plant earlier, choose longer season hybrids

Adapted from Folland et al. [2001] Observed Summer (JJA) Daily Maximum Temperature Changes (K),

Adapted from Folland et al. [2001] Observed Summer (JJA) Daily Maximum Temperature Changes (K), See Anderson presentation this afternoon

Des Moines Airport Data 1983: : : 0

Des Moines Airport Data 1983: : : 0 6 days ≥ 100 o F in the last 20 years

State-Wide Average Data

Totals above 40”

Cedar Rapids Data

Relationship of Streamflow to Precipitation in Current and Future Climates

D. Herzmann, Iowa Environmental Mesonet

State-Wide Average Data

Projected Changes* for the Climate of the Midwest Temperature  Longer frost-free period (high)  Higher average winter temperatures (high)  Fewer extreme cold temperatures in winter (high)  Fewer extreme high temperatures in summer in short term but more in long term (medium)  Higher nighttime temperatures both summer and winter (high)  More freeze-thaw cycles (high)  Increased temperature variability (high)  Longer frost-free period (high)  Higher average winter temperatures (high)  Fewer extreme cold temperatures in winter (high)  Fewer extreme high temperatures in summer in short term but more in long term (medium)  Higher nighttime temperatures both summer and winter (high)  More freeze-thaw cycles (high)  Increased temperature variability (high) Follows trend of last 25 years and projected by models No current trend but model suggestion or current trend but model inconclusive *Estimated from IPCC reports

 More (~10%) precipitation annually (medium)  Change in “seasonality”: Most of the increase will come in the first half of the year (wetter springs, drier summers) (high)  More water-logging of soils (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)  More winter soil moisture recharge (medium)  Snowfall increases (late winter) in short term but decreases in the long run (medium)  More (~10%) precipitation annually (medium)  Change in “seasonality”: Most of the increase will come in the first half of the year (wetter springs, drier summers) (high)  More water-logging of soils (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)  More winter soil moisture recharge (medium)  Snowfall increases (late winter) in short term but decreases in the long run (medium) *Estimated from IPCC reports Projected Changes* for the Climate of the Midwest Precipitation Follows trend of last 25 years and projected by models No current trend but model suggestion or current trend but model inconclusive

 Reduced wind speeds (high)  Reduced solar radiation (medium)  Increased tropospheric ozone (high)  Accelerated loss of soil carbon (high)  Phenological stages are shortened (high)  Weeds grow more rapidly under elevated atmospheric CO2 (high)  Weeds migrate northward and are less sensitive to herbicides (high)  Plants have increased water used efficiency (high)  Reduced wind speeds (high)  Reduced solar radiation (medium)  Increased tropospheric ozone (high)  Accelerated loss of soil carbon (high)  Phenological stages are shortened (high)  Weeds grow more rapidly under elevated atmospheric CO2 (high)  Weeds migrate northward and are less sensitive to herbicides (high)  Plants have increased water used efficiency (high) Follows trend of last 25 years and projected by models No current trend but model suggestion or current trend but model inconclusive *Estimated from IPCC and CCSP reports Projected Changes* for the Climate of the Midwest Other

Iowa Agricultural Producers’ Adaptations to Climate Change  Longer growing season: plant earlier, plant longer season hybrids, harvest later  Wetter springs: larger machinery enables planting in smaller weather windows  More summer precipitation: higher planting densities for higher yields  Wetter springs and summers: more subsurface drainage tile is being installed, closer spacing, sloped surfaces  Fewer extreme heat events: higher planting densities, fewer pollination failures  Higher humidity: more spraying for pathogens favored by moist conditi ons  Drier autumns: delay harvest to take advantage of natural dry-down conditions  Longer growing season: plant earlier, plant longer season hybrids, harvest later  Wetter springs: larger machinery enables planting in smaller weather windows  More summer precipitation: higher planting densities for higher yields  Wetter springs and summers: more subsurface drainage tile is being installed, closer spacing, sloped surfaces  Fewer extreme heat events: higher planting densities, fewer pollination failures  Higher humidity: more spraying for pathogens favored by moist conditi ons  Drier autumns: delay harvest to take advantage of natural dry-down conditions HIGHER YIELDS!! Is it genetics or climate? See Anderson this afternoon

Will These Agriculturally Favorable Midwest Climate Trends Continue?  In the short-term (next 5-10 years) climatic conditions will be dominated by natural variability from base conditions of the past 20 years (not long-term averages)  If we continue to have high spring and summer rainfall and soil moisture, we likely will continue to have lower chances of extended periods of extreme heat  If we continue to have high spring and summer rainfall and soil moisture, we likely will continue to have pathogens favored by high humidities  In the longer term (>50 years), hot summers, milder winters, and higher variability of precipitation will become more dominant  Failure to limit global carbon emissions will accelerate trends toward less favorable agricultural climate for Iowa  In the short-term (next 5-10 years) climatic conditions will be dominated by natural variability from base conditions of the past 20 years (not long-term averages)  If we continue to have high spring and summer rainfall and soil moisture, we likely will continue to have lower chances of extended periods of extreme heat  If we continue to have high spring and summer rainfall and soil moisture, we likely will continue to have pathogens favored by high humidities  In the longer term (>50 years), hot summers, milder winters, and higher variability of precipitation will become more dominant  Failure to limit global carbon emissions will accelerate trends toward less favorable agricultural climate for Iowa Caution: These are my speculations!!

Suitability Index for Rainfed Agriculture IPCC 2007

Summary  There is no scientifically defensible explanation for atmospheric warming, increase in ocean heat content, and loss of ocean and land ice over the last 40 year other than increase of anthropogenic greenhouse gases  Some recent climate trends in the Midwest that have been favorable to agriculture likely will continue in the next few years  Climate challenges to agriculture will intensify toward mid-century  Global and regional climate models have much to offer for understanding future Midwest and global agricultural production: Agriculture needs future climate information at regional scales.  The afternoon climate model session will be led by world experts in seasonal climate forecast models, future climate extremes, and attribution studies.  There is no scientifically defensible explanation for atmospheric warming, increase in ocean heat content, and loss of ocean and land ice over the last 40 year other than increase of anthropogenic greenhouse gases  Some recent climate trends in the Midwest that have been favorable to agriculture likely will continue in the next few years  Climate challenges to agriculture will intensify toward mid-century  Global and regional climate models have much to offer for understanding future Midwest and global agricultural production: Agriculture needs future climate information at regional scales.  The afternoon climate model session will be led by world experts in seasonal climate forecast models, future climate extremes, and attribution studies.

For More Information  National academies of science joint statement (May 2009): G8+5 Academies’ joint statement: Climate change and the transformation of energy technologies for a low carbon future. [  North American Regional Climate Change Assessment Program:  For current activities on the ISU campus, regionally and nationally relating to climate change see the Climate Science Initiative website:  Contact me directly:  National academies of science joint statement (May 2009): G8+5 Academies’ joint statement: Climate change and the transformation of energy technologies for a low carbon future. [  North American Regional Climate Change Assessment Program:  For current activities on the ISU campus, regionally and nationally relating to climate change see the Climate Science Initiative website:  Contact me directly: