1. Climate Change and Impact on Corn and Grain Quality
Eugene S. Takle
Professor of Agricultural Meteorology, Department of Agronomy
Professor of Atmospheric Science, Department of Geological and Atmospheric Sciences
Director, Climate Science Initiative
Iowa State University
49th Annual Corn Dry Milling Conference, May 2008, Peoria, IL

2. Comparison of natural variability of climate and human induced climate change
Projections of future climate change
Impact of climate change on “regions suitable for rain-fed agriculture”, including the US Midwest
What does this mean for agriculture and corn production in the US Midwest?
Outline

3. 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,

4. 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,
Pattern repeats about every 100,000 years
Natural cycles

5. IPCC Third Assessment Report

6. Carbon Dioxide and Temperature
2008
384 ppm

7. Carbon Dioxide and Temperature
2050
550 ppm

8. Carbon Dioxide and Temperature
“Business as Usual”
950 ppm

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

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

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

13. IPCC Fourth Assessment Report Summary for Policy Makers

15. 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.

16. 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

17. 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

18. 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
The temperature scale at left is in degrees Centigrade, and
temperature anomalies are calculated relative to a reference period
averaged from 1890 to 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

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

20. 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

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

24. Suitability Index for Rainfed Agriculture
IPCC 2007

25. Suitability Index for Rainfed Agriculture
IPCC 2007

26. Projected changes in precipitation between and for an energy-conserving scenario of greenhouse gas emissions
IPCC 2007

27. 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)
Follows trend of last 25 years and projected by models No current trend but model suggestion or current trend but models inconclusive
*Estimated from IPCC reports

28. Projected Changes* for the Climate of the Midwest Precipitation
More (~10%) precipitation annually (medium)
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)
Snowfall increases (late winter) in short term but decreases in long run (medium)
More winter soil moisture recharge
Follows trend of last 25 years and projected by models No current trend but model suggestion or current trend but models inconclusive
*Estimated from IPCC reports

29. Projected Changes* for the Climate of the Midwest Other
Reduced wind speeds (high)
Reduced solar radiation (medium)
Increased tropospheric ozone (high)
Accelerated loss of soil carbon (high)
Phenological states 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 models inconclusive
*Estimated from IPCC and CCSP reports

31. 2007 April Freeze Event
Gu, et al, 2008: The eastern US spring freeze: Increased cold damage in a warming world? Bioscience 58 (3),

32. 2007 April Freeze Event
Gu, et al, 2008: The eastern US spring freeze: Increased cold damage in a warming world? Bioscience 58 (3),

33. 2007 April Freeze Event
Gu, et al, 2008: The eastern US spring freeze: Increased cold damage in a warming world? Bioscience 58 (3),

34. 2007 April Freeze Event
Gu, et al, 2008: The eastern US spring freeze: Increased cold damage in a warming world? Bioscience 58 (3),

35. 2007 April Freeze Event
Gu, et al, 2008: The eastern US spring freeze: Increased cold damage in a warming world? Bioscience 58 (3),

36. Climate change since the 1970s cannot be explained on the basis of natural variation alone (consensus)
Greenhouse gases emitted from burning fossil fuels account for more than half of the current warming (consensus)
The warming already introduced will persist for more than a century (consensus)
Corn production will encounter some benefits and numerous challenges (my assessment based on consensus)
The US Midwest likely will suffer less adverse effects of climate change than many other major rain-fed agricultural areas (my assessment based on consensus)
Summary