Climate Change and Agriculture

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Climate Change and Agriculture 

• 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
• gstakle_at_iastate.edu

Agricultural Summit and Roundtable, Ames, IA 31
July 2008
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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
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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
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Source Jerry Meehl, National Center for
Atmospheric Research
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Energy intensive
Reduced Consumption
Energy conserving
Mitigation Possible
Adaptation Necessary
IPCC Fourth Assessment Report Summary for Policy
Makers
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(No Transcript)
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Suitability Index for Rainfed Agriculture
IPCC 2007
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Suitability Index for Rainfed Agriculture
IPCC 2007
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Projected changes in precipitation between
1980-1999 and 2080-2099 for an energy-conserving
scenario of greenhouse gas emissions
IPCC 2007
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Insured Crop Loss for Corn in Iowa
  Factor Percent Cold Winter 0.9 Decline
in Price 6.6 Drought 35.5 Excess
Moist/Precip/Rain 38.4 Flood
2.6 Freeze 0.1 Hail
7.2 Heat 1.2 Hot Wind
0.0 Mycotoxin (Aflatoxin) 1.0 Plant
Disease 0.3 Winds/Excess Wind
5.0 Other 1.1 Total 100.0
Milliman, Inc., based on 1995-2006 data from the
Risk Management Agency Website (http//www.rma.usd
a.gov/)
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Insured Crop Loss for Corn in Iowa
  Factor Percent Cold Winter 0.9 Decline
in Price 6.6 Drought 35.5 Excess
Moist/Precip/Rain 38.4 Flood
2.6 Freeze 0.1 Hail
7.2 Heat 1.2 Hot Wind
0.0 Mycotoxin (Aflatoxin) 1.0 Plant
Disease 0.3 Winds/Excess Wind
5.0 Other 1.1 Total 100.0
Milliman, Inc., based on 1995-2006 data from the
Risk Management Agency Website (http//www.rma.usd
a.gov/)
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Insured Crop Loss for Soybeans in Iowa
Factor Percent Cold Winter 0.6 Decline
in Price 4.8 Drought 56.8 Excess
Moist/Precip/Rain 20.2 Flood
1.4 Freeze 0.1 Hail 13.0 Heat
0.9 Hot Wind 0.0 Mycotoxin
(Aflatoxin) 0.0 Plant Disease
1.1 Winds/Excess Wind 0.2 Other
1.1 Total 100.0
Milliman, Inc., based on 1995-2006 data from the
Risk Management Agency Website (http//www.rma.usd
a.gov/)
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Insured Crop Loss for Soybeans in Iowa
Factor Percent Cold Winter 0.6 Decline
in Price 4.8 Drought 56.8 Excess
Moist/Precip/Rain 20.2 Flood
1.4 Freeze 0.1 Hail 13.0 Heat
0.9 Hot Wind 0.0 Mycotoxin
(Aflatoxin) 0.0 Plant Disease
1.1 Winds/Excess Wind 0.2 Other
1.1 Total 100.0
Milliman, Inc., based on 1995-2006 data from the
Risk Management Agency Website (http//www.rma.usd
a.gov/)
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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
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Projected Changes for the Climate of the
Midwest Precipitation

• 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)
• 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
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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