Transcript PPT File - Iowa State University

Climate Change and Possible
Impacts on US Plant and Animal
Agriculture
Eugene S. Takle
Professor of Agricultural Meteorology, Department of Agronomy
Professor of Atmospheric Science, Department of Geological and
Atmospheric Sciences
Iowa State University
[email protected]
2005 Seeds and Breeds Conference, 11-14 September 2005, Ames, IA
Climate Change
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What is changing?
How much is it changing?
Why is it changing?
How might it affect agriculturalists?
What should we do about it?
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Source: IPCC, 2001: Climate Change 2001: The Scientific Basis
Source: IPCC, 2001: Climate Change 2001: The Scientific Basis
JJA Daily Maximum Temperature Trends, 1976-2000
“Warming Hole”
˚C
DTmax (JJA)
Surface Energy Balance
Solar
IR
IR
T
Soil
Latent
Conv & Cond
Surface Energy Balance
Solar
IR
IR
T
Soil
Latent
Conv & Cond
Agung, 1963
El Chichon (1982)
Mt. Pinatubo (1991)
Hansen, Scientific American, March 2004
Carbon Dioxide and Temperature
Carbon Dioxide and Temperature
2004
(377
ppm)
Carbon Dioxide and Temperature
“Business as Usual”
(fossil intensive)
2100
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http://www.earth-policy.org/Indicators/CO2/2004.htm
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Source: Jerry Meehl, National Center for Atmospheric Research
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V
Tropical Atlantic Ocean
Hurricane Power Dissipation Index (PDI)
Sea-surface temperature
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V
V
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Emanual, Kerry, 2005: Increasing destructiveness of tropical cyclones over
the past 30 years. Nature, 436, 686-688.
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Sea-Surface Temperatures in August 2005
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Weather Underground: http://www.wunderground.com/tropical/
Source: National Center for Atmospheric Research
The planet is committed to
a warming over the next
50 years regardless of
political decisions
Source: National Center for Atmospheric Research
40% Probability
5% Probability
Source: Intergovernmental Panel on Climate Change, 2001 Report
For the Midwest**
• Warming will be greater for winter than summer (+)
• Warming will be greater at night than during the day (+)
• A 3oF rise in summer daytime temperature triples the
probability of a heat wave
• Growing Frost-free season will be longer (+, 8-9 days
longer now than in 1950)
• More precipitation (+)
• Likely more soil moisture in summer
• More rain will come in intense rainfall events (+)
• Higher stream flow, more flooding
+ already observed
** North American Regional Climate Change Assessment
Program is underway but results for impacts won’t be
available for several months.
Climate Change Impacts on Food
Animals (my speculations)
• Lower breeding success in warmer temperatures
• More freeze thaw cycles in beef-raising regions of the
Midwest (more sickness)
• Reduced milk production in warmer temperatures
• Poleward movement of tropical disease zones
• Reduced weight gain by meat animals due to heat
stress in warmer temperatures
• More intense rain events -> more care in manure
management
• More favorable conditions for meat animal production
in Canada, Russia
Climate Change Impacts on
Agricultural Plants (my speculations)
• Increase in CO2
– increase in water-use efficiency by plants and
accelerated growth
• Increase in night-time temperatures
– Higher night-time respiration by plants
– Higher soil respiration and loss of soil carbon
– Less dewfall
• Increase in daytime maximum temperatures
– More heat waves, more heat stress
– Reduced success for pollination
Climate Change Impacts on Agricultural
Plants (my speculations)
• Altered large-scale weather patterns
– Changed patterns for spread of air-borne pathogens
• Changes in precipitation
– Increased amount -> more soil erosion, more nitrate leaching
– Larger fraction of total rain will come in heavy rain events
and may produce more floods and droughts
– Longer periods between rains reduces some fungal
outbreaks
– Possible changed seasonality
– Possible changed diurnal patterns -> changes in soil
moisture
Climate Change Impacts on Agricultural
Plants (my speculations)
• Increased overwintering of pests and pathogens
• Higher absolute humidity -> more pathogens
• Decreased mean wind speed
– Reduced lateral spread of pollen, pesticides, pathogens
• Deeper atmospheric boundary layer (lowest mile of
the atmosphere)
– More vertical mixing of pollen, pesticides,pathogens
– More opportunity for long-range transport
Mitigation vs. Adaptation:
Since we are already committed to a global
warming of about 2-4o F over the next 40 years
we need to focus on:
• Adaptation to climate change for food security in
the next half decade
• Mitigation of continued rise in greenhouse
gases so our (great)n -grand children will have
as many opportunities as we have had.
• More dialog between agriculturists and climate
scientists to help prioritize climate research
efforts.
For More Information
For peer-reviewed evidence supporting these slides
(except some of my speculations), see my online Global
Change course:
http://www.meteor.iastate.edu/gccourse
Contact me directly:
[email protected]
For a copy of this presentation:
http://www.meteor.iastate.edu/faculty/takle/