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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 gstakle@iastate.edu.
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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 gstakle@iastate.edu 2005 Seeds and Breeds Conference, 11-14 September 2005, Ames, IA
Climate Change • What is changing? • How much is it changing? • Why is it changing? • How might it affect agriculturalists? • What should we do about it?
Source: IPCC, 2001: Climate Change 2001: The Scientific Basis
Source: IPCC, 2001: Climate Change 2001: The Scientific Basis
“Warming Hole” ˚C DTmax (JJA)
Surface Energy Balance Latent Conv & Cond IR IR Solar T Soil
Surface Energy Balance Latent Conv & Cond IR IR Solar T Soil
El Chichon (1982) Agung, 1963 Mt. Pinatubo (1991) Hansen, Scientific American, March 2004
Carbon Dioxide and Temperature 2004 (377 ppm)
Carbon Dioxide and Temperature “Business as Usual” (fossil intensive) 2100
V V V Source: Jerry Meehl, National Center for Atmospheric Research
Tropical Atlantic Ocean Hurricane Power Dissipation Index (PDI) Sea-surface temperature V V V Emanual, Kerry, 2005: Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436, 686-688.
Sea-Surface Temperatures in August 2005 Weather Underground: http://www.wunderground.com/tropical/
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: gstakle@iastate.edu For a copy of this presentation: http://www.meteor.iastate.edu/faculty/takle/