Global Climate Change: How did we get here and what does it mean for the Midwest?

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Global Climate Change How did we get here and
what does it mean for the Midwest?

• 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 50011
• gstakle_at_iastate.edu

Environmental Science Learning Community Iowa
State University Ames Iowa 17 November 2008
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Outline

• Changes in atmospheric carbon dioxide
• Radiative forcing
• Simulations of global climate and future climate
  change
• Climate change for the US Midwest
• Climate change and global food production

Except where noted as personal views or from the
ISU Global Change course, all materials presented
herein are from peer-reviewed scientific reports
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Pattern repeats about every 100,000 years
Natural cycles
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IPCC Third Assessment Report
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Carbon Dioxide and Temperature
2008 384 ppm
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Carbon Dioxide and Temperature
2050 550 ppm
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Carbon Dioxide and Temperature
Business as Usual 950 ppm
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Carbon Dioxide and Temperature
Business as Usual 950 ppm
?
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http//www.ncdc.noaa.gov/img/climate/research/2006
/ann/glob_jan-dec-error-bar_pg.gif
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Source IPCC, 2001 Climate Change 2001 The
Scientific Basis
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Source IPCC, 2001 Climate Change 2001 The
Scientific Basis
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IPCC Fourth Assessment Report Summary for Policy
Makers
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El Chichon (1982)
Agung, 1963
Mt. Pinatubo (1991)
At present trends the imbalance 1 Watt/m2 in
2018
Hansen, Scientific American, March 2004
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Arctic Sea-Ice Extent Observed and Projected by
Global Climate Models
2005
2008
2007
Meehl, G.A.,et al, 2007 Global Climate
Projections. In Climate Change 2007 The
Physical Science Basis. Contribution of Working
Group I to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change
Solomon, S., D. Qin, M. Manning, Z. Chen, M.
Marquis, K.B. Averyt, M. Tignor and H.L. Miller
(eds.). Cambridge University Press, Cambridge,
United Kingdom and New York, NY, USA. Chapter
10, p. 771
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Hansen, Scientific American, March 2004
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http//www.ncdc.noaa.gov/img/climate/research/2006
/ann/glob_jan-dec-error-bar_pg.gif
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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.
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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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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.
Highly Likely Not Natural
Not Natural
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http//www.pmodwrc.ch/pmod.php?topictsi/composite
/SolarConstant
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Source Jerry Meehl, National Center for
Atmospheric Research
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Energy intensive
Reduced Consumption
Energy conserving
IPCC Fourth Assessment Report Summary for Policy
Makers
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Energy intensive
Reduced Consumption
Energy conserving
The planet is committed to a warming over the
next 50 years regardless of political decisions
IPCC Fourth Assessment Report Summary for Policy
Makers
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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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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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Precipitation minus Evaporation for Western
US (25N-40N, 95W-125 W)
R. Seager, et al.,2007. Model Projections of an
Imminent Transition to a More Arid Climate in
Southwestern North America. Science, Vol. 316.
no. 5828, pp. 1181 - 1184
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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)

Estimated from IPCC reports
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
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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)
• More winter soil moisture recharge (medium)
• Snowfall increases (late winter) in short term
  but decreases in the
  long run (medium)

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

Estimated from IPCC and CCSP reports
Follows trend of last 25 years and projected by
models No current trend but model suggestion or
current trend but model inconclusive
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Observed summer (June-July-August) daily mean
temperature changes (K) between 1976-2000
(Adapted from Folland et al. 2001).
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Warming Hole
DTmax (JJA)
C
Pan, Z., R. W. Arritt, E. S. Takle, W. J.
Gutowski, Jr., C. J. Anderson, and M. Segal,
2004 Altered hydrologic feedback in a warming
climate introduces a warming hole. Geophys.
Res. Lett.31, L17109, doi10.1029/2004GL020528.
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Des Moines Airport Data
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Des Moines Airport Data
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Des Moines Airport Data
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Des Moines Airport Data
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Des Moines Airport Data
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D. Herzmann, Iowa Environmental Mesonet
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D. Herzmann, Iowa Environmental Mesonet
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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 101.6
mm (four inches) in the upper midwestern U.S.
this trend is statistically significant
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Des Moines Airport Data
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Cedar Rapids Data
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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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US Corn Yields (Bushels/Acre)
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Grain and oilseed consumption has exceeded
production 7 of last 8 years
Tostle, Ronald, 2008 Global Agricultural Supply
and Demand Factors Contributing to the Recent
Increase in Food Commodity Prices WRS-0801 May
2008. USDA/ERS
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How Will New Trends and Variability of Regional
Climate Change Affect

• Crop horticulture production
• Soil erosion
• Conservation practices
• Water supplies
• Streamflow
• Water quality
• Beef and pork daily gains
• Livestock breeding success
• Milk and egg production
• Crop and livestock pests and pathogens

• Agricultural tile drainage systems
• Natural ecosystem species distributions
• Human health
• Building designs
• Recreation opportunities
• River navigation
• Roads and bridges

Who will provide authoritative information? How
will it be delivered?
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Summary

• Global temperature change of the last 30 years
  cannot be explained on the basis of natural
  radiative forcing alone. Only when anthropogenic
  effects are considered can we explain recent
  temperature trends
• Mitigation efforts, although urgently needed,
  will have little effect on global warming until
  the latter half of the
  21st century
• Adaptation strategies should be
  developed for the next 50 years
• Some, but not all, climate changes
  consistent with model projections of future
  climate already are being observed
• There is an urgent need to assess changes
  in global food production due to
  climate change

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For More Information

• For peer-reviewed evidence supporting everything
  you have seen in this presentation, see my online
  Global Change course
• http//www.meteor.iastate.edu/gccourse
• Contact me directly
• gstakle_at_iastate.edu
• Current research on regional climate and climate
  change is being conducted at Iowa State Unversity
  under the Regional Climate Modeling Laboratory
• http//rcmlab.agron.iastate.edu/
• North American Regional Climate Change Assessment
  Program
• http//www.narccap.ucar.edu/
• For this and other climate change presentations
  see my personal
  website
• http//www.meteor.iastate.edu/faculty/takle/

Or just Google Eugene Takle