Global%20Climate%20Change:%20Recent%20Trends%20and%20Future%20Projections

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Global Climate Change Recent Trends and Future
Projections

• Eugene S. Takle, PhD, CCM
• Professor of Atmospheric Science
• Department of Geological and Atmospheric Sciences
• Professor of Agricultural Meteorology
• Department of Agronomy
• Faculty Director, University Honors Program
• Iowa State University
• Ames, Iowa 50011
• gstakle_at_iastate.edu

Chemical Engineering 302 Iowa State University 11
October 2007
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Image courtesy of NASA/GSFC
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Outline

• Changes in atmospheric carbon dioxide
• Radiative forcing
• Simulations of global climate and future climate
  change
• Four components for addressing climate change
• Climate change for Iowa and the Midwest
  adaptation strategy

Except where noted as personal views or from the
ISU Global Change course or the Iowa
Environmental Mesonet, 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
2007 380 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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Mann, M. E., R. S. Bailey, and M. K. Hughes,
1999 Geophysical Research Letters 26, 759.
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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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Ts
e
Planet Te(K) Ts(K) Earth 256
288 Venus 227 732 Mars 217 223
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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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http//www.nytimes.com/interactive/2007/10/01/scie
nce/20071002_ARCTIC_GRAPHIC.html?ex1191902400en
c94928ddecd5ba57ei5070emceta3
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http//www.nytimes.com/interactive/2007/10/01/scie
nce/20071002_ARCTIC_GRAPHIC.html?ex1191902400en
c94928ddecd5ba57ei5070emceta3
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http//www.nytimes.com/interactive/2007/10/01/scie
nce/20071002_ARCTIC_GRAPHIC.html?ex1191902400en
c94928ddecd5ba57ei5070emceta3
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http//www.nytimes.com/interactive/2007/10/01/scie
nce/20071002_ARCTIC_GRAPHIC.html?ex1191902400en
c94928ddecd5ba57ei5070emceta3
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http//www.nytimes.com/interactive/2007/10/01/scie
nce/20071002_ARCTIC_GRAPHIC.html?ex1191902400en
c94928ddecd5ba57ei5070emceta3
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http//www.nytimes.com/interactive/2007/10/01/scie
nce/20071002_ARCTIC_GRAPHIC.html?ex1191902400en
c94928ddecd5ba57ei5070emceta3
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http//www.nytimes.com/interactive/2007/10/01/scie
nce/20071002_ARCTIC_GRAPHIC.html?ex1191902400en
c94928ddecd5ba57ei5070emceta3
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Source Corell, R. W., 2004 Impacts of a
warming Arctic. Arctic Climate Impact Assessment
(www.acia.uaf.edu) Cambridge University Press
(www.cambridge.org).
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Kennedy Space Center
Impact of a 1-m rise in sea level on low-lying
areas
Projected sea-level rise In 21st century 0.5 to
1.0 m
Areas subjected to Inundation with a 1 m (3 ft)
rise in sea level
Miami
Source Corell, R. W., 2004 Impacts of a
warming Arctic. Arctic Climate Impact Assessment
(www.acia.uaf.edu) Cambridge University Press
(www.cambridge.org).
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Antarctica
Greenland
Ice Volume
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Warm
Cold
Climate
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Hansen, Scientific American, March 2004
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An exhibition of old and new photographs at the
Swiss Alpine Museum in Bern documents the gradual
disappearance of Switzerland's glaciers.?The
Rhone glacier with the Hotel Belvedere in the
foreground and the Furka pass, Canton Valais
circa 1906 and 2003?(Pictures Gesellschaft fur
okologische Forschung, Munich)
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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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Source Jerry Meehl, National Center for
Atmospheric Research
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IPCC Fourth Assessment Report Summary for Policy
Makers
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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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IPCC Fourth Assessment Report Summary for Policy
Makers
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IPCC Fourth Assessment Report Summary for Policy
Makers
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Tin and Seager
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Four-Component Approach for Addressing Climate
Change

• Mitigation policies 2050-2100
• Example reduction in GHG emissions
• Adaptation (long-term) 2015-2050
• Example Developing Iowas competitive economic
  advantage
• Adaptation (short-term) 2008-2015
• Example redefining climate normals
  when needed and scientifically justified
• Scenario planning for Iowas Katrina 2007-2100
• Example Multi-year drought, recurrent floods,
  combination of both drought and wildfire

EST personal view
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Climate Adaptation(Short-Term)
If a meteorological variable began departing from
its long-term background near or after 1970 it
may be related to the radiation imbalance and
thereby has a better chance than not of
continuing its new trend over the next 5-10 years.
EST personal view
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Projected Changes for the Climate of Iowa/Midwest
(My tentative assessment)

• Longer frost-free period (high)
• Higher average winter temperatures (high)
• Fewer extreme cold temperatures in winter (high)
• More extreme high temperatures in summer (medium)
• Higher nighttime temperatures both summer and
  winter (high)
• More (10) precipitation (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)
• Reduced annual mean wind speeds (medium)

Follows trend of last 25 years and projected by
models No current trend but
model suggestion or current trend but models
inconclusive
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Reasons Crop Yields Might Increase in the Midwest

• Longer growing season
• Warmer spring soil temperatures
• Modest or no increase in summer daily maximum
  temperatures
• Increase in nighttime temperatures
• Reduced risk of late frost in spring or early
  frost in fall
• More freeze-thaw cycles that will recharge
  soil moisture in winter

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Reasons Crop Yields Might Increase in the Midwest

• More precipitation
• More soil moisture
• Higher dew-point temperatures reduces moisture
  stress
• Higher CO2 increased carbon uptake by crops
• Higher CO2 increases the water-use
  efficiency of crops

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Reasons Crop Yields Might Decrease in the Midwest

• More precipitation extremes
• More rain events bring heavy rain
• More droughts
• More floods
• More over-wintering pests
• More pathogens due to higher humidity
• More vigorous weed growth

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D. Herzmann, Iowa Environmental Mesonet
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D. Herzmann, Iowa Environmental Mesonet
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D. Herzmann, Iowa Environmental Mesonet
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D. Herzmann, Iowa Environmental Mesonet
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D. Herzmann, Iowa Environmental Mesonet
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D. Herzmann, Iowa Environmental Mesonet
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D. Herzmann, Iowa Environmental Mesonet
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Summary

• Climate change of the past 35 years is not
  consistent with natural variations over the last
  400,000 years
• Evidence clearly shows that radiative forcing due
  to anthropogenic greenhouse gases has contributed
  over half of the warming of the last 35 years
• 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
• Recent trends and model projections
  should be used to develop adaptation
  strategies for the next 10 years

EST personal view
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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