Carbon Dioxide and Climate Change

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Carbon Dioxide and Climate Change

• Eugene S. Takle
• Agronomy Department
• Geological and Atmospheric Science Department
• Iowa State University
• Ames, Iowa 50011
• gstakle_at_iastate.edu

Lecture to Political Science Class on Science,
Technology and Public Policy Iowa State
University 7 February 2004
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Outline

• Evidence for global climate change
• Future atmospheric carbon dioxide concentrations
• Simulations of global climate and future climate
  change
• Implications for stream flow
• Impact of 2004 election decisions
• Summary

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Carbon Dioxide and Temperature
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Carbon Dioxide and Temperature
2004
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Carbon Dioxide and Temperature
2040
2004
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Carbon Dioxide and Temperature
Stabilization at 550 ppm
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Carbon Dioxide and Temperature
Business as Usual (fossil intensive) 2100
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Associated Climate Changes

• Global sea-level has increased 1-2 mm/yr
• Duration of ice cover of rivers and lakes
  decreased by 2 weeks in N. Hemisphere
• Arctic ice has thinned substantially, decreased
  in extent by 10-15
• Reduced permafrost in polar, sub-polar,
  mountainous regions
• Growing season lengthened by 1-4 days in N.
  Hemisphere
• Retreat of continental glaciers on all continents
• Poleward shift of animal and plant ranges
• Snow cover decreased by 10
• Earlier flowering dates
• Coral reef bleaching

Source Intergovernmental Panel on Climate
Change, 2001 Report
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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 Jerry Meehl, National Center for
Atmospheric Research
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Source National Center for Atmospheric Research
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Source Intergovernmental Panel on Climate
Change, 2001 Report
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40 Probability
5 Probability
Source Intergovernmental Panel on Climate
Change, 2001 Report
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Climate Change Projected for 2100
Rapid Economic Growth
Slower Economic Growth
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IPCC Summary for Policy Makers

• An increasing body of observations gives a
  collective picture of a warming world and other
  changes in the climate system
• Emissions of greenhouse gases and aerosols due to
  human activities continue to alter the
  atmosphere in ways that are
  expected to affect the climate

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IPCC Summary for Policy Makers, contd

• Confidence in the ability of models to project
  future climate has increased
• There is new and stronger evidence that most of
  the warming observed over the last 50
  years is attributable to human
  activities

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IPCC Summary for Policy Makers, contd

• Confidence in the ability of models to project
  future climate has increased
• There is new and stronger evidence that most of
  the warming observed over the last 50
  years is attributable to human
  activities

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IPCC Summary for Policy Makers, contd

• Confidence in the ability of models to project
  future climate has increased
• There is new and stronger evidence that most of
  the warming observed over the last 50
  years is attributable to human
  activities

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IPCC Summary for Policy Makers, contd

• Anthropogenic climate change will persist for
  many centuries
• Further action is required to address remaining
  gaps in information and understanding

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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 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

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Sub-Basins of the Upper Mississippi River Basin
119 sub-basins Outflow measured at Grafton, IL
Approximately one observing station per
sub-basin Approximately one model grid point per
sub-basin
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Soil Water Assessment Tool (SWAT)

• Long-term, continuous watershed simulation model
  (Arnold et al,1998)
• Assesses impacts of climate and management on
  yields of water, sediment, and agricultural
  chemicals
• Physically based, including hydrology, soil
  temperature, plant growth, nutrients,
• pesticides and land management
• Daily time steps

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SWAT Output with Various Sources of Climate Input
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Calibration of SWAT Annual Stream Flow at
Grafton, IL
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Calibration of SWAT Monthly Stream Flow at
Grafton, IL
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Validation of SWAT Annual Stream Flow at
Grafton, IL
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Validation of SWAT Monthly Stream Flow at
Grafton, IL
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Ten-Year Mean Precipitation Generated by the
RegCM2 Regional Climate Model Driven with HadCM2
Global Model Results for the Contemporary and
Future Scenario (2040s) Climate
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Ten-Year Mean Monthly Stream Flow Generated by
the RegCM2 Regional Climate Model Driven with
HadCM2 Global Model Results for the Contemporary
and Future Scenario (2040s) Climate
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Comparison of Simulated Stream Flow under
Climate Change with Various Model Biases
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Relation of Runoff to Precipitation for Various
Climates
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Election 2004Issues and Their Time Scales

• What are the election issues in 2004, and how
  long will decisions on these issues have an
  impact?

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2004 Issues

• Jobs
• US Economy
• National security, terrorism
• War
• Environment

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2004 Issues Jobs

• The average American changes jobs about every ? 7
  years?
• Tenured position at a university 35 years

-gt Time scale of jobs 7-35 years
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2004 Issues US Economy

• Economic cycles last about 5 years
• Home mortgage lasts about 20 years
• Factory is productive 50 years

-gt Time scale of economic decisions 5-50
years
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2004 Issues National Security

• Nazi Germany 10 years (impact 50 years)
• China ??
• Rawanda ??

-gt Time scale of terrorism 5-50 years
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2004 Issues War

• Wars last 2-5 years
• Impact of WWII 50-100 years

-gt Time scale of war 2-100 years
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Decisions we make now Determine global
warming For the next 200-2,000 years
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2004 Issues Environment(Global Warming)

Time scale of environmental decisions on global
warming 200 - 2,000 years !!
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2004 Issues

• Jobs 7-35 years
• US Economy 5-50 years
• National security, terrorism 5-50 years
• War 2-100 years
• Environment 200-2,000 years

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For More Information

• See my online Global Change course
• http//www.meteor.iastate.edu/gccourse
• Contact me directly
• gstakle_at_iastate.edu