Global Climate Change: Science and Consequences

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Global Climate ChangeScience and Consequences

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

Energy Awareness Group Ames Public Library, 7
September 2005
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Outline

• Evidence for global climate change
• Future atmospheric carbon dioxide concentrations
• Simulations of global climate and future climate
  change
• Impact on global food production and fresh-water
  availability
• Implications for the Midwest
• Dangerous anthropogenic inter-
  ference with the climate system?
• What can I do?
• Hurricane Katrina

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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 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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NASA photographs show the minimm Arctic sea ice
concentration in 1979 at left and in
2003.Satellite passive microwave data since 1970s
indicate a 3 decrease per decade in arctic sea
ice extent.
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Since 1979, the size of the summer polar ice cap
has shrunk more than 20 percent. (Illustration
from NASA) (http//www.nrdc.org/globalWarming/qth
inice.asp)
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http//www.earth-policy.org/Indicators/CO2/2004.ht
m
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El Chichon (1982)
Agung, 1963
Mt. Pinatubo (1991)
Hansen, Scientific American, March 2004
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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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The planet is committed to a warming over the
next 50 years regardless of political decisions
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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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
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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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

• There is new and stronger evidence that most of
  the warming observed over the last 50
  years is attributable to human
  activities
• Anthropogenic climate change will persist for
  many centuries

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http//www.grida.no/climate/vital/37.htm
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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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Climate Surprises

• Breakdown of the ocean thermohaline circulation
  (Greenland melt water)
• Break-off of the West Antarctic Ice Sheet

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Kennedy Space Center
Areas subjected to Inundation with a 1 m (3 ft)
rise in sea level
Miami
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What Consitutes Dangerous Anthropogenic
Interference with the Climate System?

• James Hansen, Director of the NASA Goddard
• Institute for Space Studies
• Radiative forcing limit 1 Watt/ m2
• 1 oC additional rise in global mean
• temperature

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El Chichon (1982)
Agung, 1963
Mt. Pinatubo (1991)
Hansen, Scientific American, March 2004
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Tropical Weather
Weather Underground http//www.wunderground.com/
tropical/
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• Saffir/Simpson Hurricane Scale
• CAT Winds Effects Surge
• 1 74-95 mph  4-5 ft  
• No real damage to building structures. Damage
  primarily to unanchored mobile homes, shrubbery,
  and trees. Also, some coastal flooding and minor
  pier damage.  
• 2 96-110 mph 6-8 ft  
• Some roofing material, door, and window damage.
  Considerable damage to vegetation, mobile homes,
  etc. Flooding damages piers and small craft may
  break their moorings.
• 3 111-130 mph 9-12 ft  
• Some structural damage to small residences and
  utility buildings, with a minor amount of
  curtainwall failures. Mobile homes are destroyed.
  Flooding near the coast destroys smaller
  structures, with larger structures damaged by
  floating debris. Terrain flooding inland.  
• 4 131-155 mph 13-18 ft  
• More extensive curtainwall failures with some
  complete roof structure failure on small
  residences. Major erosion of beach areas. Terrain
  may be flooded well inland.  
• 5 155 mph 18 ft  
• Complete roof failure on many residences and
  industrial buildings. Some complete building
  failures with small utility buildings blown over
  or away. Flooding causes major damage to lower
  floors of all structures near the shoreline.
  Massive evacuation of residential areas may be
  required.  

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US Army Corps of Engineers
Category 5 Winds greater than 155 mph Shrubs
and trees down considerable damage to roofing
all signs down. Severe and extensive damage to
windows and doors Complete roof collapse
Destruction of glass in windows and doors Some
complete building failures Small buildings
overturned or blown away Complete destruction of
mobile homes Storm surge higher than 18 feet
above normal Major damage to lower floors of all
structures less than 15 feet above sea level
within 500 yards of shore Low lying escape
routes inland cut off by rising water three to
five hours before hurricane center arrives
Massive evacuation of residential areas on low
ground within five to 10 miles of shore
possibly required
Catastrophic Hurricanes Category 3 or larger
Katrina Category 5, Winds gt 175 mph, Storm
surge gt 25 ft
http//www.sas.usace.army.mil/em/emhurcatinfo.htm
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What Can I Do?

• Conserve energy
• Adopt a simpler lifestyle
• Elegant simplicity
• Sophisticated modesty
• Affluence lite

Sustainable Development To meet the needs of the
present without compromising the ability of
future generations to meet their needs
Brundtland Commission (World Commission on
Environment and Development)
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Summary

• Climate change is real and we need to be doing
  something about it
• The longer we wait, the fewer our options
• Regional patterns of warming will be complicated
• Climate surprises cant be
• discounted
• We need dialog on what constitutes
• dangerous anthropogenic
• interference with the climate
• system
• More intense hurricanes can be expected
• in the future due to global warming

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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
• For a copy of this presentation
• http//www.meteor.iastate.edu/faculty/takle/