1. Global and Regional Climate Change: What on Earth are We Doing?!
Eugene S. Takle
Agronomy Department
Geological and Atmospheric Science Department
Iowa State University
Ames, Iowa 50011
Ames Golden K Kiwanis, 10 February 2005

2. 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?

3. Carbon Dioxide and Temperature

4. Carbon Dioxide and Temperature
2004

5. Carbon Dioxide and Temperature
2040
2004

6. Carbon Dioxide and Temperature
Stabilization at 550 ppm

7. Carbon Dioxide and Temperature
“Business as Usual”
(fossil intensive)
2100

9. 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

10. Mann, M. E., R. S. Bailey, and M. K. Hughes, 1999: Geophysical Research Letters 26, 759.

11. Source: IPCC, 2001: Climate Change 2001: The Scientific Basis

12. Source: IPCC, 2001: Climate Change 2001: The Scientific Basis

13. 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.

14. Since 1979, the size of the summer polar ice cap has shrunk more than 20 percent.
(Illustration from NASA) (

19. El Chichon (1982) Agung, 1963 Mt. Pinatubo (1991)
Hansen, Scientific American, March 2004

20. Source: Jerry Meehl, National Center for Atmospheric Research
From Jerry Meehl
This slide shows the time evolution of globally averaged surface air
temperature from multiple ensemble simulations of 20th century climate
from the NCAR Parallel Climate Model (PCM) compared to observations.
The simulations start in the late 19th century, and continue to the year
The temperature scale at left is in degrees Centigrade, and
temperature anomalies are calculated relative to a reference period
averaged from 1890 to The black line shows the observed data, or
the actual, recorded
globally averaged surface air temperatures from the past century. The
blue and red lines are the average of four simulations each from the
computer model. The pink and light blue shaded areas depict the range
of the four simulations for each experiment, giving an idea of the
uncertainty of a given realization of 20th century climate from the
climate model. The blue line shows the average from the four member
ensemble of the simulated time evolution of globally average surface air
temperature when only "natural" influences (solar variability and
volcanic eruptions) are included in the model. Therefore, the blue
line represents what the model says global average temperatures would
have been if there had been no human influences. The red line shows the
average of the four member ensemble experiment when natural forcings AND
anthropogenic influences (greenhouse gases including carbon dioxide,
sulfate aerosols from air pollution, and ozone changes) are included in
the model. Note that this model can reproduce the actual, observed data
very well only if the combined effects of natural and anthropogenic
factors are included. The conclusion that can be drawn is that
naturally occuring influences on climate contributed to most of the
warming that occurred before WWII, but that the large observed
temperature increases since the 1970s can only be simulated in the model
if anthropogenic factors are included.
This confirms the conclusion of the IPCC Third Assessment Report that
most of the warming we have observed in the latter part of the 20th
century has been due to human influences.
Source: Jerry Meehl, National Center for Atmospheric Research

21. Source: National Center for Atmospheric Research

22. The planet is committed to a warming over the next
50 years regardless of
political decisions
Source: National Center for Atmospheric Research

23. Source: Intergovernmental Panel on Climate Change, 2001 Report

24. 40% Probability 5% Probability
Source: Intergovernmental Panel on Climate Change, 2001 Report

25. Climate Change
Projected for 2100
Rapid Economic
Growth
Slower Economic
Growth

26. Source:
Corell, R. W., 2004: Impacts of a warming Arctic. Arctic Climate Impact Assessment ( Cambridge University Press (

27. Impact of a 1-m rise in sea level on low-lying areas
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 ( Cambridge University Press (

28. 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

29. IPCC Summary for Policy Makers, cont’d
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

33. 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

34. Climate Surprises
Breakdown of the ocean thermohaline circulation (Greenland melt water)
Break-off of the West Antarctic Ice Sheet

37. Areas subjected to Inundation with a 1 m (~3 ft) rise in sea level
Kennedy Space
Center
Areas subjected to
Inundation with a 1 m
(~3 ft) rise in sea
level
Miami

39. Global warming is at least as important
an issue as gay marriage or the rising cost
of Social Security.
And if it is not seriously debated in the
general election, it will measure the
irresponsibility of the entire political class.
This is an issue that cannot,
and must not, be ignored any
longer.

40. Global warming is at least as important
an issue as gay marriage or the rising cost
of Social Security.
And if it is not seriously debated in the
general election, it will measure the
irresponsibility of the entire political class.
This is an issue that cannot,
and must not, be ignored any
longer.
Walter Cronkite
12 March 2004

41. 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

42. El Chichon (1982) Agung, 1963 Mt. Pinatubo (1991)
Hansen, Scientific American, March 2004

43. Hansen, Scientific American, March 2004

44. 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)

45. 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 can’t be
discounted
We need dialog on what constitutes
“dangerous anthropogenic
interference with the climate
system”

46. For More Information
For peer-reviewed evidence supporting everything you have seen in this presentation, see my online Global Change course:
Contact me directly:
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