1. 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
Chemical Engineering 302
Iowa State University
11 October 2007

2. Image courtesy of NASA/GSFC

3. 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

4. CO2, CH4 and temperature records from Antarctic ice core data
Source: Vimeux, F., K.M. Cuffey, and Jouzel, J., 2002, "New insights into Southern Hemisphere temperature changes from Vostok ice cores using deuterium excess correction", Earth and Planetary Science Letters, 203,

5. CO2, CH4 and temperature records from Antarctic ice core data
Source: Vimeux, F., K.M. Cuffey, and Jouzel, J., 2002, "New insights into Southern Hemisphere temperature changes from Vostok ice cores using deuterium excess correction", Earth and Planetary Science Letters, 203,
Pattern repeats about every 100,000 years
Natural cycles

6. IPCC Third Assessment Report

7. Carbon Dioxide and Temperature
2007
380 ppm

8. Carbon Dioxide and Temperature
2050
550 ppm

9. Carbon Dioxide and Temperature
“Business as Usual”
950 ppm

10. Carbon Dioxide and Temperature
“Business as Usual”
950 ppm ?

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

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

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

16. Planet Te(K) Ts(K) Earth 256 288 Venus 227 732 Mars 217 223

17. IPCC Fourth Assessment Report Summary for Policy Makers

18. At present trends the imbalance = 1 Watt/m2 in 2018
El Chichon (1982)
Agung, 1963
Mt. Pinatubo (1991)
At present trends the imbalance = 1 Watt/m2 in 2018
Hansen, Scientific American, March 2004

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
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 ( Cambridge University Press (

30. Antarctica
Greenland
Ice Volume
Cold
Warm
Climate

32. Hansen, Scientific American, March 2004

33. 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)

35. Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg Grey bands indicate 68% and 95% range derived from multiple simulations.

36. Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg Grey bands indicate 68% and 95% range derived from multiple simulations.
Natural cycles

37. Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg Grey bands indicate 68% and 95% range derived from multiple simulations.
Not Natural

38. Highly Likely Not Natural
Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg Grey bands indicate 68% and 95% range derived from multiple simulations.
Highly Likely Not Natural
Not Natural

39. 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

40. IPCC Fourth Assessment Report Summary for Policy Makers

41. Energy intensive Energy conserving Reduced Consumption
IPCC Fourth Assessment Report Summary for Policy Makers

42. Energy intensive Energy conserving Reduced Consumption
The planet is committed to a warming over the next 50 years regardless of political decisions
IPCC Fourth Assessment Report Summary for Policy Makers

43. Energy intensive Energy conserving Mitigation Possible Adaptation
Reduced Consumption
Energy conserving
Possible
Mitigation
Necessary
Adaptation
IPCC Fourth Assessment Report Summary for Policy Makers

44. IPCC Fourth Assessment Report Summary for Policy Makers

45. IPCC Fourth Assessment Report Summary for Policy Makers

47. Tin and Seager

48. Four-Component Approach for Addressing Climate Change
Mitigation policies:
Example: reduction in GHG emissions
Adaptation (long-term):
Example: Developing Iowa’s competitive economic advantage
Adaptation (short-term):
Example: redefining climate “normals” when needed and scientifically justified
Scenario planning for Iowa’s “Katrina”:
Example: Multi-year drought, recurrent floods, combination of both; drought and wildfire
EST personal view

49. 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

50. 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

51. 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

52. 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

53. 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

54. D. Herzmann, Iowa Environmental Mesonet

55. D. Herzmann, Iowa Environmental Mesonet

56. D. Herzmann, Iowa Environmental Mesonet

57. D. Herzmann, Iowa Environmental Mesonet

58. D. Herzmann, Iowa Environmental Mesonet

59. D. Herzmann, Iowa Environmental Mesonet

60. D. Herzmann, Iowa Environmental Mesonet

61. 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

62. For More Information Or just Google Eugene Takle
For peer-reviewed evidence supporting everything you have seen in this presentation, see my online Global Change course:
Contact me directly:
Current research on regional climate and climate change is being conducted at Iowa State Unversity under the Regional Climate Modeling Laboratory
North American Regional Climate Change Assessment Program
For this and other climate change presentations see my personal website:
Or just Google Eugene Takle