1. Iowa’s Climate 2030 Eugene S. Takle Director, Climate Science Program
Professor of Atmospheric Science
Department of Geological and Atmospheric Sciences
Professor of Agricultural Meteorology
Department of Agronomy
Iowa State University
Ames, Iowa 50011
Municipal Utilities 2030
Ankeny, Iowa 
8 April 2010

2. “I hear so many conflicting views on climate change, I don’t know what or who to believe”
Soybean producer from NE Iowa

3. In science, the prevailing theory is the one that explains the balance of evidence
What is the evidence?

4. Global Mean Surface Temperature

5. Global Mean Surface Temperature

6. Global Mean Surface Temperature

7. NASA

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

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

10. Temperature Trends in Upper and Lower Atmosphere
Upper Atmosphere
(Stratosphere)
The question of whether climate changes are caused by humans or solar variation can only be addressed by models, since it is impossible to have a duplicate earth in which human increases in GHG are set to zero. A simple model is built around the fact that solar radiation is absorbed at the earth’s surface and in the atmosphere. If the solar energy increased, the atmosphere near the surface and far above it should increase in temperature. The observations from satellites show a decrease in high altitude temperature, which is inconsistent with expectations from solar energy increases alone.
Lower Atmosphere
(Troposphere)

11. “One of the clearest trends in the United States observational record is an increasing frequency and intensity of heavy precipitation events… Over the last century there was a 50% increase in the frequency of days with precipitation over mm (four inches) in the upper midwestern U.S.; this trend is statistically significant “
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

12. Arctic Sea-Ice Decline

13. Decline in Greenland Ice Mass
Equivalent to about 5 ft of ice over the state of Iowa each year

14. Tropical Atlantic Ocean Hurricane Power Dissipation Index (PDI)
Sea-surface temperature V V V
Emanual, Kerry, 2005: Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436,

15. Ocean Heat Content
1oC rise in top 3 m of global ocean is equivalent to a 1oC rise in entire atmosphere
Some of the recycled energy received at the surface is stored in the ocean. The increasing trend of ocean temperature is an indicator of an increase in climate system energy.

16. Where is this extra heat coming from?
Possible mechanisms:
More solar radiation
Less reflection from clouds
Less reflection from Earth’s surface
More energy trapped and recycled by ozone and greenhouse gases

17. Earth’s Energy Balance:
Incoming solar = outgoing infrared radiation
But rapid changes in atmosphere and ocean temperatures and loss of land and sea ice indicate an imbalance

18. ? ? ? ? Earth’s Energy Balance:
Incoming solar = outgoing infrared radiation
But rapid changes in atmosphere and ocean temperatures and loss of land and sea ice indicate an imbalance ? ? ?

19. 0.1%
Solar variability is about about 0.1% of incoming energy. This variability occurs on short cycles of a decade and long cycles of 10s to 100s of thousands of years.
*Other solar cycles have periods of 22,000, 41,000, and 100,000 years with 0.1% variation.

20. Forcing Factors in the Global Climate
More trapped (recycled) heat
See Arritt for details this afternoon
More cloud & land reflection
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

21. Increased Greenhouse Gases => Global Heating
Increasing greenhouse gases increases heating of the Earth
Increased Greenhouse Gases => Global Heating

22. Karl, T. R. , J. M. Melillo, and T. C. Peterson, (eds
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009.

24. Global Carbon Emissions (Gt)
Actual emissions are exceeding worst case scenarios projected in 1990

25. Warming of the Lower and Upper Atmosphere Produced by Natural and Human Causes
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

26. Warming of the Lower and Upper Atmosphere Produced by Natural and Human Causes
Note that greenhouse gases have a unique temperature signature, with strong warming in the upper troposphere, cooling in the lower stratosphere and strong warming over the North Pole. No other warming factors have this signature.
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

27. Global Mean Surface Temperature

28. Attribution studies: See Anderson this afternoon for applications to the Midwest

29. 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

30. The balance of evidence for the magnitude and distribution of warming is explained by increases in atmospheric greenhouse gases

31. The “Cone of Uncertainty”

32. More environmentally friendly
Energy intensive
Balanced fuel sources
More environmentally friendly
If current emission trends continue, global temperature rise will exceed worst case scenarios projected in 2007
Consider A1B
FI =fossil intensive
IPCC Fourth Assessment Report Summary for Policy Makers

33. IPCC 2007

34. December-January-February Temperature Change
7.2oF
6.3oF
A1B Emission Scenario
minus

35. IPCC 2007

36. June-July-August Temperature Change
4.5oF
A1B Emission Scenario
minus
5.4oF

37. June-July-August Temperature Change
4.5oF
A1B Emission Scenario
minus
5.4oF
Not the direction of current trends

38. IPCC 2007

39. Low confidence in model projection of summer precipitation
IPCC 2007

40. IPCC 2007

41. Karl, T. R. , J. M. Melillo, and T. C. Peterson, (eds
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

42. Karl, T. R. , J. M. Melillo, and T. C. Peterson, (eds
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

43. Low confidence
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

44. Trend of increase in occurrence of heavy precipitation over the 20th C is consistent with increasing GHG concentrations.
Frequency of intense precipitation events is likely to increase in the future.
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

45. The planet is committed to a warming over the next 50 years regardless of political decisions
Necessary
Adaptation
Necessary
Adaptation
Possible
Mitigation
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

46. The planet is committed to a warming over the next 50 years regardless of political decisions
Necessary
Adaptation
Necessary
Adaptation
Possible
Mitigation
Karl, T. R., J. M. Melillo, and T. C. Peterson, (eds.), 2009: Global Climate Change Impacts in the United States. Cambridge University Press, 2009, 196pp.

47. Observed Summer (JJA) Daily Maximum Temperature
Changes (K),
Adapted from Folland et al. [2001]

48. Des Moines Airport Data
1983: 13
1988: 10
2009: 0

49. 6 days ≥ 100oF in the last 20 years
Des Moines Airport Data
1983: 13
1988: 10
6 days ≥ 100oF in the last 20 years
2009: 0

50. State-Wide Average Data

51. State-Wide Average Data
Totals above 40”

53. Cedar Rapids Data

54. Cedar Rapids Data

55. D. Herzmann, Iowa Environmental Mesonet

56. State-Wide Average Data

57. Projected Changes* for the Climate of the Midwest Temperature
Longer frost-free period (high)
Higher average winter temperatures (high)
Fewer extreme cold temperatures in winter (high)
Fewer extreme high temperatures in summer in short term but more in long term (medium)
Higher nighttime temperatures both summer and winter (high)
More freeze-thaw cycles (high)
Increased temperature variability (high)
Follows trend of last 25 years and projected by models
No current trend but model suggestion or current trend but model inconclusive
*Estimated from IPCC reports

58. Projected Changes* for the Climate of the Midwest Precipitation
More (~10%) precipitation annually (medium)
Change in “seasonality”: Most of the increase will come in the first half of the year (wetter springs, drier summers) (high)
More water-logging of soils (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)
More winter soil moisture recharge (medium)
Snowfall increases (late winter) in short term but decreases in the long run (medium)
Follows trend of last 25 years and projected by models
No current trend but model suggestion or current trend but model inconclusive
*Estimated from IPCC reports

59. Iowa Agricultural Producers’ Adaptations to Climate Change
Longer growing season: plant earlier, plant longer season hybrids, harvest later
Wetter springs: larger machinery enables planting in smaller weather windows
More summer precipitation: higher planting densities for higher yields
Wetter springs and summers: more subsurface drainage tile is being installed, closer spacing, sloped surfaces
Fewer extreme heat events: higher planting densities, fewer pollination failures
Higher humidity: more spraying for pathogens favored by moist conditions. more problems with fall crop dry-down, wider bean heads for faster harvest due to shorter harvest period during the daytime.
Drier autumns: delay harvest to take advantage of natural dry-down conditions
Is it genetics or climate? Likely some of each.
HIGHER YIELDS!!

60. Wind Power: A New Energy Opportunity for Iowa

63. 54-hour Forecasts Initialized at 00UTC (6 PM CST)
Different turbulence schemes
Observations at Pomeroy, IA
Global model initialization
Midnight
Noon
Midnight
Noon
Midnight

65. __ ___________________________________
Conceptual Model of Turbine-crop Interaction via Mean Wind and Turbulence Fields
Speed recovery
day
H2O
CO2
Heat
__ ___________________________________
night

66. Summary
There is no scientifically defensible explanation for atmospheric warming, increase in ocean heat content, and loss of ocean and land ice over the last 40 year other than increase of anthropogenic greenhouse gases
Some recent climate trends in the Midwest that have been favorable to agriculture likely will continue in the next few years
Climate challenges to agriculture will intensify toward mid-century
Iowa’s wind energy resources offer an alternative for contributing to the nation’s energy needs while reducing emissions of greenhouse gases

67. For More Information
National academies of science joint statement (May 2009): G8+5 Academies’ joint statement: Climate change and the transformation of energy technologies for a low carbon future. [
North American Regional Climate Change Assessment Program:
For current activities on the ISU campus, regionally and nationally relating to climate change see the Climate Science Initiative website:
Contact me directly: