1. Climate Change and Conservation
Eugene S. Takle
Director, Climate Science Initiative
Professor of Atmospheric Science
Department of Geological and Atmospheric Sciences
Professor of Agricultural Meteorology
Department of Agronomy
Iowa State University
Ames, Iowa 50011
Iowa Water Conference
Ames, Iowa 
8-9 March 2010

2. Outline Causes of climate change
Global and regional changes in climate and projected future changes
Past trends in Iowa and producer adjustments to climate change
My speculation on future climate trends of importance to agriculture and conservation

3. NASA

4. Global Mean Surface Temperature

5. “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.

6. 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.

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

9. 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

10. 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

11. IPCC 2007

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

13. IPCC 2007

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

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

16. IPCC 2007

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

18. IPCC 2007

19. 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.

20. 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.

21. 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.

22. 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.

23. 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.

24. 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.

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

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

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

28. 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

29. “Warming Hole”: Simulations of changes in daily maximum summertime temperatures between 1990s and 2040s
A feature that corresponds to later 20th century trends. Not seen in GCMs. Linked to mesoscale circulation.
DTmax (JJA) ˚C
Pan, Z., R. W. Arritt, E. S. Takle, W. J. Gutowski, Jr., C. J. Anderson, and M. Segal,2004: Altered hydrologic feedback in a warming climate introduces a “warming hole”. Geophys. Res. Lett.31, L17109, doi: /2004GL

30. State-Wide Average Data

31. State-Wide Average Data
Totals above 40”

33. Cedar Rapids Data

34. Cedar Rapids Data

35. Relationship of Streamflow to Precipitation in Current and Future Climates

36. D. Herzmann, Iowa Environmental Mesonet

37. State-Wide Average Data

38. 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

39. 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

40. Projected Changes* for the Climate of the Midwest Other
Reduced wind speeds (high)
Reduced solar radiation (medium)
Increased tropospheric ozone (high)
Accelerated loss of soil carbon (high)
Phenological stages are shortened (high)
Weeds grow more rapidly under elevated atmospheric CO2 (high)
Weeds migrate northward and are less sensitive to herbicides (high)
Plants have increased water used efficiency (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 and CCSP reports

41. 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.

42. Will These Agriculturally Favorable Midwest Climate Trends Continue?
Caution: These are my speculations!!
In the short-term (next 5-10 years) climatic conditions will be dominated by natural variability from base conditions of the past 20 years (not long-term averages)
If we continue to have high spring and summer rainfall and soil moisture, we likely will continue to have lower chances of extended periods of extreme heat
If we continue to have high spring and summer rainfall and soil moisture, we likely will continue to have pathogens favored by high humidities
In the longer term (>50 years), hot summers, milder winters, and higher variability of precipitation will become more dominant
Failure to limit global carbon emissions will accelerate trends toward less favorable agricultural climate for Iowa

43. 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 and conservation interests will intensify toward mid-century
Global and regional climate models have much to offer for understanding future Midwest agriculture-climate and conservation-climate interactions
Agriculturists and conservationists needs future climate information at regional scales.

44. For More Information
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: