1. Image courtesy of NASA/GSFC

2. Global Climate Change: How We Got Here, and What Do We Do Now?
Eugene S. Takle
Professor of Atmospheric Science
Department of Geological and Atmospheric Sciences
Professor of Agricultural Meteorology
Department of Agronomy
Iowa State University
Ames, Iowa 50011
Biorenewable Resources and Technology 501
Iowa State University
22 February 2008
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY

3. Outline Scientific basis for climate change
Why we are confident that the that humans are responsible for a large measure of the current warming
What do we do now? ISU’s role
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

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

7. IPCC Third Assessment Report

8. Carbon Dioxide and Temperature
“Business as Usual”
950 ppm
(2100)
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

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

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

19. IPCC Fourth Assessment Report Summary for Policy Makers

20. 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

22. Hansen, Scientific American, March 2004

24. 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.

25. 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

26. 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

27. 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

29. IPCC Fourth Assessment Report Summary for Policy Makers

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

31. 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

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

33. IPCC Fourth Assessment Report Summary for Policy Makers

34. IPCC Fourth Assessment Report Summary for Policy Makers

35. Observed summer (June-July-August) daily mean temperature changes (K) between (Adapted from Folland et al. [2001]).

36. “Warming Hole” DTmax (JJA)
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

37. Precipitation minus Evaporation for Western US
(25N-40N, 95W-125 W)
R. Seager, et al.,
2007. Model Projections of an Imminent Transition to a More Arid Climate in Southwestern North America. Science, Vol no. 5828, pp

38. Precipitation minus Evaporation for Western US
(25N-40N, 95W-125 W)
R. Seager, et al.,2007. Model Projections of an Imminent Transition to a More Arid Climate in Southwestern North America. Science, Vol no. 5828, pp

39. Precipitation minus Evaporation for Western US
(25N-40N, 95W-125 W)
Colorado River Compact established, 1922
R. Seager, et al.,2007. Model Projections of an Imminent Transition to a More Arid Climate in Southwestern North America. Science, Vol no. 5828, pp

40. Intergovernmental Panel on Climate Change (IPCC)
Created in 1988 by the World Meteorological Organization (UN) and the United Nations Environmental Programme
IPCC purpose is to evaluate the state of climate science as a basis for informed policy action, primarily on the basis of peer-reviewed and published scientific literature
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

41. IPCC AR4 Conclusions Warming of the climate system is unequivocal.
Most of (>50% of) the observed increase in globally averaged temperatures since the mid-20th century is very likely (confidence level >90%) due to the observed increase in anthropogenic (human) greenhouse gas concentrations.
Hotter temperatures and rises in sea level "would continue for centuries" even if greenhouse gas levels are stabilized, although the likely amount of temperature and sea level rise varies greatly depending on the fossil intensity of human activity during the next century.
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

42. IPCC AR4 Conclusions
The probability that this is caused by natural climatic processes alone is less than 5%.
World temperatures could rise by between 1.1 and 6.4 °C (2.0 and 11.5 °F) during the 21st century and that:
Sea levels will probably rise by 18 to 59 cm (7.08 to 23.22 in).
There is a confidence level >90% that there will be more frequent warm spells, heat waves and heavy rainfall.
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

43. 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

44. 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
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY

45. 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
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY

46. 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
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY

47. What To Do Now
North American Regional Climate Change Assessment Program
ISU Climate Science Initiative
Midwest Consortium for Climate Assessment (MiCCA) (proposed to NOAA)
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

48. What To Do Now
North American Regional Climate Change Assessment Program
ISU Climate Science Initiative
Midwest Consortium for Climate Assessment (MiCCA)
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

49. Terrain and land-sea boundaries in the Hadley Centre global climate model

50. Regional climate model
information from global model results

51. North America Regional Climate Change Assessment Program: Participants
Lead agency: NSF, with contributions from NOAA and DOE
R. Arritt, D. Flory, W. Gutowski, E. Takle, Iowa State University, USA
R. Jones, E. Buonomo, W. Moufouma-Okia, Hadley Centre, UK
D. Caya, S. Biner, OURANOS, Canada
D. Bader, P. Duffy, Lawrence Livermore National Laboratories, USA
F. Giorgi, ICTP, Italy
I. Held, NOAA Geophysical Fluid Dynamics Laboratory, USA
R. Leung, Y. Qian, Pacific Northwest National Laboratories, USA
L. Mearns, D. Middleton, D. Nychka, S. McInnes, NCAR, USA
A. Nunes, John Roads, Scripps Institution of Oceanography, USA
S. Sain, Univ. of Colorado at Denver, USA
L. Sloan, M. Snyder, Univ. of California at Santa Cruz, USA

52. NARCCAP Plan A2 Emissions Scenario GFDL CCSM HADAM3 CGCM3 MM5 RegCM3
link to EU
programs
CGCM3
current
future
Provide boundary conditions
MM5
Iowa State/
PNNL
RegCM3
UC Santa Cruz
ICTP
CRCM
Quebec,
Ouranos
HADRM3
Hadley Centre
RSM
Scripps
WRF
NCAR/
Note: AGCM time slices to be included, too. Initial phase involves driving RCMs with reanalysis output.
Reanalyzed climate ,

53. What To Do Now
North American Regional Climate Change Assessment Program
ISU Climate Science Initiative
Midwest Consortium for Climate Assessment (MiCCA)
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

54. ISU Climate Science Initiative
Launched by Vice President Brighton
Colleges of Agric, Engr, LAS have taken leadership, but broad campus research participation will be emphasized
Build on research strengths in regional climate modeling, agriculture, water, landscapes, engineering
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

55. How Will New Trends and Variability of Regional Climate Change Affect
Crop & horticulture production
Soil erosion
Conservation practices
Water supplies
Streamflow
Water quality
Beef and pork daily gains
Livestock breeding success
Milk and egg production
Crop and livestock pests and pathogens
Agricultural tile drainage systems
Natural ecosystem species distributions
Human health
Building designs
Recreation opportunities
River navigation
Roads and bridges
Who will provide authoritative information?
How will it be delivered?
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

56. What To Do Now
North American Regional Climate Change Assessment Program
ISU Climate Science Initiative
Midwest Consortium for Climate Assessment (MiCCA)
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

57. Proposed new Midwest Consortium for Climate Assessment (MiCCA)

58. Midwest Consortium for Climate Assessment (MiCCA)
Create seasonal climate forecasts for the Midwest
Use ensembles of advanced regional climate models interactive web-based decision-making tools,
Translate and enhance the latest NOAA climate forecast products to maximize economic gains
Use high-volume customized delivery and feedback through the county level extension service network
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY

59. 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
Iowa State has the capacity to build on its strengths and provide authoritative information on climate change and climate variability for decision-makers
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERSITY
CLIMATE SCIENCE INITIATIVE, IOWA STATE UNIVERITY