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
Osborn Club
Iowa State University
14 January 2008

3. Outline Scientific basis for climate change The “disbelief” phenomenon
Climate change and the scientific process
What do we do now? ISU’s role

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)

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. The Great Warming Swindle, Martin Dunkin BBC, 2005

28. The Great Warming Swindle, Martin Dunkin BBC, 2005

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

31. IPCC Fourth Assessment Report Summary for Policy Makers

32. Skeptics’ Arguments It's the sun 9.0% Climate's changed before 7.8%
There is no consensus 6.4%
Surface temp is unreliable 5.8%
Models are unreliable 4.5%
Al Gore got it wrong %
Ice age predicted in the 70's 4.0%
CO2 lags temperature 3.7%
Mars is warming %
Global warming is good 3.3%

33. Exposing Anthropogenic Climate Change to Standard Scientific Evaluation
Methodological
Inductive (specific to general)
Deductive (general to specific)
Falsifiable (testable; does not rely on articles of faith)
Evidentiary : Strong consistency of evidence
Instrumental records (temperature, satellite obs)
proxy records (tree rings, lake sediments, bore holes, etc.)
Performance
Prediction
Provide useful advice
Inference to best explanation
All available evidence points towards role of human effects.
Community standards
Naomi Oreskes, 2007

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

35. 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

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

37. IPCC Fourth Assessment Report Summary for Policy Makers

38. IPCC Fourth Assessment Report Summary for Policy Makers

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

40. “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

41. 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

42. 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

43. 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

44. 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

45. NAS Assessment of IPCC Conclusions
“Greenhouse gases are accumulating in the Earth’s atmosphere as a result of human activities, causing surface air temperatures to rise and sub-surface ocean temperatures to rise”
“The IPCC’s conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue”
National Academy of Sciences Committee on the Science of Climate Change, 2001: Climate change science: An analysis of some key questions. National Academy Press.

46. IPCC AR4 (2007) Process
IPCC does not conduct its own research. It simply organizes teams of scientists to evaluate the current state of scientific knowledge
People from over 130 countries contributed to the IPCC Fourth Assessment Report over the previous 6 years.
These people included more than scientific expert reviewers, more than 850 contributing authors, and more than 450 lead authors

47. IPCC Fourth Assessment Report (2007)
“The understanding of anthropogenic warming and cooling influences on climate has improved since the Third Assessment Report (TAR), leading to very high confidence that the globally averaged net effect of human activities since 1750 has been one of warming, with a radiative forcing of +1.6 [+0.6 to +2.4] W m-2.”

48. 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.

49. 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.

50. IPCC AR4 Conclusions
There is a confidence level >66% that there will be an increase in droughts, tropical cyclones and extreme high tides.
Both past and future anthropogenic carbon dioxide emissions will continue to contribute to warming and sea level rise for more than a millennium.
Global atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased markedly as a result of human activities since 1750 and now far exceed pre industrial values over the past 650, years

51. What To Do Now
North American Regional Climate Change Assessment Program
ISU Climate Science Initiative
Midwest Consortium for Climate Assessment (MiCCA) (proposed to NOAA)

52. What To Do Now
North American Regional Climate Change Assessment Program
ISU Climate Science Initiative
Midwest Consortium for Climate Assessment (MiCCA)

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

54. Regional climate model
information from global model results

55. 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

56. 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 ,

57. What To Do Now
North American Regional Climate Change Assessment Program
ISU Climate Science Initiative
Midwest Consortium for Climate Assessment (MiCCA)

58. 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

59. 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?

60. What To Do Now
North American Regional Climate Change Assessment Program
ISU Climate Science Initiative
Midwest Consortium for Climate Assessment (MiCCA)

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

62. 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

63. 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