Image courtesy of NASA/GSFC

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 gstakle@iastate.edu Osborn Club Iowa State University 14 January 2008

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

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, 829-843.

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, 829-843. Pattern repeats about every 100,000 years Natural cycles

IPCC Third Assessment Report

Carbon Dioxide and Temperature “Business as Usual” 950 ppm (2100)

http://www.ncdc.noaa.gov/img/climate/research/2006/ann/glob_jan-dec-error-bar_pg.gif

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

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

IPCC Fourth Assessment Report Summary for Policy Makers

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

Hansen, Scientific American, March 2004

http://www.ncdc.noaa.gov/img/climate/research/2006/ann/glob_jan-dec-error-bar_pg.gif

Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg 2001. Grey bands indicate 68% and 95% range derived from multiple simulations.

Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg 2001. Grey bands indicate 68% and 95% range derived from multiple simulations. Natural cycles

Natural and anthropogenic contributions to global temperature change (Meehl et al., 2004). Observed values from Jones and Moberg 2001. Grey bands indicate 68% and 95% range derived from multiple simulations. Not Natural

The Great Warming Swindle, Martin Dunkin BBC, 2005

The Great Warming Swindle, Martin Dunkin BBC, 2005

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 2000. The temperature scale at left is in degrees Centigrade, and temperature anomalies are calculated relative to a reference period averaged from 1890 to 1919. 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

IPCC Fourth Assessment Report Summary for Policy Makers

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 4.4% Ice age predicted in the 70's 4.0% CO2 lags temperature 3.7% Mars is warming 3.3% Global warming is good 3.3%

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

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

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

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

IPCC Fourth Assessment Report Summary for Policy Makers

IPCC Fourth Assessment Report Summary for Policy Makers

Observed summer (June-July-August) daily mean temperature changes (K) between 1976-2000 (Adapted from Folland et al. [2001]).

“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:10.1029/2004GL020528.

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. 316. no. 5828, pp. 1181 - 1184

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. 316. no. 5828, pp. 1181 - 1184

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. 316. no. 5828, pp. 1181 - 1184

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

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.

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 2500 scientific expert reviewers, more than 850 contributing authors, and more than 450 lead authors

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.”

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.

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.

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 650,000 years

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

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

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

Regional climate model information from global model results

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

NARCCAP Plan A2 Emissions Scenario GFDL CCSM HADAM3 CGCM3 MM5 RegCM3 link to EU programs CGCM3 1960-1990 current 2040-2070 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 , 1979-2000

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

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

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?

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

Proposed new Midwest Consortium for Climate Assessment (MiCCA)

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

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