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Chairman CALVERT. Thank you, Doctor. Dr. Patrinos?



Mr. PATRINOS. Thank you, Mr. Chairman, members of the Subcommittee. I am pleased to testify before you today on the science of climate change and, in particular, the status of the climate prediction models with an emphasis on programs that the Department of Energy has supported over the

years. I am here both as a Department of Energy representative, but also as a representative of the Subcommittee on Global Change Research, which has the overall direction and executive oversight of the U.S. Global Change Research Program that was codified by Congress with the Global Change Act of 1990 to, among other things, provide for the development and coordination of a comprehensive and integrated U.S. research program which will assist the Nation and the world to understand, assess, predict, and respond to human induced and natural processes of global change.

The status of the science of climate change has been presented in the reports of the Intergovernmental Panel on Climate Change, references to which have already been made. And, the recent report, "Climate Change 1995: The Science of Climate Change," was published by Cambridge University Press in 1996, and in my professional judgment represents the most authoritative source on the science of climate change.

With respect to climate models, the IPCC as well as other sources, had summarized the state of our understanding of the climate models, and I can give you a few of the highlights of that consensus.

All models essentially show an increase in globally-averaged, near-surface temperatures between 1 and 3.5 degrees Celsius by the Year 2100, assuming a steady annual rate of increase in CO2 of 1 percent per year; which means an essential doubling in 70 years and continuous increase of the temperature beyond the Year 2100.

All models show a greater warming over land than over the ocean and the most pronounced warming over the temperate, high latitudes in the northern hemisphere.

All models show an increase in the global precipitation-average precipitation with most of those increases at higher latitudes in both hemispheres.

Although there is general qualitative agreement among several of the models, insofar as the regional impacts, that's the area where the major scientific uncertainty exists-how we essentially reduce or predict some of these climate changes at the regional level.

The simulations, as you've heard already, that have included sulfate aerosols, predict a lower near-surface temperature than the predictions using just CO2, as my colleague Alan Robock described to you. However, as he also said, that cooling influence is quite patchy and is insufficient to counter greenhouse warming.

Finally, the statistical comparison of the geographic patterns of climate change that he described in all four dimensions essentially—altitude, longitude, latitude, and time between the predictions and the actual climate data over the last 100 years, formed the basis for this discernible evidence of the human fingerprint on climate.

We've had other authoritative sources of the status of climate models such as a forum on global change modeling that we organized—the U.S. Global Change Research Program that is at the request of the Office of Science and Technology Policy and the General Accounting Office. Also, the Academy of Sciences was involved in another modeling activity and they're in the process of completing a report right now. All these sources pretty much agree that the models continue to improve. They also identify, as you've heard already, about the many uncertainties associated with the models, some of those being, essentially, how they represent some of the processes, particularly the feedback of aerosols in clouds and also how the oceans handle heat transfer. They also recognize that we still have insufficient computing power to deal with all the necessary simulations and the tours in parameter space we need to undertake.

Also regional resolution is still insufficient. And there are also some questions about some of the basic theoretical limitations on the predictability of the climate system, although recent results with El Nino have boosted our confidence with respect to our ability to predict climate change.

The investments that the Global Change Program has made, and also several of the programs within the Department of Energy that I would like to speak to a little bit, have contributed significantly towards improving our ability to predict climate change. In fact, most of those investments have been addressing improving climate change prediction.

I would like to say just a few words about three Department of Energy Programs that have been integral in this pursuit. The first one is the Computer Hardware Advanced Mathematics and Model Physics Program (CHAMMP), the program for Climate Modeling Diagnosis and Intercomparison; and the Atmospheric Radiation Measurement Program.

The CHAMMP program, the first one that I'd like to discuss, has been very instrumental in its contribution to improving climate modeling, primarily because it has entrained a new community of scientists, very many with strong physics backgrounds that have enriched the community dealing with climate modeling. One such example is the group JASON, which includes prominent scientists like Freeman Dyson and Bill Nierenberg, that have greatly enhanced our abilities to predict climate change with their sage advice and considerable input.

CHAMMP has also done a lot towards bringing to bear advanced scientific computing capabilities to the climate change prediction problem. We have reached out to our colleagues in the defense program laboratories within the Department of Energy and have brought to bear some of those supercomputers to the application of those problems. One such result has been the Parallel Oceans Program (POP) model, the POP model that was developed at Los Alamos National Laboratory, which is one of the best ocean climate models in the business. Of course I'm biased in that respect, but I think the community generally agrees.

Another major contribution that CHAMMP has been made is the most up-to-date climate model that is in the process of development right now under the leadership of Warren Washington at the National Center for Atmospheric Research (NCAR), which uses the NCAR Community Climate Atmospheric Model along with the Parallel Oceans (POP] Model that we developed at Los Alamos, and the Naval Postgraduate School Sea-Ice Model. This is a model that is 5 to 10 times faster than any of the contemporary models. It's one that doesn't have this flux correction that sometimes is blamed for the weaknesses of the models, and thus does not experience climate drift.

Another major program is the program for Climate Model Diagnosis and Intercomparison, which has been the test-bed for climate models around the world. Led by Larry Gates at the Lawrence Livermore National Laboratory, this program essentially is the conscience of the climate modeling community. Employing rigorous quality assurance and quality control standards, it has allowed modelers—given modelers—the opportunity to compare their models against data and to identify weaknesses in the models that they have promptly corrected. Thus, they have also provided us with the guidance to identify the necessary studies—process studies-and the measurements needed in order to improve our ability to predict climate change.

The result of one such intercomparison is, in fact, the Atmospheric Radiation Measurement Program which addresses the principal uncertainty of climate change, as you've heard already this morning, the role of clouds—essentially the cloud and aerosol feedback. With several sites around the world, this program is acquiring the necessary data to reduce this scientific uncertainty.

I believe that the investments that the Department of Energy and other agencies, such as the National Oceanic and Atmospheric Administration, the National Science Foundation, and NASA are making in the U.S. Global Change Research Program will lead to an improved ability to predict climate change at the regional level and thus contribute to more reliable assessments of the impacts of climate change on ecological systems and society.

I am, in fact, very confident that this new generation of climate models that will be used for the IPCC 2000 report will have this improved ability. In the meantime, I believe that the research results to date do not contradict any of the conclusions of the IPCC 1995 report.

This concludes my oral testimony.

[The prepared statement and attachments of Mr. Patrinos fol










OCTOBER 7, 1997

Mr. Chairman and Members of the Subcommittee:

I am pleased to appear before you today to testify on the science of climate change, and in particular the current status of large-scale climate models, including the results of intercomparisons of climate models and the development of advanced models under the Department of Energy (DOE) Computer Hardware, Advanced Mathematics and Model Physics (CHAMMP) program. I am here as both the Associate Director for Biological and Environmental Research (BER) at DOE and as a representative of the interagency Subcommittee on Global Change Research. The Subcommittee on Global Change Research, established under the Committee on Environment and Natural Resources of the President's National Science and Technology Council, provides overall direction and executive oversight of the U.S. Global Change Research Program (US/GCRP). My colleague, Dr. Robert W. Corell, who is the Assistant Director for Geosciences at the National Science Foundation, chairs the Subcommittee on Global Change Research.

The US/GCRP was codified by Congress in the Global Change Research Act of 1990 in order to provide for:

"..development and coordination of a comprehensive and integrated United States research program which will assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural process of global change.”

"...increasing the overall effectiveness and productivity of Federal global change research efforts."

The Act defines global change as “changes in the global environment that may alter the capacity of the Earth to sustain life,” and includes research areas for climate change.

Since 1990 the US/GCRP has supported research across a broad range of scientific disciplines and has contributed to major research advances that have greatly improved our understanding of the workings of the Earth system. In response to the development of scientific understanding and research capabilities, the US/GCRP is currently focusing research efforts on four areas of Earth system science that are of significant and practical importance:


Seasonal to Interannual Climate Variability, with the goal of producing forecasts of seasonal and year-to-year climate fluctuations and to apply these predictions to problems of social and economic development in the United States and abroad.


Climate Change over Decades to Centuries, with the goal of understanding, predicting, and assessing changes in the climate and the global environment that will result from the influences of projected changes in population, energy use, land cover, and other natural and human-induced factors, and providing a stronger information base needed by society

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