I want to express my appreciation for your participation in the Committee's recent hearing on Global Change modelling. Your testimony was of great value to me and to the Committee. Enclosed, you will find some additional questions which are intended to clarify certain points raised in the hearing and develop additional information for the Committee's use. Your written responses will be included as part of the hearing record. I ask that you provide your responses by February 15. You may contact Dr. William S. Smith of my staff at 202/225-4439 if you have any questions regarding this request. Once again, thank you for your assistance. Sincerely, GEORGE E. BROWN, JR. ADDITIONAL QUESTIONS FOR THE RECORD FOR DR. WATSON 1. During the course of the hearing, Dr. Michaels provided a chart which purported to show that a key model used by the IPCC did not provide an adequate representation of temperature data in the 5,000-30,000 ft layer gathered by satellites over the past 20 years. Please provide your own views on the methodology and interpretation used in this chart and its significance, if any, to the validity of the IPCC models. 2. During the course of the hearing, Dr. Michaels provided a chart which purported to show that all of the temperature change from 1965 to 1994 occurred in one year, a feature which models cannot predict. Dr. Michaels implied that the inability of models to predict such behavior called into question their use for policy purposes. Please provide you own views on the methodology and interpretation used in this chart and its significance, if any, to the validity of climate models. 3. You testified that the IPCC assessment finds that aggregate global food production under projected climate change conditions should be able to keep pace with population growth and nutritional needs. In making this projection, how does the IPCC take into account the increasing air pollution in many developing countries, soil erosion and degradation, competing demands for land and water, growing populations, the need for fertilizers, sea level rise onto productive river delta lands, and other factors that may limit the ability of agriculture to shift or increase production? What is the range of uncertainty of this projection and what are the chances that the actual consequences could be much worse? 4. Dr. Michaels testified that the climate models most heavily cited by the IPCC 1992 supplementary report on climate change were known to contain large errors at the time of adoption of the Framework Convention on Climate Change and that such errors were not disclosed with the result that the model's uncertainties were not considered in the debate surrounding this issue. Please respond to this statement. 5. Dr. Michaels testified that in 1992, in association with the signing of the Rio Treaty, Congress was knowingly misled by witnesses who withheld information regarding known errors in key models. Please respond to this statement. 6. Several witnesses have alluded to critical research programs needed to resolve the remaining uncertainties in the global warming theory. Please comment on the role and importance of the following programs and pending Congressional proposals: PROGRAM NOAA's Climate and Global Change PROPOSAL Terminate program in its current form and restrict all NOAA research to seasonal and interannual variability (H.R. 2043). ADDITIONAL QUESTION FOR THE RECORD JOINTLY FOR DR. WATSON AND DR. NIERENBERG Please provide a coordinated, joint response to the Committee for the following question. If agreement on specific issues cannot be reached, you may provide a single response which clearly identifies differing points of view. During the course of the hearing, the point was made that the lifetime for CO2 is complex in nature and may be composed of several time constants ranging from 2 years to 500 years. Recognizing that a single time constant may misrepresent the actual case, what fraction of CO2 that will remain in the atmosphere after say, 5 years, 50 years, and 500 years? How does this depend on the growth rate for emissions? What was the consensus CO2 lifetime used in the IPCC assessments? Are there models or data sets which may argue strongly for a different basis? Of the amount of anthropogenic CO2 put into the atmosphere today, what fraction will essentially never go away (i.e. be there 1000 years from now)? What additional work must be done to better characterize the CO2 lifetime? What fraction of long residence CO2 (say, that remaining after 500 years) would suggest that actions be taken now rather than a "wait and see" policy? EXECUTIVE OFFICE OF THE PRESIDENT April 3, 1996 The Honorable George E. Brown, Jr. Ranking Democratic Member U.S. House of Representatives Dear Representative Brown: Thank you for inviting me to participate in the Committee's recent hearing on global change modeling. Enclosed are answers to the additional questions you sent me to clarify certain points raised in the hearing and to develop additional information for the Committee's use. |