Mr. HASTERT. Would the chairman just yield for a second for a comment? I think one of the things you have to keep in mind, that sometimes the remunerator of efforts that have happened have never had much discipline tied to them, and I think this is a new step in international relations as well. I understand you are doing a very good job with that. Secretary O'LEARY. Well, I have a lot of help, and I am grateful for it. Mr. HASTERT. Thank you, Mr. Chairman. Mr. SHARP. We are going to recess now and let the Secretary and all of us go to the Joint Session of Congress, and we will reconvene at 1 p.m. Thank you very much. [Brief recess.] Mr. SHARP. The subcommittee will please come to order. We will continue our session on global warming. We had the Secretary of Energy this morning and took a break for the joint session with President Mandela that just occurred. Now we are pleased to get back to global warming, and very pleased to have with us Mr. Robert T. Watson, the Associate Director for Environment with the Office of Science and Technology Policy in the Executive Office of the President; Mr. Rafe Pomerance, the Deputy Assistant Secretary for Environment and Development with the Bureau of Oceans and International Environmental and Scientific Affairs for the United States Department of State; and Dr. Karl Hausker, Deputy Assistant Administrator for Policy, Planning and Evaluation with the Environmental Protection Agency. Gentlemen, I think you are quite familiar with our processes. We will make your written statements a part of our record and be happy to have your oral summary at this point. Mr. Watson, I think we will just go down the table and begin with you. Thank you. STATEMENTS OF ROBERT T. WATSON, ASSOCIATE DIRECTOR FOR ENVIRONMENT, OFFICE OF SCIENCE AND TECHNOLOGY POLICY, EXECUTIVE OFFICE OF THE PRESIDENT; RAFE POMERANCE, DEPUTY ASSISTANT SECRETARY FOR ENVIRONMENT AND DEVELOPMENT, BUREAU OF OCEANS AND INTERNATIONAL ENVIRONMENTAL AND SCIENTIFIC AFFAIRS; AND KARL A. HAUSKER, DEPUTY ASSISTANT ADMINISTRATOR FOR POLICY, PLANNING AND EVALUATION, ENVIRONMENTAL PROTECTION AGENCY Mr. WATSON. Thank you, Mr. Chairman. It is a pleasure to be here today to talk about the issue of climate change. What I would like to present today is the latest findings of the Intergovernmental Panel on Climate Change Working Group I. A large number of scientists, about 150 in total, have recently prepared a document that discusses the "Radiative Forcing of Climate Change," that is to say, how do greenhouse gasses, like carbon dioxide, methane, fluorocarbons and nitrous oxide affect the heat trapping of the earth's system. This document was not only written by 150 scientists from over 120 countries, in addition, it was peer reviewed by 231 experts from an additional 31 countries, and then it was submitted for governmental review process at 150 countries and nongovernmental organizations were asked to review it. So this is a heavily peer-reviewed document. It represents the best current view of implications of greenhouse gasses on the heat trapping of the earth's system. However, I should note, this document did not look at the validity of the general circulation models, it did not look at the observations of climate change or the implications to sea-level rise or ecological systems. That work is currently being done by working Groups I and II in a comprehensive assessment that will be published in about a year's time. What did we learn? We reaffirmed that greenhouse gasses have significantly increased since the industrial revolution due to human activities. Carbon dioxide has increased from about 280 parts per million to 360 parts per million. Reason? Combustion of fossil fuels, deforestation in the tropics. Methane has also increased. It has almost tripled from 0.7 parts per million to 1.7 parts per million, largely due to different practices such as rice production, cattle production, and leakage from coal mines and natural gas systems. Nitrous oxide has increased, largely due to the application of fertilizers by changing the nitrification, and denitrification processes in terrestrial systems. And halocarbons which are about to be controlled by the Montreal Protocol, in fact, phased out by the Montreal Protocol, have also had increased substantially since the 1930s and have also led to a change in the radiative heating of the earth's system. Between these gasses, they have actually, literally had the effect of going up by 50 percent on the preindustrial concentrations of CO2. We have increased the radiative forcing by about 2.5 watts per square meter. There are also some things that have actually decreased the radiative forcing or the heat trapping of the air sys tem. We put significant amount of aerosols into the earth's system for two reasons: One, when you combust fossil fuels, you not only liberate CO2 into the atmosphere, you also put sulfur dioxide into the atmosphere, sulfur dioxide gets oxidized, and it forms particles in the atmosphere. When you have biomass burning in the tropics, it also puts carbonaceous aerosols into the atmosphere. These aerosols can have two effects: First, they can directly reflect incoming solar radiation, hence, cooling the earth's surface. Second, they can change the optical properties of clouds, also potentially leading to a slight cooling of the earth's surface. So over the last 100 or so years, we have warmed the earth through putting greenhouse gasses into the atmosphere, but we have led to some offset of this warming due to our industrial practices of burning coal and biomass burning, to put aerosols in the atmosphere. However, there are significant uncertainties associated with the amount of aerosols we put in the atmosphere, and even though there may be a significant offset in the so-called radiative forcing, this does not mean to say there will not be significant climatic im plications. So we have learned that we have changed the heat forcing. We then looked, the next part of the document then looked effectively at the convention, and the convention states that the goal or the objective is stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. What we did was we asked ourselves the question: What would it take to stabilize carbon dioxide, methane, and the other greenhouse gasses at different levels? We don't know today what we can define as a dangerous level. So we asked ourselves what would it take to stabilize at today's level, 360 parts per million, what would it take to stabilize at twice preindustrial levels, 550, and what would it take to stabilize at 750, almost triple preindustrial levels? We then did a series of calculations to find out basically what levels of emissions would be allowable. If one looked at some of the figures in my testimony, we come to a number of conclusions. First, even if you could stabilize emissions at today's concentration, the atmospheric abundance of CO2 would continue to rise for over the next 200 years because of its long atmospheric residence time and it would increase from 360 parts per million today to about 500 parts per million by the year 2200. So even if we stabilize emissions, atmospheric concentrations still go up for the next 200 years. We then recognized that if you wanted to stabilize at literally any level between today's level of 350 parts per million and even 750 parts per million, that is triple preindustrial, you would have to have a significant reduction in greenhouse gas emissions below today's level eventually and, in fact, from the figures, what one can see is after the year 2200, you would have to have emission levels much less than today's. We also looked to see how many greenhouse gasses could you put into the atmosphere over the next 100 years. If, indeed, one wants to stabilize at today's level, one would only be able to average about 2 to 3 to 4 gigatons per year. That is significantly less than what we put into the atmosphere today, which is around 6 to 7 gigatons per year. If one wanted to stabilize at 550 parts per million, that is twice preindustrial, one would be able over the next 100 years to average between about 8 and 10 billion tons of carbon per year, that is only slightly greater than the 6 or 7 billion tons per year we put in today. If one looks at the projections of future emissions of carbon dioxide, which clearly depend on a lot of factors, such as population, Gross National Product, energy supply, energy prices, new technologies, then one finds that there is a plausible range of emission scenarios that could argue at the low end we could conceivably be, roughly, constant, that is to say, 6, 7 billion tons per year. But at the high end projected by the year 2100, the emissions could be as high as 35 billion tons per year. So what one notes, if you look to see what it would take to stabilize greenhouse gas emissions, particularly CO2, compared to the most plausible futures in the absence of climate controls, one would need to have a significant reduction in emissions compared to most likely plausible futures. In other words, action would have to be taken to stabilize carbon dioxde at levels between 350 and 750 parts per million. The last thing we looked at was something called the Global Warming Potential of these gasses, that is to say, how can you compare the effects of methane, a ton of methane versus a ton of carbon dioxide versus a ton of halocarbons. There is an index that basically can tell you what the relative influence of these gasses is on the earth's climate system. We have recalculated all of these indices, we have got a better understanding of the carbon model, we have a better understanding of the atmospheric lifetimes of many of these gasses, and since the last two major assessments of 1990 and 1992, the indices have changed by somewhere between 0 and 30 percent, most of them have gone up by typically 20 percent. What we should note, however, is these indices are not perfect indices. They are probably only accurate to plus or minus 35 percent, they are very important indices. If one wants to put a national plan together, such as the United States where we want to look at the implications of all greenhouse gasses together, you have to have a way of relating methane to CO2 to fluorocarbons. The implications of these new numbers for the U.S. National Action Plan is somewhat more effective than we previously thought insofar as the global warming potential for methane has gone up somewhat. If I were to summarize, we know human activities have changed, the atmospheric concentrations of carbon dioxide led to a significant increase in the heat trapping of the earth's atmosphere. We have also increased the aerosol abundance of the earth's atmosphere, that will have somewhat of an offset, but we do not fully understand the implications for the earth's surface. New theoretical calculations have been performed so we can quantify the implications more exactly. We have looked at the carbon dioxide situation, stabilization of emissions today would still lead to significant increase in concentrations over the next 200 years. And if one wanted to stabilize at any level below 750 parts per million, one would eventually have to have a decrease in emissions compared to today, and certainly reductions in the cumulative emissions over the next 100 years. And lastly, we have these new calculations for Global Warming Potential indices, not significantly different from before. We have more confidence in them, and they have a slightly beneficial effect on how you look at the U.S. National Action Plan. Thank you. [The prepared statement of Dr. Robert T. Watson follows:] Statement of Dr. Robert T. Watson Associate Director for Environment Mr. Chairman and Members of the Subcommittee: My name is Robert Watson and I am the Associate Director for Environment in the Office of Science and Technology Policy. I welcome the interest of Congress in this very important issue of human-induced climate change, and appreciate the opportunity to meet with you this afternoon to discuss the recently released scientific assessment by Working Group I of the Intergovernmental Panel on Climate Change (IPCC) on the "Radiative Forcing of Climate Change". The dramatic increase in world population and industrial activities during the last century is affecting the environment at all geographical scales from local to regional to global. Global issues such as human-induced climate change are no longer the sole concern of the scientific community and environmentalists, but their importance is now well recognized by the private sector and governments around the world. That human-induced climate change, otherwise known as global warming, is a serious issue was recognized at the Earth Summit in Rio de Janeiro, Brazil in 1992 when more than 150 countries signed the Framework Convention on Climate Change. The major objective of the Convention was stated to be: "stabilization of greenhouse concentrations in the atmosphere at a level that would Sound national and international environmental policies must be based on a solid foundation of scientific, technical, and economic understanding of the relevant facts. The IPCC assessments provide a critical review of scientific, technical and socio-economic issues associated with humaninduced climate change. The first part of my testimony is a verbatim copy of the executive summary of the assessment, and the second part discusses the significance of the report. The scope of the 1994 Working Group I of the Intergovernmental Panel on Climate Change (IPCC) is not comprehensive like the IPCC 1990 and 1992 assessments. The assessment includes five chapters related to the radiative effects of climate change, but does not discuss issues such as model predictions of climate change, observations of climate change, projected sea level rise, or ecological consequences of climate change. These issues will be reviewed in detail as part of the ongoing 1995 assessment. The background documents upon which the executive summary was based was prepared by about 150 lead authors and contributors from about 20 countries, peer reviewed by 231 reviewers from 31 countries and non-governmental organizations (NGOs), and followed by a governmental review by experts from about 150 countries and NGO organizations. The executive summary and a summary for policymakers was agreed verbatim in Maastricht, Netherlands by delegates from 82 countries and a number of NGOs. PART I: Executive Summary of 1994 IPCC Working Group I Assessment of Introduction In its first Scientific Assessment of Climate Change in 1990, the IPCC concluded that the increase of greenhouse gas concentrations due to human activities would result in a warming of the Earth's surface. "Radiative forcing" is the name given to the effect which these gases have in altering the energy balance of Earth-atmosphere system and, using this concept, the 1990 report introduced a tool for policy makers, the Global Warming Potential, which allowed the relative warming effect of different gases to be compared. Other factors, natural and human, also caused radiative forcing. The 1990 report not only examined these factors, but also reviewed a wide range of information on how climate has behaved in the past and how it might change in the future as a result of human influence. |