Chairman CALVERT. Thank you for you testimony. Next is Dr. Robert Watson, who is the new Chair of the Intergovernmental Panel on Climate Change. Doctor, you're recognized. TESTIMONY OF ROBERT T. WATSON, CHAIR, Mr. WATSON. Thank you, Mr. Chairman. I appreciate the opportunity to testify before you and the other members of this Committee. In my opinion, the overwhelming majority of scientific experts both recognize that scientific uncertainties exist but, in spite of those scientific uncertainties, believe that human-induced climate change is inevitable. The key question is the exact magnitude, where, and when. The IPCC concludes that human activities are already changing the Earth's climate. Greenhouse gas concentrations have gone up significantly and, even though your figure only shows that human activities are 4 percent of the emissions of CO2, which is absolutely correct, we have actually increased the natural amount by 30 percent. That's why some people call it a pollutant and we've doubled the atmospheric concentration of methane. There's no doubt we've increased the amount of sulfur dioxide and other particulars in the Earth's atmosphere and they partially cool the Earth's atmosphere. The Earth's atmosphere has warmed about half a degree Centigrade and much of it since 1940. Sealevel has increased 10 to 25 centimeters, glaciers have retreated globally and there's serious evidence of an increase in heavy precipitation events, especially in the United States of America. Can we explain these observed changes are natural variability alone? The majority of scientists, clearly not all, including Pat Michaels, do not believe we can attribute it to natural variability. Hence, we believe now there is a discernible human influence on the Earth's climate system. If there's not a global, and I stress global, effort to reduce greenhouse gas emissions, we would expect a 1 to 3.5 degree Centigrade rise in temperature by the Year 2100, an increase in sea level of 15 to 95 centimeters, and significant changes in precipitation patterns, both the spatial and the temporal precipitation pat terns. Why should we as a society care? A significant increase in vectorborne diseases, especially malaria and dengue, obviously, not in the United States, but in tropical and subtropical climates. Global food production may not be affected by global warming by significant change in the distribution, far less productivity in Africa and Latin America as much as 30 percent, even when you take into account the positive effects of CO2. A sea level rise of 1 meter at the topend of the climate predictions by the Year 2100, but clearly in the middle of projects thereafter, could displace tens of millions of people in Bangladesh, Egypt, China, and whole low-lying islands may be threatened. Complex ecological systems, especially forests, could clearly be threatened. Indeed, we believe that while there may be an immediate greening of the planet, sooner or later there would be a significant disruption to these ecological systems and water resources clearly would be threatened in many parts of the world, remembering that literally 20 nations today are already water stressed or water-scarce and, indeed, part of the United States have significant difficulties. Clearly, the bottom line is that climate change is a global issue but we have to note that developing countries are more vulnerable than developed countries. Global GDP losses have been estimated to be 1 to 2.5 percent of GDP, in a double CO2 world, would the numbers 5 to 9 percent in developing countries. I believe these numbers are quite uncertain but it did leave 2,000 economists to argue that the United States and others should take the lead because the costs of inaction were greater than the costs of action. Those same economists articulated a market strategy, as you heard from actually the two previous speakers and Senator Lieberman. Energy supply, energy demand, there are many, many opportunities to reduce the projected rate of increase of greenhouse gases. No one is arguing to curtail energy use. People are arguing to curtail greenhouse gas emissions. The more efficient production of energy and converting away from dirty coal, even to oil and gas, and using renewable energies like wind and solar. It's not a question of starving the world. We recognize the United States and developing countries all need energy services. So, it's a question of not curtailing energy, it's new energy systems. The IPCC recognizes, and it was taken up in President Clinton's announcement, that process would be facilitated with joint implementation. The costs of reductions in developing countries and countries in-economies in transition— are much less than in developed countries. Therefore, the right sort of joint implementation system would reduce the costs in developed countries, transfer technologies to developing countries, and allow developing countries to share in the cost savings. There are uncertainties, but they go in two directions. We could be underestimating or overestimating the impact of climate change. Therefore, it's a risk calculation. I'd like to remind you that manynot many, a few scientists, including Pat-questioned whether or not we knew anything about ozone depletion. Pat argued, as did Fred Singer, and many others, the data is poor, the models were poor and the models didn't agree with data. Pat will show you the same sort of arguments on climate change. Pat was right, the models were poor. We underestimated the extent of ozone depletion and we now recognize even with complete elimination of long-lived chlorine- and bromine-containing compounds, ozone will remain depleted for another 50 years. So, there are there's no question, there are uncertainties. The question is how we manage the risk and why should we be optimistic? All the uncertainties are going in one direction. The other thing that we need to recognize is the time constraints, Mr. Chairman, and that is if we wait for perfect knowledge, it would take centuries to even millennia to reverse that damage. So, the question here is when does one need to take action? Only you, our politicians, can make that decision. That is not a scientific judgment but one should note if we wait for perfect knowledge and we do not like that new world, we cannot reverse the damage quickly. Thank you. [The prepared statement and attachments of Mr. Watson follow:] Testimony of Robert T. Watson IPCC Chair before the Subcommittee on Energy and Environment Committee on Science U.S. House of Representatives November 6, 1997 Mr. Chairman and members of the subcommittee, it is pleasure to be appear before you today to discuss an issue of critical importance to this and future generations: global climate change. My name is Robert T. Watson and I am testifying today as the chair of the Intergovernmental Panel on Climate Change (IPCC). Prior to assuming the overall chairmanship of IPCC in September of this year I was the co-chair of IPCC Working II, which assessed the vulnerability of human health, ecological systems and socio-economic sectors to climate change and the potential to mitigate climate change using a broad portfolio of technologies and policies. Mr. Chairman, you are to be commended on holding this hearing to examine the Administration's position regarding global climate change negotiations given the importance of the upcoming meeting in Kyoto later this year. My testimony briefly describes the current state of understanding of the Earth's climate system and the influence of human activities; the vulnerability of human health, ecological systems, and socio-economic sectors to climate change; and approaches to reduce emissions and enhance sinks. Overview The overwhelming majority of scientific experts recognize that scientific uncertainties exist, but still believe that human-induced climate change is inevitable. The question is not whether climate will change in response to human activities, but rather where (regional patterns), when (the rate of change) and by how much (magnitude). It is also clear that climate change will adversely effect human health (particularly vector-borne diseases), ecological systems (particularly forests and coral reefs), and socio-economic sectors, including agriculture, forestry, fisheries, water resources, and human settlements, with developing countries being the most vulnerable. These are the fundamental conclusions of a careful and objective analysis of all relevant scientific, technical and economic information by thousands of experts (including, climatologists, theoretical modellers, oceanographers, meteorologists, chemists, biologists, technologists, economists and social scientists), from academia, governments, industry and environmental organizations from around the world under the auspices of the United Nations International Panel on Climate Change. The good news is, however, that the majority of energy experts believe that significant reductions in greenhouse gas emissions are technically feasible due to an extensive array of technologies and policy measures in the energy supply and energy demand sectors at little or no cost to society. In addition, changes in land-use practices can also reduce net carbon emissions cost-effectively. Decision-makers should realize that the atmospheric residence time of carbon dioxide, the major anthropogenic greenhouse gas, is more than a century, which means that if policy formulation waits until all scientific uncertainties are resolved, and carbon dioxide and other greenhouse gases are responsible for changing the Earth's climate as projected by all climate models, the time to reverse the human-induced changes in climate and the resulting environmental damages, would not be years or decades, but centuries to millennia, even if all emissions of greenhouse gases were terminated, which is clearly not practical. The Earth's Climate System: The Influence of Human Activities The Earth's climate has been relatively stable (global temperature changes of less than 1°C over a century) during the present interglacial (i.e., the past 10,000 years). During this time modern society has evolved, and, in many cases, successfully adapted to the prevailing local climate and its natural variability. However, the Earth's climate is now changing. The Earth's surface temperature this century is as warm or warmer than any other century during the last six hundred years; the Earth's surface temperature has increased by about half a degree centigrade over the last century; and the last few decades have been the hottest this century. In addition, there is evidence of changes in sea level, that glaciers are retreating world-wide, and that the incidence of extreme weather events is increasing in some parts of the world. Not only is there evidence of a change in climate at the global level, but there is observational evidence that the climate of the U.S. is changing: increased temperatures (day and night), more intense rainfall events (defined as two inches within a 24 hour period), increased precipitation in winter, and less day-day variability in temperature. The atmospheric concentrations of greenhouse gases have increased because of human activities, primarily due to the combustion of fossil fuels (coal, oil and gas), deforestation and agricultural practices, since the beginning of the pre-industrial era around 1750: carbon dioxide by about 30%, methane by more than a factor of two, and nitrous oxide by about 15%. Their concentrations are higher now than at any time during the last 160,000 years, the period for which there are reliable ice-core data, and probably significantly longer. In addition, the atmospheric concentrations of sulfate aerosols have also increased. Greenhouse gases tend to warm the atmosphere and, in some regions, primarily in the Northern hemisphere, aerosols tend to cool the Theoretical models that take into account the observed increases in the atmospheric concentrations of greenhouse gases and sulfate aerosols simulate the observed changes in surface temperature and the vertical distribution of temperature quite well. This, and other information, suggests that human activities are implicated in the observed changes in the Earth's climate. In fact, the observed changes in climate cannot be explained by natural phenomena alone (e.g., changes in solar output and volcanic emissions). Future emissions of greenhouse gases and the sulfate aerosol precursor, sulfur dioxide, are sensitive to changes in population and gross domestic product, the rate of diffusion of new technologies into the market place, production and consumption patterns, land-use practices, energy intensity, and the price and availability of energy. Most projections suggest that greenhouse gas concentrations will increase significantly during the next century in the absence of policies specifically designed to address the issue of climate change. For example, carbon dioxide emissions from the combustion of fossil fuels are projected to range from 6 to 36 GtC per year in the year 2100: compared to current emissions of 6 GtC per year. However, in the last few months, two major oil companies, Shell and British Petroleum, have suggested that the mix of energy sources is likely to change radically during the next 50 years, with renewable energy sources (solar, wind and modern biomass) possibly accounting for as much as half of all energy produced by the middle of the next century. Such a future would clearly eliminate the highest projections of greenhouse gases being realized. Based on the range of climate sensitivities (an increase in the equilibrium global mean surface temperature of 1.5 - 4.5°C for a doubling of atmospheric carbon dioxide concentrations) and plausible ranges of greenhouse gas and sulfur dioxide emissions (IPCC IS 92), climate models project that the global mean surface temperature could increase by 1 to 3.5°C by 2100. These projected global-average temperature changes would be greater than recent natural fluctuations and would also occur at a rate significantly faster than observed changes over the last 10,000 years. These long-term, large-scale, human-induced changes are likely to interact with natural climate variability on time-scales of days to decades (e.g., the El Nino-Southern Oscillation (ENSO) phenomena). Temperature changes are expected to differ by region with high latitudes projected to warm more than the global average. However, the reliability of regional scale predictions is still low. Associated with these estimated changes in temperature, sea level is projected to increase by 15 - 95 cm by 2100, caused primarily by thermal expansion of the oceans and the melting of glaciers. However, it should be noted that even when the atmospheric concentrations of greenhouse gases are stabilized, temperatures will continue to increase for several decades because of the thermal inertia of the climate system (temperature by another 3050%), and sea level for an even longer period of time. Model calculations show that evaporation will be enhanced as the climate warms, and that there will be an increase in global mean precipitation and an increase in the frequency of intense rainfall. However, not all land regions will experience an increase in precipitation, and even those land regions with increased precipitation may experience decreases in soil moisture, because of enhanced evaporation. Seasonal shifts in precipitation are also projected. In general, |