The information in this report is a product of the Board's review of the issues at a May 19, 1997 meeting with three experts1 and a WIEB staff briefing paper issued on May 5, 1997. The report, which is organized into a question and answer format, addresses three issues:
The state of the science of global climate change;
The U.S. position in international negotiations; and
Options for controlling emissions.
The report summarizes and unavoidably simplifies the many complex issues involved in global climate change.
1. Are man's activities causing a change in the global climate?
There is broad agreement in the scientific community that the balance of evidence suggests that there is a discernible human influence on global climate. Historical data show that the atmospheric concentration of carbon dioxide, the major man-made greenhouse gas2, is increasing. Since the 1880s, the amount of carbon dioxide in the atmosphere has increased approximately 30 percent. The major cause of this increase is the burning of fossil fuels. Deforestation plays a lesser role in the increase in carbon dioxide. The concentration of other greenhouse gases is increasing faster than carbon dioxide.
2. Is the earth's temperature rising? If so, how fast and how much is the temperature rising?
The data on global temperature change are not as complete as the data on carbon dioxide concentrations in the atmosphere. The best temperature data comes from land-based temperature readings, sampling of ocean temperatures, and, most recently, satellites. These data show a warming trend, although the warming has not been uniform around the globe. Prior to the 1880s, there are few direct readings of temperature. To estimate temperatures prior to 1880, one must rely on secondary sources such as ice core samples and glacial data which become increasingly difficult to quantify as one moves back in time. The readings from land-based thermometers have been adjusted to take into account localized temperature increases due to increasing urbanization. Without such adjustments, land-based temperature readings would falsely indicate greater global warming than has actually occurred.
There is broad agreement that warming of the earth has occurred. However, the scientific community does not know how much of this warming to attribute to increases in carbon dioxide and other greenhouse gases in the atmosphere.
Climate models, which are increasingly able to replicate past changes in the earth's climate, project an increase in the earth's average surface temperature of between 1.6 and 6.3 degrees Fahrenheit by 2100. While temperature forecasts by climate models are not definitive, the models do provide important indicators of the direction and severity of potential changes in the climate.
The major uncertainties with climate models relate to the impact of feedback mechanisms. Continued research is required to answer the following questions on climate feedback mechanisms. Does the change in water vapor in the atmosphere which occurs with rising temperatures amplify or dampen the rise in temperatures? Will changing cloud cover amplify temperature increases by trapping heat or increase the amount of the sun's radiation which is reflected back into space thereby dampening temperature increases? How might the circulation of ocean currents change in response to increases in temperature? How will the amount of the earth covered by snow and ice affect the absorption of the sun's radiation? What biologic feedback mechanisms may be at work to alter the rise in temperature?
The uncertainties in the scientific community over the impact of climate feedback mechanisms are not as significant as frequently reported in the press. For example, the predominant scientific opinion is that increasing water vapor will amplify the warming effect.
It is important to remember that temperature is only one measure of climate change. The most important effects of climate change may be changes in precipitation, changes in sea level, and hurricane intensity, not changes in temperature.
The basic scenario leading to global warming begins with an increase in greenhouse gases in the atmosphere, followed by increasing opacity of the atmosphere to infrared (heat) radiation from earth. These conditions then lead to increases in ocean temperatures, increases in evaporation, increases in absolute humidity and finally warming of the earth's surface. Scientists have varying degrees of confidence in the sequence of events leading to warmer temperatures. The chart shows the relative degree of confidence in each of these steps.
3. What are the impacts of a rise in temperature?
The most certain impact of a rise in global temperatures will be a continued rise in sea level. Changes in precipitation and soil moisture patterns are less certain. It is uncertain what impact a rise in temperature will have on the severity of storms such as hurricanes.
Changes in El Niņo, the periodic perturbation in the atmosphere's and ocean's temperature and circulation, have the largest effect on climate after annual seasonal change. El Niņo is associated with extreme global climatic events, including droughts and major flooding. There is some evidence that El Niņo is more prevalent with warmer temperatures.
There are a host of other potential impacts which are not well understood. Some regions could experience extreme high-temperature events, floods and droughts — with consequences such as fires, pest outbreaks, the spread of diseases such as malaria, and the loss of biodiversity and agricultural production. Changes in local climates are expected. Since economic and biological systems are adapted to the current climate, any large change is disruptive. For example, it would be disruptive for many harbors if sea level rose or fell by even a few feet. The current most likely forecast is for a sea level rise of about 1.5 feet by 2100.
4. What are the impacts of a rise in temperature on western states?
The ability of climate change models to forecast regional impacts is poor. Therefore, no definitive conclusions can be made about the impact of climate change on western states.5. How reversible are the effects of global climate change?
Changes in climate are not quickly or easily reversible, at least in the foreseeable future. For example, carbon dioxide molecules can stay in the atmosphere for hundreds of years. Similarly, it may take more than 50 years for the temperature of the oceans to respond to changes resulting from increased greenhouse gases in the atmosphere.
5. How reversible are the effects of global climate change?
Changes in climate are not quickly or easily reversible, at least in the foreseeable future. For example, carbon dioxide molecules can stay in the atmosphere for hundreds of years. Similarly, it may take more than 50 years for the temperature of the oceans to respond to changes resulting from increased greenhouse gases in the atmosphere.
6. What emphasis should be placed on adaptation as opposed to reduction in greenhouse gas emissions?
Past man-made emissions will result in future changes in climate. This will require that adaptive measures be taken.
An almost certain impact of climate change will be a rise in sea levels. Over the next century, coastal areas will likely be required to undertake significant adaptation. As the science of climate change progresses and the forecasting ability of climate change models improves, further adaptive measures will likely be required. The uncertainty of local climate impacts makes it difficult to implement adaptive measures because it is difficult to determine if changes are aberrations or trends. There is general agreement that developed nations are more able to adapt to climate changes than developing nations.
It is likely that increased greenhouse gas emissions will accelerate changes in climate. Accelerated climate changes will require expanded adaptation measures.
Greenhouse gas emission reduction strategies are likely to lessen the severity of future changes and therefore reduce the cost of future adaptation. Since the magnitude and timing of the climate changes are uncertain and potentially severe, emission reduction strategies serve to reduce the risk of catastrophic changes which would require more costly adaptive action.
1. What international agreements are there on global climate change?
The Framework Convention on Climate Change, signed in Rio de Janeiro in 1992, set the goal of stabilizing greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. The desired level of such gases was not specified, nor did the agreement establish any binding emission reduction targets. The U.S. will not meet its goal of limiting emissions in 2000 to levels achieved in 1990. The Rio accord was ratified by the U.S. Senate. The next major step will occur in Kyoto, Japan in December. The U.S. position is that the Kyoto talks should produce an agreement that sets a realistic, verifiable, and binding medium-term (post -2000) emissions target. Any agreement coming out of Kyoto would have to be ratified by the U.S. Congress. The Administration believes that, in order to secure Congressional approval, there must be some certainty that the U.S. can achieve the emissions target resulting from the Kyoto negotiations.
2. What is the U.S. position in ongoing negotiations?
The U.S. is proposing that each developed country be allocated a multi-year emissions budget. Budgets would be established for at least two time periods, with the budget for the second time period being lower than the budget for the first time period. Each country would determine how best to meet its emissions budget. The U.S. proposes full emissions trading among countries with emission budgets and "joint implementation," through which countries without emissions budgets could create and sell emissions reduction credits achieved by qualified projects. Countries could bank excess emission reductions and borrow emission allowances from their allocation in a future time period. The U.S. believes that by allowing flexibility in the timing of required emission reductions and allowing trading between countries, the cost of reductions can be cut by as much as 85 percent.
The U.S. is advocating that developing countries adopt and report on "no regrets" measures and be provided with assistance from developed nations. Developing countries would be allowed to adopt a binding emissions budget and participate in the international emissions trading system. The U.S. wants all nations to have binding emissions budgets by some future year. Only the date for establishing emission budgets for developing countries would be agreed upon in Kyoto. Actual emissions budgets for developing countries would be negotiated after the Kyoto agreement.
The U.S. has not proposed the level of the emissions budgets for developed countries, in part, because this would become a marker against which the European nations will demand greater reductions.
3. What positions are other countries taking?
There are widely divergent views which must be accommodated in the final two negotiating sessions this year in order to sign an accord in Kyoto. The European Union (EU) has generally supported binding targets and timetables for emissions reductions. The European countries want a 15 percent cut in emissions by 2010 and are contemplating a Europe-only trading system. The non-EU developed countries (e.g., Japan, U.S., Canada) have generally urged a more "flexible" approach. Australia, Norway, Japan and Canada are interested in setting different budgets for different countries. The U.S. does not believe there is adequate time before the December meeting to negotiate such country-specific budgets. Countries with economies in transition (e.g., the former Soviet republics and eastern Europe) have generally experienced declining emissions due to economic decline. The Group of 77 (developing countries) and China have differing views. China has focused on making its coal resources available. African countries have tended to focus on vulnerability and effects of climate change. Asian "tigers" are concerned that they may be the next in line for emissions reduction targets. The Association of Small Island States supports a 25 percent emissions reduction due to concerns of sea-level rise which could lead to their extinction. OPEC countries have emphasized scientific uncertainties and have argued for a cautious approach. OPEC countries also want compensation for lost oil revenues.
4. What are the consequences for the U.S. of not meeting its emissions budget? The U.S. is not contemplating making non-compliance with emission budgets an issue that can be brought before the World Court. The most likely consequences of non-compliance are a loss of a country's voting rights on future agreements and an inability to participate in the international emissions trading system.
5. What are the next steps the Administration will take? In early June, the Administration will issue new language on a proposed international agreement. The Administration will also be releasing the results of its modeling of the impacts of different greenhouse gas emissions reduction scenarios. The Administration is holding regional conferences to discuss the assessments of different levels of greenhouse gas controls. There will be two more international negotiating sessions, in July-August and in late October, prior to the December 1-12 meeting in Kyoto.
1. What would be the impact of an individual country, such as the United States, unilaterally controlling emissions?
The U.S. accounts for nearly one-quarter of all energy-related carbon emissions.3 Thus, a reduction in U.S. emissions would have a measurable impact on total world emissions in the near-term. However, the growth in emissions from the U.S. is slowing while emissions from the developing world are increasing rapidly. This trend is likely to continue. The developing world already accounts for a quarter of the world's emissions. As a result, successful unilateral actions to cut greenhouse gas emissions in the U.S. will have a decreasing impact on total world emissions. To achieve a stabilization of greenhouse gas emissions, both developed and developing countries must control emissions. This may be achieved by fostering emissions reductions in all countries and economic sectors, but not necessarily deep cuts in emissions in a few countries or economic sectors. See the graph for recent trends in energy-related carbon emissions by region.
2. If there were binding emissions budgets for each country, what are the policy options for meeting the budget?
The general options for limiting greenhouse gas emissions are: (1) an emissions cap with trading of emissions rights; (2) carbon taxes; (3) energy standards, such as appliance, building and vehicle energy efficiency standards and renewable energy production standards; (4) funding and incentives for the research, development and market penetration of new energy efficiency technologies and low emission energy resources such as renewable and nuclear energy; and (5) voluntary programs. There are opportunities to reduce emissions in all sectors of the economy.4 Ultimately, technology development will be the decisive factor in determining if emissions are to be stabilized. Thus far, voluntary programs have not been effective in stemming the growth of greenhouse gas emissions.
A cap and trade system which includes carbon dioxide emissions and emissions of other greenhouse gases is the most far reaching option. Emission allowances under a cap and trade system could be allocated or auctioned. Cap and trade systems would be easiest to administer if those receiving the emission allowances are upstream in the production process (e.g., at the fuel production level rather than at the level of the individual consumer). An international cap and trade system is likely to produce emission reductions at lower cost than one limited to the U.S., but may be difficult to implement, particularly in developing countries. States are unlikely to play a major role in the administration of cap and trade systems.
3. Are there any aggressive policy options for reducing greenhouse gas emissions which have positive economic benefits?
Many observers advocate incremental actions as part of a "no regrets" approach to mitigating climate change. Under such a philosophy, those actions which have the effect of reducing greenhouse gas emissions, and which can be justified on other grounds (e.g., lower costs), should be taken. Policies to improve the efficiency of energy use (e.g., appliance efficiency standards) are frequently cited as a "no regrets" emissions strategy which provides economic benefits.
Some organizations, such as the Intergovernmental Panel on Climate Change, define "no regrets" from the perspective of society as a whole; that is, society as a whole would be better off as a result of the action. Others, such as The Business Roundtable, use a narrower perspective when applying the term "no regrets," under which no action should be taken if any individual is worse off as a result of the action, even if society as a whole benefits.
It is important to distinguish a "no regrets" strategy from a voluntary strategy. There are likely to be policy options that could significantly reduce greenhouse gas emissions at little overall cost to society. However, such options may require government action in the form of incentives, expenditures or regulations.
The U.S. government is conducting an evaluation of the economic impacts of various emissions reduction levels. The evaluation has not yet been completed.
To date, there has not been an estimate made of the cost of taking no action to reduce emissions.
1 Dr. Richard Somerville, Professor of Meteorology at the Scripps Institution of Oceanography University of California, San Diego, briefed the Board on the state of the science. Ned Helme, Director of the Center for Clean Air Policy, reviewed emission control options. Dirk Forrister, Chairman of the White House Climate Change Task Force, briefed the Board on the U.S. negotiating position. The information and views expressed in this report are those of the Board and do not necessarily reflect those of the panelists.
2 The significant man-made greenhouse gases are carbon dioxide, methane, nitrous oxide, and halocarbons (e.g., chlorofluorcarbons or CFCs).
3 There is less certainty about the U.S. share of other greenhouse gases. The U.S. share of methane and nitrous oxide emissions is likely to be lower than the U.S. share of world carbon dioxide emissions, while the U.S. share of other greenhouse gases, such as halocarbons, is likely to be higher.
4 Nationally, utilities account for 35 percent of U.S. carbon-related emissions; industry 34 percent; and transportation 31 percent. This distribution of emissions, however, may not be the same in the West. For example, in California utilities account for only 16.2 percent of emissions in the state, while transportation contributes 57 percent of emissions. Nationally, and in the West, emissions from the transportation sector are growing the fastest. Data on the distribution of emissions of non-carbon-related greenhouse gases (e.g., methane, nitrous oxide and halocarbons) are not available.