Реферат: Climate change

The U.S. market economy is based on property rights and a reliance on the efficiency of the market as a means of allocating resources. The government plays a key role in addressing market failures and promoting social welfare, including through the imposition of regulations on pollutants and the protection of property rights, but is cautious in its interventions. Thus, the infrastructure exists to limit emissions of greenhouse gases--although the strong political and economic preference is to undertake such controls through flexible and cost-effective programs, including voluntary programs and market instruments, where appropriate.

U.S. economic growth averaged 3 percent annually from 1960 to 1993, and employment nearly tripled as the overall labor force participation rate rose to 66 percent. The service sector--which includes communications, utilities, finance, insurance, and real estate--has grown rapidly, and now accounts for more than 36 percent of the economy. The increasing role of trade in the U.S. economy heightens concerns about the competitiveness effects of climate policies.

During the 1980s, the U.S. budget deficit grew rapidly, as did the ratio of debt to gross domestic product, and a political consensus emerged on the goal of a balanced budget. The result is a tighter federal budget with many competing priorities.

The United States is the world's largest energy producer and consumer. Abundant resources of all fossil fuels have contributed to low prices and specialization in relatively energy-intensive activities. Energy consumption has nearly doubled since 1960, and would have grown far more, because of growth in the economy, population, and transportation needs, had it not been for impressive reductions in U.S. energy intensity. Industrial energy intensity has declined most markedly, due to structural shifts and efficiency improvements. In the residential and commercial sectors, efficiency improvements largely offset the growth in the number and size of both residential and commercial buildings. Likewise, in the transportation sector, efficiency moderated the rise in total fuel consumption from 1973 to 1995 to only 26 percent, despite dramatic increases in both the number of vehicles and the distances they are driven. Fossil fuel prices below levels assumed in the 1993 Climate Change Action Plan, however, have contributed to the unexpectedly large growth in U.S. emissions.

While unique national circumstances point to the reasons for the current levels (and increases) in U.S. emissions, they also suggest the potential for emission reductions. Successful government and private-sector programs are beginning to exploit some of the inefficiencies in the manufacturing sector. The development of new, climate-friendly technologies is a rapidly growing industry, with significant long-term potential for domestic and international emission reductions.

Greenhouse Gas Inventory

Inventorying the national emissions of greenhouse gases is a task shared by several departments within the executive branch of the federal government, including the Environmental Protection Agency, the Department of Energy and the Department of Agriculture. The Greenhouse Gas Inventory chapter summarizes the most current information on U.S. greenhouse gas emission trends--and represents the 1997 submission from the United States in fulfillment of its annual inventory reporting obligation. The estimates presented in this chapter were compiled using methods consistent with those recommended by the IPCC Guidelines for National Greenhouse Gas Inventories; therefore, the U.S. emissions inventory should be comparable to those submitted by others under the FCCC.

Table 1-1 summarizes the recent trends in U.S. greenhouse gas emissions from 1990 to 1995. The three most important anthropogenic greenhouse gases are carbon dioxide (CO₂ ), methane (CH₄ ), and nitrous oxide (N₂ O). Hydrofluorocarbons (HFCs) are also inventoried. Consistent with the requirements in the Climate Convention only to address emissions of gases not controlled by the Montreal Protocol on Substances That Deplete the Ozone Layer, chlorofluorocarbon (CFC) emissions are not inventoried, nor are mitigation measures for these compounds described.

Overall, U.S. greenhouse gas emissions have increased annually by just over one percent. The trend of U.S. emissions--which decreased from 1990 to 1991, and then increased again in 1992--is a consequence of changes in total energy consumption resulting from the U.S. economic slowdown in the beginning of this decade and its subsequent recovery.

Carbon dioxide accounts for the largest share of U.S. greenhouse gases--approximately 85 percent--although the carbon sinks in forested lands offset CO₂ emissions by about 8 percent. During 1990-95, greenhouse gas emissions continued to rise in the United States, with CO₂ increasing approximately 6 percent, methane approximately 4 percent, N₂ O nearly 10 percent, and HFCs approximately 7 percent. Fossil fuel combustion accounts for 99 percent of total U.S. CO₂ emissions. (Chapter 3 of this report explains the use of MMTCE in converting emissions of greenhouse gases to carbon equivalents.)

Although methane emissions are lower than CO₂ emissions, methane's footprint is large: in a 100-year time span it is considered to be twenty-one times more effective than CO₂ at trapping heat in the atmosphere and is responsible for about 10 percent of the warming caused by U.S. emissions. In addition, in the last two centuries alone, methane concentrations in the atmosphere have more than doubled. Emissions of methane are largely generated by landfills, agriculture, oil and natural gas systems, and coal mining, with landfills comprising the single largest source of the gas. In 1995, methane emissions from U.S. landfills were 63.5 MMTCE, equaling approximately 36 percent of total U.S. methane emissions. Agriculture supplied about 30 percent of U.S. methane emissions in that same year.

Nitrous oxide is also emitted in much smaller amounts than carbon dioxide in the United States and is responsible for approximately 2.4 percent of the U.S. share of the greenhouse effect. However, like methane, it is a more powerful heat trap--310 times more powerful than carbon dioxide at trapping heat in the atmosphere over a 100-year period. The main anthropogenic activities producing nitrous oxide are agriculture, fossil fuel combustion, and the production of adipic and nitric acids. Figures from 1995 show the agricultural sector emitting 46 percent of the total (18.4 MMTCE), with fossil fuel combustion generating 31 percent.

Hydrofluorocarbons (HFCs) are among the compounds introduced to replace ozone-depleting substances, which are being phased out as a result of the Vienna Convention and its Montreal Protocol on Substances That Deplete the Ozone Layer, and the Clean Air Act Amendments of 1990. Because HFCs have significant potential to alter the Earth's radiative balance, they are included in this inventory. Many of the compounds of this nature are extremely stable and remain in the atmosphere for extended periods of time, which results in a significant atmospheric accumulation over time. U.S. emissions of these gases have risen nearly 60 percent as they are phased in as substitutes for gases that are no longer allowed under the Montreal Protocol--a rate of growth that is not anticipated to continue. Currently, HFCs account for less than 2 percent of U.S. radiative forcing.

Mitigating Climate Change

In October 1993, in response to the threat of global climate change, President Clinton and Vice President Gore announced the Climate Change Action Plan (CCAP). The Plan was designed to reduce U.S. emissions of greenhouse gases, while guiding the U.S. economy toward environmentally sound economic growth into the next century. This report updates the programs in the CCAP (including an appendix providing one-page descriptions of each program), describes several additional initiatives developed to further reduce emission growth rates, and estimates future emissions based on the current set of practices and programs.

CCAP programs represent an effort to stimulate actions that are both profitable for individual private-sector participants as well as beneficial to the environment. Currently, more than forty programs are in effect, combining efforts of the government at the federal, state, and local levels with those of the private sector. The CCAP has five goals: preserving the environment, enhancing sustainable growth environmentally and economically, building partnerships, involving the public, and encouraging international emission reductions.

Carbon dioxide emissions constitute the bulk of U.S. greenhouse gas emissions. CCAP recognizes that investing in energy efficiency is the most cost-effective way to reduce these emissions. The largest proportion of CCAP programs contains measures that reduce carbon dioxide emissions while simultaneously enhancing domestic productivity and competitiveness. Other programs seek to reduce carbon dioxide emissions by investing in renewable-energy and other low-carbon, energy-supply technologies, which will also provide longer-term benefits, such as increased efficiency and related cost-savings and pollution prevention. A smaller number of programs are targeted at methane, nitrous oxide, and other greenhouse gases (Table 1-2).

A review and update of the CCAP was initiated in 1995, involving a federal government interagency review process and a public hearing and comment period. Revisions to the CCAP (and to the calculation of the effects of its measures) were initiated in light of comments received during this process and are reflected in this document. In addition, as called for under FCCC reporting guidelines, the projections of the effects of measures taken are extended to the year 2020, with the understanding that uncertainties become greater in more distant years.

One of the principal products of the review was an assessment of the effectiveness of the CCAP programs, which were rated to be successful at reducing emissions. Currently, more than 5,000 organizations are participating in programs around the United States. The pollution-prevention benefits of these innovative programs are beginning to multiply rapidly in response to the groundwork laid and the partnerships made. In all, the programs are expected to achieve a large portion of the reductions projected in the CCAP. In fact, it is estimated that these programs will result in energy cost savings of $10 billion annually in 2000.

However, the review has also made clear the significantly reduced impact to be expected from the programs as a result of the nearly 40 percent reduction of CCAP funding by Congress from the amount requested by the President, higher-than-expected electricity demand, and lower-than-expected energy prices. In addition, before the programs' implementation, CCAP program managers could not always anticipate the impacts of projected climate change emission reductions. Information available from the first tranche of activity was considered in developing the current projections.

A second product of the review was the identification of several measures that have since been added to the CCAP portfolio. The most significant of these is the Environmental Stewardship Initiative, which greatly expands activities already included in the CCAP, and focuses on reducing the emissions of extremely potent greenhouse gases from three industrial applications--semiconductor production, electrical transmission and distribution systems, and magnesium casting. The expanded initiative is anticipated to reduce emissions by an additional 6.5 MMTCE by 2000, and 10.0 MMTCE by 2010. Other programs include improving energy efficiency in the construction of and supply of energy to commercial and industrial buildings, expanding residential markets for energy-efficient lighting products, and providing information on renewable energy to reduce barriers to the adoption of clean technologies.

The analysis of individual actions is integrated with revised forecasts of economic growth, energy prices, program funding, and regulatory developments to provide an updated comprehensive perspective on current and projected greenhouse gas emission levels. This analysis involved an updating of the baseline calculation in light of new economic assumptions regarding energy prices, economic growth, and technology improvements, among other factors. In 1993, the first U.S. submission projected year 2000 baseline emissions to be 106 MMTCE above their 1990 levels; with current program funding, emissions are now projected to exceed 1990 levels by 188 MMTCE. Two principal factors are responsible:

· The analysis used to develop CCAP significantly underestimated the reductions that would be needed by programs to return emissions to 1990 levels by the year 2000. This was due to several factors, including lower-than-expected fuel prices, strong economic growth, regulatory limitations within and outside of CCAP, and improved information on emissions of some potent greenhouse gases.

· In addition, diminished levels of funding by Congress have affected both CCAP programs and other federal programs that reduce emissions, limiting their effectiveness.

While neither the measures initiated in 1993 nor the additional actions developed since then and included in this report will be adequate to meet the emissions goal enunciated by the President, they have significantly reduced emissions below growth rates that otherwise would have occurred. Based on current funding levels, the revised action plan is expected to reduce emissions by 76 MMTCE in the year 2000--or 70 percent of the reductions projected in the CCAP. Annual energy cost savings to businesses and consumers from CCAP actions are anticipated to be $10 billion (1995 dollars) by the year 2000. Even greater reductions are estimated from these measures in the post-2000 period: reductions of 169 MMTCE are projected for 2010, and 230 MMTCE for 2020. Annual energy savings are projected to grow to $50 billion (1995 dollars) in the year 2010.

A separate component of this chapter addresses the U.S. Initiative on Joint Implementation. Projects undertaken through this initiative allow private-sector partners to offset emissions from domestic activities through reductions achieved in other countries. The Climate Convention established a pilot program for joint implementation at the first meeting of the Conference of the Parties. Guidelines for reporting under the pilot program were established by the Subsidiary Body for Scientific and Technological Advice at its fifth session in February 1997. This report uses those guidelines to report on project activity.

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