BACKGROUND: The environmental challenges confronting the world today are greater than at any time in recent history. Although developed countries have made considerable progress since the mid-1970s in cleaning air and water, the world's ecosystem is under increasing stress that cannot be alleviated without regional and global cooperation. President Bush has noted that "around the world, there's a growing recognition that environmental problems respect no borders."

Among the important environmental issues requiring attention are ozone depletion, the potential for global warming and climate change, air pollution and acid rain, international transport and disposal of hazardous wastes, tropical deforestation and sustaining biological diversity, and protection of endangered species. President Bush has given high priority to environmental issues, placing the United States in a position of international leadership to develop a balanced approach. Within the U.S. government, the Department of State's Bureau of Oceans and International Environmental and Scientific Affairs is the focal point for dealing with all international environmental issues.PROTECTION OF THE OZONE LAYER: U.S. scientists were the first to recognize the threat of ozone layer depletion and, in 1977, the United States banned the use of chlorofluorocarbons in aerosol spray cans. The United States led in developing the Vienna Convention for the Protection of the Ozone Layer in March 1985 and in negotiating the Montreal Protocol on Substances that Deplete the Ozone Layer, in September 1987. Forty-eight countries, including the European Community, are parties to the latter agreement. The United States supports international efforts to phase out chlorofluorocarbons by the year 2000, provided safe substitutes are available.

GLOBAL CLIMATE CHANGE: Recognizing that an international process was needed to address the impact of increasing emissions of carbon dioxide and other ''greenhouse" gases on global climate, the United States called on the governing bodies of the World Meteorological Organization and the United Nations Environment Program to establish an organization to study the problem and formulate responses. In the summer of 1987, the Intergovernmental Panel on Climate Change was established. Washington believes the panel, which has broad international representation, should be the principal international body to address climate change issues. In January 1989, the United States hosted the first meeting of the panel's Response Strategies Working Group, with 35 countries participating. In May 1989, President Bush said the United States looked forward to playing a significant role in efforts to assess the potential for climate change and, as appropriate, develop responses. He said he expected these efforts would lead to formal negotiations on the establishment of a framework convention on global climate change.

ACID RAIN AND AIR POLLUTION: Acid rain and air pollution are environmental issues particularly prominent in U.S. relations with Canada and Mexico. Initial U.S. efforts to address acid rain and air pollution focused on studying the problem and improving clean coal technology. In February 1989, President Bush reaffirmed the U.S. commitment to solving acid rain problems across the U.S.-Canada boundary. He proposed revisions to the Clean Air Act of 1973 to reduce emissions that are precursors of acid deposition. The United States is supporting efforts by the Mexican government to improve the air quality of Mexico City. Mr. Bush also has announced an environmental initiative in Eastern Europe that includes clean coal technology transfer, air quality monitoring networks, a water quality program for the city of Krakow, Poland and an international environmental center in Budapest, Hungary.

TRANS-BOUNDARY MOVEMENT OF HAZARDOUS WASTES: U.S. laws regarding the disposal of hazardous wastes are among the strictest in the world, and the United States has been a leader in requiring formal consent of receiving countries before allowing exports of hazardous wastes. In March 1989, President Bush proposed to extend this leadership by seeking new legislation that would give the U.S. government the authority to ban all exports of hazardous wastes, except where there is an agreement with the receiving country providing for its safe handling and disposal. The United States is now studying the final text of an agreement reached in Basel, Switzerland, in March 1989 that provides for environmentally sound trans-boundary movements of hazardous and other wastes.

TROPICAL DEFORESTATION: Tropical deforestation contributes to loss of biological diversity, degradation of soils and watersheds and carbon dioxide accumulation. U.S. policy is to reverse the trend of deforestation through bilateral and multilateral assistance programs, such as the International Tropical Timber Organization and the Tropical Forest Action Plan. U.S. development and technical agencies are contributing to research on and monitoring of tropical forest resources.

WILDLIFE CONSERVATION AND PROTECTION OF ENDANGERED SPECIES: The United States belongs to the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Actions by convention partners have helped lead to the resurgence of the alligator, the leopard and other species. Recent restrictions on ivory trade and the convention's placing of the African elephant on its list of endangered species are contributing to the protection of these animals.

FOR FURTHER INFORMATION ON THIS TOPIC: Contact the Bureau of Public Affairs, U.S. Department of State, at (202) 647-1208.