With prospects dimming for a strong agreement to combat global warming, negotiators from more than 100 nations were returning today to New York to try to break a yearlong deadlock between the United States and the other industrialized countries over pollution limits.
The negotiations are part of a United Nations effort launched a year ago to develop an effective treaty on climate change, which is seen as the centerpiece for an "Earth summit" to be held in June. At that meeting, heads of state from around the world will gather in Brazil to discuss environmental and development issues and work to create a framework for cooperation and action in the 21st century.
The U.N. General Assembly asked the International Negotiating Committee, the organization handling the climate negotiations, to prepare a treaty with "appropriate commitments" in time for signing by heads of state in Brazil.
Environmentalists, however, fear that U.S. opposition to pollution limits could not only undermine the climate treaty but also threaten the summit itself by heightening tensions between industrialized and developing countries.
"There are some pretty big stakes riding on this," said Alden Meyer of the Union of Concerned Scientists, a national group based in Cambridge, Mass., that is concerned with issues of technology, energy and the environment.
Over the past year, the United States has disagreed with the consensus among other industrialized nations that the treaty should set a target for industrial countries of limiting emissions of carbon dioxide, the leading "greenhouse" gas, to 1990 levels by the year 2000.