Negotiators made slow progress on key issues of a global warming agreement Tuesday, but the United States appeared stymied in its efforts to extend new limits on fuel emissions to the Third World. A U.S. Senate delegation flew into Japan, and its leader warned that any treaty deal excluding developing nations would be rejected by the Senate. “It won’t even be close,” said Sen. Chuck Hagel, a Nebraska Republican. The U.S.-Third World impasse troubled other negotiators. “This seems to be one of the major problems that could eventually . . . break the whole process,” said Joergen Henningsen, the environment chief of the European Union, which offered to mediate the dispute. Tuesday was the second of 10 scheduled days of negotiations involving 150 countries.
