WORLD IN BRIEF : WORLDWIDE : U.S. Balks as Global Warming Talks End

Talks aimed at slowing global warming ended with the United States, in isolation from its industrialized partners, continuing to reject mandatory cuts in emissions of “greenhouse” gases. The United States is the world’s biggest producer of carbon dioxide, the main man-made gas thought to cause atmospheric warming. U.S. officials say too little is known about the causes of global warming and that mandatory reductions would be too costly. Environmentalists and delegates to the talks in Nairobi, Kenya, said the lack of U.S. agreement is a major impediment to forging a treaty to be signed by heads of state at the so-called Earth Summit next June in Brazil.