Signatories to the United Nations Framework Convention on Climate Change will meet later this year to decide on targets for greenhouse gas emissions. Our correspondents in Washington, London and Tokyo report on the prospects.

washington President Bill Clinton is likely to promise “real action” to cut US greenhouse-gas emissions when he addresses a special session of the United Nations General Assembly in New York on 26 June, commemorating the fifth anniversary of the Rio treaty.

But despite anticipated pressure from the other government leaders at a G-8 summit in Denver, Colorado, before he goes to New York, Clinton is unlikely to specify at this stage what action he proposes. Instead, according to several government officials, the administration will wait until September to announce what emission targets the United States will support at the critical meeting of the parties to the Rio treaty in Kyoto, Japan, at the end of this year.

Senior administration officials met last week to discuss how Clinton should approach concern about climate change that is expected to be raised at Denver by Tony Blair, the new British prime minister, and Helmut Kohl, the German chancellor. They also discussed the content of his address to the United Nations a few days later.

Debate continues to rage within the administration about how best to approach the issue. But optimism is growing among environmentalist groups that Clinton will share the view of Katie McGinty, his environmental adviser, and Jack Gibbons, his science adviser, that the United States must prepare for a Kyoto agreement that requires developed countries to take genuine steps to reduce greenhouse-gas emissions.

Observers strongly doubt that the US Senate will ratify such an agreement, however, or that the United States will itself do anything to cut its emissions. These are now 7 per cent higher than they were in 1990, and projected to grow to 25 per cent above 1990 levels by the year 2010. Unlike Blair or Kohl, Clinton lacks the power to follow through directly on any agreement: he would have to persuade a deeply sceptical Congress that action is warranted.

But the administration may agree to cut emissions at Kyoto, and sell the idea to Congress later. “I'm more optimistic than I was three months ago that the administration will make real reductions in greenhouse-gas emissions,” says Jonathan Lash, president of the World Resources Institute, a moderate environmental group, and co-chair of Clinton's Council of Advisors on Sustainable Development.

Clinton is likely to press other leaders at Denver for changes in their trade policies which will force trading partners in the developing world to plan for “sustainable development”. He will also seek to impress them with demonstrations of ‘clean cars’ developed under the Programme for a Next Generation of Vehicles (PNGV), one of the US president's favourite technology programmes.

The administration is assessing the economic impact of any action the United States might take to cut emissions. But results of the analysis, which were due this month, are running late, and Everly Ehrlich, undersecretary of commerce and the official leading the assessment, has just left his post.

Nevertheless, the administration appears happy to announce its plans later rather than sooner, as this will minimize the opportunity for domestic criticism of them to build up before Kyoto. Any proposal for cuts is likely to come under sustained attack from opponents in US industry. Last week, the Business Roundtable, a powerful forum of 200 leading American business leaders, announced a $1-million advertising campaign against such cuts in the run-up to the UN session.

And even if Clinton agrees to mandatory emissions cuts in Kyoto, the political outlook for substantive action on US greenhouse-gas emissions is uncertain, say observers on both sides of the debate. Such measures would be opposed not just by Republicans, who control both houses of the Congress, but by key Democrats as well.

John Dingell (Democrat, Michigan), for example, the senior Democrat on the Commerce Committee in the House of Representatives, is worried that they could hurt car manufacturers in Detroit, and Richard Gephardt (Democrat, Missouri), leader of the House Democrats, may oppose them to help win support among trade union leaders in preparation for his expected bid for the Democrat presidential nomination.

But the administration, prodded by the European states, may agree to emissions cuts in Kyoto and think about implementation afterwards. “Immediate ratification [of a Kyoto agreement] by the Senate is not the key,” says Lash, who argues that a strong agreement there will put pressure on the Senate to take the threat of global warming seriously.

It would then be up to Clinton and to Al Gore, the vice-president and by far the strongest advocate of emission limits in the administration, to win treaty ratification in the Senate and support for enforcement legislation in both houses of Congress.

Gore, who has been keeping a low profile after some political embarrassments over fund-raising earlier this year, has recently been silent on the issue. Environmentalists argue that if he does not continue to take a firm stand on global warming, he will lose credibility in his own bid for the presidency.

But Gore's political handlers may view the matter differently. Like other US politicians, he has little to gain, but much to lose, by demanding economic sacrifice in response to a threat that does not affect the daily lives of most Americans.