A summit of rich nations this week could pave the way for a world deal on global warming even if Washington opposes German calls for an agreement to slash emissions immediately.
The UN's top climate official Yvo de Boer said today the June 6th-8th meeting of the Group of Eight in the German town of Heiligendamm could lay down principles for starting formal negotiations on a long-term pact beyond 2012 at a UN meeting in Bali in December.
"Something relatively banal like 'let's go to Bali and do our job' would be pretty good from my point of view," he said.
"It's difficult to see how it's going to be possible to agree at this G8 on a maximum temperature increase or an emissions reduction percentage by the middle of the century," he said.
German Chancellor Angela Merkel, who favours a 50 per cent cut in emissions of greenhouse gases by 2050, has acknowledged she will probably fail to overcome US objections to her call for a deal to limit warming to a rise of 2 degrees Celsius.
But de Mr Boer, head of the UN Climate Change Secretariat in Bonn, said the G8 could still salvage some impetus for a world deal to succeed the Kyoto Protocol.
US President George W Bush, who left for Europe today, unveiled his first plan for fighting global warming beyond 2012 last week, saying he wanted the top 15 emitters to agree on cuts by the end of 2008.