A meeting of rich nations next month in Germany will be a "litmus test" of how the United States plans to help the world fight climate change, the head of the UN Environment Programme (UNEP) said today.
The United States, the world's biggest polluter, said this month it would continue to reject targets or plans to cap greenhouse gas emissions blamed for global warming because it fears such caps could jeopardise economic growth.
Germany, which hosts leaders of the G8 industrialised countries next month, wants them to agree to halve carbon emissions by 2050, and UNEP boss Achim Steiner said no one should prejudge Washington's position as the pressure mounts.
"There is no option but to move forward, and I think that is the debate now taking place in the US as a whole, but also in the US administration: how to bring US initiatives to the table that can help," Mr Steiner told a news conference.
"We are just few days away from a major litmus test of that. That will be a moment we will see how the US administration sees itself playing that constructive and positive role in building an international consensus," Mr Steiner said.
Amid growing public concern about climate change and damning scientific reports on its effects, nations remain in gridlock in talks to widen action to brake warming beyond the end of the first period of the UN's Kyoto Protocol in 2012.
President Bush opposes Kyoto-style emissions caps he says will cost US jobs and wrongly exclude poor nations, and some climate experts believe new talks on any Kyoto successor will have to wait until he leaves office in 2009.
But Mr Steiner said domestic pressure was building, with a "remarkable alliance" of major corporations now asking the US government to introduce emissions targets and more than 450 US cities committing voluntarily to reduce emissions.
Last week, Democratic congressional leaders also urged Mr Bush to "reverse course" and strengthen the US stance on climate change ahead of the G8 summit.