By Richard Black
Environment correspondent, BBC News website
The US is trying to block sections of a draft agreement on climate change prepared for next month's G8 summit, according to documents seen by the BBC.
The US appears to be on a different road from other G8 members
Washington objects to the draft's targets to keep the global temperature rise below 2C this century and halve greenhouse gas emissions by 2050.
The draft, prepared by the German G8 presidency, said action was imperative.
With UN talks struggling to extend the current Kyoto targets, the G8 summit is seen as a vital way to regain momentum.
Germany's Chancellor Angela Merkel has made climate a priority for the organisation, with backing from other leaders including Tony Blair.
But the US's proposed revisions, obtained by BBC News, mark a fundamentally different stance.
A clause saying "climate change is speeding up and will seriously damage our common natural environment and severely weaken (the) global economy... resolute action is urgently needed in order to reduce global greenhouse gas emissions" is struck out.
So are a statement that "we are deeply concerned about the latest findings confirmed by the Intergovernmental Panel on Climate Change (IPCC)", and a commitment to send a "clear message" on international efforts to combat global warming at the next round of UN climate talks in December.
US negotiators also want to remove from the draft firm targets for improving energy efficiency in buildings and transport, and a call for the establishment of a global carbon market.
Many observers believe that such a market can only be effective if there are binding caps on emissions.
A spokeswoman for the White House Council on Environmental Quality said the administration did not talk about ongoing private discussions, but commented: "There is consensus that the Earth is warming, and we are working with our G8 partners as well as developing nations to identify the promising new technologies that will help the whole world address the long term challenges of climate change.
"The US continues to lead the global effort on climate change."
The European Union, which includes half of the G8 members, has already adopted commitments to aim for a global temperature rise of less than 2C, and to reduce greenhouse gas emissions by 20% from 1990 levels by 2020.
Japanese news organisations recently reported that Prime Minister Shinzo Abe's government was also planning to push fellow G8 members for tough targets.
Japan has recently endorsed tough action on emissions
President Bush's administration has long championed voluntary agreements as an alternative to global pacts such as the Kyoto Protocol which seek binding emissions caps.
The US is a key player in the Asia-Pacific Partnership on Clean Development and Climate, a six-nation pact which promises greenhouse gas mitigation without targets.
"I think the real objective (of the US negotiators) is not just to keep the lid on and have nothing happen while President Bush is in office, but they are trying to lay landmines under a post-Kyoto agreement after they leave office," commented Philip Clapp, president of the Washington-based National Environmental Trust, who has seen the US's proposed amendments.
"It lies in the hands of Prime Minister Blair and Chancellor Merkel, whether it's all sweetness and light or whether they are prepared to stand up and say 'I'm sorry, but the rest of the world is moving in a different direction from you'," he said.
Preparations for the 2005 G8 summit in the Scottish resort of Gleneagles also began with a climate change draft which grew weaker as discussions continued.
Leaders decided then to agree a weak document rather than leave with no agreement at all.