Reports are emerging of a thawing of relations between US negotiators and other delegates at this week's US-hosted meeting of major polluters in Hawaii.

Although a major breakthrough is not expected at the two day conference attendees said that there is a renewed sense of co-operation between the different negotiating teams following the agreement at last month's UN conference in Bali of a roadmap for agreeing a post Kyoto treaty by 2009.

Speaking to Reuters, the UN's top climate change official Yvo de Boer said that the early rounds of talks had been characterised by a more optimistic outlook than the first round of US-hosted talks in September when many delegates criticised the US refusal to countenance binding emissions targets.

The US has not shifted its position on mandatory targets, but de Boer insisted there had been a change in mood. "I think people feel a lot more comfortable now given that there was an outcome in Bali establishing the issues that need to be part of both the negotiations and a post-2012 package," he said.

Andy Karsner of the US Energy Department agreed telling reporters that the meeting marked a "turning of the page" compared to previous more hostile negotiations. "It really exemplifies how significant the Bali roadmap has been in terms of all the nations of the world beginning to signal the areas that they will concentrate on over a very limited timetable," he said.

The new sense of détente may in part be down to the fact the vexed topic of mandatory emission cuts is being sidelined from the talks in favour of negotiations over international technology transfer and tariffs on green products.

Earlier this week President Bush announced plans for a $2bn fund to aid adoption of clean technologies in developing nations. Meanwhile, Jim Connaughton, chairman of the White House's Council on Environmental Quality, said that removing trade tariffs on green products would be high on the agenda at the Hawaii talks.

"The World Bank has estimated that with the elimination of tariffs, global trade in lower-carbon technologies could increase by up to 14 percent per year, " he said in a conference call with journalists. "So we are talking about a very easy thing to do, that should have been done years ago, that could produce massive economic benefits, massive productivity benefits, and massive greenhouse gas reduction benefits."

The talks come days after the Hawaii state government and the US Department of Energy set out targets to generate 70 per cent of the state's energy from renewable resources by 2030. State officials said that the plan would serve as "a demonstration test bed" for the rest of the US and island communities globally.