Hopes for the Copenhagen climate summit in December have been boosted after it emerged more than 60 presidents and prime ministers planned to attend.
The talks are not expected to result in a new treaty and there are doubts over whether the biggest polluters will commit to emissions reduction targets.
But observers say the number of leading attendees will raise expectations for the talks, from 7 to 18 December.
Delegations from 192 countries will be attending the summit. The talks will attempt to draw up a new global climate treaty to supplant the UN’s 1997 Kyoto Protocol.
Danish Prime Minister Lars Lokke Rasmussen said the involvement of heads of state and government was “crucial” to the success of the summit.
“That is why we are encouraged that already more than 60 heads of state and government have confirmed they will participate, and just as important that many more have also been positive,” he told a meeting of his Liberal Party on Sunday, according to a spokesman.
Talks ‘very tough’
UK Prime Minister Gordon Brown, who will be attending, has said a new deal will be more likely if heads of governments put their own reputations on the line.
Australian Prime Minister Kevin Rudd, who will be a key negotiator at the summit, has said he believes those involved in the summit are capable of reaching a non-binding political agreement that would be codified sometime next year.
“I believe there is a strong and high degree of political resolve from many of the leaders around the world to land a Copenhagen agreement,” he told the BBC.
But he said reaching what he called an “operational framework agreement” was “not inevitable” and that the negotiations will be “very tough”.
Australia is the world’s largest exporter of coal and has the highest per capita emissions of any developed nation, but Mr Rudd has said he wants to be part of the solution.
He says every nation will be entering the talks with dirty hands so that should not stand in the way of an agreement.
The leaders of China, the US and India - some of the world’s biggest polluters - are so far not on the list to attend the Copenhagen meeting.
But the BBC’s environment correspondent Roger Harrabin says the increasing number of senior leaders planning to make the journey undoubtedly increases the political stakes.
‘Violated’
The news comes as a row continues over e-mails between climate scientists which were stolen from a British university computer.
Climate sceptics say the e-mails, stolen from the University of East Anglia by a hacker, show that important data behind the climate change debate has been manipulated.
They are demanding an independent inquiry into the science behind any deal in Copenhagen.
The scientists behind the research say the scientific debate about climate change is sound and have accused the sceptics of trying to undermine Copenhagen.
Kevin Trenberth, of the US National Center for Atmospheric Research (NCA) in Colorado, whose e-mails were among those accessed, said the timing of the hacking was “not a coincidence”.
He told the Associated Press News agency 102 of his e-mails had been posted on the internet and he felt “violated”.
Critics say the e-mails show that scientists have distorted the facts of climate change, but Mr Trenberth said the e-mails had been “taken out of context”.
