Rocket take-offWill world leaders rocket at Copenhagen?Photo: jurvetson via Flickr Creative CommonsSuddenly — and just in the nick of time — next month’s Copenhagen conference is starting to gain momentum. National leaders have rushed to say they are going, elevating it to the status of a major summit. More and more commitments to action are coming in, from both developed and developing countries. And there are signs that even the United States may put an, albeit provisional, offer on the table.

It has all been enough to cheer up the phlegmatic Yvo de Boer, who — as  Executive Director of the U.N. Framework Convention on Climate Change — is in charge of the talks. Last month he was sounding downbeat, but now he says: “There is no doubt in my mind that (the meeting) will yield a success.”

“Almost every day now we see new commitments and pledges from both industrialized and developing countries,” he added. “I am confident that the President of the United States can come to Copenhagen with targets and a financial commitment.”

Maybe de Boer is now erring on the optimistic side, but there is no doubt that there is, at present at least, a new mood in the air. It is reflected in — and partly caused by — a stampede of heads of governments promising to come.

By the weekend, just a week after the Danish Government had sent out the formal invitations, 65 leaders had committed themselves to attend. They included such heavyweights as British Prime Minister Gordon Brown,  German Chancellor Angela Merkel, President Nicolas Sarkozy of France, Prime Ministers Yuki Hatoyama and Kevin Rudd of Japan and Australia, and Presidents Luiz Inacio Lula da Silva and Susilo Bambang Yudhoyono of Indonesia.

Several key leaders have yet to reply — including President Hu Jintao of China, India’s Prime Minister Manmohan Singh, South African president Jacob Zuma and, of course, Barack Obama. But so far the Danes have not had a single refusal, and expect many more acceptances.

The promised turn-out is a big vindication for Gordon Brown, who was the first leader to commit to going — as long ago as September. Brown insisted that only heads of governments would have the authority to negotiate and strike a deal. He has since spent much time telephoning and talking to other leaders face-to-face to persuade them to attend.

He will be at it again this weekend at the summit of leaders of the former colonial countries that belong to the British Commonwealth in Trinidad. Manmohan Singh and Jacob Zuma can expect to come under particular pressure if they have not accepted by then.

Meanwhile offers of emission reductions continue to come in. Russia has agreed at a summit with the E.U. last week to accept a 25 percent cut on 1990 levels by 2020, doubling its previous target. This is hardly ambitious because the collapse of its economy in the 1990s means its emissions are now much lower than they were at the start of that decade — but it is important because it represents another developed country coming into the range which will trigger the big cuts promised by the E.U., Japan, and Australia if others followed suit.

South Korea offered a four percent reduction from 2005 levels by 2020. Again, this may appear paltry, but is psychologically important because the country is (somewhat anomalously) classified as a developing one, making South Korea the first developing country to announce an absolute cut in emissions as opposed to just reducing its rate of growth.

Even more importantly, Brazilian officials made clear last week that the ambitious target of at least a 36.1 reduction in projected 2020 emissions, would involve an absolute cut of at least 10 percent from current levels.

The big questions are what the U.S. and China will offer. President Hu has promised a “notable” reduction in expected 2020 emissions, and is expected to attach a figure on it in Copenhagen. And Todd Stern, the chief U.S. negotiator indicated that  President Obama was considering going with a provisional number for emissions reduction even if the Senate had not voted on it by then.

There is also a growing consensus on the even more important — and difficult — issue of providing finance to the world’s poorest countries to help them tackle their own pollution and adapt to the devastating impacts of climate change. This is settling out at an acceptance that about $100 billion a year will be needed by 2020 (a figure originally proposed by Gordon Brown last summer), that 22-50 billion euros of this would come from international aid, and that “fast-track finance” of 5-7 billion euros should be provided to finance immediate action.

Of course there will be many stomach-turning ups and downs before the leaders leave the Danish capital, and it could well all come unstuck. But the very fact that leaders are going makes that more unlikely, because the one thing that unites them is a determination to avoid being associated with failure.