By Guardian Unlimited / World news 10:51am

A dark cloud hangs over proceedings here in Montreal at the start of the last day of the UN climate change summit. The mood could not have changed more violently, writes Simon Retallack.

Just 24 hours ago, under a crystal clear blue sky, the atmosphere here was one of unexpected optimism – epitomised by the cheerfulness of the UK environment secretary, Margaret Beckett, in her meetings and interviews. The talks seemed to have reached an early breakthrough, with agreement said to be very close on a package that would see the launch of negotiations to deliver a second phase of the Kyoto protocol (with new emission cuts by industrialised countries) and the start of a process to engage a broader group of countries including developing ones in discussions on future action.

The mood improved still further with news that Bill Clinton would be gracing the summit, rock star-like, with a surprise appearance later today at the invitation of Canada’s prime minister, Paul Martin. There was even a report that a group of US students had moved members of the US negotiating team here in Montreal to tears following a plea for them to act on climate change. If that could happen, surely anything was possible. People even began contemplating an early exit home.

Then as temperatures were plunging outside, phones began ringing with news that the US delegation had destabilised the talks in dramatic fashion. The Canadian hosts were reported to have confirmed that the US had rejected a deal to start talks outside the Kyoto track between developed and developing countries to discuss future action on climate change, even though the already anodyne text sanctioning these talks had just been weakened further, now stating that whatever emerged would be entirely non-binding.

It’s possible that the result could be disastrous for the Montreal summit, preventing a green light being given to any new negotiations starting on global action to address climate change when the first phase of the Kyoto protocol runs out in 2012. If the US insists on rejecting even the discussion of future action by all countries, it could stop Japan and others from agreeing to develop a new round of emission cuts by industrialised countries, potentially killing off the prospects of Kyoto mark II.

Rumours have been circulating that any change in the US approach is the result of a direct intervention in the talks by the US vice-president, Dick Cheney, and that this was precisely the result he sought.

But with a day and possibly long night of negotiations still to go, much could yet change. In fact it could be that this apparent US tactic backfires, provoking other countries to move ahead without the US and agree a unified and probably more effective set of talks under the Kyoto protocol involving both industrialised and developing countries.

However, let’s face it, the overall implications are not good. When scientists tell us on a weekly basis that the problem of climate change is worse than we thought, when the damage that will be caused from inaction is so huge, and when the scale and urgency of the challenge ahead is so large, taking pot shots at the proposals on the table here in Montreal is tantamount to playing Russian roulette on a global scale. It’s a game that only the criminally insane could think we can afford to play and win.

Simon Retallack is senior research fellow on climate change policy at the Institute for Public Policy Research, Britain’s largest thinktank. He will be at Montreal until the end of the week; read his blog posts from yesterday, Wednesday, Tuesday and Monday.

http://blogs.guardian.co.uk/news/archives/2005/12/09/playing_russian_roulette_with_the_world.html