Leading article: Hot air will not save the Antarctic

Another week. Yet more compelling evidence of how global warming is forever changing the face of the planet and blighting people's lives. Today we report that the British Antarctic Survey has linked the dramatic collapse of Antarctica's Larsen B ice-shelf to climate change, and how drought is devastating Australia, George Bush's willing ally in his persistent attempts to sabotage the Kyoto Protocol. These are only the latest in a stream of events that show the heating of the planet is happening faster and proving nastier than scientists predicted.

The good news is that the Government finally seems to be waking up to the extent of the danger. On Friday, Tony Blair, who has pushed the issue up the international agenda but has been over-ready to pander to President Bush, wrote to his fellow European leaders warning, in richly mixed metaphors: "We have a window of only 10 to 15 years to take the steps we need to avoid crossing catastrophic tipping points." The day before, David Miliband, the Secretary of State for the Environment, in a far-reaching but little-noticed speech in Berlin, made the vital point that "economic competitiveness, energy security and climate change" all demand the same priority be given to saving energy and developing clean resources.

Next week, Chancellor Gordon Brown will belatedly come out at full throttle by publishing the long-awaited Stern Report, which shows that the economic benefits of combating climate change far exceed the costs. Not to be outdone, Margaret Beckett is making the issue a priority of her tenure of the Foreign Office. David Cameron should take a bow. He may have turned green faster than the Incredible Hulk, having shown little interest before running for his party's leadership, but there is no doubt that the priority he has given to it has changed the political weather.

Words are one thing, actions another. There are two crucial tests ahead. Next month, international negotiations resume in Nairobi on what should succeed Kyoto. Britain must lead in accelerating them, defying and isolating the Toxic Texan, the only approach that has budged him in the past. And ministers must cut Britain's carbon dioxide emissions; it is a scandal that, despite the rhetoric, they have actually risen since Labour came to power.