Michael McCarthy: It's down to Osborne to keep climate change on the agenda

A common complaint of environmentalists during the Tony Blair years was that while the prime minister's rhetoric on the subject of global warming was first rate – indeed, he was largely responsible for the issue rising to the top of the international agenda – it was not remotely matched by commensurate action on climate change at home.

This seemed very puzzling, and it was a long time before the quite improbable, behind-the-scenes truth began to dawn upon us all: that Mr Blair was not in charge of the domestic policy of his own government. Gordon Brown was.

For most of his time as Chancellor, Mr Brown did not "get" climate change, seeing it as a diversion from more vital tasks such as reducing poverty – I have spoken to someone who sat in meetings with him who said that when the climate issue came up, he looked out of the window – so, in Budget after Budget, he did the minimum he could.

Eventually, he was converted – the first sign being his commissioning of the Stern report on climate change economics – and, during his premiership, he at last presided over decisive action, which included setting up the Department of Energy and Climate Change, the passing of the Climate Change Act, and an attempt to get something out of the climate conference last December in Copenhagen.

But what we are witnessing now, in the gap between aspiration and achievement so forcefully pointed out by the Committee on Climate Change, is the legacy of the Brown years of inaction – of 10 Budgets in which the Chancellor did next to nothing on the matter his Prime Minster thought so crucial. "We've just been talking about it for years," a committee source said yesterday.

Moving from talking to making a difference now falls in the first instance on the shoulders of Chris Huhne, the Energy and Climate Change Secretary, but in an uncanny parallel with the years of Chancellor Brown, the key figure may actually turn out to be Chancellor Osborne. Is George Osborne prepared to sanction high levels of spending on climate policy when cutting the deficit is the imperative, and the climate issue has gone off the boil politically? We'll know soon enough.