From riding to Westminster on his bike (chauffeur in tow) to installing a wind turbine on his roof, David Cameron has made strenuous efforts to claim the mantel of green issues for the Conservatives since he became Tory leader exactly one year ago to. The man with responsibility for shoring up Labour’s position is the fresh-faced environment secretary, David Miliband. Unsurprisingly, he is sceptical of the Tory leader’s efforts to convince voters of his green credentials: ‘When people think about him on his bicycle with his car driving behind him they begin to think how real is it?’

Cameron’s call to ‘Vote blue, go green’ has, of course, formed part of a concerted effort to win the support of liberal-minded voters who have deserted the Tories in the last three elections. The environment secretary concedes that the Conservative leader’s efforts may have won him a ‘short term advantage’. But, in the long term, he says, ‘I don’t believe David Cameron can deliver that sort of internationalist, interventionist, activist, climate change agenda we need.’

Indeed, the government, claims Miliband, is in a unique position to meet the challenge of global warming because ‘the climate change agenda speaks to Labour values in a very profound way.’ ‘This is an issue that speaks to our domestic interests and our internationalism,’ he says. Rather than ceding the political territory to the Conservatives, therefore, the minister says Labour should take the Tory leader’s professed interest in the environment ‘as a spur to develop our own agenda’.

Another spur to the government’s agenda has been the publication at the end of October of Nicholas Stern’s report for the Treasury on the economic impact of climate change. It warned that a ‘business as usual’ approach could see global temperatures rise by five degrees celsius above pre-industrial levels, leading to a five to 20 per cent cut in global living standards. In the Queen’s Speech, the government announced it would be introducing a climate change bill in this parliamentary session, with the aim of reducing UK carbon emissions by 60 per cent by 2060. Downing Street also said it would press for a new global deal on carbon emissions with the G8 and five leading developing countries by 2008, to replace the existing Kyoto protocols due to run out in 2012. This programme, says Miliband, proves that Labour has got ‘the balls politically’ to see the environment agenda through.

The environment secretary describes the Stern report as ‘a landmark moment’ in the battle against global warming. ‘It showed that climate change is not an environmental issues but it is a social, economic, cultural and political issue.’ Miliband accepts the report is a ‘cause for anxiety and alarm’. Nonetheless, he sees it ultimately as an ‘optimist report’ and ‘call to action’. The minister also dismisses the critics of the report who say its findings are overly alarmist. ‘I think Stern is right,’ he says. ‘He has taken away the refuges of those who wanted to deny the science but didn’t know how to, that refuge being that we can’t afford to tackle climate change. Actually, we can’t afford not to.’

But is the government itself taking the threat of climate change seriously enough? After all, wasn’t the idea for a climate change bill originally floated by Cameron at his speech to the Tory party conference in the autumn? Miliband, however, gives short shrift to the suggestion that the government is playing ‘catch up’ with the Conservatives. ‘We have been in the climate change business for the last nine years,’ he says. ‘The chancellor and prime minister appointed Nicholas Stern before David Cameron had even been thought of, lets not forget that.’ The minister cites the support of Al Gore, who has just been appointed Gordon Brown’s advisor on the environment, as evidence of Labour’s lead over the Conservatives. ‘We have been in that business [of tackling climate change], as Al Gore says, in a way that can “make British people proud” of what they’ve done. So take his word for it – don’t take David Cameron’s word for it.’

Miliband is also dismissive of Conservative calls for binding annual targets on carbon emissions to be included in the bill, against the government’s proposal of interim targets. ‘The Kyoto process deliberately rejected annual binding targets in favour of longer term, and I think that’s sensible,’ he says. ‘I think it’s whether you are in to gestures or you are serious. If you have a cold winter and all the emissions go up, to say you then have to change all of your policies for next year is not sensible.’ He continues: ‘Actually, the Tory spokesman is already writing articles saying that they are not actually binding, they are annual targets but they aren’t rigid targets. That’s part of politics.’

Whatever the domestic wrangling over the government’s record, however, it is at the international level that an enduring solution to the problem of climate change will need to be found. Crucial to the success of any potential global deal on carbon emissions will be persuading America, which currently produces 25 per cent of the world’s carbon emissions, to sign up. In 2001, president George W Bush withdrew the US from the Kyoto protocols, which had been agreed to (but never ratified) by Bill Clinton in 1998.

Following the Republicans’ ‘thumping’ at the hands of the Democrats in November’s mid-term elections, Miliband has a suggestion for the current beleaguered occupant of the White House: ‘I can think of no greater legacy, for the next two years in American politics, the last two years of George Bush’s presidency, the two years now of the Democratic leadership of the house, than putting America right, in a bipartisan way, at the heart of a hard emissions agreement.’

The environment secretary admits it is ‘difficult to tell’ whether the Democrats’ victory in the House and Senate is prescient of a wider change of attitudes in the US on climate change. But he cites re-elected Californian governor Arnold Schwarzenegger’s recent bill on emissions’ targets, and the pledge by California, seven north-eastern states and more than 300 American cities to abide by the Kyoto protocols, as evidence of a potential shift in opinion. ‘The American government may not be party to Kyoto but some of the American people are,’ he says.

Another challenge to a global deal on emissions will be persuading developing economies, such as India and China, of the merit and justice of committing to targets from which the developed western economies have previously been exempt. Miliband accepts that ‘a global agreement has to be on the basis of the ability to make a contribution; the richest countries have to do the most.’ Nonetheless, he insists it is in developing countries’ interests to embrace the climate change agenda. ‘Fighting climate change is part of the development agenda not the antithesis of the development agenda,’ he says. ‘And they want the industrialised countries to show they mean business. This is what our hard long-term commitments mean and that’s what the EU’s long-term commitments mean.’

Indeed, the minister feels more than ever before that ‘the world needs progressive values’, a fact that should stand Labour in good stead as it attempts to ‘defy political gravity’ by seeking a fourth term against the Conservatives. ‘If you believe interdependence is what defines the human condition at the moment,’ he says, ‘whether locally, nationally or internationally, that immediately speaks for the needs for progressive values of collective action, social justice and, in my view, solidarity and co-operation. I think that should give us confidence.’