Tories 'could put climate change agreement at risk'

A historic climate change deal would be put at risk by a Conservative government because of the "injustice" of the way they would fund the battle against global warming in developing nations, David Cameron is warned today.

The Tory leader has promised to safeguard the international aid budget in an attempt to soften his party's image. However, unlike the other parties, he has refused to put a cap on the amount of money set aside for aid that could be raided to pay for helping poorer nations deal with climate change.

Writing in The Independent today, Nicholas Stern, the climate change economist, Kofi Annan, the former UN secretary general, and the Kenyan Nobel Peace Prize winner, Wangari Maathai, warn that using the aid budget would be "unacceptable" and that all money designed to fight climate change in poor areas should be additional.

"Any [international climate-change] agreement must provide for greatly increased financial assistance," the letter states. "It is imperative that this assistance include new and additional finance, not just a reallocation of existing commitments to promote development. We are increasingly concerned that some countries are refusing to commit to additional finance for climate change and instead seem intent on taking climate assistance solely from monies already allocated for development. Such injustice would be unacceptable and would jeopardise any future climate agreement."

World leaders failed to come up with a deal on reducing climate change during the Copenhagen summit last year. However, they did agree that global warming must be limited to no more than two degrees, making a new international deal critical. "On the day designated as 'Climate change day' in the British election campaign we urge all political parties to commit to an international climate agreement that will also provide for the world's poorest people," the three influential figures write.

Only the Liberal Democrats have said all money handed to poor nations to battle climate change should come on top of the aid budget. Labour has pledged that no more than 10 per cent of its overseas aid budget can be used for tackling climate change in the developing world after 2013. The Conservative manifesto only contains a pledge that it would "work to make our aid 'climate smart'", meaning it would always consider the climate implications of the aid projects it funds.

Aid groups are concerned about the Tory approach, arguing that the party's refusal to promise not to raid the aid budget to pay for climate change mitigation will make it impossible for any international deal to be struck. "If countries are allowed to simply promise money that would otherwise go towards poverty reduction, there is no deal – they have simply promised the same money twice," said an aid agency senior source. "This is not a theoretical argument. What you could see is the poorest countries suddenly unable to spend as much on anti-retroviral drugs, or sending children to school."

Phil Bloomer, policy director at Oxfam, said, "If climate change financing is not additional, we're going to hear the sucking sound of aid being taken out of poverty reduction in the poorest nations and into places like China, potentially at the cost of health and education programmes in sub-Saharan Africa."

A spokesman for the Conservatives said it welcomed the "timely letter from these three widely-respected figures". "We agree that climate change isn't just an environmental issue; it is also one of international social justice," he said. "The Conservative Party wants to see an ambitious global deal to limit emissions and make available financial resources for adaptation and mitigation. We believe global mechanisms are by far the best way to lock in adaptation and mitigation commitments."

The parties battled over green issues yesterday, with both Labour and the Liberal Democrats launching their own "green manifestos". Today, Ed Miliband, the Climate Change Secretary, will take part in a debate with Greg Clark, the shadow Climate Change Secretary, Simon Hughes, from the Liberal Democrats, and Darren Johnson, from the Greens.