Sir David King, a former chief scientific adviser, writes in the Guardian to urge prime minister to fill ‘leadership vacuum’ David Cameron must end his silence on climate change and “step up to the plate” to provide international leadership, the former government chief scientific adviser Prof Sir David King says on Wednesday. Writing in the Guardian, King also reveals that after his declaration that global warming was a greater threat than global terrorism in 2004, then US president, George Bush, asked Tony Blair, then prime minster, for to have him gagged. King’s warning made headlines around the world at the time. “But I refused to be gagged, and that statement and others spurred the UK to develop a leadership role on climate change among the international community,” King writes. He argues that the UK’s 2008 Climate Change Act – the most ambitious legally binding emissions targets in the world – along with actions such as its early engagement with China on global warming put the UK at the forefront of global negotiations on climate action in the runup to the UN summit in Copenhagen in 2009 . This summit, attended by scores of world leaders, failed to reach a global deal, and subsequent summits have been far less prominent. “There is, again, a leadership vacuum among heads of states on this issue, just as there was in the early 2000s. Will David Cameron step up to the plate, please? Prime minister, will you take your stated credentials as [wanting to lead] the ‘ greenest government ever ‘ into the global arena?” writes King, who is now director of the Smith School of Enterprise and the Environment at Oxford University, where a world forum on “valuing ecosystem services” opens today. Downing Street was unable to provide a comment, but a spokesperson at the d Department of Energy and Climate Change said: “From the top down, the coalition has no intention of letting up in its efforts to get a legally binding agreement. [Energy and climate change secretary] Chris Huhne, with the prime minister’s full backing, played a crucial role at the UN climate conference in Cancún to get agreement on the overall goal of limiting climate change to two degrees, to establish a new climate ‘green fund’ and to take further action to reduce deforestation.” A Liberal Democrat source in government also pointed out that deputy prime minister Nick Clegg , the deputy prime minister, had emphasised climate change issues during recent visits by Barack Obama and China’s premier, Wen Jiabao . Green party MP Caroline Lucas said: “I share Sir David King’s deep disappointment at the prime minister’s lack of personal engagement in the international climate negotiations process. It is astonishing that Cameron has yet to make a single statement on his commitment to securing an international climate change agreement.” Cameron has had to intervene repeatedly to ensure his coalition’s green commitments were not derailed, including in a fierce cabinet battle over the UK’s target of a 50% cut in greenhouse gas emissions by 2025 . He also had to face down Treasury objections to the government’s green investment bank and, most recently, has contended with a mutiny among his MEPs over European emissions targets. The prime minister has made high-profile speeches defending the UK’s relatively high level of international aid spending , – one of very few areas ring-fenced from cuts – but he has yet to make any similar intervention on climate change. Phil Bloomer at Oxfam , which praised the government’s stance on international aid, said: “If David Cameron wants to lead the greenest government ever, he must urgently take on the international leadership needed to inject fresh life in the UN talks, so the empty climate fund is filled and poor communities can protect themselves from the impacts of climate change.” King praises the government’s domestic action on climate change. “My cynicism about pre-election statements was squashed with the announcement that the UK will cut its CO 2 emissions by 50% by 2025,” he writes, noting that policies on the green investment bank, on improving home energy efficiency , and on reforming the electricity market to deliver low-carbon electricity provide “excellent opportunities for the radical transition to a low-carbon economy”. He says the UK is once again “setting the bar high for other countries”, but adds: “There has been no statement at all from the government about the need for collective action on the critical issue [of climate change].” Barry Gardiner MP, who is Ed Miliband’s special envoy on climate change, said: “If Cameron had spent a quarter of a billion pounds tackling climate change instead of bombing Gaddafi , he could have transformed Britain’s energy infrastructure to meet our 2025 targets, protected a million hectares of rainforest from deforestation, or fitted solar [panels] to 100,000 homes. It is clear that he thinks Libyan oil is a bigger priority.” Friends of the Earth ‘s senior parliamentary campaigner Martyn Williams said: “The need for bold leadership on climate change is more urgent than ever but the prime minister and leader of the opposition rarely speak out on climate change, and this has created a dangerous vacuum. Urgent action is needed to avoid a climate disaster and reap the huge financial opportunities that would be created by building a low-carbon future.” Climate change Carbon emissions David Cameron Green politics Liberal-Conservative coalition Nick Clegg Damian Carrington guardian.co.uk