Britain must take lead in global warming battle, says Ed Davey

Ed Davey claims the 'flat earthers' in the coalition have been defeated. Photograph: Danny Lawson/PA

Britain must lead the international battle against global warming, says energy and climate change secretary Ed Davey, who added that not to do so would be "deeply irresponsible".

His comments, made on the eve of a landmark UN report on the impacts of global warming, are in pointed contrast to chancellor George Osborne's statement in September that he did not want the UK to be "the only people out there in front of the rest of the world".

"Climate change is hugely threatening to our way of life, in the UK, Europe and the world," said Liberal Democrat minister Davey, in an interview with the Observer. "Not to lead is deeply irresponsible. If you don't lead, you will not bring others with you."

The report, from the Intergovern-mental Panel on Climate Change(IPCC), will be published on Monday and is expected to state that global warming has already left its mark "on all continents and across the oceans", harming food supplies and driving extreme weather like floods and heatwaves. The report, the work of more than 2,000 scientific experts, will warn that even a small amount of further warming could lead to "abrupt and irreversible changes".

The green agenda has been the battleground for the some of the coalition's bitterest rows. The most recent saw eco levies – reportedly dubbed "green crap" by David Cameron – cut from energy bills, leaving 400,000 homes without the insulation that would cut carbon emissions and bills. Britain also recently defeated a European attempt to setrenewable energy targets for 2030 for each nation.

But Davey insisted that climate-change sceptics – "flat earthers" – in the government had been defeated. "Those of us who care about climate change and believe it is something we need to lead on have won the argument internally," he said. "People don't realise that we got a deal across the coalition that puts Britain right at the head, the most ambitious country." He said Britain's agreed position was to slash emissions by 50% by 2030 as part of a global deal: "That is way out there."

Davey added that global warming was not a distant threat to far-flung low-lying Pacific islands, but was here, now: "Climate change is impacting our way of life in the UK."

He criticised the 40% cut to funding for climate change adaptation made by environment secretary Owen Paterson, whose department also cut annual flood defence spending. "The experience of flooding brought home to the whole government and the whole country that preparing for climate change should be a national priority," he said.

The IPCC report was "an incredibly robust piece of science", Davey said, adding that people should be "more worried" by climate change than ever. "The impacts on our people could be huge. We could see problems of real devastation from flooding and other severe weather events hitting food and water availability – really significant things," he said.

However, Davey claimed that there was also reason to feel "more hopeful" than ever about the UN's global negotiations towards a 2015 treaty to reduce the impacts of climate change, a treaty he said would rank alongside the greatest in history. "At the UN the science has won out," he said. "People can see the rational debate there."

It was also highly significant that the world's two biggest emitters – China and the US – were moving fast to cut emissions, particularly from coal. "Over in Beijing the change in a short period of time is massive. China has woken up to the fact that it is in its enlightened self-interest to start taking this seriously," he said.

"On one level it is about the political control of the Communist party: the unrest in towns and cities is mostly related to environmental disputes. If your [only] child is ill because the water in the rivers and the streams is filthy and the air they breathe in cities is disgusting, you don't like your government." Climate change also made China vulnerable to food and water shortages, while rising sea level threatened its coastal cities, he said.