"There is an urgent need for the international debate on climate change to move beyond 'them and us' and recognise the world's shared dilemma," Foreign Secretary Margaret Beckett said.

Environment Secretary David Miliband added: "This report confirms our concerns that the window of opportunity to avoid dangerous climate change is closing more quickly than previously thought.

"It is another nail in the coffin of the climate change deniers and represents the most authoritative picture to date, showing that the debate over the science of climate change is well and truly over."

United Nations scientists meeting in Paris warned Friday that fossil fuel pollution would raise temperatures this century, worsen floods, droughts and hurricanes and melt polar sea ice.

The report by the Intergovernmental Panel on Climate Change (IPCC) -- the UN's paramount scientific authority on climate change -- confirms the problem "is worse and more urgent than had been previously understood," Beckett said.

"Failure to grow our economies will threaten peace and prosperity, but if we grow our economies at the expense of the climate, the same peace and prosperity will be threatened," she said in a statement.

She said she was glad that new UN Secretary General Ban Ki-moon "has focused so quickly on the wide-ranging importance of climate security," adding it was of concern to the United Nations as a whole not just its environmental bodies.

"We will be working to build political ambition throughout the UN in the coming months," Beckett said.

"As Britain has long recognised, if we wait for others to make the first move we all lose."

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