"With only days to go before Copenhagen, we mustn’t be distracted by the behind-the-times, anti-science, flat-earth climate sceptics," Brown told The Guardian newspaper ahead of the landmark UN summit in the Danish capital.

"We know the science. We know what we must do. We must now act and close the five-billion-tonne gap. That will seal the deal."

Government advisor Nicholas Stern estimated that 10 billion tonnes of greenhouse gas emissions must be removed from the atmosphere by 2020 to cut global warming. Action pledged so far would only achieve half that.

Brown was speaking amid a row over leaked emails from a key climate research unit in Britain, which sparked claims that scientists were trying to suppress data which did not support the view that climate change is happening.

Professor Phil Jones has stood aside as head of the Climatic Research Unit (CRU) at the University of East Anglia — a world leader in the field — pending an investigation.

He denies the claims but some US lawmakers and a top Saudi official have said the emails undermine the science of climate change and will have a huge impact on the December 7-18 Copenhagen talks.

AFP/Expatica