British Science Museum unveils climate change map showing impact of 4C rise

The map shows the impact of an average 4C rise in global temperature, which John Beddington, the government's chief scientist, said would be "disastrous". A study by the Met Office last month said that such a 4C rise could come as soon as 2060 without urgent and serious action to reduce emissions.

The map was launched to coincide with the London Science Museum's new Prove it climate change exhibition by David Miliband, foreign secretary and his brother Ed Miliband, energy and climate change secretary. It comes in advance of key political talks on climate change in December in Copenhagen, where British officials will push for a new global deal to curb emissions.

The Miliband brothers said a new deal needed to be strong enough to limit global temperature rise to 2C, although many involved in the negotiations privately believe this to be impossible. A joint press release from the government and the Met Office released to promote the map says the government is aiming for an agreement that limits climate change "as far as possible to 2C".

The map's release marks a significant shift in political discourse on climate change, with many politicians until recently unwilling to discuss the possibility of a failure to hit the 2C target.