Brown: '50 days to save world' Watch Video
The UK faces a "catastrophe" of floods, droughts and killer heatwaves if world leaders fail to agree a deal on climate change, the prime minister has warned.
Gordon Brown said negotiators had 50 days to save the world from global warming and break the "impasse".
He told the Major Economies Forum in London, which brings together 17 of the world's biggest greenhouse gas-emitting countries, there was "no plan B".
World delegations meet in Copenhagen in December for talks on a new treaty.