British-based Forum for the Future, a charitable think-tank, and researchers from Hewlett-Packard Labs, said they wanted to stir debate about how to avert the worst effects of global warming by presenting a radical set of possible futures.

'Climate change will affect the economy at least as much as the 'credit crunch',' their 76-page report study said.

The scenarios range from a shift to greater energy efficiency, where desalination plants run on solar power help turn the Sahara green, to one where refugees are moving to Antarctica because of rising temperatures.

'We still have the chance to alter the future,' Mr Peter Madden, head of the Forum, told Reuters. 'This is what the world could be like and some of these options are not very pleasant.'

Mr Madden said that most reports about climate change focused on scientific findings about carbon dioxide emissions, mainly from burning fossil fuels, without taking account of psychological or social responses.

'Historians of the future may look back on these as the 'climate change years',' he said. 'They will either look back on our generation as heroes or view us with incomprehension and disgust - as now we look back on those who allowed slavery.'

He said the crystal ball survey did not seek to project what was most likely to happen, just some of the possibilities.

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It gave the following five scenarios: