Business looks to costs of climate change

'It isn't a debate... If anyone tells you the variations we are seeing is natural, please don't believe them,' Bill McGuire, professor of geophysical hazards at University College London, told business leaders. 'It is a climate change signal we're seeing.'

Most of those dismissing the effects of global warming were not scientists and had political and commercial associations that influenced their arguments, he said."

It was likely that the economic costs of global warming would at least double to $150 billion annually over the coming 10 years, he added.

"We don't know what will happen, but uncertainty means greater risk, and we need to do more now to manage it," he said.