Economist warns of 'radical' climate change, millions at risk

France 24 via AFP: The author of an influential 2006 study on climate change warned Tuesday that the world could be headed toward warming even more catastrophic than expected but he voiced hope for political action. Nicholas Stern, the British former chief economist for the World Bank, said that both emissions of greenhouse gas and the effects of climate change were taking place faster than he forecast seven years ago.

Without changes to emission trends, the planet has roughly a 50 percent chance that temperatures will soar to five degrees Celsius (nine degrees Fahrenheit) above pre-industrial averages in a century, he said.

"We haven't been above five degrees Centigrade on this planet for about 30 million years. So you can see that this is radical change way outside human experience," Stern said in an address at the International Monetary Fund.

"When we were at three degrees Centigrade three million years ago, the sea levels were about 20 some meters (65 feet) above now. On sea level rise of just two meters, probably a couple of hundred million people would have to move," he said.

Stern said that other effects would come more quickly including the expansion of deserts and the melting of Himalayan snows that supply rivers on which up to two billion people depend...

Nicholas Stern at Davos in 2009, shot by World Economic Forum, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license