Nicholas Stern suggests that trace amounts of CO2 may cause the oceans to rise 65 feet

Economist warns of 'radical' climate change, millions at risk - FRANCE 24

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.
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"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.