Sea levels are rising faster than predicted, warns Antarctic Survey

The global sea level rise caused by climate change, severely threatening many of the world's coastal and low-lying areas from Bangladesh to East Anglia, is proceeding faster than UN scientists predicted only five years ago, Professor Chris Rapley, director of the British Antarctic Survey, said yesterday.

Climate change is causing sea levels to rise around the world because water expands in volume as it warms, and because land-based ice, such as that contained in the Greenland and Antarctic ice sheets, adds to the volume when it melts and slips into the sea.

The present prediction of the UN's Intergovernmental Panel on Climate Change, from its third assessment report in 2001, is that global sea levels will rise by between 9cm and 88cm by 2100, depending on a number of factors including how far emissions are controlled, with a best guess of about 50cm over the century.

Rises of this order will present a substantial threat of flooding, storm surge and even complete submersion of many of the world's populous low-lying areas,such as Bangladesh, the Nile Delta and even London.

But the new evidence, from a series of scientific papers published this year, indicates that this rate would be exceeded, said Professor Rapley, who runs the world's leading institute on Antarctic science - although he could not say what any new rate would be.

Professor Rapley was speaking at the Liberal Democrat conference in Brighton, at a meeting of the Climate Clinic, formed by Britain's leading green groups, with The Independent as media partner, to press for tougher political action on climate change. "We have learned in the last 18 months that the ice sheets are capable in selected areas of much more rapid changes and dynamic discharges than we previously thought," he said.

Last week, two American studies showed that the melting of the winter sea ice in the Arctic had accelerated enormously in the past two years, with a section the size of Turkey disappearing in just 12 months.