Sea levels around the world will rise one metre this century, according to German scientists who warn that global warming is happening much faster than hitherto predicted.

Citing UN date on climate change, two senior German scientists say that previous predictions were far too cautious and optimistic.

Earlier estimates predicted a rise of 18 to 59 centimetres in sea levels this century. But that estimate is woefully understated, according to Hans Joachim Schellnhuber, who heads the Potsdam Institute for Research on Global Warming Effects, and Jochem Marotzke, a leading meteorologist.

"We now have to expect that the sea level will rise by a metre this century," said Schellnhuber in Berlin.

He said it is "just barely possible" that world governments will be able to limit the rise in average global temperatures to just 2 degrees Celsius by the end of the century, if they all strictly adhere to severe limits in carbon dioxide emissions.

Those restrictions call for halving greenhouse emissions by 2050 and eliminating CO2 emissions entirely by the end of the century. But the German researchers said the resulting limited increase in temperature is predicated on strict adherence to those restrictions without exception, and even then there are many variables which could thwart the goals.

Schnellnhuber, who is official adviser to German Chancellor Angela Merkel on climate-change issues, said the new findings employed data unavailable to the Intergovernmental Panel on Climate Change (IPCC) for its most recent global warming report.

The two experts said the IPCC report had been based on data up to 2005 only, but since then ice loss in the Arctic had doubled or tripled. Schnellhuber charged that 20 per cent of the loss of the ice sheet on Greenland could be directly linked to the added carbon dioxide emissions from new Chinese coal-fired power stations.

The new prognostications of higher sea levels, according to Schellnhuber, are based on studies of melting Himalaya glaciers and the shrinking Greenland ice cap.

He blamed the rapidly diminishing size of the Greenland ice cap on soot particles from Chinese coal-fired power plants.

"That is truly a global effect," he said. Soot settles on the ice, preventing the ice from reflecting as much sunlight back into space. The result is that the ice absorbs sunlight rays, raising the temperature of the ice and causing it to melt.

"Air pollution plays a massive role in the accelerating pace of climate change, he said.