Vienna - Global sea levels are likely to rise faster than predicted by the United Nations climate panel, possibly endangering millions in developing countries, scientists said in Vienna Thursday.

The increase was largely due to the world's glaciers melting faster that previously estimated, geoscientists speaking at the European Geosciences Union's (EGU) annual meeting taking place this week in the Austrian capital said.

A statistical reconstruction of sea levels over the past 2,000 years showed that while sea levels remained stable within 20 centimetres in the past two millenia, they can be expected to rise by 0.8 to 1.5 metres by 2100, Svetlana Jevrejeva of Britain's Proudman Oceanographic Laboratory said.

Those projections, up to three times the estimates published by the UN's Intergovernmental Panel on Climate Chance
(IPCC), are likely to raise some hackles in the scientific community.

"The IPCC's estimates are regarded as conservative in the scientific community," Simon Holgate of Proudman said.

IPCC was awarded the 2007 Nobel Peace Prize together with climate campaigner Al Gore.

IPCC's 2007 assessment did not provide an upper bounds for sea level changes, as the projections did not include uncertainties in climate-carbon cycle feedbacks nor the full effects of changes in the ice sheet flow, the UN climate panel said in its report.

Scientists said they still lacked exact data, but the broad consensus was that a rise of more than 1 metre was not out of the question. IPCC had predicted rises between 18 and 59 centimetres.

In order to determine the speed of these changes, the main challenge now was to analyze the factors contributing to the rising waters.

Increasing amounts of water from the planet's land masses were entering the oceans from Greenland and Antarctica's melting ice sheets and glaciers from around the world.

Sea levels were also pushed higher by the thermal expansion of water due to higher temperatures, Steve Nerem of the University of Boulder, Colorado said.

One possible explanation for the lower IPCC predictions was that the UN model did not take into account the ice sheet dynamics, the scientists at EGU said.

Scientists had to revise downwards the calculations regarding the speed of glaciers melting due to ice sheet dynamics, Holgate said.

While in the past, they believed it would take 8,000 years for the ice covering Greenland to melt, this was revised down to
1,000 years.

Meltwater was running down through cracks in the glacier to the bottom, becoming a lubricant which caused glaciers to flow a lot faster, Holgate explained.

Jevrejeva's findings seemed to be corroborated by the latest results from satellite-based studies on global sea levels.

"We noticed an increase of sea levels by 3.5 millimetres per year over the past 15 years," Nerem said. This ratio was likely to increase, he added.

The rise in sea levels would of course have regional differences, with the situation becoming worse in areas already affected by extreme tidal differences.

The scientists at the Vienna panel admitted that much more research was needed, but agreed that the world's poorest countries, which are often most densely populated in coastal regions, are likely to suffer most.

A 1-metre-increase in sea level would for example cover around 90 per cent of Bangladesh, Holgate said.

"If you live in the Ganges delta, you are in big trouble," he said.

In China, sea level rises as predicted by the scientists could force around 72 million people to relocate.

Asked whether they would rely on IPCC predictions or their own, more alarming, estimates when considering where to buy a house for their grandchildren, the scientists said that they would rather move a little further off the beach. (dpa)