"We want to be more prescriptive," said David Carlson, head of International Polar Year (IPY) starting in March 2007.

The two year study, announced on Wednesday by the International Council for Science (ICSU), will be the first coordinated probe in 50 years of the ice-bound ends of the earth under the onslaught of climate change.

ICSU is a non-governmental organisation whose members include the national science academies of 103 countries.

"Part of the reason scientists stay in the comfort zone is that they can always say: 'well we don't know enough,'" Carlson told Reuters. "We are going to take away the uncertainty.

"If we come out of this and say 'we still don't know enough' then we will not have done our job," he added in an interview.

Scientists say the earth's temperature will rise by at least two degrees centigrade this century due to greenhouse gases from burning fossil fuels for transport and electricity, putting millions at risk from extreme weather and rising oceans.

A new United Nations' report states that up to 50 million people could become environmental refugees from floods and famines due to climate change within five years.

And a study last year found that Arctic temperatures were rising twice as fast as in the rest of the world.

"I can guarantee that we will have a much more accurate sea level prediction," Carlson said.

"We will know what the West Antarctic ice sheet is going to do. We will know what the Greenland ice sheet is going to do."

One estimate says that if the Greenland ice sheet -- the second biggest after Antarctica -- melts completely, sea levels will rise by seven metres and drown vast areas of the world.

But that is nothing compared with the estimated 200 metres that sea levels will rise if all the Antarctic ice melts in the coming thousands of years.

Carlson is not worried that the scientists might enter the political arena where -- as was illustrated earlier this year in Britain's struggle to get the Group of Eight to agree a climate action plan -- landmines await the unwary.

Right up to the last minute at the July G8 summit in Scotland, US President George W. Bush's officials were stating that global warming was a natural not a man-made phenomenon -- and they even questioned whether it was happening at all.

But it is not just rising sea levels that are at stake.

The melting of the Arctic ice caps will dilute the salinity of the North Atlantic and slow down the life-giving Gulf Stream current that warms northern Europe.

Apart from ice, the IPY research will focus on big themes such as the northern climate system with a faltering Gulf Stream and thawing permafrost, and the ability of the southern oceans to absorb carbon.