A band of environment ministers landed in this remote corner of the icy continent on Monday, in the final days of an intense season of climate research, to learn more about how a melting Antarctica may endanger the planet.

Representatives from more than a dozen nations, including the US, China, Britain and Russia, were to rendezvous at a Norwegian research station with American and Norwegian scientists coming in on the last leg of a 1,400-mile (2,300-kilometer), two-month trek over the ice from the South Pole.

The visitors will gain "hands-on experience of the colossal magnitude of the Antarctic continent and its role in global climate change," said the mission's organizer, Norway's Environment Ministry.

They'll also learn about the great uncertainties plaguing research into this southernmost continent and its link to global warming: How much is Antarctica warming? How much ice is melting into the sea? How high might it raise ocean levels worldwide?

The answers are so elusive that the Intergovernmental Panel on Climate Change (IPCC), a Nobel Prize-winning UN scientific network, excluded the potential threat from the polar ice sheets from calculations in its authoritative 2007 assessment of global warming.

The IPCC forecast that oceans may rise up to 23 inches (0.59 meters) this century, from heat expansion and melting land ice, if the world does little to reduce emissions of carbon dioxide and other greenhouse gases blamed for atmospheric warming.

But the UN panel did not take Antarctica and Greenland into account, since the interactions of atmosphere and ocean with their enormous stores of ice - Antarctica has 90 percent of the world's ice - are poorly understood. And yet the West Antarctic ice sheet, some of whose outlet glaciers are pouring ice at a faster rate into the sea, "could be the most dangerous tipping point this century," says a leading US climatologist, NASA's James Hansen.

"There is the potential for several-meter rise of sea level," Hansen said last week. The scenario is "frightening," says the IPCC's chief scientist, Rajendra Pachauri, who met with the ministers in Cape Town before their nine-hour flight here from South Africa.

Finding the answers has been key to the 2007-2009 International Polar Year (IPY), a mobilization of 10,000 scientists and 40,000 others from more than 60 countries engaged in intense Arctic and Antarctic research over the past two southern summer seasons - on the ice, at sea, via icebreaker, submarine and surveillance satellite.

The 12-member Norwegian-American Scientific Traverse of East Antarctica - the trekkers "coming home" to Troll - was one important part of that work, having drilled deep cores into the annual layers of ice sheet in this little-explored region, to determine how much snow has fallen historically and its composition.

Such work will be combined with another IPY project, an all-out effort to map by satellite radar the "velocity fields" of all Antarctic ice sheets over the past two summers, to assess how fast ice is being pushed into the surrounding sea.

Then scientists may understand better the "mass balance" - how much the snow, originating with ocean evaporation, is offsetting the ice pouring seaward.

"We're not sure what the East Antarctic ice sheet is doing," David Carlson, IPY director, explained last week from the program's offices in Cambridge, England. "It looks like it is flowing a little faster. So is that matched by accumulation? What they come back with will be crucial to understanding the process."

The visiting environment ministers were those of Algeria, Britain, Congo, the Czech Republic, Finland, Norway and Sweden. Other countries were represented by climate policymakers and negotiators, including Xie Zhenhua of China and Dan Reifsnyder, a deputy assistant US secretary of state.

During their long day here under the 17-hour sunlight of a dying southern summer, when temperatures still drop to near zero Fahrenheit (-20 degrees Celsius), the northern visitors took in the awesome sights of Queen Maud Land, a forbidding, mountainous icescape 3,000 miles (5,000 kilometers) southwest of South Africa, and toured the Norwegians' high-tech Troll Research Station, upgraded to year-round operations in 2005.

The politics of climate inevitably mixed with the science. Stranded in Cape Town an extra two days when high Antarctic winds scrubbed a planned weekend flight, the ministers were gently lobbied at lunch and dinner by Scandinavian counterparts favoring urgent action on a new global agreement to succeed the Kyoto Protocol, the deal to reduce greenhouse gases that expires in 2012.

US President Barack Obama's new administration has promised action after years of US resistance to the Kyoto process. But the complexity of issues and limited time before a Copenhagen conference in December, target date for a deal, makes the outcome as uncertain as the future of Antarctica's glaciers and offshore ice shelves.

Much more research lies ahead, say the scientists, including investigations of the possible warming and shifting currents of the Southern Ocean ringing Antarctica. "We need to put more resources in," said IPY's Carlson.

Outspoken scientists say political action may be even more urgently needed.

"We are out of out cotton-pickin' minds if we let that process get started," Hansen said of an Antarctic meltdown. "Because there will be no stopping it."

(China Daily via Agencies February 24, 2009)