Greenland ice could be next puzzle for U.N. panel
By Alister Doyle, Environment Correspondent
BALI, Indonesia (Reuters) - A thaw of Greenland ice that could raise world sea levels may be the next puzzle for the U.N. climate panel that won the Nobel Peace Prize, a senior member of the group said.
Dutch scientist Bert Metz said the risk of an accelerating melt of Greenland's ice sheet was among the unsolved issues in the U.N. reports this year that blame mankind for causing global warming and urge quick action to avert the worst impacts.
"There are still questions about the behavior of the big ice sheets, like Greenland, and the consequences of sea level rise," he told Reuters on the sidelines of a 190-nation U.N. climate conference in Bali, Indonesia.
Recent studies suggested risks that vast chunks of ice could slip into the sea instead of a slow melt of surface ice tied to global warming. It was not clear how remote those risks were.
"On that issue it would be feasible I think to do a report in a couple of years" if governments agreed, Metz said.
Greenland stores enough ice to raise world sea levels by about 7 meters (23 ft) if it all melted, perhaps over thousands of years, swamping many coastal cities and Pacific islands.
Governments are considering whether to launch a new round of studies of global warming by the U.N.'s Intergovernmental Panel on Climate Change (IPCC), perhaps for release around 2013. This year's overview reports followed ones in 2001 and 1995.
"There are voices that say we should postpone (a global overview) a bit and in the meantime do more focused special reports," said Metz, who will be among 25 experts from the panel in Oslo next week to collect the Nobel Peace Prize on December 10.
The behavior of ice sheets was a main candidate for a special report, along with one already likely about renewable energies, he said. Arctic summer ice this year thawed to the smallest since satellite records began in the 1970s.
Metz is a co-chair of one of three main IPCC reports. The IPCC will share the award with ex-U.S. Vice President Al Gore.
And another scientist said that so far unpublished research showed that one area of Greenland's surface melted for about two months this summer, twice the normal melt season.
The IPCC projects that world sea levels will rise between 18 and 59 centimeters (7-23 inches) this century but says that does not include risks of an accelerating melt of Greenland, nor of the larger areas of Antarctic ice that are colder and considered more stable.
Antarctica has enough ice to raise levels by 57 meters.
A few years ago "we thought a thaw of Greenland might happen but it would take thousands and thousands of years -- 'this chunk of ice will melt gradually from the outside'," Metz said.
"But now the latest information is that there may be different mechanisms, of water going down into crevasses and acting as a lubricant" beneath large areas of ice, he said.
If that happened, there was a risk that ice could slip into the sea. And more fresh water entering the North Atlantic could slow the Gulf Stream that keeps Europe warm, bringing a regional cooling despite an overall warming of the climate.
The latest IPCC report says that an abrupt slowdown of the Gulf Stream this century is "very unlikely" but that the risks beyond that cannot be assessed with confidence.
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(Editing by David Fogarty)