NASA Puts Its Weight Behind Warming Signs
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Pollution Soaring to Crisis Levels in Arctic [
NASA Puts Its Weight Behind Warming Signs
By Miguel Llanos
MSNBC
Monday 13 March 2006
Press release on ice sheet survey follows internal changes.
In a press release for the survey, NASA directly tied the changes to warming and described the survey as "the most comprehensive" ever in both regions.
That stand can in part be explained by lead author Jay Zwally's warning.
"If the trends we're seeing continue and climate warming continues as predicted, the polar ice sheets could change dramatically," he said in the press release last Wednesday. "The Greenland ice sheet could be facing an irreversible decline by the end of the century."
But Zwally, a scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., told MSNBC.com that the press release also follows an internal NASA change that seems to be taking place to allow scientists greater freedom.
Complaint Made a Difference?
A change in policy appears to be occurring after NASA scientist Jim Hansen complained about being silenced because of the Bush administration's opposition to mandatory curbs on greenhouse gases that many scientists tie to global warming.
"A few months ago this press release might have been seriously edited or not approved," Zwally said.
Based on satellite mapping of ice sheets and published in the Journal of Glaciology, the survey validated computer models projecting impacts on Earth from global warming.
"The survey documented for the first time extensive thinning of the West Antarctic ice shelves, an increase in snowfall in the interior of Greenland and thinning at the edges," NASA said in the press release. "All are signs of a warming climate predicted by computer models."
The press release followed the two Antarctica and Greenland studies, which included NASA research. And while those received considerable attention because of data that showed rapid changes in the ice, the press releases sent out with them did not emphasize global warming.
Warming 'Has Really Just Started'
In the most recent press release, NASA did not directly tie the warming to humans and the burning of fossil fuels, which emits carbon dioxide, a key greenhouse gas.
But Zwally noted that the predicted climate warming cited in the press release is caused by manmade emissions. A natural warming cycle is technically possible, he said, but not likely given how closely the warming and models track.
Zwally said he expects to have even stronger satellite data within a year.
"We're seeing the early signs of changes in the ice sheets," he added. "The climate warming from greenhouse gases has really just started."
Pollution Soaring to Crisis Levels in Arctic
By Robin McKie
The Observer UK
Sunday 12 March 2006
Scientists plead for action to save poles from "tipping point" disaster.
Researchers have uncovered compelling evidence that indicates Earth's most vulnerable regions - the North and South Poles - are poised on the brink of a climatic disaster.
The scientists, at an atmospheric monitoring station in the Norwegian territory of Svalbard, have found that levels of carbon dioxide in the atmosphere near the North Pole are now rising at an unprecedented pace.
In 1990 this key cause of global warming was rising at a rate of 1 part per million (ppm). Recently, that rate reached 2 ppm per year. Now, scientists at the Mount Zeppelin monitoring station have discovered it is rising at between 2.5 and 3 ppm.
'The fact that our data now show acceleration in the rise of carbon dioxide level is really a source for concern,' said Professor Johan Strom, of Stockholm University's department of applied environmental science, which runs the Mount Zeppelin station. 'The increase is also seen at other stations, but our Zeppelin data show the strongest increase.'
The news of the latest carbon dioxide figures comes as scientists prepare to announce details of the forthcoming International Polar Year programme, which will involve teams of scientists from around the world making a concerted attempt to understand the impact of global warming in the world's high latitudes. In particular, they will concentrate on the social impact of climate change there and also the threats to the regions' wildlife, such as polar bears and walruses.
In the last two decades, carbon dioxide levels in the atmosphere have risen from 350 to 380 ppm and scientists warn that once levels reach 500, there could be irreversible consequences that would tip the planet toward disaster: glacier melts triggering devastating sea-level rises and spreading deserts across Africa and Asia.
Scientists and campaigners are desperate for politicians to reach agreements that will prevent the 500 ppm 'tipping point' being breached in the next half-century. These new data suggest they may have a far shorter period of time in which to act.
'Fortunately, this rate of rise of carbon dioxide is not yet seen round the world,' added Strom. 'However, it may be that we have been the first to detect it, and that we are seeing some kind of special effect that could have widespread consequences in a few years.'
One theory proposed by Strom is that heating of the oceans could be leading to the release of carbon dioxide. Other scientists suggest that as the world warms, the Arctic tundra - previously gripped by permafrost - may be giving off carbon dioxide as it melts, releasing gas from vegetation trapped within it that has now started to rot. Thus levels of the gas would increase with particular rapidity near the North Pole.
The latest data from Mount Zeppelin comes in the wake of a series of other alarming reports about the effects of global warming in the Arctic and Antarctic. It was recently discovered that ice sheets are now covering less of the Arctic Ocean than ever before; that Greenland is shedding sheets of ice far faster than previously realised; that the West Antarctic ice cap is dwindling at an unexpectedly high rate; and that the Gulf Stream is showing worrying signs of being disrupted by Arctic meltwaters.
The last effect is particularly worrying, because the waters of the Gulf Stream play a key role in keeping Britain and Europe from freezing in winter. Should it disappear, the consequences for the country would be profound.
'The crucial point is that you can't look at the Arctic and Antarctic in isolation,' said Professor Chris Rapley, head of the British Antarctic Survey. 'What happens there has profound consequences for the rest of the planet.'
It was thought until recently that it would take up to 1,000 years for heat to penetrate the Greenland ice shield and melt it. But the latest data show that large parts of it are actually sliding in lumps into the sea. 'That means it is likely to take far less time to raise sea levels,' added Rapley. 'And if Greenland's ice melts, we will be in trouble. There will be a seven-metre rise in the oceans. The Thames Barrier would be swamped.'
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