Alarm bells over Greenland ice meltOctober 26th, 2011 - 7:08 pm ICT by IANS
Washington, Oct 26 (IANS) Greenland ice sheet can experience extreme melting even when temperatures don?t hit record highs, say scientists.
A new analysis by Marco Tedesco, assistant professor in earth and atmospheric sciences at The City College of New York, suggests that glaciers could undergo a self-amplifying cycle of melting and warming that would be difficult to halt.
?We are finding that even if you don?t have record-breaking highs, as long as warm temperatures persist, you can get record-breaking melting because of positive feedback mechanisms,? said Tedesco, who directs the college’s Cryospheric Processes Lab.
Tedesco and his team collected data this past summer during a four-week expedition to the Jakobshavn Isbrae glacier in western Greenland. Their arrival preceded the onset of the melt season, the college said.
Combining data gathered on the ground with microwave satellite recordings and the output from a model of the ice sheet, Tedesco and graduate student Patrick Alexander found a near-record loss of snow and ice this year.
The extensive melting continued even without last year?s record highs.
The team recorded data on air temperatures, wind speed, exposed ice and its movement, the emergence of streams and lakes of melt water on the surface, and the water?s eventual draining away beneath the glacier.
This lost melt water can accelerate the ice sheet?s slide towards the sea where it calves new icebergs. Eventually melt water reaches the ocean, contributing to the rising sea levels associated with long-term climate change.
The model showed that melting between June and August was well above the average for 1979 to 2010. In fact, melting in 2011 was the third most extensive since 1979, lagging behind only in 2010 and 2007.
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- Melting glaciers to contribute 12cm to world sea-level increases by 2100 - Jan 11, 2011
- Sea levels may rise much higher, says fossil study - Jul 16, 2012
- Scientists estimate sea level rise by studying past carbon dioxide levels - May 02, 2011
- Global warming taking giant bites out of underbellies of Greenland's glaciers - Feb 15, 2010
- Warm ocean currents cause ice loss from Antarctica - Apr 26, 2012
- Warming ocean layers melt polar ice sheets faster - Jul 04, 2011
- Short-term weather extremes, not warming, driving Greenland ice sheet flow: Study - Dec 09, 2010
- Believe it or not - glaciers are growing! - Jan 28, 2011
- Greenland ice sheet is safer than scientists previously believed - Jan 27, 2011
- Shrinking snow and ice cover 'making global warming worse' - Jan 19, 2011
- Global warming curbs won't prevent steep sea rise - Mar 21, 2012
- Melting glaciers on Arctic islands play major role in rise of sea level - Apr 21, 2011
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