In study published today in the Journal Science the researchers found that on average Antarctica’s Ice Shelves are thinning by about 1.6 feet (50 cm) per year, but some of them are thinning faster by as much as 328 feet (100 meters) annually faster than ever, according to Eric Rignot a co-author and researcher at the University of California.
Traditionally has been considered that the Antarctic Icebergs become smaller when chunks of ice breaks off of floating ice shelves but new research reveals something that is invisible to the naked eye: the Icebergs primarily melt from below.
When ice shelves lose mass, they speed up the melting, contributing to global sea levels to rise.
The Journal Science found that on average, Antarctica’s ice shelves are thinning by about 1.6 feet per year and some are melting even faster.
“These changes are faster and larger than anything people anticipated,” said Eric Rignot, a study co-author and researcher at the University of California.
Antarctica’s Larsen B Ice Shelf that collapsed in 2002 has melted and the glaciers that were slowed by the shelf’s enormous mass have speed up, flowing to sea up to 8 times faster than before the collapse.
This is the first “comprehensive estimate of all Antarctic ice-shelf melting and calving,” said Paul Holland, a researcher at the British Antarctic Survey who wasn’t involved in the study. Due to the large amount of data that went into the study, it took nearly a decade to complete, Rignot said.
They calculated the mass of ice shelves using information from NASA’s Ice Bridge Mission which was a 6 year campaign to survey and monitor Earth’ Polar Ice Sheet and also satellites and airplane radar readings, penetrating the ice and measuring their thick.
They also calculated snowfall using computer models that show the flux of moisture from the atmosphere to the ground. By combining these data, the scientists figured out “what fraction of Antarctic glacial ice is lost through icebergs, and what is lost through ocean melting,” Holland said.
“This was quite a big gap in our understanding of how the ice sheets interact with their surroundings, and what it shows is that the oceans play a bigger role than we’d previously thought,” says Hamish Pritchard, a glaciologist at the British Antarctic Survey in Cambridge who led the Nature study. Other teams are working on similar analysis, Pritchard says, but “Eric won the race.”
Antarctica’s Icebergs are melting faster than ever, an example is the Getz Ice Shelf, that produces more melt water than ice shelves around the continent that are ten times its size.
Written by Edgar Soto
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9 Responses
The increase in ice shelf basal melt is most likely due to changes in ocean circulation bringing in warmer waters from further north of the Antarctic coast. Winds play a major role in driving this ocean circulation. The wind patterns are driven by atmospheric pressure gradients which are ultimately set up by temperature gradients at the Earth surface and in the atmosphere. So the point is that changes in climate can change ice shelf melt, via their effects on the oceans.
Exactly…it has to do with Climate Change…and the scientist are not looking at the whole picture.
Well I don’t no about Global Warming “in the polar regions. But there is no Global Warming in Minnesota. With snow in May. Cold all spring. June 13 still cold. Spring there was none.
http://theconsensusproject.com/
It needs more than editing. Whoever wrote this obviously didn’t read the report. It basically says that ice loss is due to changed sea currents moving warmer water under the ice, not due to increased air temperatures:
“We find that iceberg calving is not the dominant process of ice removal. In fact, ice shelves mostly melt from the bottom before they even form icebergs,”
In other words, this is NOT due to “Global Warming”.
If it is not due to global warming…why do you think the oceans are warmer, temperatures are rising and the International Energy Agency is giving us recommendations to fix the problem? Check our article https://guardianlv.com/2013/06/global-warming-is-out-of-control-says-international-energy-agency/
It is the global warmth brought to the submarine Antarctic by ocean currents causing the basal melt. I would like to see calculation of how melt of ground-sitting basal ice may tend to lower sea level, since melt-water has a lower volume than the ice it came from. According to Wikipedia the satellite-measured global mean sea level dropped some 5 mm from 2010 to 2011. By Archimedes principle basal melt of floating ice would not change sea level. But calving off of bits of land-supported ice would. A further point: ice-melt water has a lower density than salt water and so will rise. It also has higher freezing point, so will freeze more easily at the surface, increasing sea ice.
This needs editing.
Could you tell me why?