Net WAIS Ice Loss In 2006 - 132 Billion Tons; Total Antarctic Mass Loss Up 75% In Ten Years - AFP

[hatrack]

PARIS: Global warming has caused annual ice loss from the Antarctic ice sheet to surge by 75 percent in a decade, according to the most detailed survey ever made of the white continent's coastal glaciers.

In 2006, accelerating glaciers spewed an estimated 192 billion tonnes of Antarctic ice into the sea, scientists calculate. The West Antarctica ice sheet lost some 132 billion tonnes, while the Antarctic Peninsula, the tongue of land that juts up towards South America, lost around 60 million tonnes. But there was a "near-zero" loss in East Antarctica, the world's biggest icesheet, the paper says.

Investigators from five countries, led by Eric Rignot of NASA's fabled Jet Propulsion Laboratory (JPL), used interferometry radar from four satellites to build a picture of the periphery of Antarctica. They sought to measure the velocities of glaciers that shift ice to the coast from the massive sheets that cover Antarctica's bedrock. They built up a picture of around 85 percent of Antarctica's coastline thanks to the data supplied by the European Space Agency's two Earth Remoting Sensing (ERS) satellites, the Canadian Radarsat-1 and Japan's Advanced Land Observing satellites.

"Over the time period of our survey, the ice sheet as a whole was certainly losing mass, and the mass loss increased by 75 percent in 10 years," according to the study, published online by the specialist journal Nature Geoscience.

EDIT

http://timesofindia.indiatimes.com/Antarctica_ice_loss_accelerating_Study/articleshow/2696201.cms

[philb]

1. So what does this contribute to sea level rise?

Is the Greenland melting more significant?
Any recent indication of accelerating sea level rise?

[hatrack]

2. This is more than Greenland's losing by about one-third . . .

However, the article notes that it's the WAIS and specifically the Pine Island region of WAIS that's contributed the most from that side of the Antarctic. Given that Pine Island Glacier's the metaphorical cork in the bottle as far as that side of the continent is concerned, and how rapidly its grounding line has receded in just the past ten years or so, grounds for concern. The East Antarctic Sheet - not so much of a problem so far.

As far as comparisons go, Greenland lost about 220 cubic kilometers of ice in 2005, more than doubling over 1996. More to the point, WAIS is losing substantially more (about 30%) than what Greenland's already losing, about 132 billion tons to Greenland's loss of about 100 billion in 2006.

EDIT

From 1996 to 2000, widespread glacial acceleration was found at latitudes below 66 degrees north. This acceleration extended to 70 degrees north by 2005. The researchers estimated the ice mass loss resulting from enhanced glacier flow increased from 63 cubic kilometers in 1996 to 162 cubic kilometers in 2005. Combined with the increase in ice melt and in snow accumulation over that same time period, they determined the total ice loss from the ice sheet increased from 96 cubic kilometers in 1996 to 220 cubic kilometers in 2005. To put this into perspective, a cubic kilometer is one trillion liters (approximately 264 billion gallons of water), about a quarter more than Los Angeles uses in one year.

EDIT

http://www.sciencedaily.com/releases/2006/02/060217091552.htm

EDIT

But Dr. Jay Zwally, a climate scientist with NASA, said he thinks the latest trend is different.

"The current warming trend in Greenland is very extensive and is not likely to be explained by natural variability alone," he said. Zwally said the warming is consistent with scientific predictions about the effects of man-made greenhouse gases.

Last year, satellite data collected by NASA scientists revealed Greenland is losing 100 billion tons of ice each year, more than it is gaining from snowfall in the interior. Steffen and others have also detected a new, faster movement of the ice sheet, causing the glaciers to dump more ice into the ocean, where it melts and contributes to sea-level rise.

Part of this faster flow is caused by moulins, deep holes in the ice sheet that allow water to flow beneath the surface.

"During the summer months, as the ice sheet melts, large running rivers of melt water snake down through the ice, to the bedrock base below," Steffen said.

EDIT

http://www.cnn.com/2007/TECH/science/10/23/greenland.melting/index.html

[NickB79]

3. But Glen Beck told me Antarctica has more ice than ever!

Are you telling me that a rightwing nutjob would lie to me? How dare you!

[phantom power]

5. Ice *cover* did increase last year. However, area can increase while volume decreases.

[n2doc]

4. Figure from study

Satellite-derived image of the surface topography of Antarctica. Shown in color are the flow speeds of glaciers draining ice into the oceans. The scale is meters per year. It is noticeable how the rate speeds up in narrow glacier outlets. (Credit: Jonathan Bamber)

http://www.sciencedaily.com/releases/2008/01/080113143438.htm