ICE Satellite Maps Profound Polar Thinning

xp65 writes "Researchers have used NASA's Ice, Cloud and Land Elevation Satellite to compose the most comprehensive picture of changing glaciers along the coast of the Greenland and Antarctic ice sheets. The new elevation maps show that all latitudes of the Greenland ice sheet are affected by dynamic thinning — the loss of ice due to accelerated ice flow to the ocean. The maps also show surprising, extensive thinning in Antarctica, affecting the ice sheet far inland. The study, led by Hamish Pritchard of the British Antarctic Survey in Cambridge, England, was published September 24 in Nature."

Comments

What is the net effect?

[msevior]

I'm no climate change skeptic, but from just looking at the images it's not clear that the reduction in some places is not balanced by the increase in others. What is the net effect? Can these data be compared to model predictions?

Re:What is the net effect?

[blind biker]

Yes for Antarctica - there does, indeed, seem to be a balancing between areas with thinning and those with thickening ice. But not for Greenland, which appears to be pretty much on a dramatic thinning regimen.

Re:What is the net effect?

[gregraven]

I, too, am curious that this story appeared the day after a story entitled, "Antarctic Ice Is Growing, Not Melting Away." http://www.news.com.au/story/0,27574,25348657-401,00.html

Do they know if this is unusual?

[n2rjt]

I see on the maps that some areas are thinning, near the coasts, and other areas are thickening.
I wonder if that is the usual pattern, or if they are seeing something unusual.
The article didn't mention that, as far as I could tell.

Re:Do they know if this is unusual?

[khayman80]

Higher average global temperatures imply higher upper ocean temperatures, which imply a higher water vapor pressure. Thus more water vapor will evaporate into the atmosphere. Yes, Roderick 2007 showed that wind speed had a stronger affect on the evaporation rate than changes in temperature, but I doubt that affects the expected theoretical equilibrium vapor pressure from basic thermodynamics. When that more humid air is carried across a tall mountain range, its temperature decreases and the water precipitates.

Re:Do they know if this is unusual?

[MrKaos]

Qualitatively, what you'd expect from climate change is more precipitation (because there's more evaporation)

What you are not taking into account is Global Dimming. This phenomenon (do,do, do.do.do) blocks photons from hitting bodies of water which is what is *required* for evaporation to occur. Records of rainfalls taken in Israel has shown a decline in the amounts of rainfall as the amount of particulate matter (from pollution) increases in the atmosphere and blocks light from reaching the earth.

This promotes drought. Less evaporated water in the atmosphere means less rainfall for landmasses and, critically, less snowfall for the polar regions. If the snow hasn't fallen on the polar regions, it still means ice mass is not regenerated at the same rate.

Re:Do they know if this is unusual?

[Troed]

You should try verifying that graph scientifically. Some have, with interesting results.

http://wattsupwiththat.com/2009/09/23/taking-a-bite-out-of-climate-data/