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Greenland ice breakup seen from NASA ER-2 cockpit during a MABEL flight (NASA)

Scientists Set Their Sights on Arctic Ice Loss

3 May , 2012

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NASA researchers have just completed science mission flights over Greenland and the surrounding seas, gathering data on ice distribution and thickness with the MABEL (Multiple Altimeter Beam Experimental Lidar) laser altimeter instrument mounted in the nose of an ER-2 aircraft. WIth MABEL’s unprecedented ability to detect individual photons, researchers will be able to even more accurately determine how Arctic ice sheets are behaving in today’s changing climate.

At the same time, news has come in from researchers with the University of Washington, who have completed a NASA- and NSF-funded study of the enormous island’s glaciers spanning a ten-year period. What they have found is that the glaciers have been increasing in speed about 30% over the past ten years — which is actually less than earlier studies had anticipated.

“In some sense, this raises as many questions as it answers. It shows there’s a lot of variability,” said Ian Joughin, a glaciologist in the UW’s Applied Physics Laboratory and coauthor of the paper, published May 4 in Science.

Previous research had suggested that Greenland’s melting glaciers could contribute up to 19 inches to global sea level rise by 2100. But the behavior of Greenland’s vast ice fields and ocean-draining glaciers was not yet thoroughly researched. Based on this new study, the outlet glaciers have not sped up as much as expected.

Still, ocean-draining (a.k.a. marine-terminating) glaciers move much faster than their land-based counterparts, and the UW researchers have found that their speeds are increasing on average — up to 32% in some areas.

The team realizes that the study may just not have observed a long enough period of time. (These are glaciers, after all!)

Icebergs calve from the edge of Greenland's Gyldenlove glacier in April 2011. (NASA/GSFC/Michael Studinger)

“There’s the caveat that this 10-year time series is too short to really understand long-term behavior, so there still may be future events – tipping points – that could cause large increases in glacier speed to continue,” said Ian Howat, an assistant professor of earth sciences at Ohio State University and a co-author of the paper. “Or perhaps some of the big glaciers in the north of Greenland that haven’t yet exhibited any changes may begin to speed up, which would greatly increase the rate of sea level rise.”

What the researchers didn’t find was any evidence that the rate of flow is slowing down. Though the true extent of the effect of Greenland’s ice on future sea level rise may not be unerringly predictable down to the inch or centimeter, even at the currently observed rate a contribution of 4 or more inches by the end of the century is still very much a possibility.

Meanwhile, the data gathered from the MABEL science flights over the past four weeks will be used to calibrate NASA’s next-generation ice-observing satellite, IceSat-2, planned for launch in 2016. Once in orbit, IceSat-2 will provide even more detailed insight to the complex behavior of our planet’s ice sheets.

Read more on the UW News release here.

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Nexus
Member
May 3, 2012 10:45 PM

Stampede of science deniers in 3… 2…

SteeleMadeline301
Guest
SteeleMadeline301
May 4, 2012 7:58 PM

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Bobr
Member
Bobr
May 4, 2012 3:35 PM

Haven’t the glaciers been receding since the last ice age?

(Hysterical responses in 3…2…)

TheDirtBoy
Guest
TheDirtBoy
May 4, 2012 6:25 PM
Short answer, no. After the last ice age the glaciers did recede for a while but then, more or less, struck a balance. They would grow alittle then shrink alittle over periods of hundreds of years. Over the last hundred years ice caps and glaciers all over the world have been melting. This is the conundrum we find ourselves in, is this normal or man made. As the article states, ten years or even one hundred years isn’t enough time to definitively reach a conclusion. This is where the hysteria comes in, and rightly so. If this melting is normal then no big deal, the only question is when will it turn around again and how much will… Read more »
Bobr
Member
Bobr
May 4, 2012 6:47 PM

By your own admission, you’re fretting and active about something that may be completely natural, thereby possibly tampering and interfering with Mother Nature!

Continents are still rising, rebounding from the weight of glaciers, so* massive* flooding is silly. I’m not qualified to say there would be NO flooding.
Ice fields are receding in some areas, advancing in others.
Your Venusian-Earth scenario is ridiculous and without merit, too.

Your (religious?) sect of “The Gullibles” (as opposed to the deniers) have predicted a doomed planet for the past fifty years plus, but when the predictions don’t come to fruition, the clock gets re-set again…just like Harold Camping continues to do.

TheDirtBoy
Guest
TheDirtBoy
May 5, 2012 2:10 AM
OK, maybe the Venus idea is a bit melodramatic. My point isn’t that we should interfere with natural processes, only to change our own bad habits. If we do change our ways and it all turns out to be normal fluctuations then the worst we’ve done is invest in a cleaner more efficent way of life. If we don’t change and we are the cause of the current warm up, then what? Massive flooding, drought, famine, global economic and political upheaval. You say I’m gullible, I think you should look in a mirrior when you say that. I ask you, who stands to lose the most if fossil fuels were made obsolete, the general public or corporate billionaires,… Read more »
Ray Fowler
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Ray Fowler
May 4, 2012 8:01 PM

You sounded reasonable until you mentioned Venus. You need to get the notion of global warming leading to a Venus scenario completely out of your head.

The Earth has been drastically warmer in the past and supported life. It would take millions of years to reach a Venus scenario, and humans would have long died or corrected the problem well before then.

Super Earth
Member
Super Earth
May 4, 2012 11:07 PM

Last ice age ended 10 000 years ago. Then there was a strong (natural) global warming and extensive meltdown. After that, the melt stopped.

Now, after 10 000 years of relative stability, glaciers have began to melt again.Why?

Perhaps because the humans have raised the concentration of warming greenhouse gases (mainly CO2) to levels not seen in 15 million years?

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