From the University of California – Irvine something that pretty well makes Steig et al 2009 even more irrelevant, since in that paper they did a survey of air temperatures and then smeared them around the continent using some Mannian style math, which was later shown to be faulty by O’Donnell et al.
UC Irvine found that ocean currents cause most of the observed melt, so air temperature really isn’t much of an issue.
Warm ocean drives most Antarctic ice shelf loss, UC Irvine and others show
Findings are a game changer for future forecasts about thawing continent
Irvine, Calif. – Ocean waters melting the undersides of Antarctic ice shelves, not icebergs calving into the sea, are responsible for most of the continent’s ice loss, a study by UC Irvine and others has found.
The first comprehensive survey of all Antarctic ice shelves discovered that basal melt, or ice dissolving from underneath, accounted for 55 percent of shelf loss from 2003 to 2008 – a rate much higher than previously thought. Ice shelves, floating extensions of glaciers, fringe 75 percent of the vast, frozen continent.
The findings, to be published in the June 14 issue of Science, will help scientists improve projections of how Antarctica, which holds about 60 percent of the planet’s freshwater locked in its massive ice sheet, will respond to a warming ocean and contribute to sea level rise.
It turns out that the tug of seawaters just above the freezing point matters more than the breaking off of bergs.
“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,” said lead author Eric Rignot, a UC Irvine professor who’s also a researcher with NASA’s Jet Propulsion Laboratory in Pasadena. “This has profound implications for our understanding of interactions between Antarctica and climate change. It basically puts the Southern Ocean up front as the most significant control on the evolution of the polar ice sheet.”
Ice shelves grow through a combination of land ice flowing to the sea and snow falling on their surfaces. The researchers combined a regional snow accumulation model and a new map of Antarctica’s bedrock with ice shelf thickness, elevation and velocity data captured by Operation IceBridge – an ongoing NASA aerial survey of Greenland and the South Pole. (Rignot will host a planning session of Operation IceBridge scientists at UC Irvine on June 17 and 18.)
Ocean melting is distributed unevenly around the continent. The three giant ice shelves of Ross, Filchner and Ronne, which make up two-thirds of Antarctica’s ice shelves, accounted for only 15 percent. Meanwhile, less than a dozen small ice shelves floating on relatively warm waters produced half the total meltwater during the same period.
The researchers also compared the rates at which the ice shelves are shedding ice with the speed at which the continent itself is losing mass and found that, on average, the shelves lost mass twice as fast as the Antarctic ice sheet did.
“Ice shelf melt can be compensated by ice flow from the continent,” Rignot said. “But in a number of places around Antarctica, they are melting too fast, and as a consequence, glaciers and the entire continent are changing.”
Other authors are Jeremie Mouginot and Bernd Scheuchl of UC Irvine and Stanley Jacobs of Columbia University. Funding was provided by NASA, the National Science Foundation, and the National Oceanic & Atmospheric Administration.
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Melting due to warmer water does explain why the Antarctic sea ice level is significantly below the 30 year average.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png
Oh…… wait !!!!
“As we speak there is a big chunk of Antarctica where the 2m temperature is minus 55 C…and the temperature at 10,000m is minus 60 C, now that’s what I CALL and adiabatic lapse rate!”
You need to see the whole temperature gradient. not just 2 points.
The various alarmists asking innocently here what makes the waters warm, implying that it can only be their beloved CO2, should take notice of their hero Kevin Trenberth who openly admits that he doesn’t know why.
“Sensitivity experiments illustrate that surface wind variability is largely responsible for the changing ocean heat vertical distribution.”
http://onlinelibrary.wiley.com/doi/10.1002/grl.50382/abstract
In the paper he admits that he doesn’t have the faintest clue about how THE WIND transports heat into the depths of the oceans.
We can therefore say that Trenberth does not have a theory, he has conjecture; because for a theory, a physical mechanism must exist. Trenberth does not propose one.
To the various alarmists again: CO2 LWIR does not penetrate water beyond the skin layer.
ps, I suspect the tropopause is currently quite low in these areas, lower than the usual 7-8km over the Antarctic.
Where to find the data?
What causes wind variability?
Whatever the water temps are / have been, the Antarctic Sea Ice anomoly is positive and the trend is up?
But I was also told that Antarctic sea ice expansion is due to melt? Was THIS an April Fools Joke???
It seems it was not an April Fools joke after all.
More models for ya. Why can’t they go there and measure, observe, etc.?
Yet just in November 2012 the Guardian was touting another reason for Antarctic sea ice expansion from peer review. Wind. This really is becoming climate voodoo.
Shouldn’t the Guardian have said theorize and not solve?
To make ice (at atmospheric temperatures), you have to be below the freezing point of water.
Warming does not cause this to happen.
Just before being called out as a fake, dontdistortthescience wrote:
Which is, of course, a typically logic-challenged warmist response.
Almost every day the wind blows from a different direction. However, for the most part we get our weather from the west. This year, there have been far more weather systems rolling in from the east, which – although unusual – is not “change”. A quick look at the satellite animations shows the spiraling systems that are doing this, and it’s not a big deal. Overall the air is flowing west to east.
The biggest logic-fault of the science distorter is his apparent belief that because something is different than “usual”, it must therefore be a change. And, just like reduced Arctic sea ice, although the numbers might be different from “usual”, it is not a change. And basing the baseline from a point when we KNOW there was unusual coolness is still a ridiculous way to run a “science” endeavor. If the goal was to document actual sea ice extent, each and every year from first accurate records, up to and including last year would be part of the “average”. Then, after waiting for a full climate cycle (not 30, but 60 or so years), a meaningful sea ice extent “average” could be determined. Until that happens there is absolutely NO reason to worry in any way about sea ice extents, either Arctic or Antarctic.
Weather and the ocean are in a constant state of change around this planet, especially as you get farther from the equator. This is because the “goal” of the atmosphere and oceans (yes, that anthropomorphizes them, but hey) is to move heat from where the sun always hits to where the sun rarely hits. The reason we have ocean currents and jet streams and tornadoes and every other form of moving gases and fluids is to get heat energy to where it is most effectively removed from the planet. This is why, even if CO2 caused increase heat to be trapped in the atmosphere, it would make no difference.
By the way – letting the warmists define “climate” as a 30 year period is still an absolute travesty and needs to be strongly contested.
How old are these ice shelves? It seems Larsen B is around (stable) for 12,000 yrs old and Larsen A only around in the last 4,000 yrs.
UAH land and ocean data for 60S-85S shows this region has been getting COLDER over the past 34 years, land and ocean both. What warming?
Peter Foster says:
June 14, 2013 at 1:08 am
“It is virtually impossible to measure snowfall in Antarctica for several reasons. Firstly a blizzard is not falling snow it is blown snow. I have observed gales on the polar plateau where the blown snow was over 1000 m high with no cloud and blue sky above. The snow gauge in the Wright Valley measured 5mm water equivalent for the 12 months from Dec 1884 to Dec 1985 but was this snow blown off the Plateau or actual fallen snow ?”
It seems the Wright Valley is used as a comparison for the whole of Antarctica. This is a desert and surely can’t be used to describe the whole of Antarctica, otherwise we could describe South America as a desert because the Atacama desert is there?
No, because they said it went deep, deep undercover. Anyway, Antarctica sea ice is expanding!
Jimbo – are coverage and total mass the same? And is the ice expanding on both land and sea?
Interesting comments on the increase in humidity when the ice melts. Logical. Clear ice however does not, I think, allow IR to pass from warm water below to the sky above. Visibly transparent ice is black to infra-red.
The warmists like to tell you the Arctic is warming up, but the current temp is below the 40 year average for this time of year. !!
http://ocean.dmi.dk/arctic/plots/meanTarchive/meanT_2013.png
The warmists totally ignore real data, and reality.
A bunch of fraudsters !!!
The question shouldn’t be where did the warm water come from. It is warmer than the ice, or it would be ice. This is glacial ice extending out into an ocean as has been going on for millions of years. Does the AGW theory hold that the entire Antarctic Ocean should be frozen? This study just found out what every geologist has known since their first year in college. The real question should be – is what is being observed outside natural variability and well understood physical processes?
I think this study is just saying that when ice leaves/melts on Antarctica, more that was believed before comes from melt on the bottom side of floating ice-shelves rather than iceberg calving.
Large depiction here.
http://www.nasa.gov/images/content/755402main_earth20130613b-full.jpg
It doesn’t say anything about how much ice is accumulating/forming.
A new recent study, which consolidated all the recent estimates using the newest glacial isostatic adjustment algorithms, reduced the ice mass losses on Antarctica by about half. Mass loss was estimated to be between 200 GT/yr (loss) to 100 GT/yr (gain). [ignore the Greenland estimates here, they have not been updated yet].
http://www.nature.com/nature/journal/v498/n7452/images_article/nature12238-f1.2.jpg
http://www.nature.com/nature/journal/v498/n7452/abs/nature12238.html
Two observations: 1) This may also fit in the category of placing heat and melting in places where no one can effectively verify anything, and 2) If they resort to data smearing in the atmospheric temps across a frozen continent, then undershelf observations and data reliability are even worse. Think of the data system first before considering the conclusions.
Are they saying the water is any warmer? Or are they merely saying more melting occurs on the underside of ice shelves “than they previously thought.”
Am I missing something here? I don’t see any mention of “warmer” water. Just that the melting ice is due to warm water, warm being defined as “just above the freezing point.” It seems this paper is merely discussing the natural processes by which the Antarctic loses ice, and concludes that undercutting by warm water, not warming water, is the primary process with calving being a distant second place.
Jimbo says:
June 14, 2013 at 2:23 am
BBC 1 April 2013
Melt may explain Antarctica’s sea ice expansion
Works for me – just as well as “global warming causes cooling” does.
🙂
Has anyone considered the theory that warmed water welling up at the poles is the way things are supposed to happen? Think periodically equatorally recharged and then poleward overturning ocean. If this great conveyor belt ever stops what it does: melting polar ice (IE the belt stops, and equatorial warmed water never rises at the poles to melt ice), the quiet sleeping ocean sends cold dense water to the bottom and warm water to the top to escape Earth. Eventual result: Frozen ball.
Back in the old days of the “sky is falling” AGColding, idiots said that CO2 will stop the conveyor belt and send us into a frozen ball state. Now that the idiots realize the conveyor belt is still working, they are saying that the conveyor belt is still working and we will all fry.
The chameleon of AGW continues to entertain.
Pamela – what would drive such a change if not changing energy levels? Or is there magic at work in that as well?
Anyone notice how the MSM reported this? The MSM reports were attrocious in their distortion of these facts. They made it seem like the continential ice was melting from the bottom up when in fact this report addressed shelf ice in a small portion of the Antarctic margin.