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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dontdistortthescience says:
June 13, 2013 at 5:29 pm
Any why exactly is the water warmer Anthony?”
Perhaps the answer is quite simple. For 30 years (1976-2006), the Pacific Ocean was dominated by El Nino events. The residual ocean currents in turn saw step increases in their surface level temperatures. I would not be surprised if over time scientists discover long term SST oscillation near the Antarctic which controls sea ice development.
dontdistortthescience says:
June 14, 2013 at 7:05 am
Pamela – what would drive such a change if not changing energy levels? Or is there magic at work in that as well?
The answer is simple: ENSO.
I can’t wrap my brain around exactly how on one end of the planet, sea ice levels are decreasing due to warming, but at the other end sea ice levels are increasing due…to……warming???
Would a reduction in extent indicate reduced melting? Has mass reduced?
If correct then it could be worse than we thought.
And of course, the ocean is heated locally by submarine volcanoes – particularly off the Antarctic Peninsula and a belt of volcanism dots the entire western Antarctica where all this “alarming” ice loss has been happening (and spread “statistically” across the eastern Antarctica).
The study isn’t out yet (tomorrow), but according to The Australian newspaper, “warming” oceans are responsible for what the researchers describe as ice shelves that are melting too fast to maintain balance.
http://www.theaustralian.com.au/higher-education/warm-oceans-melting-ice-from-bottom/story-e6frgcjx-1226664021131
Calving is the breaking off of the ice shelf, whether from warm basal surface melt. According to the article that sparked this thread, the researchers think basal melt is 55% responsible for the calving.
Too early to draw conclusions, but it seems that in certain areas around the Antarctic, ice shelf melt is occurring faster from warmer waters (and possibly air temps). Perhaps WUWT will update when the paper comes out.
See, I told you these idjits are a religion. That’s as clear an admission of belief of a static constant unchanging climate as you will get. They believe we were born into a Garden of Eden and humans dared to eat the apple of a non-agrarian lifestyle, tapping the forbidden fruits of fossil fuel and disrupting the natural order given us by their God – Mother Nature.
It never occurs to them that a planet comprised of a molten core surrounded by a viscous mantle with huge continents drifting all around a globe on a tilted axis wobbling its way around a star that serves as primary source of warmth causing chaotic local effects of clouds and precipitation plus infinite other variables, could possibly be driving climate.
No, it was humans, born but a second ago in geological timescale that created our climate, and that is quite a feat indeed. No sir, you EcoNuts are the ones who believe in magic.
So, the Antarctic ice sheet is losing mass, faster and faster, WE’RE DOOMED!
Uh huh.
In 2011, Zwally and Giovinetto published the paper “Overview and assessment of Antarctic Ice-Sheet mass balance estimates: 1992-2009.” Surveys in Geophysics 32: 351-357. These are two NASA scientists. They examined a number of estimates of ice mass balance
for the Antarctic. They stated that their preferred estimate was -31 Gt/year. Less than 3% of the annual mass input, and about 0.2 mm of “sea-level equivalent” per year. Also, some of the surface mass balance estimates were in fact POSITIVE, including from the EU’s ERS satellite (+28 Gt/year). The very high negative values were from GRACE data, which has been demonstrated to have very high errors.
The fact is, we don’t even know if Antarctica is actually losing ice mass at all, 31 gigatonnes
of ice sounds like a lot, per year–but with ice having a density of 917 kilograms/cubic METER,
it amounts to less than 1 cubic kilometer per year! That’s a pretty finicky estimate for an ice sheet that contains 26.5 million cubic km of ice!
while people are diddling with a degree/century and 2.5mm of sea level rise a year, are they aware that over 50 million cubic kilometres of ice from the last ice age melted and warmed up 17C and raised the oceans over~ 120 metres (400 feet)! This took 20 trillion MJ of heat to do it, enough to bring the top 100m of ocean to the boiling point if the climate had no way to dissipate the heat. Finally, we don’t know how this happened but it sure wasn’t a few 100ppmv of CO2. I hope my calcs of heat are correct after my mini-tirade.
Undersea volcanoes?
Antarctic
http://www.scienceandentertainmentexchange.org/blog/new-volcanoes-worry-about
Arctic
http://www.sciencedaily.com/releases/2008/06/080625140649.htm
http://www.canada.com/topics/news/story.html?id=81bb2fd3-63f1-476f-b0be-f48c0dc90304
Do we know when the undersea volcanoes start erupting or when they stop and if it effects sea ice.
I thought warm water caused ice to form because as the planet warms there is more moister and this warm moist air caused more snow to fall. /sarc
{ dontdistortthescience says: }
Can you read?
LOL, Tim Clark (at 2:16PM), good one.
Let’s keep in mind that we aren’t reading the article in Science, we are reading some summary together by someone, presumably at the University, who may or may not fully understand the details.
For example, we know that Antarctica gains ice each winter, and some of it melts each summer. It is an appropriate scientific question to wonder how much of the annual melt is attributable to water, and how much is due to air. One possibility is that the actual article concludes that the proportion is more weighed toward water than previously thought. This is a useful scientific inquiry, and the results may be useful.
I agree that the phrase “speed at which the continent itself is losing mass” leaves the impression that there is a net loss over years, but it may be that this is just a wording accident. Let’s look at the actual article, which is supposed to be available today.
Yes barry, you are taking this site way to literally. The site makes more sense once you realize most of the articles are “funnies” and not to be taken literally.
On ‘Abstract’ page in Nature, 6/13/13, about this study, parag. 8, they say the new data doesn’t imply greater ice loss than previously thought:
Subhead, ‘Wax and Wane,”
“But although these latest data highlight the overall ice-shelf dynamics, they do not necessarily imply that the continent’s cumulative ice loss is greater than previously thought: Nearly half of the ice shelves are thinning, but others are thickening or in a state of equilibrium. Nonetheless, the authors argue, the results do point towards ocean–ice interactions that are not being captured in current computer models.”…
You sound too high to be reasoned with. As usual. You Magic Gas failures are always shocked anyone can be sure of anything – because everything you say gets laughed at until you’re forced to shut your stupidity faucet.
———-
Tim Folkerts says:
June 13, 2013 at 7:54 pm
It is always interesting to see people who are 100% sure of anything in climate science. Especially when pretty everyone else agrees that CO2 has some effect on the global temperatures.
“This is because the “goal” of the atmosphere and oceans (yes, that anthropomorphizes them, but hey) is to…
equilibrate gradients in physical and chemical potentials…that which can never be done until time infinite…so who cares; that is your point? It has all happened before so what?
Ponder your navel never? Plan your garden or grave? Climb a mountain ’cause it is there even though it shall not always be there?
thanks to all u Zen masters?
It is simple physics.
Air is inefficient at melting ice because the thermal gradient is stacked against the process. Warm air that does succeed at melting ice is cooled by the heat of fusion tax (albeit the wimpier phase change). It is not going anywhere. It stays right there to impede further melting.
Water is efficient at melting ice from underneath because the situation is reversed. Warm water cooled by the fusion tax sinks to be replaced by warmer water to continue the process of melting.
Basically the difference between being on top or underneath, amplified by the greater enthalpy of water.
BTW, if you do the math, the enthalpy of fusion from all the melted ice in the last 35 years is orders of magnitude too small to explain the “missing heat”.
So now the Antarctic melt is caused by warm water and the paper gets a big play. About what? That there is melting under the ice but the Antarctic continent is not melting away as we already knew? I proved two years ago that Arctic warming is caused by warm water carried into the Arctic Ocean by currents and these guys know nothing about it. But they are big climate scientists supported by NASA, NSF, and NOAA who undoubtedly paid millions for this research. I did my work on my pension, proved that Arctic warming is not greenhouse warming, and put it into global climate context. It started at the turn of the twentieth century, prior to which there was nothing but two thousand years of slow cooling. It paused in mid-century for thirty years, then resumed, and is still going strong. Its cause is probably a rearrangement of the the North Atlantic current system at the turn of the century that started to carry warm Gulf Stream water into the Arctic Ocean. The mid-century pause was probably due to a temporary return of the former flow pattern. Direct measurement of current temperature in 2009 showed that its temperature exceeded anything seen in the Arctic within the last two thousand years. We are now in the middle of a global warming standstill (or hiatus or whatever you want) but the Arctic is the exception to the rule. It is the only place in the world that is still warming because it is not warmed by carbon dioxide greenhouse effect but by warm ocean currents carrying that Gulf Stream water north. If you want full details get my paper that is available on Climate etc. blog.
Duh ! Are these chumps really claiming that heat energy would much rather flow from the bottom of the ice to the gazillions of gallons of high specific heat, high thermal conductivity, warmer ocean surface waters, that circulated down there from the tropics; (look up “gulf stream” and “Coriolis force”, and “planetary rotation” in Wikipedia), than take the much more effective escape route through the way less dense, very poor thermal conductivity, low specific heat atmospheric gases above the ice ??
Some people will believe almost anything! And what of the rumor, that the whole South Pacific Ocean, and the whole South Atlantic Ocean, collectively AKA , “The Southern Ocean”, slosh back and forth twice a day in that narrow gap between South America, and the misnamed Antarctic Peninsula, which actually isn’t in the Antarctic. With all that tidal water sloshing back and forth on both sides of the near Antarctic Peninsula, some people might think that it would bulge up under those ice shelves, like a tree root bulging up under the non-pre-stressed concrete, sidewalk/footpath/whatever, until the concrete; excuse me ice shelf breaks. There are rumors, that ice, like non-pre-stressed concrete, has near zero tensile strength, so if you bend it, it breaks by cracking open, on the tensioned upper side of the shelf.
Well, I see it’s the University of California; I think they all just voted themselves a big pay raise. Well maybe that will attract a better class of chumps to the University of California
Mixing an unproven computer model with real world data is like mixing a spoonful of excrement with a barrel of aged bordeaux. It may not be adding much of value but it taints the whole thing.
Several months ago, the University of Kentucky hosted of forum on climate change with three excellent speakers who were all self-described conservatives. Liberals reported how they better understand that there are thoughtful conservative perspectives on, and solutions to, climate change, thus allowing for a broadened public discussion. In turn, conservatives in attendance learned the same thing. You can watch the recording of this event at http://bit.ly/135gvNa. The starting time for each speaker is noted at this page, so you can listen to the speakers of greatest interest to you.