No Record Low Sea Ice Extent this Season

In all likelyhood, there will not be a new record low Arctic sea ice extent at the end of this melt season. It also looks like the 2009 minimum will even be higher than last year's minimum, but not by much. Check out the latest chart below, courtesy of the national Snow and Ice Data Center.

According to the NSIDC, the decrease in sea ice in the Arctic Basin slowed significantly during the first two weeks of August due to natural changes in the atmospheric circulation pattern over the Arctic.

Early in the summer, the circulation pattern promoted winds that helped push ice out of the Siberian coastal seas, and also brought clear skies and warm temperatures that helped induce melt.

By late July the pattern started to change and led to winds that redirected the motion of the ice cover, pushing the ice edge outward toward the Siberian coast and discouraging ice from exiting the Arctic Ocean through Fram Strait.

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One question I hear from time to time..........

Why don’t we hear much about Antarctic sea ice?

Thanks to the NSIDC, here is the answer............

NSIDC scientists do monitor sea ice in the Antarctic, and sea ice in the Antarctic is of interest to scientists worldwide. While many have published peer-reviewed journal articles on the topic, it has received less attention than the Arctic. There are several reasons for this.

Unlike Arctic sea ice, Antarctic sea ice disappears almost completely during the summer, and has since scientists have studied it. Earth’s climate system over thousands of years has been "in tune" with this annual summertime disappearance of Antarctic sea ice. However, satellite records and pre-satellite records indicate that the Arctic has not been free of summertime sea ice for at least 5,500 years and possibly for 125,000 years. So Earth’s climate system and ecosystems, as they exist today, did not develop in conjunction with an ice-free Arctic. Such an ice-free Arctic summer environment would be a change unprecedented in modern human history and could have ramifications for climate around the world.

Lab experiment regarding CO2 “snow” in Antarctica at -113°F (-80.5°C) – not possible

Frozen CO2 at the poles of Mars - but not possible on Earth

A couple of days ago WUWT carried a story, talking about intense cold in Antarctica, carbon dioxide, and the icecap of Mars. This one passage stirred up a significant debate:

According to Weather Underground, Vostok, Antarctica is forecast to reach -113F on Friday. That is four degrees below the freezing point of CO2 and would cause dry (CO2) ice to freeze directly out of the air.

It seemed (at the time) a reasonable statement. The freezing point of CO2 is -109.3 degrees Fahrenheit (-78.5 degrees C). There’s been mentions of this supposed phenomenon of CO2 freezing out of the air before on other blogs and websites. One of the best examples was even an entry in the website “ask a scientist” where the question of CO2 freezing out of the air was posed, and the answer from an Argonne National Laboratory scientist seemed to indicate that CO2 could indeed precipitate as a solid from the air if the temperature was low enough at Earth’s South Pole, specifically Vostok Station, which holds the record for the lowest temperature recorded on Earth at −89.2°C (−128.6°F)

Certainly, at least some of the carbon dioxide in the atmosphere at the poles does freeze out during the winter. However, there is not enough frozen out to accumulate to any extent at the present.

David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory

So, it seemed possible. But as WUWT commenters soon pointed out, temperature is only part of the equation needed to deposit CO2 as a solid from the free atmosphere at that temperature.

Soon we were discussing gas laws, phase diagrams, and partial pressures. The debate mainly centered on whether or not this phase diagram for carbon dioxide applied to 1 atmosphere of pressure of pure CO2 versus simply 1 atmosphere of pressure independent of the purity of the gas.

The author of the post, Steven Goddard wrote:

The phase diagram shows unambiguously that the equilibrium state of CO2 at one atmosphere at 113F is solid. The freezing point of CO2 is -109F at 1 atmosphere.
http://www.chemicalogic.com/download/co2_phase_diagram.pdf

The PDF referenced doesn’t translate well to the blog size format, but this less detailed phase diagram for CO2 does fit and was mentioned in comments also:

Since many of us know from experience that with ice, be it water ice or CO2 (dry) ice, that a phase change can occur directly from solid to gas (sublimation). It seemed reasonable to conclude that the reverse could be possible, going from a gas to a solid as long as the temperature was below the “triple point” of CO2 as well as the freezing point at 1ATM.

The freezing point/sublimation point of CO2 at 1ATM is at -78.5C (-109.3F). In the situation described in the forecast for Vostok station, the temperature was forecast to reach below the freezing point for CO2 at -80.5 C (-113F ). It seemed reasonable then to concludes that CO2 would freeze right out of the air, much like frost does from water vapor. Plus we had a statement from a scientist at a National Laboratory saying it was possible also. What’s not to like?

One small detail: partial pressure.

The concentration of CO2 in the free atmosphere is very small. Thus the partial pressure of CO2 in the atmosphere is about 0.0004 atmospheres. But wait there’s more. Vostok station is at a high elevation, 3288 meters above sea level (10,787 feet) and the atmosphere is thinner. Thus the partial pressure of CO2 is even lower.

Commenter George E. Smith summed it up pretty well with this paragraph:

At -78.5 deg C (-109F), that equilibrium occurs at a partial pressure of CO2 of 760 mm Hg, one atmosphere. Below that pressure, there isn’t enough abundance of CO2 molecules in the vapor phase for collisions with the solid surface to occur at a fast enough rate to make up for the ones that escaped; so the solid CO2; dry ice, will continue to sublimate.

Basically, there are so few CO2 molecules in the free atmosphere, sublimation rules over deposition as a solid. Yes some CO2 may deposit on a surface at at -80.5 C (-113F ), but it would quickly sublimate back into the free atmosphere, and thus accumulation would not occur.

Meanwhile WUWT reader Ric Werme had written to Dr. David Cook of Argonne National Lab to ask about his original opinion he wrote for “ask a scientist” web site. Ric reports he responded with this:

Ric,

You are correct. In my attempts at being simplistic I made a mistake in my answer to “Freezing CO2″ on the Ask-A-Scientist page. -57 C is the boiling point of CO2. The freezing point of CO2 at atmospheric pressure is -78.5 C (-109.3 F). If the temperature reaches -113 F at Vostok, Antarctica, some carbon dioxide might freeze out of the air, assuming that the carbon dioxide vapor pressure drops to its saturation vapor pressure.

The vapor pressure must reach the saturation vapor pressure for dew or frost to form. This happens at the dew point or frost point temperature, which is dependent on atmospheric pressure and the absolute amount of vapor in the air. As atmospheric temperature increases, the dew/frost point temperature increases. As atmospheric pressure increases, the vapor pressure increases. At very low temperatures, the dew/frost point temperature is very low.

When the temperature of the surface (whether grass or a car window) is below freezing, frost will usually form instead of dew, although water can be super-cooled and not produce dew, fog, or clouds in some cases. Surfaces on the Earth cool off sooner than the air, so dew/frost will normally form on them before fog (water or ice) forms in the air.

The temperature being at “freezing” or below does not imply that frost will form on surfaces or in the air. The vapor pressure must be high enough (saturation vapor pressure) and the temperature low enough (the frost point temperature) for frost to form.

So it seems, Dr. Cook (and our own Steve Goddard) made the basic and simple error of not taking vapor pressure into account. Given our human experience with the everyday freezing of water, we don’t often think about it. I didn’t catch it either initially, nor did some WUWT commenters.

It does demonstrate though, how little CO2 there is in our atmosphere, we can’t even precipitate it to solid under any natural condition of earth.

But, even with the debate apparently settled, the CO2 freezing question was still all in the realm of opinions and phase diagrams. Some people really wanted to see some empirical proof. Some thoughts on experiments were tossed about.

Enter WUWT reader Dr. Thomas Thatcher of the University of Rochester who had not only an idea for an experiment, but the means with which to carry it out. He had a lab freezer which would “maintains -80˚C (-112˚F) in my lab, and it can be set as low as -86˚C (-122˚F).”.

He proposed that he could use that freezer to do a test with dry ice:

The argument, as far as I can tell, is that at the atmospheric partial pressure of CO2, dry ice at -113F will sublimate faster than it forms (which may be different than how a pure CO2 atmosphere would behave). I am in a position to test this, as described above.

…

Based on the arguments presented here, the two postulated outcomes are,
1) significant loss of mass, as the sublimation rate exceeds the deposition rate
2) no change, or negligible gain in mass.

(I suspect that any gain in mass will evaporate on the short walk from the freezer to the balance.)

It’s admittedly an imperfect experiment. But I expect the outcome will be rather obvious; the dry ice will be gone in the morning. We’ll see.

He conducted his experiment overnight between Thursday and Friday, and writes:

The freezer is a VWR brand ultralow temperature upright freezer, similar to models shown here.
http://www.vwrsp.com/catalog/product/index.cgi?catalog_number=14230-120&inE=1&highlight=14230-120

It is set to -86C, the temperature typically rises 1-3C when opened, and recovers in about 30 minutes. (Factory temperature calibration was NIST-traceable but it has not been recalibrated since it was installed here.) The samples were loaded at 4:30 pm and removed at 9:30 am, so the freezer will have been largely undisturbed during that time.

The interior is mostly filled with stainless steel racks that hold cardboard boxes for storing biological samples. I placed the test samples in two boxes on the bottom shelf at the rear of the freezer, the coldest zone and closest to the temperature probe.

One sample was placed in an open box with extra holes cut to allow air circulation. The other sample was placed in small zip top plastic bag inside a cardboard box. The samples were weighed by difference before being placed in the freezer and after removal in the morning. Additional weighings were taken to estimate the amount of sublimation during the weighing procedure and the amount of water that might condense on the boxes, but these amounts proved insignificant next to the overall results.

The samples were placed in the freezer at 4:30pm (reading -82C) and removed at 10:00am (reading -83C).

Open container, start weight 36.5g dry ice, end weight 0g, amount sublimated 100%.
Zip-top bag, start weight 27.6g dry ice, end weight 25.3g, amount sublimated 8.3%

Proving, I think, that CO2 will freeze and remain frozen at below -78.5C if the partial pressure of CO2 is near 1 ATM, but the CO2 will rapidly sublimate is the partial pressure of CO2 is near atmospheric normal.

And he concludes:

Bottom line, 40g of dry ice placed in an open container at -82C completely sublimated overnight, while 27g of dry ice placed in a zip top bag retained 90% of its mass. This proves two things, first, that the temperature of the freezer did not exceed -78.5C for any appreciable period of time, and second that yes indeed, the partial pressure of CO2 is the key to the problem.

Best of all, he sent photos of the experiment he conducted:

Interior of the freezer showing sample box racks

The placement of the two sample boxes for the CO2 sublimation experiment

The two sample boxes with dry ice of equal weights, enclosed on the left, open on the right, just before they were placed into the freezer for the night.

The sample boxes immediately after removal the next morning.

With the plastic bag removed, showing the leftmost sample still about 90% intact.

Thanks to everyone who participated in the debate, including Ric Werme for his correspondence help and especially Tom Thatcher for conducting the experiment and taking photos.

We all learned something, we had a little fun, some online yelling occurred, and some egos were bruised. Overall though it was worthwhile that this myth of “CO2 snow at Vostok station” was finally put to rest.

Natural Carbon Sequestration In Antarctica – A Litmus Test For Global Warming?

How cold is it in Antarctica? According to Weather Underground, Vostok, Antarctica is forecast to reach -113F on Friday. That is four degrees below the freezing point of CO2 and would cause dry (CO2) ice to freeze directly out of the air.

A small child being subjected to massive amounts of EPA listed toxin – CO2

The south pole of Mars (seen below) similarly has an eight metre thick layer of dry (CO2) ice on top of the H2O ice.

Mars Southern Ice Cap

The Mars dry ice cap has been shrinking however, due to global warming on that planet. As explained in National Geographic in 2007.

Mars, too, appears to be enjoying more mild and balmy temperatures. In 2005 data from NASA’s Mars Global Surveyor and Odyssey missions revealed that the carbon dioxide “ice caps” near Mars’s south pole had been diminishing for three summers in a row. Habibullo Abdussamatov, head of space research at St. Petersburg’s Pulkovo Astronomical Observatory in Russia, says the Mars data is evidence that the current global warming on Earth is being caused by changes in the sun. ”The long-term increase in solar irradiance is heating both Earth and Mars,” he said.

If Dr. Abdussamatov is correct, the Mars ice caps should now be growing, due to the solar minimum. Does anyone have any information about this? A cooler earth coincident with a cooler Mars coincident with solar minimum would be difficult to argue with. Note that the diminishing Mars ice occurred at the same time as diminishing Arctic ice below.

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.jpg

Perhaps the IPCC should have their next polar melting discussion at Vostok in -113F weather? That would seem more fitting than Bali or Honolulu.

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Global warming linked to gravity

[insert your own caption here]

Vacouver Sun/Reuters January 13, 2009

ANTARCTICA — Sea levels will rise at varying rates around the world because of a quirk of the earth’s gravity linked to global warming, a leading glaciologist said.

“Everyone thinks sea level rises the same around the world,” David Vaughan, of the British Antarctic Survey, said on Tuesday at the Rothera Base on the Antarctic Peninsula. “But it doesn’t”.

Rises could vary by tens of centimetres from region to region if seas gained by an average of one metre by 2100 as temperatures rise, he said. Worst-affected nations would have to budget billions of dollars more than others on coastal defences.

Vaughan said big ice sheets on Antarctica and on Greenland have a gravitational pull that lifts the seas around them — water levels around Antarctica, for instance, are higher than if the frozen continent were an open ocean.

As ice thaws, Antarctica would get smaller and its gravitational tug would diminish.

Going Cold on Antartic Warming

Professor Eric Steig last month announced in Nature that he'd spotted a warming trend in West Antarctica that previous researchers had missed through slackness -- a warming so strong that it more than made up for the cooling in East Antarctica. The implication was that we finally had proof that Antarctica as a whole was warming, and not cooling. In other words, global warming really is global now, explains the Melbourne Herald Sun.

The paper was immediately greeted with suspicion, not least because one of the authors was Michael Mann of the infamous "hockey stick," now discredited, and the data was reconstructed from very sketchy weather station records, combined with assumptions from satellite observations. But Steve McIntyre, who did most to expose Mann's "hockey stick," now notices a far more embarrassing problem with Steig's paper:

• Previous researchers hadn't overlooked the data, what they'd done was to ignore data from four West Antarctic automatic weather stations in particular that didn't meet their quality control.
• One showed no warming, a second showed insignificant warming and a fourth -- from a station dubbed "Harry," shows a sharp jump in temperature that helped Steig and his team discover their warming Antarctic.

Harry in fact is a problematic site that was buried in snow for years and then re-sited in 2005. But, worse, the data that Steig used in his modeling, which he claimed came from Harry was actually old data from another station on the Ross Ice Shelf known as Gill with new data from Harry added to it, producing the abrupt warming. The data is worthless. According to McIntyre:

• Considered by itself, Gill has a slightly negative trend from 1987 to 2002.
• The big trend in "New Harry" arises entirely from the impact of splicing the two data sets together.

It's a mess. So why wasn't this error picked up earlier? Perhaps because the researchers got the results they'd hoped for, and no alarm bell went off that made them check, says the Herald Sun.

Source: Andrew Bolt, "Going cold on Antarctic warming," Melbourne Herald Sun.

Antarctic sea creatures hypersensitive to warming

ROTHERA BASE, Antarctica (Reuters) - Thriving only in near-freezing waters, creatures such as Antarctic sea spiders, limpets or sea urchins may be among the most vulnerable on the planet to global warming, as the Southern Ocean heats up.

British marine biologist Simon Morley holds up an Antarctic marine woodlouse -- related to far smaller woodlice found on land -- in an aquarium at the British Rothera research station in Antarctica, January 20, 2009. (REUTERS/Alister Doyle)

Isolated for millions of years by the chill currents, exotic animals on the seabed around Antarctica -- including giant marine woodlice and sea lemons, a sort of bright yellow slug -- are among the least studied in the world.

Now scientists on the Antarctic Peninsula are finding worrying signs that they can only tolerate a very narrow temperature band -- and the waters have already warmed by about 1 Celsius (1.6 Fahrenheit) in the past 50 years.

"Because this is one of the most rapidly warming areas on the planet and because the animals are so temperature sensitive...this marine ecosystem is at higher risk than almost anywhere else on the planet," said Simon Morley, a marine biologist at the British Antarctic Survey at Rothera.

"A temperature rise of only 2-3 degrees (Celsius) above current temperatures could cause these animals to lose vital functions," he said.

In warmer waters, laboratory studies show that clams and limpets lose the ability to right themselves if they land upside down. Such a skill is vital in Antarctica's shallows, where icebergs regularly scrape across rocks on the seabed.

"Will they be here in 100 years' time?" Morley said, standing by blue tanks of sea cucumbers, worms and others. "I think that we will see changes in the ecosystems, more in some species and less in other species.

"It does look as if these mechanisms are truly applicable worldwide," he said.

Studies of clams in Singapore also show that they find it hard to burrow if temperatures rise, he said. Coral reefs can also suffer damage if temperatures rise even slightly.

The U.N. Climate Panel has a best estimate that air temperatures may rise by between 1.8 and 4.0 Celsius this century, due to a build-up of greenhouse gases.

Rothera's waters range from about minus 2 Celsius in winter, kept from freezing by saltiness, to 1 Celsius in summer.

DIVERS, ICEBERGS, INVADERS

On a recent trip into Rothera's bay, Ali Massey and Terri Souster, dressed in thick black dive-suits, disappeared into the water from a red inflatable speedboat and re-emerged 20 minutes later with a haul of the little-understood creatures.

"It is a fascinating place to dive," said Souster, a 24-year-old South African.

The inshore habitat is largely separate from the open ocean, where penguins and whales feed on krill that in turn consume algae. Big predators in the shallows are starfish and fish such as Antarctic cod.

In Antarctica, another linked threat is from icebergs that now scour each part of the shallow seabed on average once a year -- smashing many of the creatures.

Divers off Rothera are extending a 5-year study of iceberg scours by placing small white concrete blocks on the seabed. They are later retrieved to see how many are cracked by icebergs.

And iceberg poundings could become more frequent since warming could bring a decline in sea ice. Winter sea ice locks icebergs into position -- when it melts they can get moved around by winds and tides and swept into the shallows.

Another worry is that non-native species will arrive off Antarctica if the oceans warm, perhaps organisms floating on a piece of plastic or stuck on the hull of a ship. Invasive species, usually transported by humans, can oust local species.

"It's something we are really concerned about," Morley said, noting that at current rates of warming the danger was about 50 years away.

-- For Reuters latest environment blogs click on http://blogs.reuters.com/environment/

Antarctica warming? An evolution of viewpoint

Above: Mt Erebus, Antarctica,picture by Sean Brocklesby

A press release today by the University of Washington makes a claim that Antarctica is warming and has been for the last 50 years:

“The study found that warming in West Antarctica exceeded one-tenth of a degree Celsius per decade for the last 50 years and more than offset the cooling in East Antarctica.”
…
“The researchers devised a statistical technique that uses data from satellites and from Antarctic weather stations to make a new estimate of temperature trends.”
…
“People were calculating with their heads instead of actually doing the math,” Steig said. “What we did is interpolate carefully instead of just using the back of an envelope. While other interpolations had been done previously, no one had really taken advantage of the satellite data, which provide crucial information about spatial patterns of temperature change.”

Satellites calculate the surface temperature by measuring the intensity of infrared light radiated by the snowpack, and they have the advantage of covering the entire continent. However, they have only been in operation for 25 years. On the other hand, a number of Antarctic weather stations have been in place since 1957, the International Geophysical Year, but virtually all of them are within a short distance of the coast and so provide no direct information about conditions in the continent’s interior.

The scientists found temperature measurements from weather stations corresponded closely with satellite data for overlapping time periods. That allowed them to use the satellite data as a guide to deduce temperatures in areas of the continent without weather stations.

…
Co-authors of the paper are David Schneider of the National Center for Atmospheric Research in Boulder, Colo., a former student of Steig’s; Scott Rutherford of Roger Williams University in Bristol, R.I.; Michael Mann of Pennsylvania State University; Josefino Comiso of NASA’s Goddard Space Flight Center in Greenbelt, Md.; and Drew Shindell of NASA’s Goddard Institute for Space Studies in New York City. The work was supported by grants from the National Science Foundation.

Anytime Michael Mann gets involved in a paper and something is “deduced” it makes me wary of the veracity of the methodology. Why? Mann can’t even correct simple faults like latitude-longitude errors in data used in previous papers he’s written.

But that’s not the focus of the moment. In that press release they cite NASA satellite imagery. Let’s take a look at how the imagery has changed in 5 years.

NASA’s viewpoint - 2004

Click for larger image

NASA’s viewpoint - 2009

Click for larger image

Earth’s viewpoint - map of Antarctic volcanoes

Click for larger image

From the UW paper again:

“West Antarctica is a very different place than East Antarctica, and there is a physical barrier, the Transantarctic Mountains, that separates the two,” said Steig, lead author of a paper documenting the warming published in the Jan. 22 edition of Nature.

But no, it just couldn’t possibly have anything at all to do with the fact that the entire western side of the Antarctic continent and peninsula is dotted with volcanoes. Recent discovery of new volcanic activity isn’t mentioned in the paper at all.

From January 2008, the first evidence of a volcanic eruption from beneath Antarctica’s ice sheet has been discovered by members of the British Antarctic Survey.

The volcano on the West Antarctic Ice Sheet began erupting some 2,000 years ago and remains active to this day. Using airborne ice-sounding radar, scientists discovered a layer of ash produced by a ’subglacial’ volcano. It extends across an area larger than Wales. The volcano is located beneath the West Antarctic ice sheet in the Hudson Mountains at latitude 74.6°South, longitude 97°West.

Thanks to wattsupwiththat

Antarctica as a Whole is Indeed Warming

Recent discussion that Antarctica was actually cooling and defying overall global warming trend might have to be put on hold...............

Antarctica.

A new study indicates that Antarctica as a whole is warming, and has been doing so for the past 50 years.

"Antarctica is warming, and it's warming at the same rate as the rest of the planet," said study co-author Michael Mann of Penn State University. Mann is also well know for his famous, but controversial "hockey stick", which is a plot of the global temperature anomaly over the past 1000 years.

Comparing weather station and satellite data, the research team developed a statistical technique to make a new estimate of Antarctica temperature trends.

Research does indeed show that the East Antarctic Ice Sheet has been getting colder, which is mainly due to ozone depletion.

The results of their work also showed that in addition to the Antarctic Peninsula warming, the interior of West Antarctica was warming as well.

How did the authors come to the overall conclusion?

The study, funded by the National Science Foundation, found that warming in West Antarctica exceeded about 0.18 degree Fahrenheit (0.1 degree Celsius) per decade for the last 50 years -- more than enough to offset the cooling in East Antarctica, according to the LiveScience article.

"Efforts to repair the ozone layer eventually will begin taking effect and the hole could be eliminated by the middle of this century. If that happens, all of Antarctica could begin warming on a par with the rest of the world," said Eric Steig of the University of Washington and lead author of the study.

----------------------

The author(s) of the study have already noted some misleading interpretations of their work in the media and blogosphere and respond with a post on RealClimate.org.

thanks to global-warming.accuweather

Scientists say Global warming hitting all of Antarctica

AFP/File – An enormous iceberg (R) breaks off the Knox Coast in the Australian Antarctic Territory in 2008. Scientists …

PARIS (AFP) – Scientists on Wednesday unveiled evidence to suggest global warming is affecting all of Antarctica, home to the world's mightiest store of ice.

The average temperature across the White Continent has been rising for the last half century and the finger of blame points at the greenhouse effect, they said.

The research, published in the British journal Nature, takes a fresh look at one of the great unknowns -- and dreads -- in climate science.

Any significant thaw of Antarctica could drown many coastal cities and delta regions. Bigger than Australia, Antarctica holds enough ice to raise global sea levels by 57 metres (185 feet).

Previous monitoring has already pinpointed the Antarctic Peninsula -- the tongue that juts 800 kilometres (500 miles) towards South America -- as a "hotspot" where hundreds of glaciers have been in retreat since the start of the decade.

But until now the news has been reassuring regarding Antarctica's two massive icesheets.

Indeed, a common belief is that the icy slabs have even cooled slightly and possibly thickened, partly in response to the chilling seasonal effects of the ozone hole over the South Pole.

Not so, the new study says.

It calculates that West Antarctica has been warming by 0.17 degrees Celsius (0.3 degrees Fahrenheit) per decade over the past 50 years.

This is even more than the Peninsula, where the average rise is estimated as 0.11 C (0.2 F) per decade.

There has indeed been some cooling in East Antarctica, but this was mainly in the autumn, and occurred as a result of the ozone hole. There was also a period of strong cooling between 1970 and 2000.

But, overall and when calculated over 50 years, East Antarctica has warmed too -- by an average of 0.1 C (0.18 F) per decade, a figure that the authors describe as "significant".

"The sense of 'Oh, it's cooling in East Antarctica,' is based essentially on the 1970-2000 period, and it's warmed since then -- although we don't have a lot of data for the most recent period -- and it definitely warmed prior to the 1970s," Eric Steig, a professor of Earth and space sciences at the University of Washington, told AFP.

"When you look at the big picture on that, the average [trend in East Antarctica] is actually warming."

Put together, the average temperature rise for Antarctica is put at 0.12 C (0.22 F) per decade, the study said.

The work is based on a 25-year archive of observations by satellites measuring the intensity of infrared light radiated by the snow pack. These were buttressed by data from automated weather stations deployed around the Antarctic coast since 1957.

The paper does not venture any estimate about ice loss or predict the icesheets' stability, but says only global warming can logically explain the temperature trend.

"This shouldn't cause anyone to worry more than they did before. But what it does do is kill off the rather silly and careless statements out there from some people to the effect that Antarctica's cooling," said Steig.

Such comments "put into question all the other science that supports the idea that there is warming and it's human beings' fault," he said.

There could be bad news a few decades down the road, when efforts to fix the ozone hole bear fruit, added Steig.

"The hole could be eliminated by the middle of this century. If that happens, all of Antarctica could begin warming on a par with the rest of the world," he warned.

The West Antarctic icesheet, which holds enough ice to boost global sea levels by up to six metres (19.5 feet), lies at an average height of about 1,800 metres (6,000 feet).

The East Antarctic icesheet, divided from West Antarctica by a mountain chain, has an average elevation of around 3,000 metres (10,000 feet), which makes it not only bigger but also colder.

If it melted in its entirety -- something that most scientists discount except only as a very distant doomsday scenario -- today's coastlines would be drowned to a height of 50 metres (165 feet).