Why Antarctic sea ice cover has increased under the effects of climate change

Nov 11, 2012
Credit: British Antarctic Survey

The first direct evidence that marked changes to Antarctic sea ice drift have occurred over the last 20 years, in response to changing winds, is published this week in the journal Nature Geoscience. Scientists from NERC's British Antarctic Survey (BAS) and NASA's Jet Propulsion Laboratory (JPL), Pasadena California explain why, unlike the dramatic losses reported in the Arctic, the Antarctic sea ice cover has increased under the effects of climate change.

Maps created by JPL using over 5 million individual daily ice motion measurements captured over a period of 19 years by four US Defense show, for the first time, the long-term changes in drift around Antarctica.

Lead author, Dr Paul Holland of BAS says: "Until now these changes in ice drift were only speculated upon, using computer models of Antarctic winds. This study of direct shows the complexity of climate change. The total -ice cover is increasing slowly, but individual regions are actually experiencing much larger gains and losses that are almost offsetting each other overall. We now know that these regional changes are caused by changes in the winds, which in turn affect the ice cover through changes in both ice drift and air temperature. The changes in ice drift also suggest large changes in the ocean surrounding Antarctica, which is very sensitive to the cold and produced by sea-ice growth."

This video is not supported by your browser at this time.
An animation showing the extent of sea ice surrounding Antarctica throughout the year

"Sea ice is constantly on the move; around Antarctica the ice is blown away from the continent by strong northward winds. Since 1992 this ice drift has changed. In some areas the export of ice away from Antarctica has doubled, while in others it has decreased significantly."

Sea ice plays a key role in the – reflecting heat from the sun and providing a habitat for marine life. At both poles sea ice cover is at its minimum during late summer. However, during the winter freeze in Antarctica this ice cover expands to an area roughly twice the size of Europe. Ranging in thickness from less than a metre to several metres, the ice insulates the warm ocean from the frigid atmosphere above.

The new research also helps explain why observed changes in the amount of sea-ice cover are so different in the two Polar Regions. The Arctic has experienced dramatic ice losses in recent decades while the overall ice extent in the Antarctic has increased slightly. However, this small Antarctic increase is actually the result of much larger regional increases and decreases, which are now shown to be caused by wind-driven changes. In places, increased northward winds have caused the sea-ice cover to expand outwards from Antarctica. The Arctic Ocean is surrounded by land, so changed winds cannot cause Arctic ice to expand in the same way.

Dr Ron Kwok, JPL says, "The Antarctic sea ice cover interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent."

There has been contrasting climate change observed across the Antarctic in recent decades. The Antarctic Peninsula has warmed as much as anywhere in the Southern Hemisphere, while East Antarctica has shown little change or even a small cooling around the coast. The new research improves understanding of present and future climate change. It is important to distinguish between the Antarctic Ice Sheet – glacial ice – which is losing volume, and Antarctic sea – frozen seawater – which is expanding.

Explore further: Aging Africa

More information: Wind-driven trends in Antarctic sea ice motion, Nature Geoscience, 2012.

Related Stories

Declining sea ice to lead to cloudier Arctic: study

Mar 31, 2012

Arctic sea ice has been declining over the past several decades as global climate has warmed. In fact, sea ice has declined more quickly than many models predicted, indicating that climate models may not be correctly representing ...

Under-ice habitat important for Antarctic krill

Mar 08, 2012

The importance of the under-ice habitat for Antarctic krill was probably under-estimated in the past and emphasise the susceptibility of this ecological key species to changes in the sea ice habitat induced ...

Antarctic sea ice reaches new record high

Oct 12, 2012

(Phys.org)—Two weeks after a new record was set in the Arctic Ocean for the least amount of sea ice coverage in the satellite record, the ice surrounding Antarctica reached its annual winter maximum—an ...

Resolving the paradox of the Antarctic sea ice

Aug 16, 2010

While Arctic sea ice has been diminishing in recent decades, the Antarctic sea ice extent has been increasing slightly. Researchers from the Georgia Institute of Technology provide an explanation for the seeming paradox ...

Recommended for you

Aging Africa

Aug 29, 2014

In the September issue of GSA Today, Paul Bierman of the University of Vermont–Burlington and colleagues present a cosmogenic view of erosion, relief generation, and the age of faulting in southernmost Africa ...

NASA animation shows Hurricane Marie winding down

Aug 29, 2014

NOAA's GOES-West satellite keeps a continuous eye on the Eastern Pacific and has been covering Hurricane Marie since birth. NASA's GOES Project uses NOAA data and creates animations and did so to show the end of Hurricane ...

EU project sails off to study Arctic sea ice

Aug 29, 2014

A one-of-a-kind scientific expedition is currently heading to the Arctic, aboard the South Korean icebreaker Araon. This joint initiative of the US and Korea will measure atmospheric, sea ice and ocean properties with technology ...

User comments : 17

Adjust slider to filter visible comments by rank

Display comments: newest first

julianpenrod
1.7 / 5 (23) Nov 11, 2012
This demonstrates a facet of global warming which the New World Order won't mention. At least in the short run, even if the earth warms alarmingly, the poles will still stay cold! Even ignoring such things as localized extremes, the effects of winds, and so on, if the entire planet suddenly becomes uniformly 10 degrees Centigrade warmer, the poles will still he frozen! Currently, the poles average about 25 degrees befolow 0 Centigrade. If the temperqature of the entire planet rose 10 degrees Centigrade, the poles would still be below freezing, year round! That means there will always be a gradient in termperature between the poles and the equator, but, consdering that that gradient will involve water supposedly no more active at 15 below 0 than at 25 below zero and water much more active at 100 degrees Celsius than, say, 85 degrees Celsius, more significant weather events do seem indicated.
VendicarD
3.5 / 5 (16) Nov 11, 2012
http://www.youtub...j9eR7t0g

"If the temperqature of the entire planet rose 10 degrees Centigrade, the poles would still be below freezing, year round!" - SpudBoy
julianpenrod
2.2 / 5 (21) Nov 11, 2012
Another example of the character assassination machine the works through PhysOrg in action. They place ratings on 1 as soon as possible on those they hate and want to hurt. They would give them a 0 if they could, but Phys Org doesn't allow that. If they give no rating at all, then those who do give ratings will be counted. The effect of a 1 rating is that it drags down other legitimate ratings. If they give two 1's and someone later gives a 5, that knocks the final rating down to 2.3. Also, giving definitive 1's at the beginning can convince others not to place higher rankings. And this is a deliberate act of character assassination. If a statement is so non credible it deserves a 1, it could be considered to deserve no rating. A 1 means there is some validity. But note the failure to follow up with a discounting of what I said! PhysOrg could change its rules by requiring comments validating ratings.
ubavontuba
2.3 / 5 (12) Nov 11, 2012
even if the earth warms alarmingly, the poles will still stay cold! Even ignoring such things as localized extremes, the effects of winds, and so on, if the entire planet suddenly becomes uniformly 10 degrees Centigrade warmer, the poles will still he frozen! Currently, the poles average about 25 degrees befolow 0 Centigrade. If the temperqature of the entire planet rose 10 degrees Centigrade, the poles would still be below freezing, year round! That means there will always be a gradient in termperature between the poles and the equator, but, consdering that that gradient will involve water supposedly no more active at 15 below 0 than at 25 below zero and water much more active at 100 degrees Celsius than, say, 85 degrees Celsius, more significant weather events do seem indicated.

Generally speaking, this is (more or less) true of Winter ice, and continental Antarctica year-round, but not the Arctic ice durng the melt season. And probably not even Greenland.
ubavontuba
2.8 / 5 (18) Nov 11, 2012
PhysOrg could change its rules by requiring comments validating ratings.
Then you'd just get a bunch of personal attacks perpetrated by petulent children. It's best just to ignore the ratings. Science isn't a popularity contest, anyway.

verkle
3.3 / 5 (13) Nov 11, 2012
PhysOrg could change its rules by requiring comments validating ratings.
Then you'd just get a bunch of personal attacks perpetrated by petulent children. It's best just to ignore the ratings. Science isn't a popularity contest, anyway.



Well said.

VendicarD
3.1 / 5 (17) Nov 11, 2012
It is sad that UbVontard's comments are perpetually rated 1 out of 5 by rational people.

"Then you'd just get a bunch of personal attacks" - UbVonTard
StarGazer2011
2 / 5 (16) Nov 12, 2012
Climate change; is there nothing it cant do?
VendicarD
3.8 / 5 (16) Nov 12, 2012
Apparently Climate Change can't increase StarGazer's below average IQ.
julianpenrod
1.9 / 5 (13) Nov 12, 2012
If popularity isn't a consideration, why does PhysOrg have the rating system and why does no one else criticize it, but, instead, engage in handing out ratings themselves? And popularity isn't the essence of the rating system. It conveys a sense of whether what you're saying is considered to have any credence. Someone breezing through cursorily can see a low rating and be convinced that the comment has no validity, and so ignore it. And, if requiring reply comments would result in "a bunch of personal attacks perpetrated by petulant children", all the better to demonstrate the ilk who condemn valid statements! Rather than allow valid statements to be condemned by non legitimized low ratings, allow the demonstrated low class of attackers to indicate the correctness of what they denounce.
And, note, Arctic ice never completely disappears, even now. There is still a region about the size of the United States composed of ice at the pole.
Shinobiwan Kenobi
2.7 / 5 (7) Nov 12, 2012
Being suprised that your perpetually ignorant posts are being down-rated really doesn't help your assertions that you're capable of contributing anything relevant.
Egleton
2 / 5 (4) Nov 12, 2012
I am the Mighty Wizard. It is I, and I alone who has orchestrated this climate conspiracy. All bow!!
We are going to take over the world!!! Bwa ha ha ha.

(Well actually, me and the Bureau of Meteorology and me mate Jim H. And I have to mention Al G. Great Guy Al.)
Shinobiwan Kenobi
3.7 / 5 (3) Nov 12, 2012
^ seems legit.
rubberman
3.7 / 5 (6) Nov 12, 2012
Climate change; is there nothing it cant do?


Ignore our effect.
Fix stupid people.
Penetrate the counter logic of the wilfully ignorant.
Unite humanity.
Make Mila Kunis uncontrollably attracted to my girfriend...and me.
rockwolf1000
4.2 / 5 (5) Nov 12, 2012
Another example of the character assassination machine the works through PhysOrg in action. They place ratings on 1 as soon as possible on those they hate and want to hurt. They would give them a 0 if they could, but Phys Org doesn't allow that. If they give no rating at all, then those who do give ratings will be counted. The effect of a 1 rating is that it drags down other legitimate ratings. If they give two 1's and someone later gives a 5, that knocks the final rating down to 2.3. Also, giving definitive 1's at the beginning can convince others not to place higher rankings. And this is a deliberate act of character assassination. If a statement is so non credible it deserves a 1, it could be considered to deserve no rating. A 1 means there is some validity. But note the failure to follow up with a discounting of what I said! PhysOrg could change its rules by requiring comments validating ratings.

No one attacks your character more than you do.
ubavontuba
1 / 5 (6) Nov 13, 2012
popularity isn't the essence of the rating system.
Apparently, you don't understand the basics of democratic systems.

It conveys a sense of whether what you're saying is considered to have any credence.
It isn't peer review.

Someone breezing through cursorily can see allow rating and be convinced that the comment has no validity, and so ignore it.
Then that someone is ignorant of the ways of the internet.

And, if requiring reply comments would result in "a bunch of personal attacks perpetrated by petulant children", all the better to demonstrate the ilk who condemn valid statements!
Consequently filling the comments with shrill drivel. No thank you.

Rather than allow valid statements to be condemned by non legitimized low ratings, allow the demonstrated low class of attackers to indicate the correctness of what they denounce.
If they were informed and reasonable, they'd already be commenting. Their silence already says more than enough.

ubavontuba
1.8 / 5 (5) Nov 13, 2012
And, note, Arctic ice never completely disappears, even now. There is still a region about the size of the United States composed of ice at the pole.
So far it hasn't completely disappeared in the recent record, but this doesn't mean it won't.