North and Tropical Atlantic Ocean bringing climate change to Antarctica, study finds

Jan 22, 2014
The surface of a glacier, taken from a helicopter (30 meters above the ice): Land ice is melting and caving under the warm air. Credit: Xichen Li

The gradual warming of the North and Tropical Atlantic Ocean is contributing to climate change in Antarctica, a team of New York University scientists has concluded. The findings, which rely on more than three decades of atmospheric data and appear in the journal Nature, show new ways in which distant regional conditions are contributing to Antarctic climate change.

"Our findings reveal a previously unknown—and surprising—force behind climate change that is occurring deep in our : the Atlantic Ocean," says Xichen Li, a doctoral student in NYU's Courant Institute of Mathematical Sciences and the study's lead author. "Moreover, the study offers further confirmation that in one region can have far-reaching effects in another."

Over the past few decades, Antarctica has experienced dramatic climate change, with its peninsula exhibiting the strongest warming of any region on the planet. During its summer, Antarctic changes have been attributed to greenhouse gas increase and stratospheric ozone loss. However, less clear are the forces behind climate changes that occur during its winter. In addition, the effects of these changes during the cold season are complex, further stifling efforts to find the atmospheric culprit.

It has long been known that the region's climate is affected, in part, by changes in the distant Pacific Ocean climate. But the phenomena brought on by the Pacific have shorter-term influences—for instance, due to El Niño. Less understood are the longer-term forces that have produced warming along the Antarctic Peninsula or the sea-ice redistribution in the southern hemisphere's winter over many decades.

To address this question, the NYU researchers focused on a different candidate: the Atlantic Ocean, which has been overlooked as a force behind Antarctic climate change.

Water fall on the land ice front: Land ice is melting under the warm air, releasing fresh water into the ocean. Credit: Xichen Li

Specifically, the scientists studied the North and Tropical Atlantic's Sea Surface Temperature (SST) variability—changes in the ocean's surface temperature—focusing on the last three decades. This metric, the Atlantic Multidecadal Oscillation (AMO), had previously not been considered in seeking explanations for Antarctic climate change.

Using a time-series analysis, in which the scientists matched changes in the North and Tropical Atlantic's SST with subsequent changes in Antarctic climate, the researchers found strong correlations. Specifically, they observed that warming Atlantic waters were followed by changes in sea-level pressure in the Antarctic's Amundsen Sea. In addition, these warming patterns also preceded redistribution of sea ice between the Antarctic's Ross and Amundsen-Bellingshausen-Weddell Seas.

David Holland, co-author of the study, a professor at NYU's Courant Institute and past director of NYU's Center for Atmospheric Ocean Science, explained that the research consisted of two parts, which incorporated both the use of observational data and computer modeling.

The first part of the study, using the observational data, found a link, or correlation, between the Atlantic and Antarctic data sets. But a correlation means simply that two things appear to happen in conjunction and does not explain what may be causing a phenomenon.

The second used a global atmospheric model, which allowed the researchers to create a simulated warming of the North Atlantic. The model responded, as the researchers had suspected, by "changing" the climate in Antarctica.

"While our data analysis showed a correlation, it was the use of a state-of-the-art computer model that allowed us to see that North Atlantic warming was causing Antarctic and not vice versa," he said.

The study's findings raise a number of deeper questions, such as, is Antarctic sea-ice change fundamentally different from the well-reported changes in the Arctic? In contrast to the sea-ice decline over the Arctic, Antarctic sea ice has not diminished. Rather, it has redistributed itself in ways that have perplexed scientists, with declines in some areas and increases in others.

Holland observes: "From this study, we are learning just how Antarctic sea-ice redistributes itself, and also finding that the underlying mechanisms controlling Antarctic are completely distinct from those in the Arctic."

Explore further: New ice core record shows West Antarctic climate variability

More information: Paper: dx.doi.org/10.1038/nature12945

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Maggnus
3.3 / 5 (15) Jan 22, 2014
And another nail in the coffin of the conspiratorial denialist's argument that Antarctic sea ice extent somehow disproves global warming.

Like it needed another nail.
gregor1
2.7 / 5 (13) Jan 23, 2014
The catastrophic AGW hypothesis is based entirely on the "evidence" of computer models which 'robustly' predicted the decline of sea ice in the Antarctic. Instead we find the sea ice there at an all time record high. This doesn't disprove global warming- we all agree the globe has been in a warming cycle- but it does question the reliability of computer modeling and wether we should panic about crazy predictions that have never been right yet.
http://hockeyscht...tly.html
Maggnus
3.5 / 5 (8) Jan 23, 2014
The catastrophic AGW hypothesis is based entirely on the "evidence" of computer models
No gregor, it's not. Models play their role, because. you know, predicting what may be coming is exceptionally hard with a system as chaotic and complicated as climate.
which 'robustly' predicted the decline of sea ice in the Antarctic. Instead we find the sea ice there at an all time record high.
A zombie argument, and one which has been addressed multiple times on any number of articles detailing ice extent and ice mass in Antarctica. Ice extent has shown an increase, but ice volume has shrunk.
but it does question the reliability of computer modeling and wether we should panic about crazy predictions that have never been right yet
Another zombie argument. No one says this! On the contrary, most studies suggest past predictions have not gone far enough - mostly in an attempt to placate mostly non-scientific denialists! (http://www.newsci...climate)
Cocoa
4.1 / 5 (8) Jan 23, 2014
gregor1 " we all agree the globe has been in a warming cycle"

Actually gregor - many on this board argue exactly the opposite - we spend hours playing pop a mole with the commenters who insist that 'there has been no warming for the past 16 years' However - I think your premise that the globe is warming is accurate - and supported by gigatons of data.

The next two questions I would like to see you answer are these - 1. How long have we been in this warming trend. 2. What are the driver/s of this warming trend.

Thanks.
runrig
4.3 / 5 (6) Jan 23, 2014
The catastrophic AGW hypothesis is based entirely on the "evidence" of computer models which 'robustly' predicted the decline of sea ice in the Antarctic. Instead we find the sea ice there at an all time record high. This doesn't disprove global warming- we all agree the globe has been in a warming cycle- but it does question the reliability of computer modeling and wether we should panic about crazy predictions that have never been right yet.
http://hockeyscht...tly.html

Greggy baby:
How many more times before it twigs in your fessed up denialist brain that GCM's CANNOT ever give a qualitative forecast of global temps as they are an ENSEMBLE product that merge ALL climate cycles into a blur that NECESSARILY omits the actuality of a cycle such as a ENSO/PDO ( which is what is primarily causing the current pause). And NO that does not INVALIDATE them - it just means we look at periods of ~30years for the SIGNAL. geddit?
Whydening Gyre
3.3 / 5 (3) Jan 23, 2014
Models play their role, because. you know, predicting what may be coming is exceptionally hard with a system as chaotic and complicated as climate.

By default, wouldn't the act of modeling, subject to the same complication and chaos?
Maggnus
3.9 / 5 (7) Jan 24, 2014
Models play their role, because. you know, predicting what may be coming is exceptionally hard with a system as chaotic and complicated as climate.

By default, wouldn't the act of modeling, subject to the same complication and chaos?


Yes, which is why literally thousands them are run and researchers use what is essentially an averaging algorithm to come up with a range. That is also why there are these things called error bars.

But more importantly to the issue I was addressing, models are most definitely not the entirety of the evidence supporting anthropogenically caused global warming.

antigoracle
2.3 / 5 (6) Jan 27, 2014
Another desperate act of deceit from the AGW Alarmists, to prop up their last faltering lie - All the heat is going into the oceans. This is just fodder for the hungry Chicken Littles, who call this science, as they gobble it up. In the meanwhile, in the real world, we are headed for another Little Ice Age.
Captain Stumpy
3.4 / 5 (5) Jan 28, 2014
@antigoracle
Another desperate act of deceit from the AGW Alarmists, to prop up their last faltering lie

opinion not supported by facts
links/references?
- All the heat is going into the oceans

links/references?
This is just fodder for the hungry Chicken Littles, who call this science, as they gobble it up

opinion not supported by facts
links/references?
In the meanwhile, in the real world, we are headed for another Little Ice Age

opinion not supported by facts
links/references?

Try doing some reading and research and support your illation with data and facts
Maggnus
3.4 / 5 (5) Jan 28, 2014
Stumpy, you think Uba is bad, wait til againstseeing gets going. Talk about woo woo!!
AlexCoe
1 / 5 (1) Mar 09, 2014
The ONLY thing constant in nature IS CHANGE.

That being said, you idiots who think that man is somehow smart enough to be able to "fix" a system that you can barely begin to understand is completely comical, if it weren't so tragic that is.

The real tragedy is that you actually believe you know enough to be a good steward. The complete lack of understanding you, know it all's exhibit is truly pathetic.

Let the moron's choir continue to sing, just like the corrupt political leaders, eventually the people will wake up and drive you all out.

The saddest part is distrust it will bring about for the science community in the long run. That part IS truly sad and it's the biggest casualty in this entire passion play, the trust in science.

It will bring about a new dark age for humanity, but then that's really what you AGW's want any way isn't it?

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