Ocean winds keep Antarctica cold, Australia dry

May 11, 2014
Clouds over Australia are shown. Credit: NASA

New Australian National University-led research has explained why Antarctica is not warming as much as other continents, and why southern Australia is recording more droughts.

Researchers have found rising levels of carbon dioxide in the atmosphere are strengthening the stormy Southern Ocean winds which deliver rain to southern Australia, but pushing them further south towards Antarctica.

Lead researcher Nerilie Abram, from the ANU Research School of Earth Sciences, said the findings explained the mystery over why Antarctica was not warming as much as the Arctic, and why Australia faces more droughts.

"With greenhouse warming, Antarctica is actually stealing more of Australia's rainfall. It's not good news – as greenhouse gases continue to rise we'll get fewer storms chased up into Australia," Dr Abram said.

"As the westerly winds are getting tighter they're actually trapping more of the cold air over Antarctica," Abram said. "This is why Antarctica has bucked the trend. Every other continent is warming, and the Arctic is warming fastest of anywhere on earth."

While most of Antarctica is remaining cold, rapid increases in summer ice melt, glacier retreat and ice shelf collapses are being observed in Antarctic Peninsula, where the stronger winds passing through Drake Passage are making the warm exceptionally quickly.

Until this study, published in Nature Climate Change, Antarctic climate observations were available only from the middle of last century.

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Dr. Nerlie Abram, from the Australian National University, explains why ocean winds have stopped Antarctica from warming as much as other continents. Her research also explains droughts in Southern Australia. Credit: ANU Media

By analysing ice cores from Antarctica, along with data from tree rings and lakes in South America, Dr Abram and her colleagues were able to extend the history of the westerly winds back over the last millennium.

"The Southern Ocean winds are now stronger than at any other time in the past 1,000 years," Abram said.

"The strengthening of these winds has been particularly prominent over the past 70 years, and by combining our observations with climate models we can clearly link this to rising greenhouse gas levels."

Study co-authors Dr Robert Mulvaney and Professor Matthew England said the study answered key questions about in Antarctica.

Dr. Nerilie Abram is shown working on an ice core. Credit: Paul Rogers

"Strengthening of these westerly winds helps us to explain why large parts of the Antarctic continent are not yet showing evidence of climate warming," said Dr Mulvaney, from the British Antarctic Survey.

"This new research suggests that do a good job of capturing how the respond to increasing ," added Professor England, from the Climate Change Research Centre at UNSW.

"This isn't good news for farmers reliant on winter rainfall over the southern part of Australia."

Explore further: How wind helps Antarctic sea ice grow, even as the Arctic melts

More information: Evolution of the Southern Annular Mode during the past millennium, DOI: 10.1038/nclimate2235

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ubavontuba
1.9 / 5 (14) May 11, 2014
"...large parts of the Antarctic continent are not yet showing evidence of climate warming,"
Antartic sea ice is off the hook!

http://arctic.atm...ive.html

Caliban
3.5 / 5 (10) May 11, 2014
"Strengthening of these westerly winds helps us to explain why large parts of the Antarctic continent are not yet showing evidence of climate warming," said Dr Mulvaney, from the British Antarctic Survey.

"This new research suggests that climate models do a good job of capturing how the westerly winds respond to increasing greenhouse gases," added Professor England, from the Climate Change Research Centre at UNSW.

"This isn't good news for farmers reliant on winter rainfall over the southern part of Australia."


Just give it a little while.

It's the pendulum swing of the heat energy balance searching for a new equilibrium point.

This increase in wind speed isn't sustainable, and will eventually collapse, just as the Arctic Polar Vortex did. Australia can expect a series of deluges in the coming years. I would estimate starting in 2-3 years.

Antartica's weather, as a result, will become very chaotic, but warming and snow/ice loss will accelerate even more.

Caliban
3.9 / 5 (11) May 11, 2014
"...large parts of the Antarctic continent are not yet showing evidence of climate warming,"
Antartic sea ice is off the hook!

http://arctic.atm...ive.html


OMG!!!! Seasonal sea surface ice extent is off the hook!!!!!!!

LOL!

As you are well aware, ubybooby, --it'll all be melted at the end of this season, and then some.

Meanwhile, West Antarctic snow/ice balance went negative some time ago, and now, it is expected that loss of Multi-year, grounding-ice boundaries in East Antarctica are about to fail, and release the interior ice which they have been keeping contained.

How's that University of Colorado NSIDC snow'n'ice extent lookin', assclown?

LOL! LOL! LOL! LOL! LOL! LOL! LOL!

runrig
3.7 / 5 (9) May 11, 2014
Cali,
It will collapse eventually but I'd give it longer than you.
What is described is basically a strengthening Southern Polar jet as opposed to a weakening one which is the case for the NH.
Cold over Antarctica is holding ground whilst warming is occurring from the temperate zone to the equator. We would need to see mid to upper tropospheric temps increase for this effect to weaken. The O3 hole does not help (O3 is of course a GHG) and the general isolation of the vortex will preclude a break-down any time soon. I would expect a continued increase in the extent of winter-time sea-ice as well as winds/divergence increases and fresh-water melt does to.
Caliban
3.5 / 5 (8) May 11, 2014
Cali,
It will collapse eventually but I'd give it longer than you.
[...]I would expect a continued increase in the extent of winter-time sea-ice as well as winds/divergence increases and fresh-water melt does to.


runrig,

Largely agree with what you say, but let's not forget that this jet circulation will prolly cause more rapid overturning, and heat contribution to atmosphere over the ocean- especially inshore.
You're right that it will take a long time for this large scale effect to completely collapse, but I'm looking for some near-term (big) wobbles as a new equilibrium is reached. And I should have said Deluge/Drought, rather than just "Deluge".

For the sake of all our fellow life-forms in the SH, however, I hope you are right.

Cheers,

Caliban
verkle
1.3 / 5 (12) May 11, 2014
Another weather postulation. "give it time and it may prove true..."

These kind of ideas come a dime a dozen these days. And not many are proving themselves true.

Why keep focusing on the religion of the environment?
gregor1
1 / 5 (7) May 12, 2014
Good old Matthew England. Always good for a laugh. Here's an appraisal.Worth reading the comments.http://joannenova...-effect/
runrig
4.4 / 5 (7) May 12, 2014
This from your link greggy.....
The skeptic Blog of a scientist whose "major was microbiology, molecular biology". (wiki).

"The climate models didn't predict Antarctic sea ice extent trends. Polar amplification was supposed to mean it would warm twice as fast at the poles, yet inconveniently after years of massive output of CO2 — above the levels assumed in the models — Antarctic sea ice has hit another record high. Finally in the eighth round of making excuses for their excuses, the Scientific Truth has emerged to sweep away the scientific untruths that went before. (After all, climate models couldn't possibly have been expected to understand heat flow around the planet could they?)"

The above quote could have come from you - is an example of staggering ignorance of the science and denial of the obviously vastly different extreme that is Antarctica from the Arctic.

In other words - worthless opinion from a non-expert blogger with rousing cheers from the fan-boys.
TegiriNenashi
1 / 5 (6) May 12, 2014
"...vastly different extreme that is Antarctica from the Arctic..."

Yeah, right: you started singing how Antarctica is different from the Arctic only after the temperature refused to follow your way. Before that, the majority of climate science was perfectly fine with polar amplification in southern hemisphere:
http://www.nature...1a0.html

Captain Stumpy
4 / 5 (4) May 12, 2014
you started singing how Antarctica is different from the Arctic only after the temperature refused to follow your way
@tegiri
personal conjecture projecting your personal incompetence into another
Runrig has NEVER said they were the same, and I challenge you to prove it with quotes and links. The Antarctic has a Continent under it's ice, the Arctic is ice over water which ANY logical person would then instantly know that the conditions would very between the two, an

Runrig has always pointed this out to denialist morons ... to make a claim like above, you would have to be illiterate as well as intentionally obfuscating for reasons of inanity as well as creating/sowing dissent through posting lies