Study: Changing winds cause melting of coastal Antarctic glaciers

From the AGU: Anthropogenically induced changes in winds in the Southern Hemisphere are playing a key role in recent warming of subsurface waters around Antarctica, according to a new study by Spence et al. The warming water increases melting of coastal glaciers and thus could affect sea levels in the future.

Since the 1950s, westerly winds in the Southern Hemisphere have been picking up and shifting poleward, due to anthropogenic global climate warming. The authors combined half a century of atmospheric data with a model of the coastal currents that shuttle water around Antarctic glaciers. Easterly winds create surface currents that pump cool fresh water downward, the authors demonstrated, keeping the temperatures at the bases of glaciers cool and pushing warm water away. But the westerly winds reduce these currents, and as a result, warm water creeps inward and upward toward the shore, where it heats up glaciers. Warm temperatures along grounding lines—where the glacier meets the ocean floor—especially increase melting.

The authors found that the changing westerly winds are responsible for an increase in water temperature of 2.5 °C on the western side of the Antarctic Peninsula, at critical depths of 200–700 meters. They calculated that the total heat increase in that region was enough to cause a sea level rise of 5.5 mm over the past 50 years (assuming that the grounded ice remains stationary). Based on the strong relationship between temperature increases and these winds, the authors think that current projections for sea level rise may be significantly underestimated.

Rapid subsurface warming and circulation changes of Antarctic coastal waters by poleward shifting winds

Abstract

The southern hemisphere westerly winds have been strengthening and shifting poleward since the 1950s. This wind trend is projected to persist under continued anthropogenic forcing, but the impact of the changing winds on Antarctic coastal heat distribution remains poorly understood. Here we show that a poleward wind shift at the latitudes of the Antarctic Peninsula can produce an intense warming of subsurface coastal waters that exceeds 2°C at 200–700 m depth. The model simulated warming results from a rapid advective heat flux induced by weakened near-shore Ekman pumping and is associated with weakened coastal currents. This analysis shows that anthropogenically induced wind changes can dramatically increase the temperature of ocean water at ice sheet grounding lines and at the base of floating ice shelves around Antarctica, with potentially significant ramifications for global sea level rise.

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Bloke down the pub
October 22, 2014 4:13 am

So the changing wind patterns have moved more heat polewards where it can more readily radiate out into space. Sounds like yet another negative feedback to me.

DrTorch
Reply to  Bloke down the pub
October 22, 2014 6:27 am

Yes, I’ve been pointing out that the high temps reported at the south pole would be the best negative feedback possible: dark for 6 months, and virtually no water in the atmosphere to absorb the emitted IR.
If warming is really an issue, then it seems nature is doing a great job or mitigating it.

Brian H
Reply to  DrTorch
October 23, 2014 5:24 pm

“Anthropogenically” altered winds, no less. Is there no limit to our powers? I’m calling BS on this one, too.

MattN
October 22, 2014 4:17 am

“We can’t think of anything else it could be so we’re going to go with ‘climate change’ so we can secure another grant.”

Bobl
October 22, 2014 4:18 am

Hmm I wonder how much energy that consumes from global warming – another energy ignorant paper. Why is it that climate modellers never sanity check their work by calculating the radiative flux necessary to fuel their particular version of armageddon.

Joe Crawford
Reply to  Bobl
October 22, 2014 8:10 am

I doubt if 5% of them ever took or much less passed Thermo 101. Why would you expect them to even think of radiative heat flux.

Alan the Brit
October 22, 2014 4:21 am

Since the 1950s, westerly winds in the Southern Hemisphere have been picking up and shifting poleward, due to anthropogenic global climate warming.
And the supporting evidence for this blanket statement is? Yet another computer model that is programmed to show whatever they want it to show. Are they going to claim that, unlike other scientists who studied things like “water memory” & other alleged “properties” in Wholistic medicine, climate scientists don’t suffer from bias?

Gerry, England
Reply to  Alan the Brit
October 22, 2014 6:01 am

The use of the word ‘model’ brings a tired yawn. Pertinent question is that they used 50 years data – so how do they know that this wind change hasn’t happened before?

Randy
Reply to  Alan the Brit
October 22, 2014 11:46 am

Yeah Id love to see proof that a fraction of a degree of warming changed wind patterns. Especially since this shift started in the 50s before we potentially had co2 driven warming.

October 22, 2014 4:28 am

No mention of those volcanoes under the ice on coastal Antarctica that WUWT reported on a short time ago?

Jimbo
Reply to  Dave
October 22, 2014 1:39 pm

Dave
October 22, 2014 at 4:28 am
No mention of those volcanoes under the ice on coastal Antarctica that WUWT reported on a short time ago?

No mention of extreme snowfalls offsetting sea level rise. Here is what they say in the press release.

They calculated that the total heat increase in that region was enough to cause a sea level rise of 5.5 mm over the past 50 years (assuming that the grounded ice remains stationary).

Do they mean just over 1mm every decade! Now take a look at what else has been happening recently. Why worry over a non-problem?

Abstract – 2 NOV 2012
Snowfall-driven mass change on the East Antarctic ice sheet
An improved understanding of processes dominating the sensitive balance between mass loss primarily due to glacial discharge and mass gain through precipitation is essential for determining the future behavior of the Antarctic ice sheet and its contribution to sea level rise. While satellite observations of Antarctica indicate that West Antarctica experiences dramatic mass loss along the Antarctic Peninsula and Pine Island Glacier, East Antarctica has remained comparably stable. In this study, we describe the causes and magnitude of recent extreme precipitation events along the East Antarctic coast that led to significant regional mass accumulations that partially compensate for some of the recent global ice mass losses that contribute to global sea level rise. The gain of almost 350 Gt from 2009 to 2011 is equivalent to a decrease in global mean sea level at a rate of 0.32 mm/yr over this three-year period.
http://onlinelibrary.wiley.com/doi/10.1029/2012GL053316/abstract
=================
Abstract – 7 JUN 2013
Recent snowfall anomalies in Dronning Maud Land, East Antarctica, in a historical and future climate perspective
Enhanced snowfall on the East Antarctic ice sheet is projected to significantly mitigate 21st century global sea level rise. In recent years (2009 and 2011), regionally extreme snowfall anomalies in Dronning Maud Land, in the Atlantic sector of East Antarctica, have been observed. It has been unclear, however, whether these anomalies can be ascribed to natural decadal variability, or whether they could signal the beginning of a long-term increase of snowfall. Here we use output of a regional atmospheric climate model, evaluated with available firn core records and gravimetry observations, and show that such episodes had not been seen previously in the satellite climate data era (1979). Comparisons with historical data that originate from firn cores, one with records extending back to the 18th century, confirm that accumulation anomalies of this scale have not occurred in the past ~60 years, although comparable anomalies are found further back in time. We examined several regional climate model projections, describing various warming scenarios into the 21st century. Anomalies with magnitudes similar to the recently observed ones were not present in the model output for the current climate, but were found increasingly probable toward the end of the 21st century.
http://onlinelibrary.wiley.com/doi/10.1002/grl.50559/abstract
=================
Abstract2014
High-resolution 900 year volcanic and climatic record from the Vostok area, East Antarctica
…..The strongest volcanic signal (both in sulfate concentration and flux) was attributed to the AD 1452 Kuwae eruption, similar to the Plateau Remote and Talos Dome records. The average snow accumulation rate calculated between volcanic stratigraphic horizons for the period AD 1260–2010 is 20.9 mm H2O. Positive (+13%) anomalies of snow accumulation were found for AD 1661-1815 and AD 1992-2010, and negative (-12%) for AD 1260-1601. We hypothesized that the changes in snow accumulation are associated with regional peculiarities in atmospheric transport.
http://www.the-cryosphere.net/8/843/2014/tc-8-843-2014.html

policycritic
Reply to  Jimbo
October 22, 2014 10:43 pm

Thanks for these, Jimbo.

Steve Keohane
October 22, 2014 4:30 am

It’s the windmills, they have to come down now! 😉

tango
October 22, 2014 4:38 am

latest news from Australia to much ice in Antarctica caused by global warming http://www.skynews.com.au/news/top-stories/2014/10/22/ice-could-cause-grief-for-antarctic-vessels.html

richard
Reply to  tango
October 22, 2014 5:01 am

this could come back to haunt them-
“Over the past three years there has been a steady increase in sea ice, which scientists have linked to global warming”
Antarctic sea ice melting – a sign of global cooling?

Mohatdebos
Reply to  tango
October 22, 2014 6:29 am

Amazing that anyone can state the following with a straight face: “Over the past three years there has been a steady increase in sea ice, which scientists have linked to global warming, and a reduction in the mass of the Antarctic ice shelf.”

Paul
Reply to  Mohatdebos
October 22, 2014 8:14 am

“Amazing that anyone can state the following with a straight face…”
Yet they do, and people listen without question. Appeal to authority is a tough nut to crack.

Ken Hall
October 22, 2014 4:38 am

The authors combined half a century of atmospheric data with a model…..
Stop! No more, I have heard enough. Another bunch of quacks presenting a hypothesis as validation of their own hypothesis. I label this scientific fraud.

Rhoda Klapp
October 22, 2014 4:42 am

A whole fifty years of data AND a model. How could they be wrong?

October 22, 2014 4:44 am

As I discuss in Don’t Sell Your Coat, the “forcing” attributed to AGW appears to have certain characteristics of magic: the South Pole has been cooling for decades, Antarctic sea ice has been increasing over the same span, and yet everything is getting hot, hot, hot. Pure magic!

M Seward
October 22, 2014 4:47 am

“The authors combined half a century of atmospheric data with a model of the coastal currents “.
Yeah? And just what bloody good would that do. WHat would that tell you apart from sketch a cartoon around a tiny data set.
This sounds like more Hockey Schtick Science. Ice Hockey Schtick!
LOL

mwh
October 22, 2014 4:56 am

Well, well well – ‘the model simulated warming events………’ For a moment I thought they had factual evidence of recent warming at the 200 – 700m depth, do they?

mwh
October 22, 2014 4:58 am

in fact do they have any evidence of 200 – 700m temperatures in the 1950s to base this knowledge on

RACookPE1978
Editor
October 22, 2014 5:07 am

… water temperature of 2.5 °C on the western side of the Antarctic Peninsula, at critical depths of 200–700 meters. They calculated that the total heat increase in that region was enough to cause a sea level rise of 5.5 mm over the past 50 years (assuming that the grounded ice remains stationary).

But the Antarctic Peninsula is only 1.7% of the whole continent, and – because it sticks out INTO the strong westerly currents always flowing around Antarctica, it WILL BE always affected differently than the remaining 98% of the land mass and the remaining 98% of the continental ice mass!
What did they model – how much of the continent? How far out to sea? How did they “model” these grounding lines of the glaciers – themselves only a very, very small part of the total continental coast? In other words, are they treating the entire 45,300 kilometer coastline like a single huge Pine Island Glacier?
Length of Antarctic Peninsula = 1,340 km.
West Coast of Antarctic Peninsula = ~1600 km (it curves significantly)
Thus, “Glaciers across the entire North Slope of Canada will melt faster based on wind studies modeling the Newfoundland Coast that show the Gulf Stream might go faster near Cape Cod in the future.”

Cold in Wisconsin
Reply to  RACookPE1978
October 22, 2014 7:02 am

Isn’t the peninsula the area that has the subsurface volcanoes? Is that why there is warming in that area of Antarctica?

Jeff
Reply to  RACookPE1978
October 22, 2014 12:35 pm

The northern end of the Antarctic peninsula seems to have been the place where the sea ice extent was closest to average most of this past winter anyway. If their model predicts ice should be increasing along the peninsula, it would seem to be a failed forecast.

LeeHarvey
October 22, 2014 5:21 am

This analysis shows that anthropogenically induced wind changes can dramatically increase the temperature of ocean water at ice sheet grounding lines and at the base of floating ice shelves around Antarctica, with potentially significant ramifications for global sea level rise.

I’m gonna go way out on a limb here, and guess that the temperature of ocean water at an ice sheet grounding line is 271 K… or exactly the same as it has been for quite a while, now.

latecommer2014
Reply to  LeeHarvey
October 22, 2014 6:01 am

How does man change the strength of the wind? Just asking.

tadchem
Reply to  latecommer2014
October 22, 2014 11:38 am

More to the point, how does the wind change the temperature of the ice-water interface – the melting point temperature of ice?

Don Perry
October 22, 2014 5:23 am

Three degrees required to become a “climate scientist”:
BS = self-defining
MS= More of the Same
PhD= Piled Higher and Deeper
‘Nuf said.

Paul
Reply to  Don Perry
October 22, 2014 8:19 am

“Three degrees required to become a “climate scientist”
Are those 3 degrees in F, C or K?

Auto
Reply to  Paul
October 22, 2014 12:31 pm

I wouldn’t mind The Three Degrees.
http://en.wikipedia.org/wiki/The_Three_Degrees
Even Prince Charles – who gives CO2 to his plants by talking to them – liked The Three Degrees!
Auto

Alan Millar
October 22, 2014 5:30 am

Well let’s see the actual data and sources for their alleged changes. Then they can show us……
1. What was the strength, at various latitudes, of the westerly winds in the Southern Hemisphere in 1950?
1a. What is the data for each year up to the present?
2. What was the temperature of the subsurface waters around Antarctica in 1950?
2a. What is the data for each year up to the present?
3. What was the temperature of the subsurface water on the western side of the Antarctic Peninsula at depths of 200–700 meters in 1950?
3a. What is the data for each year up to the present?
Until this is shown, everything they say and their alleged ‘Model’, is absolute bollocks.
Don’t hold your breath!
Alan

Patrick B
Reply to  Alan Millar
October 22, 2014 5:40 am

Don’t forget to ask for proper error analysis with the measurements. Exactly how accurate do you think the temperature measurements in 1950 were for the entire ocean around the Antarctic Peninsula? My bet is that proper error analysis wipes out any ability to claim any change.

Ken Hall
Reply to  Patrick B
October 22, 2014 6:17 am

You are putting in much more thought that this paper deserves. Although your questions are correct, I feel it is giving that model based paper much more credibility than it warrants.

tty
Reply to  Alan Millar
October 22, 2014 9:12 am

I suggest that you have a look at the historical coverage for SST and winds here:
http://icoads.noaa.gov/r2_fig1d.html
http://icoads.noaa.gov/r2_fig2d.html
White/Grey/Dark blue have coverage ranging from less than once per ten years to less than once per month. Red areas have daily coverage.
Draw your own conclusions.

October 22, 2014 5:31 am

“Since the 1950s, westerly winds in the Southern Hemisphere have been picking up and shifting poleward, due to anthropogenic global climate warming. ”
During the 50s and 60s it was an equatorward shift.
From the mid 70s to 2000 it was indeed a poleward shift.
From 2000 it has been an equatorward shift.
Only by cherry picking the start and end points can one say what they did.
The shifts were caused by variations in solar activity:
http://www.newclimatemodel.com/new-climate-model/

Pamela Gray
Reply to  Stephen Wilde
October 22, 2014 5:54 am

Once again Stephen, tell me which system invades the Stratosphere, the top down “needs to be amplified to work” unobserved mechanism you propose, or the bottom-up invasion of Rossby Waves observed to be the source of such disturbances in the Stratosphere over the poles (especially the Arctic).
Here is a link to a very cool demonstration of such events, that are not only random in the short term, but such invasions have oscillations over longer time scales. They are easily identified in measures of atmospheric pressure systems via satellite.
http://geosci.uchicago.edu/~nnn/LAB/DEMOS/RossbyWave.html
Sometimes the old papers are the best source. They are pre-debate and untainted with AGW versus solar hysteria. These waves (generated by teleconnected systems here are Earth) are well understood and you seem all too eager to ignore them. Between your hypothesis and known observations, I will side with known observations.
http://www.pmel.noaa.gov/pubs/PDF/kess1113/kess1113.pdf

Reply to  Pamela Gray
October 22, 2014 6:45 am

The known observations are entirely consistent with my hypothesis.
The top down mechanism has now been observed:
http://hockeyschtick.blogspot.ca/2014/10/new-paper-finds-significant-missing.html
I disagree with the authors that the effect is only regional.

Pamela Gray
Reply to  Pamela Gray
October 22, 2014 4:24 pm

Stephen, you know very well that paper does not state that the top-down mechanism has been observed. The only thing observed was the well known diminution of the ozone layer as a result of the solar cycle, especially at the poles. This does not in any way explain the rising trend nor the pause in temperature data.

Reply to  Pamela Gray
October 23, 2014 12:37 am

Pamela,
The ozone layer is supposed to decrease when the sun is inactive and increase when it is active.
The paper shows that in fact it decreases above the stratopause when the sun is active and the effect is transmitted down through the polar vortices to change tropopause height above the poles and thereby influence tropospheric circulation patterns.
That is the essence of my 2010 hypothesis.

Solomon Green
October 22, 2014 5:32 am

“The ‘model’ simulated warming results from a rapid advective heat flux induced by weakened near-shore Ekman pumping and is associated with weakened coastal currents.”
“This analysis shows that ‘anthropogenically induced’ wind changes can dramatically increase the temperature of ocean water…”
Are any comments necessary?

Lawrence
October 22, 2014 5:46 am

Didn’t http://wattsupwiththat.com/2014/10/21/john-cooks-claim-of-a-warmer-southern-ocean-is-proven-wrong/ say there was no evidence of ocean warming around Antartica?

Barry
Reply to  Lawrence
October 22, 2014 6:06 am

Those were surface temps. This article refers to subsurface temps. at depths of 200-700 meters.

Eliza
October 22, 2014 6:02 am

What amazes me is how the Australian Government still allows public expenditure on this C@ (ie boat in Antarctica too measure how acidity will affect ocean in 100 years due to AGW). Its about time they actually terminated ALL AGW funding in Government, CSIRO, Universities ect. Abbott needs to move faster on this.

xyzzy11
Reply to  Eliza
October 22, 2014 6:29 am

Yep – unfortunately there are too many warmists in Abbott’s government to push things as quickly as we would like. (Sadly)

Harry Passfield
October 22, 2014 6:10 am

‘the model simulated warming events………’

There’s a typo: a ‘t’ is missing from the third word.

TImo Soren
October 22, 2014 6:14 am

I would love to actually read a paper that proves “anthro” induced wind changes in the antarctic.

Peter Dunford
October 22, 2014 6:20 am

Isn’t this another rehash of the discredited missing heat hiding theory. We know from the recent work by Bob Tisdale as shown by Paul Homewood that the SSTs down there were level and falling. So how did the heat get into the lower layers without warming the top ones?

Barry
Reply to  Peter Dunford
October 22, 2014 6:30 am

Warmer water from lower latitudes has higher salinity, which causes it to sink.

mpainter
Reply to  Barry
October 22, 2014 6:35 am

Barry:
Water cools as it moves toward higher latitudes, but there is no poleward current in the SH. The model invents one. This paper is garbage.

tty
Reply to  Barry
October 22, 2014 9:21 am

Actually it is the very cold and saline water that is “frozen out” when sea-ice forms that sinks and moves outwards from Antarctica as AABW (AntArctic Bottom Water). This is the main reason the deep ocean is so very cold, so it will take some very advanced Climate Science™ to explain it away.

Auto
Reply to  Barry
October 22, 2014 2:36 pm

And ‘The Science is Settled’.
We know – we’ve read it in/on the warmist organs, so it must be true. [Ummm. /Sarc.]
The catastrophic increase of deadly CO2, from three parts in ten thousand to – now, fasten your seat belts & take a deep breath – as much as four parts in ten thousand, has been the cause of many unwanted changes in the biosphere.
I didn’t see a hawk in my garden yesterday – fifteen years ago I did. Bull-gore warming.
Giant chamois extinct; slightly smaller chamois thrive. Boll-goure warming.
Urban heat islands expand with temperature: Gull-bore effect.
Plant crops improve wholesale. Gure-Boll happenstance.
[Mod – I’m not sure if any of this is /sarc, given that the science has been oh-so-firmly settled . . . . . .]
Am I getting warm?
No – it’s autumn [fall for N America] in the UK.
Decidedly not – on the station this morning.
But that, I am positive, is merely [Merely??] weather – ‘cos the ‘science is settled’.
So I read, folks.
Auto

Barry
Reply to  Peter Dunford
October 22, 2014 6:39 am

And as the abstract notes, Ekman pumping is another process affecting the vertical transfer of heat:
http://en.wikipedia.org/wiki/Ekman_transport

mpainter
Reply to  Barry
October 22, 2014 7:30 am

Barry: The Ekman pumping in those waters is pure invention, found only in the model.
The whole study is a hypothetical premise, from the “anthropogenically” induced change in the wind to the warming of the waters. In short, it is another alarmist invention with _no_ observational basis. It is garbage, not even fit for the CAGW propaganda mill.

Cold in Wisconsin
Reply to  Peter Dunford
October 22, 2014 7:07 am

Where are the subsurface volcanoes?

Stevan Makarevich
Reply to  Cold in Wisconsin
October 22, 2014 8:48 am

Using AGW logic, models show that subsurface volcanoes cause cooling of the water.

H.R.
October 22, 2014 6:24 am

From the article:
“Anthropogenically induced changes in winds …”
??!?!!?
Everybody in the Southern Hemisphere needs to walk around hunched over so they don’t affect the wind so much? Lower all flags to half staff? Cut down power poles and only use underground cable? Ban kite flying?
I’d like a little evidence that there is an anthropogenic component changing the winds, perhaps a few centuries of observations that show there were no changes prior to the last 50 years or so.

Alx
Reply to  H.R.
October 22, 2014 7:32 am

You got to be kidding, you want evidence? Evidence, really? This is a climate science paper, which means it is self-re-enforcing, the evidence is in the claim itself. You start with the premise AGW is causing x and then you conclude that AGW is causing x because the premise is AGW is causing x. Circular logic like you find in debating intelligent design proponents.

H.R.
Reply to  Alx
October 22, 2014 11:32 am

“You got to be kidding, you want evidence? Evidence, really?”
People in hell want ice water, Alx. I hadn’t planned on holding my breath until evidence was provided.

lee
Reply to  H.R.
October 22, 2014 8:34 pm

Everybody in the Southern Hemisphere needs to walk around with clenched cheeks.