Claim: large Antarctic polynyas to disappear, yet some are still found in satellite imagery

Venti catabatici

Katabatic wind driven polynya in Antarctica click image to enlarge

This PR from McGill University  claims that the “deep ocean heat has been unable to get out and melt back the wintertime Antarctic ice”.  That might be true, but still, there are polynyas present in the location of interest (Weddell Sea) that they don’t mention. In fact, there’s even a large offshore polynya in progress in the Weddell Sea right now according to NSIDC imagery, and the Weddell sea has a lot more ice where it is not supposed to be according to “normals”. See below – Anthony

Global warming felt to deepest reaches of ocean

Study shows climate change has put a freshwater lid on the Antarctic ocean, trapping warm water in ocean depths

In the mid-1970s, the first available satellite images of Antarctica during the polar winter revealed a huge ice-free region within the ice pack of the Weddell Sea. This ice-free region, or polynya, stayed open for three full winters before it closed.

Subsequent research showed that the opening was maintained as relatively warm waters churned upward from kilometres below the ocean’s surface and released heat from the ocean’s deepest reaches. But the polynya — which was the size of New Zealand — has not reappeared in the nearly 40 years since it closed, and scientists have since come to view it as a naturally rare event.

Now, however, a study led by researchers from McGill University suggests a new explanation: The 1970s polynya may have been the last gasp of what was previously a more common feature of the Southern Ocean, and which is now suppressed due to the effects of climate change on ocean salinity.

The McGill researchers, working with colleagues from the University of Pennsylvania, analyzed tens of thousands of measurements made by ships and robotic floats in the ocean around Antarctica over a 60-year period. Their study, published in Nature Climate Change, shows that the ocean’s surface has been steadily getting less salty since the 1950s. This lid of fresh water on top of the ocean prevents mixing with the warm waters underneath. As a result, the deep ocean heat has been unable to get out and melt back the wintertime Antarctic ice pack.

“Deep ocean waters only mix directly to the surface in a few small regions of the global ocean, so this has effectively shut one of the main conduits for deep ocean heat to escape,” says Casimir de Lavergne, a recent graduate of McGill’s Master’s program in Atmospheric and Oceanic Sciences and lead author of the paper.

The scientists also surveyed the latest generation of climate models, which predict an increase of precipitation in the Southern Ocean as atmospheric carbon dioxide rises. “This agrees with the observations, and fits with a well-accepted principle that a warming planet will see dryer regions become dryer and wetter regions become wetter,” says Jaime Palter, a professor in McGill’s Department of Atmospheric and Oceanic Sciences and co-author of the study. “True to form, the polar Southern Ocean – as a wet place – has indeed become wetter. And in response to the surface ocean freshening, the polynyas simulated by the models also disappeared.” In the real world, the melting of glaciers on Antarctica – not included in the models – has also been adding freshwater to the ocean, possibly strengthening the freshwater lid.

The new work can also help explain a scientific mystery. It has recently been discovered that Antarctic Bottom Water, which fills the deepest layer of the world ocean, has been shrinking over the last few decades. “The new work can provide an explanation for why this is happening,” says study co-author Eric Galbraith, a professor in McGill’s Department of Earth and Planetary Sciences and a fellow of the Canadian Institute for Advanced Research. “The waters exposed in the Weddell polynya became very cold, making them very dense, so that they sunk down to become Antarctic Bottom Water that spread throughout the global ocean. This source of dense water was equal to at least twice the flow of all the rivers of the world combined, but with the surface capped by freshwater, it has been cut off.”

“Although our analysis suggests it’s unlikely, it’s always possible that the giant polynya will manage to reappear in the next century,” Galbraith adds. “If it does, it will release decades-worth of heat and carbon from the deep ocean to the atmosphere in a pulse of warming.”

###

The research was supported by the Stephen and Anastasia Mysak Graduate Fellowship in Atmospheric and Oceanic Sciences, by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery programme, by the Canadian Institute for Advanced Research (CIFAR) and by computing infrastructure provided by the Canadian Foundation for Innovation and Compute Canada.

==============================================================

To help readers understand what they are talking about, here is a pictorial via NSF.

Graphic: sea ice/ ice shelf

In autumn when the ice cover is expanding, the ice acts as a distillation system, separating sea water into low salinity ice and high salinity brine, which sinks and increases the density of Antarctic Bottom Water, a globally distributed water mass. In winter, during its maximum extent, the ice shuts down the exchange of heat between the ocean and the atmosphere, lowering the surface air temperature by as much as 30°F and increasing the reflectivity (albedo) of the surface. In spring, melting releases microbes and plankton that had been growing in the ice and seeds of phytoplankton bloom. In summer it provides a breeding place for seals. For most of the year the transition zone from ice to open water is one of enhanced biological activity, where birds, seals, and whales congregate to feed. The schematic (© Scientific American 1988, after Gordon and Comiso, 1988) illustrates these actions.

What they don’t mention in this press release though, is that polynyas near the coast are often the result of Katabatic winds. The Turney Ship of Fools surely knows about what happens when the winds shift and the ice starts packing in when the polynya closes.

They also don’t mention that a large polynya appeared in November 2011 in the Weddell sea they are wailing about that might be “… the last gasp of what was previously a more common feature of the Southern Ocean…”.

From NASA Earth Observatory:

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image of a polynya off the coast of Antarctica, near Ross Island and McMurdo Station on November 16, 2011. The polynya was likely caused by katabatic winds, which derive their name from the Greek term for “descent.” The winds blow off Antarctica’s high interior toward the ocean and can attain hurricane strength—up to 200 miles (320 kilometers) per hour.

Strong winds have pushed sea ice away from the coast in this image, but not uniformly. Ross Island and the mountains to the west block some winds, so sea ice lingers near those landforms. Along the lower-elevation area east of Ross Island, winds clear the ice from a large stretch of ocean. North of the polynya, sea ice shows varying degrees of thickness, perhaps the result of alternating windy and calm spells.

Polynya off the Antarctic Coast

acquired November 16, 2011 click to download large image (1 MB, JPEG, 2800×3600)

Here is another from 2008:

csm_Fig4_cad9c4fa7c[1]

Figs. 4: MODIS infrared imageries of the 3rd September of 2008, showing a polynya opening in the south-eastern Weddell Sea. Dark colors indicate warm brightness temperatures (legend in K)

Source: http://www.uni-trier.de/?id=40208

And, there’s even a large polynya in progress in the Weddell Sea right now according to this NSIDC image via the WUWT Sea ice page:

NSIDC_S_bm_extent_hires

(image annotated by A. Watts, click image for original) Source: http://nsidc.org/data/seaice_index/images/daily_images/S_bm_extent_hires.png

The orange lines indicate the “normal” sea ice extent for this time of year, and clearly there is more ice than normal in the Weddell sea, but somehow an offshore polynya managed to open up.

The paper: Ocean-atmosphere heat fluxes at the Ronne Polynya, Antarctica by UEA’s Anna Fiedler suggests that the Ronne Polynya, while wind-driven, still has an important role in heat flux transport, and that they actually help manufacture more sea ice:

The Ronne Polynya is a coastal polynya, a region of thin ice or open water in sea ice, caused by the offshore transport of the ice

by strong winds from the land (Figure 1). As soon as the ice is transported offshore, new ice forms on the exposed ocean surface and is also advected offshore in a continual process,

earning this type of polynya the nickname ‘ice factory’. These polynyas have an important impact on the regional meteorology and oceanography of the high latitudes

as well as on the global ocean circulation.

One wonders what role these features may have in building up the sea ice increase around Antarctica.

Source: Cryosphere Today – Arctic Climate Research at the University of Illinois – Click the pic to view at source

While it is certainly possible that the 1970’s polynya was caused by warm water upwelling, it is also equally possible that it was at least aided by a persistent wind pattern. Wind has an equal if not stronger effect on sea ice than upwelling.

And, it seems that according to a NOAA researcher (Robert Grumbine) who setup a tracking page, there was an event in 1998 that was of interest:

In 2000, we had no noteworthy polynas in the Weddell Sea.  There was only a small area of reduced ice concentration between approximately 26 August 2000 and 2 September 2000. 2001 and 2002 were even more boring. Not even an attempt to form a polynya.

In 1999, the Weddell Sea was quiet until mid-July. Towards the end of the month, a sizeable area of reduced ice concentration opened up. This was preceded (in time at least) by the formation of a large polynya in the Cosmonaut Sea in early-mid July. Interesting times! 29 July 1999. 4 August 1999: I’ve got to stop looking at the area. As soon as I wrote the above, the proto-polynya began closing back up. I’ll quit looking for a while, so you may find something happening again.

In 1998, while not a full-blown (large area of zero ice) polynya, there was less ice than usual in the Weddell Sea, in the same area as the giant Weddell polynya of the ’70’s.  Because the polynya is such a spectacular feature when it does occur, we have established this page to make it easier to keep track of the current state of the Weddell Sea ice pack.

Here is the June 1998 polynya (I’ve made a small change to the GIF animation to make it loop, previously it played only once):

jun98_Polynya

What I find most interesting about their claim is they act as if the 1974-1976 giant polynya was part of a “normal” activity there, saying it was “a more common feature of the Southern Ocean”, yet we only have a scant 40 years of satellite data to monitor such events. Suggesting that it is likely to never reappear based on modeling is just as nonsensical as the pronouncements we saw in 2000 that “snowfall is a thing of the past”.

The Earth’s mechanisms operate at much longer and slower timescales than 30-40 years, it has often made fools of climate scientists making projections of “phenomena disappearance” before, and I suspect it will again.

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Doug Proctor

When you limit your study to a small portion of both problem and observation, any conclusion is possible. Note that the “no” conclusion will be reached, but “any”.
Nature abhors a vaccum but so does a career path and grant application .

daddylonglegs

Muddle-headed wishful thinking. Total crap.

Brilliant work, very helpful to know about these matters deep ocean is supposed to hide the missing heat .. so there have to be a reason that we dont see much of it emerging, right?
(The “fresh water” on top of the ocean is supposed to explain the increase in ice area around Antarctica. Is it really true that the salinity has been declining in the upper waters for decades? And what is the mechanism supposed to have led to this?)
Thanks a lot, this article is a keeper..

Pamela Gray

So:
We won’t know what snow is.
We won’t know what polynyas are
We won’t know what drizzle is since it will all come down in downpours
What else will we not know?
I have one: We won’t know what good science is.

“… The 1970s polynya may have been the last gasp of what was previously a more common feature of the Southern Ocean, and which is now suppressed due to the effects of climate change on ocean salinity.”
Boy oh boy, that CO2 stuff can do anything. Got a problem? “Climate change” is the answer! (except with the wife; I tried that excuse last time I got in trouble and the girl turns out to be a dang skeptic!)

a jones

Ah I see. More warming means more ice which means that the heat can be stored undetected beneath it but which will accumulate and break out in a hundred years or so to warm the globe.
It is all so wonderfully clear is it not? .
Pshaw. I have heard much better tall tales than that.
Kindest Regards.

Pittzer

Funny. As I was reading this I was thinking if this happened every 40 years for the past million years it wouldn’t be so “rare” a phenomenon.

charles nelson

So let me get this straight… fresh water from melting ice is trapping ocean heat in Antarctica thus warming the oceans and keeping the Antarctic cold…….but in the Arctic open sea and fresh water caused by melting ice is allowing ocean [born] heat to escape into the atmosphere thus warming the Arctic ocean and the atmosphere of the Arctic?
Did I get that right?
Can I become a Climate ‘scientist’ please?

I’m not a climate scientist. I’m an expedited driver, so I have some good idea of conditions I’m likely to encounter in the American Midwest for professional reasons. So, I would not be so foolish as to declare myself an expert on Arctic/Antarctic climate/weather conditions. Having said that, however– I do not hesitate to call the idea that polynyas will disappear the leavings of the South end of a North-bound horse. More computer modeling, no doubt. I can model ANYTHING in a computer if I feed it the “right” data.

tty

The image of the Ross Sea polynya is pretty irrelevant, since there is always a polynya in the Ross Sea in summer (or at least there has been one every time the area has been visited since it was discovered by Ross in 1841).
Not so in the Weddell sea though it was apparently largely ice-free in 1823 when discovered by, you guessed it, Weddell, but as far as known this has never happened again. Instead the Weddell sea has been notorious för heavy pack ice, not polynyas. It took 90 years until somebody managed to get into it again (Filchner 1911-1912). His ship got caught in the ice but managed to get loose after drifting for a year. Shackleton tried next in 1914, but was less lucky, he got caught in the ice and had his ship crushed. The Weddell sea remained the last unmapped coastline on Earth until the Ronne expedition in 1947-48.
So, yes, I think it could be argued that open water is a rare event in the Weddell sea. There is certainly no evidence to the contrary.

KNR

“deep ocean heat remind me what actual data not model guesses they have on “deep ocean heat”

David Ball

Antarctic Bottom Water. Sounds refreshing,…..

The stories these paid shills (formerly known as scientists) are spewing, just keep getting more unbelievable, as their desperation sets in. They’re not fooling anyone.

Alan Robertson

When I saw that Nature Climate Change had published the work, I knew that my psyche was once again about to be battered with feelings of sadness and inadequacy at no longer being young enough to read through all of the pretzel- logic twists and incredulous propositions and emerge at the end of the article thinking that I “understood” what the authors were talking about.
Oh, to be young and stupid, again.

What a load of nonsense.

Nik

If less dense surface water stops heat coming up, logically should it not stop atmospheric heat reaching the depths?

ockham57

I am quite certain that if the frequency of polynyas was on the increase, after much careful study, the only reasonable explanation would be that it is unequivocally due to global warming.

The science is all settled but they keep on making all these new discoveries of which they had no previous knowledge. This gives them even greater confidence that the Science is settled, as they have just settled it again. They have 97% confidence that the grants will continue to roll on in, as long as they can continue to fool the public all of the time.

ed K

heat can tell the difference between salt and freshwater, I must have missed that class

gh

How does lower salinity water repel or block higher salinity? Don’t different concentrations tend to move into one another and mix? Maybe I’m missing something or didn’t read carefully.

Paul Westhaver

For those of you who understand the saline currents… (I don’t) Would not the warming of the planet increase the saline gradients poles to equator?
ie more polar melting > more fresh dense fresh water at the poles thereby forcing current flows to the equator where there is more evaporation and very high salinity but lower density water.
I am not an oceanographer.
Could the polynyas contribute to an increase in the conveyor belt? That is, I don’t see why the polynyas would suppress anything necessarily. What principle am I missing?

hunter

More desperate arm waving. “hiding the heat” is like Joe McCarthy hunting commies in the 1950’s.

Tom J

‘ “True to form, the polar Southern Ocean – as a wet place – has indeed become wetter. ‘
Um, can somebody explain to me how an ocean becomes “wetter”? I need this explained to me because I must admit that I was unaware that an ocean was a “wet place.” How wet can an ocean be? Is there a scale of wetness? Is there wet, wetter, and wettiest? Different shades of wetness? How wet can a wetty thing be if a wetty thing can be wet?
I have read plenty of ludicrous things concerning the effects of the cloven hoofed, pitchfork toting, all powerful CO2 molecule, but the gyrations presented in this article genuinely makes me wonder if we’ve reached a stage where our halls of higher education have taken what could’ve been rational human beings, and turned them into indoctrinated, enthusiastic, thoroughgoing idiots.

And, of course, the press release includes the obligatory it’ll-come-back-to-haunt-us clause.
Utter nonsense.

David Ball

Did anyone ask Chris Turney?

Tom J says: “Um, can somebody explain to me how an ocean becomes ‘wetter’?”
Thanks.

They need to get their story straight. Less saline surface waters are preventing “deep ocean heat” from warming the planet, thus “explaining” the warming halt. But the atmosphere is supposed to be the source of the heating! So any heat in the deep oceans must have come from a time when the atmosphere was cooler, so a connection between the atmosphere and the deep oceans should increase the rate of heat flow downwards, not upwards, and thus lessen cooling, while a disconnection should be making the heating go up even faster. Either way the halt is evidence against the theory, but this “explanation” makes their case even weaker.

Theo Goodwin

Excellent post, Mr. Watts. Also, a good read. (I really enjoy your “nature features.”) You are getting sharper with age.

Peter Miller

Of course, this stuff would only apply in the Antarctic.
The Arctic is different, of course, where salinity is not relevant and ‘deep ocean heat’ somehow does not come to surface. So there CO2 is the reason behind a slowly retreating summer icecap, but in Antarctica “rising deep ocean heat” somehow causes the icecap to expand.
Even by ‘climate science’ standards this is quite special.
In seeking grants for climate research, the following often/usually applies:”What a complicated web we weave, when first we start to deceive.”

David L

As soon as I read this part: “… The 1970s polynya may have been the last gasp of what was previously a more common feature of the Southern Ocean, and which is now suppressed due to the effects of climate change on ocean salinity.”, I stopped. It’s revisionist history to fit the AGW meme. No need to read further.

The old saying was that if you paid peanuts you get monkeys. These days you seem to get monkeys no matter what you pay. 🙂

Louis Hooffstetter

Their study… shows that the ocean’s surface has been steadily getting less salty since the 1950s. “This lid of fresh water on top of the ocean prevents mixing with the warm waters underneath. As a result, the deep ocean heat has been unable to get out and melt back the wintertime Antarctic ice pack.”
If this lid of fresh water has been progressively preventing mixing since the 1950s, how did all that heat get in the deep oceans in the first place? Remember that these rocket surgeons (and their predecessors) were telling us in the 70′s that global cooling was going to cause an ice age.
Climate witch doctors at work.

What gets to me is the talk of “warm” deep waters. The waters down deep in the oceans are quite cold, only a few degrees above freezing. Only in Antarctica could such water be called “warm,” because water up at the surface, if not frozen, is right at freezing.
Second, consider the fact they claim the water at the surface is “fresh.” If it was fresh, there would be a massive die-off of salt-water creatures. In actual fact it is only slightly less saline. I’m not sure of the details, but if the situation is anything like the situation in the arctic, the “freshwater lens” is still so salty that it will not freeze until nearly as cold as “ordinary” salt water. We are talking a difference of a tenth or two-tenths of a degree. Rather than freezing at minus-1.9 degrees the water freezes at minus-1.7 degrees.
Will this slight difference in salinity make all that much of a difference? Remember, the Katabatic winds come screaming down from the highlands at gale force, storm force, and even hurricane force, at temperatures that can be down below minus-fifty. They rip and tear at the surface water, freezing it nearly as rapidly as they drive the ice off-shore. Will a slight difference in salinity matter a hill of beans, in such extreme situations?
Lastly, consider the fact that having winds of fifty-below to nearly a-hundred-below churning open sea water freezes the water so swiftly that a veritable rain of salt (or salt brine) falls from newly formed ice. There are videos of the brine sinking in shallow places, and being so cold that it freezes starfish solid even as they crawl along the bottom. And, even with this rain of salt descending, these scientists are worried about the water being too fresh?
Amazing. Simply amazing.

hunter

And just for the record, the headline is inaccurate
The ARGO system indicates the deep oceans are not warming up.

Billy Liar

They don’t mention the elephant in the room: those katabatic winds. Do we have 40 years of history of the strength of the katabatic winds in the region? Thought not.

stan stendera

For Hunter above: The “commies” Joe McCarthy hunted turned out to be real according to Russian documents.

Theo Goodwin

Caleb says:
March 2, 2014 at 3:14 pm
Yeah, reminds me of another article discussed here a few months ago. Some climate scientists were claiming that there is less snow beneath fir trees than in open areas because of down radiation from the trees.

Bill Illis

I calculated once that glacial melt from the continent had no hope of changing the salinity conditions around Antarctica whatsoever. It has to come from fresh-water glaciers on land/ice-shelves. Since this amount of melting is extremely small in relative terms compared to the hundreds of thousands of sq./cubic kilometers of ocean, it can make no difference at all. The math does not work. Climate science papers never go this far. It is always just musing about the apocalypse rather than proving their point with the hard numbers.

Mac the Knife

“Although our analysis suggests it’s unlikely, it’s always possible that the giant polynya will manage to reappear in the next century,” Galbraith adds. “If it does, it will release decades-worth of heat and carbon from the deep ocean to the atmosphere in a pulse of warming.”
What pathetic drivel, pitched as catastrophism!
The asinine statements of unfounded conjecture contained in this statement alone shows clearly their ‘analyses’ were not motivated by scientific understanding of either emergent trends or chaotic behavior.

usurbrain

This theory does not seem to jive with a recent Discovery(?) show where they had an underwater shot showing a rivulet of melting water sink to the bottom of the Antarctic which enveloped and froze small creatures/plants (don’t remember what they were.) Fresh water would have had too low a SG to sink, and just where did the highly salty water that would have been heavy enough to sink come from?

Steve from Rockwood

Of the 19 professors listed on the McGill Atmospheric and Oceanic Studies, only 3 are at McGill while 5 are Emeritus. The rest are based at different universities including Penn State. What kind of department is that? And for that they have 8 administrative staff.
http://www.mcgill.ca/meteo/facultystaff

Steve from Rockwood

Mac the Knife says:
March 2, 2014 at 4:43 pm
————————————-
“… our analysis suggests … it’s unlikely that the giant polynya will manage to reappear in the next century…”
Fixed it for you. And I didn’t change their meaning, only the way they expressed their alarmism.

bushbunny

It is summer time in Antarctica right now. Or are they back dating, either way it is irrelevant.

JJ

hunter says:
More desperate arm waving. “hiding the heat” is like Joe McCarthy hunting commies in the 1950′s.

No. There actually were commies in the US in the1950s, and we now have confirmation from Russian commies that they were pretty much where Joe said they were.
Conversely, there wasn’t any global warming in the 1950s. Even IPCC admits that. Which makes one wonder how this happened:

Their study, published in Nature Climate Change, shows that the ocean’s surface has been steadily getting less salty since the 1950s.

Global warming is so magical, it can alter the salinity of oceans in the past.

RoHa

So global warming makes Antarctica warm and melts the ice.
This makes a layer of fresh water which traps warmer water underneath it.
The heat from the warmer water cannot get up through the fresh water, so the Antarctic gets cold.
Because it is cold, the fresh water freezes.
So warming the Antarctic makes it colder and melting the ice makes it freeze.
Have I got that right?

bushbunny

There are quite a few undersea volcanic vents in the seas around Antarctica. But fresh water comes from sea ice melts, and it is lighter than sea water I believe. So no marine life are there in fresh water they all go deeper. I just think this report is so out of date, why don’t they give a really update. Maybe will see the Southern lights in Australia, down in Tasmania perhaps. Because of the solar activity.

Harry van Loon

I thought it was common knowledge that polynyas form because of the wind pattern, but apparently it isn’t.

george e smith

Didn’t know that pollyannas were a critical part of Antarctic life, but now I do. So the fresh water blocks out the heat from the salt water.
I learn something new every day.
They do know that pumping heat to Antarctica, is a fools game. That place has no way to get rid of heat, so it will just warm the place up. And you can’t just keep going further south.

Lauren R.

Two questions (well three technically):
Is pretty much anything and everything caused by global warming now? Is that “science” settled?
Why is everything caused by global warming bad?

dwright

So there’s Ninja heat lurking in the deep oceans, waiting until we least expect it to strike.
Gotcha, I’ll try not to lose any sleep over that.