Retreating sea ice linked to changes in ocean circulation, could affect European climate
From the UNIVERSITY OF TORONTO
Retreating sea ice in the Iceland and Greenland Seas may be changing the circulation of warm and cold water in the Atlantic Ocean, and could ultimately impact the climate in Europe, says a new study by an atmospheric physicist from the University of Toronto Mississauga (UTM) and his colleagues in Great Britain, Norway and the United States.
“A warm western Europe requires a cold North Atlantic Ocean, and the warming that the North Atlantic is now experiencing has the potential to result in a cooling over western Europe,” says professor G.W.K. Moore of UTM’s Department of Chemical & Physical Sciences.
As global warming affects the earth and ocean, the retreat of the sea ice means there won’t be as much cold, dense water, generated through a process known as oceanic convection, created to flow south and feed the Gulf Stream. If convection decreases, says Moore, the Gulf Stream may weaken, thereby reducing the warming of the atmosphere, in comparison to today.
Their research, published in Nature Climate Change on June 29, is the first attempt to examine and document these changes in the air-sea heat exchange in the region — brought about by global warming — and to consider its possible impact on oceanic circulation, including the climatologically important Atlantic Meridional Overturning Circulation.
Previous studies have focused instead on the changing salinity of the northern seas and its effects on ocean circulation.
Moore and his fellow researchers based their findings on wintertime data from 1958 to 2014 that was provided by the European Centre for Medium-Range Weather Forecasts and model simulations.
Traditionally, the Gulf Stream moves warm water north toward western Europe, says Moore, where it loses heat and moisture to the atmosphere, acting to moderate the climate in this region. The resulting colder, denser water sinks and returns south at a great depth eventually rising to the surface in the tropics, where the cycle, known as the Atlantic Meridional Ocean Circulation, begins all over again.
The Iceland and Greenland Seas are among the only places worldwide where conditions are right and this heat exchange is able to change the ocean’s density enough to cause the surface waters to sink. The largest air-sea heat exchange in these seas occurs at the edge of the sea ice.
In the past, this region of maximum heat exchange has coincided with the location where oceanic conditions are optimal for convection to occur. However, in recent years, the sea ice has retreated and with it the region of maximum heat exchange. As a result, there has been a reduction in the heat exchange over the locations where sinking occurs in the ocean. This has the potential to weaken oceanic convection in the Greenland and Iceland Seas.
“The heat exchange is weaker — it’s like turning the stove down 20 percent,” says Moore. “We believe the weakening will continue and eventually cause changes in the Atlantic Meridional Overturning Circulation and the Gulf Stream, which can impact the climate of Europe.”
The paper’s other authors are Kjetil V?ge from the University of Bergen, Robert Pickart from Woods Hole Oceanographic Institution and Ian Renfrew from the University of East Anglia.
###
Update: The original headline was unintentionally misleading, a product of travel pressures today back from the Kennedy Space Center where I witnessed the SpaceX launch and explosion yesterday. Thanks to free WiFi at Dallas Love Field, he headline has been corrected to accurately reflect the article. My apologies to readers for the error. – Anthony
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Did they utilize the actual temperature and sea ice data, the ERA model outputs, or both?
If they did not utilize actual data, it may be premature to accept their conclusions.
Eh, except it’s not working that way. Colder, denser water at the surface does sink, of course, provided its density is higher than that of water masses below. However, it never rises to the surface again on its own against the gravitational gradient, least of all in the tropics, where the surface is warm, therefore water masses above are buoyant. The next thing that happens is the abyss gets saturated with cold, dense water and the meridional overturning grinds to a halt. Water, even at the ice margin, can’t get dense enough to sink any more, because it is already cold and dense all the way down.
Clearly, one needs an active process somewhere else, which replenishes buoyancy at depth.
That “other process” is deep turbulent mixing, which is not driven by thermodynamic forces, but by pure (low entropy) mechanical energy input, provided by tides &. winds. It is most active not in the “tropics”, but at mid latitudes, mostly over the Southern ocean and to a lesser extent, over the Northern Atlantic, at specific sites, intermittently. That’s what makes room below for more cold dense water to sink at the ice / water interface.
That is, the overall flux of meridional overturning is not set by surface waters ready to sink in polar regions, but by tides and winds elsewhere.
Of course, once deep waters get diluted by deep turbulent mixing, downwelling will occur in regions with the highest water density. As density of seawater depends on temperature, pressure and salinity, it is quite difficult to predict where it would happen, but we are not entirely clueless.
As long as there is an interface between ice and water anywhere on the face of the globe, it will happen somewhere next to it, because density of seawater, unlike that of fresh water, is highest just above freezing. What is more, ice crystals do not like salt very much, so upon freezing brine exclusion occurs, that is, salinity of water not frozen gets even higher, than it was before freezing started and with it, its density also increases.
Around the North Pole ice is restricted to a thin layer close to the surface, so in this region pressure does not have a role. Downwelling will happen at sites where salinity is highest and temperature is below freezing (-1.9 C).
However, it is an entirely different game around Antarctica. The ice / water interface there goes down to considerable depth at many sites, several hundred meters, even a kilometer. Therefore liquid water next to the ice can have a high pressure, up to a hundred atmospheres. Melting point of ice decreases with pressure, so these water masses are cold indeed, their virtual temperature is well below freezing (but they are still liquid). What it means is that such a water mass, if it were instantly brought to the surface, would freeze immediately. However, usually it sinks instead, because, being cold, its density is high even at a lower salinity.
The net result is that Antarctic bottom water is colder and denser than Atlantic deep water coming from North, but the latter has a higher salinity. When they meet around the equator at the bottom of the Atlantic basin, the Atlantic deep water forms a layer above Antarctic bottom water, then they start exchanging salts (but not heat) through salt fingering. In this process bottom water becomes even denser.
The ice margin is long and it goes down to a considerable depth at some sites, so its surface area is high. Along this surface downwelling will happen where density is highest, that is, at a few sites at any specific time. Those sites and times are dependent on climate indeed, but the overall downwelling flux not so much.
That is, downwelling may decrease in the North, but it will increase by the same amount in the South and vice versa. However, I do not think it will happen. Salinity of the Arctic basin is high all over the Atlantic side and sea ice will not go away entirely, least of all during Arctic winters. That is, downwelling will still happen at the ice margin, even if it is displaced, sucking in somewhat warmer waters from the South at the surface.
What is still true however, is that only a slight displacement may have dramatic effects on regional climate, while next to none on global one.
But that’s not what they’re trying to tell us.
except that it isn’t…
http://polarview.met.no/regs/c_map1.jpg
I’m having a hard time, not withstanding all the fine print in the lower left corner, in identifying the coastline of this map – perhaps you can shed some light ?
Greenland on the left, northern Norway at the bottom, Siberia on the right.
Thanks Sir … popped right out of your reply .
Hmmm! I’ve heard of the Greenland sea but not the Iceland sea. Didn’t I read that there was more ice off of the east coast of Greenland and around Iceland than usual this past winter?
Darling?
Yes Dear.
Where’s the thermostat for the planet?
I think the last place I saw it was uh…near Greenland.
So…a strong Gulf Stream is putting more warm water into the Arctic Ocean, which is reducing ice cover, which will change the pattern of oceanic convection, which will weaken the Gulf Stream, which will cool the Arctic Ocean, which will result in more ice cover, which will change the pattern of oceanic convection, which will strengthen the Gulf Stream, which will reduce the ice cover.
Repeat as required.
I’d like Willis to have a look at this to see if we have another negative feedback providing self correction for the system.
hmmmm. I don’t think it matters which Arctic street corner evaporation and heat release occurs. The current will continue to bring warmed water into the Arctic pole area where it will eventually get cold enough to start the process, even in Summer. And without an ice cover, the more the better. I am thinking evaporation and sinking might even be faster. I would even guess that this already happens seasonally. The Gulf stream naturally meanders into the Arctic further in the Summer, cools off, sinks, and goes on its merry way, while in Winter it doesn’t meander quite as far, cools off, sinks, and goes on its merry way.
Idiots.
Since the big dogs have their paper behind a paywall, I want sloothing. I found a doctoral thesis. K. Moore, one of the authors of the above paper was a part of Marilena’s committee. Notice the connection to Woods Hole and the submission data. What do you want to bet she did some of the grunt work on the above study.
“Strong wind events across Greenland’s coast and their influence on the ice sheet, sea ice and ocean”
by Marilena Oltmanns
B.S. in Earth and Space Sciences, Jacobs University Bremen (2009)
Submitted in partial fulfillment of the requirements for the degree of
Doctor of Philosophy
at the
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
and the
WOODS HOLE OCEANOGRAPHIC INSTITUTION
June 2015
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=10&cad=rja&uact=8&ved=0CGMQFjAJ&url=https%3A%2F%2Fdarchive.mblwhoilibrary.org%2Fbitstream%2Fhandle%2F1912%2F7353%2FOltmanns_Thesis.pdf%3Fsequence%3D1%26isAllowed%3Dy&ei=CcyRVZXZApetoQTQyoWIDA&usg=AFQjCNEld-Q7XPQBVWAwKaxqGL6dtaHaeg&sig2=puWRtuZ4JRXcd_T-J_e4GQ&bvm=bv.96783405,d.cGU
They seem to say that it matters where the maximum heat exchange happens.
You point out that there should be more total heat exchange. That’s true. Ice is an insulator and water below the ice loses heat much slower than it would if it weren’t covered by ice. With less ice, the system as a whole should lose heat more quickly.
We can’t see the paper so we can’t tell if they have dealt with the obvious problem that you point out.
This seems to be exactly what they did. They used a fixed distance from the sea ice extent to measure heat flux, giving them a fixed area that migrated over time for which heat transfer was measured. The heat transfer of this fixed area decreased as it migrated north, but they ignored the area where they were previously measuring as if it were insignificant because it was no longer the area of maximum heat transfer. Adding in the old areas would probably erase their 20% discrepancy. Or, maybe not, and this is the reason for the pool of abnormally warm water off the coast of Nova Scotia.
The articles’s claim is a gigantic stretch, to put it mildly.
“As global warming affects the earth and ocean, the retreat of the sea ice means…”
No point reading any further than that, it’s baloney. Increased forcing of the climate increases positive NAO, and that means a faster AMOC and a cooler Arctic and less ice melt.
That the AMO has warmed since 1995 nearly as fast as from 1925, shows how little increased GHG’s have inhibited that warming.
Maurice Ewing understood the Arctic better in the 1950s than most people do today.
He always asserted that low sea ice caused cooling.
He may have, without knowing it, discovered the AO. When the Jan Feb Mar indices is below climatological average, cold outbreaks occur outside of the normally constrained Arctic Circle making us shiver https://nsidc.org/cryosphere/arctic-meteorology/weather_climate_patterns.html. Then again, he may have discovered that weather pattern variation and regimes shifts are a wickedly complex problem to figure out https://www.ncdc.noaa.gov/sotc/synoptic/201505.
But let’s give him the benefit of the doubt. Notice that the AO may provide clues about sea ice buildup and sea ice being flushed South. http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/JFM_season_ao_index.shtml. When it is heading up, sea ice build up, likely because of a tight vortex and jet stream keeping cold air and ice building up in the Arctic circle. When it is heading down, sea ice decreases, likely because of a less tight vortex and jet stream sending cold air and ice out of the Arctic.
Pamela Gray:
I see a similarity between your link:
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/JFM_season_ao_index.shtml
JFM AO, and this one from Francis:
In her plot, Fall and Winter have fallen off the table, though I’d wish she’d update it. I think the NH jet stream patterns are telling us something. Meridional or wavy is mixing and atmospheric cooling, and zonal or rigid is atmospheric warming. I hadn’t connected that to sea ice until I read your comment. If the Arctic is cut off by zonal flow – building sea ice. If it’s mixing – losing sea ice. If JFM AO continues into negative territory, we should continue with a mixing air flow, the pause, yet lose NH sea ice. When we lose insulating sea ice, this not alarming, as the ocean would be cooling.
Yes. I have noticed several papers related to wind regime shifts.
“Meridional or wavy is mixing and atmospheric cooling, and zonal or rigid is atmospheric warming”
Correct. I’ve been pointing that out since 2008.
After a while, though, the cooling of the system allows an increase in ice despite increased air flows in and out of the polar regions.
Latest version of my hypothesis here:
http://joannenova.com.au/2015/01/is-the-sun-driving-ozone-and-changing-the-climate/
Stephen Wilde:
At your link there are two diagrams, inactive and active sun. I like to test my ideas against the glacial/interglacial cycle. What works now, should work on long time scales. What jet stream pattern do you think is predominant during a glacial and then an interglacial? My guess is that during a glacial we have zonal flow to preserve life towards the equator. During an interglacial meridional flow sets up to move heat to the poles and to prevent overheating of the equatorial regions. I am guessing ice expands to provide insulation for a glacial and contracts to provide cooling otherwise.
Ragnaar.
The ice age / interglacial transitions are driven more by insolation changes during the Milankovitch cycles than by insolation changes from variations in global cloudiness caused by solar behaviour.
Otherwise you make a good point in that once glaciations are in progress they push the jets so far equatorward that their ability to wave about meridionally is reduced so one would see a more intense zonal flow around the ice perimeter.
My hypothesis is limited to the effects of solar variability within the current interglacial.
“Maurice Ewing understood the Arctic better in the 1950s than most people do today.
He always asserted that low sea ice caused cooling.”
Certainly there is regional cooling for example in the northeast US and northwest Europe at the same time as low sea ice, that does not mean that the low sea ice caused the regional cooling though.
They are both the result of negative NAO/AO episodes, which are caused by short term episodes of weaker solar forcing. Increased forcing of the climate increases positive NAO/AO and cools the Arctic, which is what the Sun did though 2013-2014. But it won’t last, the next ten years will see the weakest part of this solar minimum, and a sharp rise in negative NAO/AO, and many summers with low sea ice extent again like 2007 and 2012 and worse.
Arctic amplification is bunkum, what explains the accelerated Arctic warming since the mid 1990’s, is the decline in solar wind pressure increasing negative NAO/AO, increased forcing of the climate cools the Arctic by increasing positive NAO/AO.
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-3-5-6.html
Don’t these people know that much of the melt is from UNDERNEATH THE ICE, precisely because of the Gulf Stream waters and not CO2 and global warming from the top. If these currents are interfered with, it will be much more than the UK’s children continuing to see snow. The arctic ice will thicken rapidly, less seawater will be exposed and northern Europe will join Svalbard as ice bound land masses. Hey, climate scientists don’t know enough to be effective forecasters so they shouldn’t ignore what we do know.
Then why does Sept Arctic sea-ice minima strongly correlate with spring melt-ponds?
http://www.nature.com/nclimate/journal/v4/n5/full/nclimate2203.html
Gary Pearse is exactly right.
In fact, I would go further. In many places most of the melt is from underneath.
My previous organization camps on the ice in the arctic archipelago. The camp constructs an airstrip on the ice because it is much smoother than the adjoining land. The ice thickness is a ‘big deal’ because the airplanes won’t land if the ice is too thin. That means it is necessary to pack up and leave in early May. The temperature is still well below freezing but the ice has thinned enough that the plane is willing to make only one last flight.
By the time melt ponds appear a couple of months later, most of the ice thickness is gone.
I really don’t get all this Arctic sea ice panic and worrying.
Biological markers clearly indicate that during the first half of the Holocene, Arctic sea ice was seasonal at most. There are ports on the north coast of Russia, which haven’t been open of a long time.
The current level of sea ice is ANOMALOUSLY HIGH compared to the last 10,000 years, mainly because the planet is still only just above the coldest period in the whole 10,000 years of this current interglacial.
The AMO is flipping already. Cold N Atlantic and MDR are happening. Where is JB with the graphic? He has been talking about that for a while. I dont have the links in my phone….. dangit.
Dude, did you even read the first sentence of the press release before writing the headline? You’ve inverted the findings of the study.
Confirmation bias rears it head…
People see what they want to see, regardless of what is there…
…or family and/or business forced a cursory read and a quick post. Been there, done that.
If so, there is hope that the Tile will be revised …
But note how many commenters swallowed the title raw. [judging from only a handful complaining].
I forgive Anthony’s title mixup because I judge it might be closer to the truth than the press release about the paper.
Doc, Anthony did say he was traveling this weekend. Tired perhaps,
michael
glad U said that instead of me.
This place is more of a social hangout for many of the participants. Think many are aware of the bias (one hopes) but don’t care.
You are probably right. And many enjoy flaunting their bias, that is, after all, what we all have in common.
Headline fixed, tired, distracted, pressed for time. Sometimes it’s better to wait. Thanks to all who pointed out my error.
Leif writes You are probably right. And many enjoy flaunting their bias, that is, after all, what we all have in common.
Sarcasm? I’m here because I’m naturally sceptical and like to see what sceptical arguments are put forward. Pro AGW sites tend to make the supportive argument only. Some are better than others of course…but WUWT is the most popular for a reason…
Sea ice: it comes and it goes
Maybe they should find out what that big rift down the middle of the Atlantic ocean is doing, They are not above ignoring volcanic activity, specifically in areas of ice loss, especially when it suits their agenda. I see they do not note increased snow cover on land masses, increased ice in the great lakes.. ect ect. I see a lot of could, may, might and possibly but no has, did or even a solid will. Its crap science with enough outs to make it useless.
Off topic.
I think ISIS has been a blessing in disguise for conservatives here in the U.S. Obama really wants it to go away so he and his left wing cronies can get on with fundamentally changing us to a socialist hellhole. If it weren’t for the threat of ISIS, and people having that reality of the real world hanging over their heads, many would quietly go down that idiot path to socialist bliss.
“may be changing the circulation”
“could ultimately impact the climate”
“has the potential to result in a cooling”
Weasel words everywhere – that’s not science.
Science attributes probability and error bars.
Would you read that?
The AMO is currently at the tail-end of it’s 30 year WARM cycle (started in 1994) and is expected to switch to its 30-yr COOL cycle around 2022 (the same year the weakest solar cycle since 1715 starts).
The PDO entered its 30-yr cool cycle in 2008, and already Arctic sea ice is growing on the Pacific side of the Arctic.
The warmunists have to devise excuses now to account for the cooling that’s already started. That way, when a cooling trend becomes irrefutable even with the highly “adjusted” temperature datasets, they can point to these old silly pal-reviewed papers and say, “See, the cooling trend was predicted years ago– warming causes cooling….”
It’s like that old parlor trick, where numbers are pre-written on the bottom of various items on a desk, and when someone is asked to pick a number between 1 and 10, the person is asked to look at the bottom of the item that corresponds to the chosen number— Voila!, clairvoyance!! …
CAGW has become a cheap parlor trick to fool the foolish..
The Gulf Stream is primarily caused by the Coriolis Effect of a spinning Earth…. When the Earth stops spinning, the Gulf Stream will stop… I don’t see that happening anytime soon….
From the apparent period of the AMO alone, it would be cooling again in the mid 2030’s, and reach its coldest in the mid 2040’s. And if you could predict that the solar wind will be fast and dense in the mid 2040’s as it was through the mid 1970’s, then you could be certain of that being the next coldest point.
It’s very interesting then to see from the data that Arctic ice has become much thicker over a larger area as we enter the new Little Ice Age.
The proof is very simple: the onset of melting of thick ice, shown by a sudden fall in the rate of reduction of area, is a month earlier this year: http://ocean.dmi.dk/arctic/icecover.uk.php
^As global warming affects the earth and ocean, the retreat of the sea ice means………..”. With two decades of global temperature stasis, Arctic sea ice above its minimum and Antarctic sea ice above its long term average I would say the entire paper, and all the conjecture resulting from it, is irrelevant.
“The PDO entered its 30-yr cool cycle in 2008, and already Arctic sea ice is growing on the Pacific side of the Arctic.”
Really ?… well SST’s around the Bering sea don’t seem to agree with you.
http://www.ospo.noaa.gov/data/sst/anomaly/2015/anomnight.3.30.2015.gif
http://www.ospo.noaa.gov/data/sst/anomaly/2015/anomnight.6.29.2015.gif
In the past many scientific papers used SIDC’s sunspot numbers, thus to reproduce results of their findings access to the ‘old’ uncorrected SIDC’s sunspot numbers is essential, but they may (or may not) be available from the 1st of July.
For time being the ‘old’ uncorrected SIDC’s sunspot numbers may be found HERE
Except it seems ocean currents have not changed in any significant way……
It seems to me the currents change naturally. How much ice there is does not affect the current. Probably the current is about to change — not as much warm water flowing into the arctic ocean and the ice will return. Amount of ice in the arctic is cyclical based upon where the current is flowing. England will probably warm a bit as the arctic ice increases.
It is too late and I am falling asleep. good night all.
Eugene WR Gallun