Posted on 08/31/2012 2:10:24 PM PDT by Ernest_at_the_Beach
Reposted from the Hockey Schtick
A new paper published in Nature Geoscience finds “From about 50,000 to 11,000 years ago, the central Arctic Basin from 1,000 to 2,500 meters deep was … 1–2°C warmer than modern Arctic Intermediate Water.” This finding is particularly surprising because it occurred during the last major ice age.
Horizontal axis is thousands of years ago with modern temperatures at the left and 50,000 years ago at the right. Temperature proxy of the Intermediate Water Layer of the Arctic Ocean is shown in top graph with degrees C anomaly noted at the upper right vertical axis. Note this graph is on an inverse scale with warmer temps at the bottom and colder temps at the top. |
Here’s the paper:
Deep Arctic Ocean warming during the last glacial cycle
T. M. Cronin, G. S. Dwyer, J. Farmer, H. A. Bauch, R. F.
Spielhagen, M. Jakobsson, J. Nilsson, W. M. Briggs Jr &
A. Stepanova
Nature Geoscience (2012) doi:10.1038/ngeo1557
Abstract:
In the Arctic Ocean, the cold and relatively fresh water
beneath the sea ice is separated from the underlying warmer
and saltier Atlantic Layer by a halocline. Ongoing sea ice
loss and warming in the Arctic Ocean have
demonstrated the instability of the halocline, with
implications for further sea ice loss. The stability of the
halocline through past climate variations is unclear.
Here we estimate intermediate water temperatures over the
past 50,000 years from the Mg/Ca and Sr/Ca values of
ostracods from 31 Arctic sediment cores. From about 50 to
11 [thousand years] ago, the central Arctic Basin from
1,000 to 2,500m was occupied by a water mass we call
Glacial Arctic Intermediate Water. This water mass was
1–2°C warmer than modern Arctic Intermediate Water,
with temperatures peaking during or just before millennial-scale Heinrich cold
events and the Younger Dryas cold interval. We use
numerical modelling to show that the intermediate depth
warming could result from the expected decrease in the flux
of fresh water to the Arctic Ocean during glacial conditions,
which would cause the halocline to deepen and push the
warm Atlantic Layer into intermediate depths. Although not
modelled, the reduced formation of cold, deep waters due to
the exposure of the Arctic continental shelf could also
contribute to the intermediate depth warming.
(updated higher quality graph thanks to Roger “Tallbloke”)
fyi
I didn’t know paper had advanced to the point where it could make independent findings.
That warming period was natural. It wasn’t - in other words - caused by Republicans, which are obviously not part of the natural world.
Therefore it was all right, and the “hockey stick” model is still valid.
Obviously the authors of this paper didn’t understand Science.
Did they find the remains of drowned polar bears?
Guess I will look at the comments....seems to be an unusual graphical method....at least to me.
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Theodore says:
“Quinx says:
August 29, 2012 at 7:29 am
Interesting. Perhaps the real cause of increased summer ice melt is the reduction in cold fresh water reaching the Arctic Ocean following the damming and diversion of many large rivers in North America and North Asia for agriculture.”
I recall some articles on cyclical current shifts taking water from northern Russian rivers in different directions. Under some current conditions, that fresh water moves east toward the Berring Strait which is a natural chokepoint keeping fresher water in the Arctic making ice formation a lot easier. In the current conditions, that water is flowing west toward the North Atlantic where it disperses more easily and is a smaller influence on a much larger body of water.
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We don’t need ice, we can make it.
As this occurred during an ice age, presumably there would have been rather more (i.e. thicker) ice on the surface than we’re used to. Assuming that the warmth probably originated, then as now, from undersea volcanoes, could it just be basically a case of better ‘insulation’ preventing it from escaping?
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vukcevic says:
This finding is particularly surprising because it occurred during the last major ice age.
Inflow of warm heavier salty water from the N. Atlantic’s currents would circulate at some depth below lighter fresh water, while totally frozen surface would prevent any mixing due to tides or storms above; thermo-haline circulation had ideal conditions.
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Steven Mosher says:
yup vuc!
And as we observed this past melt season when the ice is thin storms can induce mixing of the warmer saltier water to the surface where it really does a nice job of melting the ice.
All you have to do is look at bouy data to see the large disturbances the storm caused in the vertical structure of the ocean column.
it’s not surprising that deeper water would be warmer during that period. no open surface no chance to see what we witnessed this season.
Not sure why people think this is surpising. maybe cause the read the word ‘warmer’ and didnt follow what happened during this past storm to the vertical structure.
of course, before the storm hit people at nevens were already explaining what would happen.
and, yup, they were right. ekman pumping. cool stuff. amazing what you can learn if you keep an open mind.
here of course people argued that there would not be a storm. argued that it would have no effect and argued that it was common.. then, of course, they changed their minds about all of that.
now they argue that the storm was rare and that all the ice disappeared because of it. go figure.
There is a lesson in their somewhere
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Crispin in Waterloo says:
Building on Steven and Vuc:
Solar salt water ponds were develop in the early 80′s by some Israelis, looking at natural formations at hot springs, I believe. The idea is that if you have increasing salinity with depth (usually in steps) you can maintain at the bottom a much hotter body of water than at the top, somewhat contradicting the axiom that hot water rises. By putting these stratified salty layers into a pond with the bottom painted black, solar heat warms the lowest layer, to quite high temperatures like 60 C.
The process of placing salty water from the Atlantic under the cooler water above, with different quantities of water for both, can lead to unexpected warmth trapped at depth.
Disturbing the carefully balanced layers could cause what can be termed disruptive mixing which allows the structure to progressively collapse across a whole region. The result would be a sudden (faster than usual) melting of ice from the untrapping of the heat, followed by a lower than average temperature throughout the water column (because the heat is lost more efficiently from the warmer surface).
To have a 1-2 degree difference over sugh a depth would be easy if the water is slightly saltier (denser). That heat is not collected locally of course, it is imported.
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Philip Bradley says:
Not really surprising. Sea ice is an insulator. The Earth has a net heat loss from the Arctic. Increase the sea ice and less heat is lost.
This confirms that increased snowfall and snow accumulation on land causes the glacial phases of ice ages. The metric to watch is NH winter snowfall, which has increased about 20% over the last decade.
Lol, technology marches on.
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Ike says:
Don´t know where to put it, but Pierre has a great piece on his blog:
http://notrickszone.com/2012/08/29/new-major-film-featuring-top-climate-scientists-exposes-climate-change-hoax/
just click watch now, enter you edress an watch that film.
Regards Ike
Let me go through my archived floppy disks and get back to you. /s
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| GGG managers are SunkenCiv, StayAt HomeMother & Ernest_at_the_Beach | |
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Thanks Ernest. |
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Continental glaciers are causes by larger amounts of snow in high northern latitudes that does not melt in the Summer. A warmer Arctic ocean would increase winter snows in the north.
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