Two new studies summarized in a news article in Science magazine point to wind-induced circulation changes in the ocean as the dominant cause of the recent ice losses through the glaciers draining both the Greenland and West Antarctic ice sheets, not ‘global warming.’
The two stuides referred to are:
‘Acceleration of Jakobshavn Isbræ triggered by warm subsurface ocean waters’ by Holland et al, published in Nature Geoscience.
The Abstract states:
Observations over the past decades show a rapid acceleration of several outlet glaciers in Greenland and Antarctica1. One of the largest changes is a sudden switch of Jakobshavn Isbræ, a large outlet glacier feeding a deep-ocean fjord on Greenland’s west coast, from slow thickening to rapid thinning2 in 1997, associated with a doubling in glacier velocity3. Suggested explanations for the speed-up of Jakobshavn Isbræ include increased lubrication of the ice-bedrock interface as more meltwater has drained to the glacier bed during recent warmer summers4 and weakening and break-up of the floating ice tongue that buttressed the glacier5. Here we present hydrographic data that show a sudden increase in subsurface ocean temperature in 1997 along the entire west coast of Greenland, suggesting that the changes in Jakobshavn Isbræ were instead triggered by the arrival of relatively warm water originating from the Irminger Sea near Iceland. We trace these oceanic changes back to changes in the atmospheric circulation in the North Atlantic region. We conclude that the prediction of future rapid dynamic responses of other outlet glaciers to climate change will require an improved understanding of the effect of changes in regional ocean and atmosphere circulation on the delivery of warm subsurface waters to the periphery of the ice sheets.
And:
‘Modelling Circumpolar Deep Water intrusions on the Amundsen Sea continental shelf, Antarctica’ by Thoma et al, published in GRL.
The Abstract states:
Results are presented from an isopycnic coordinate model of ocean circulation in the Amundsen Sea, focusing on the delivery of Circumpolar Deep Water (CDW) to the inner continental shelf around Pine Island Bay. The warmest waters to reach this region are channeled through a submarine trough, accessed via bathymetric irregularities along the shelf break. Temporal variability in the influx of CDW is related to regional wind forcing. Easterly winds over the shelf edge change to westerlies when the Amundsen Sea Low migrates west and south in winter/spring. This drives seasonal on-shelf flow, while inter-annual changes in the wind forcing lead to inflow variability on a decadal timescale. A modelled period of warming following low CDW influx in the late 1980’s and early 1990’s coincides with a period of observed thinning and acceleration of Pine Island Glacier.
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What are they doing here, actually trying to do a scientific study? Don’t they know that the science is settled? Global warming causes everything. Everybody knows this. They must be in the pay of big oil or big coal or big whatever. /sarc off>
What these studies do appear to show is that the reality is a lot more complicated than any AGW press release.
The flow of ice into the North Atlantic down the East coast of Greenland is really noticeable.
Lots of similar work out there….note the dates…..
From Koberle et al:
Two other papers:
Rigor et al suggests that Arctic warming is not melting the ice, but thinner ice is warming the arctic.
Holloway et al suggests that shifting winds are responsible for ice thickness change.
AGW changed the atmospheric circulation. Didn’t you know that. God forbid it should be of natural causes.
I wonder if this change in glacier melt is caused by the AMO ( atlantic multidecadal oscillation ) which was warming during the 90’s and is incidently now entering a cool phase. The AMO correlates well with global temperature variation over the past 100 years, not as well as CO2 but the two together give a pretty good fit.
The papers, now I read the full text does suggest AMO as the cause for the the Arctic and ENSO and SAO for Antarctica.
Do you notice the great blue hole that appears over the volcano in 1999? Supposedly clouds covered the area so no one know if the area was open sea or warmer ice, or what. Andy Revkin knows someone who can get the photos, and I’d like some meteorologists to look at the clouds to see if they are normal Arctic clouds or the sort of clouds that would appear over open water or warmer ice. I don’t think anyone knows for sure what effect the volcano of 1999 had. I submit that you can see its effect, first with the great blue spot suddenly appearing, surrounded by thicker stuff, then the dissolution of the spot as it moves south, finally flushed out in 2001 and carrying some old ice with it.
Just go look and see; the spot is right over the ridge, in the approximate area of the volcano.
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REPLY: huh???? what volcano are you talking about? -Anthony
AO, AMO, PDO, ENSO, NAO
Plus the interaction between them. These authors suggest that all temperature anomalies of the 20th century can be explained by major cycles and their interactions.
Click here for Science Daily article
“American Geophysical Union (2007, August 2).
Synchronized Chaos: Mechanisms For Major Climate Shifts.”
and thanks to the moderator for cleaning up my HTML. Its appreciated.
Kim ok I think I did see a blue spot at 1999…
Kim, I went through the animation step by step and extracted an image. Is this what you are referring to?
http://wattsupwiththat.files.wordpress.com/2008/10/20070822_oldice-1999-225.gif
Yes, Anthony; it is approximately over the volcano on the Gakkel Ridge which erupted in 1999. The cloud photos are satellite ones, and hard to get.
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This is so off topic, but I was reading on EUReferendum dot com and saw this:
“…Smurfit School of Business and the Management Institute of Paris”
Have a Smurferiffic day! La la la la la la, Laaa la la la laa…La la la la la la, la la la la laaa……
That fast animation of the arctic reminds me of a beating heart. It’s still beating.
Anthony,
This is what Kim is referring to. She brought this up some months ago as well.
http://environment.newscientist.com/article/mg19826625.800
It is said there wasn’t enough heat from the volcano(s) to affect the Arctic ice melt.
Winds are Dominant Cause of Greenland and West Antarctic Ice Sheet Losses
Doesn’t look much like the Antarctic to me. 🙂
Mauna Loa September CO2 number is almost exactly on the trend line.
I predict that in a few months we’ll never even be able to see the little stumble. After all, the new carbon economy will require a very stable and trustworthy data set.
I’ve been reading this very interesting Watts site for some time (thank-you) and previous to that I was looking into the solar based weather forecasts made by a man called Piers Corbyn in the UK. You’ve probably heard of him but if not I thought these links may be of interest to your readers. I personally studied his stuff and found him to be accurate to what he says which took some time to glean from the forecast indexes. He doesn’t believe CO2 drives the weather at all. An article about spotless sun by Piers http://co2sceptics.com/news.php?id=1771
Main site http://weatheraction.com/
Global Forecasts http://www.lowefo.com
Cheers, Ed.
As predicted by the objective scientists, (as opposed to the warmers who predicted the Arctic would be free of ice nearly in perpetuity as a result of global warming according to media reports), the ice has rapidly refrozen in the Arctic over the past three weeks (an increase of 780,000 km2) as it has every year for probably a very long time (if not for the entire timeline noted in the following paragraph).
As predicted by the astronomers, the North Pole has gone into 24 hours of darkness (as opposed to the warmers who have no idea this kind of thing can actually happen) for the next six months as has happened every year for the last 4.5 billion years and it will continue to get colder until the North pole reaches its normal middle of winter -40C to -60C.
It is interesting to note, wind…or the moon’s gravity, can load up a bay with water then instead of the water relaxing back from whence it came learn it may escape down a trough to emerge at a far distance to effect a change in weather.
Celestial influence on ocean currents, weather, climate!? are computer models tuned into the horoscope?
“the ice has rapidly refrozen in the Arctic over the past three weeks (an increase of 780,000 km2) as it has every year for probably a very long time”
Looks like a swifter rebound than the average:
http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png
I wonder if anyone would publicize a record increase, if it so happens.
“What actually happening during July, August and September has now been analysed by the same scientists. They found that the summer melting period for 2008 was unusual in that more first-year ice survived at the end of the 2008 summer compared to 2007. This was due to a combination of factors, such as the more northerly latitudes where the first-year ice was found, the warmer temperatures, and winds that had not compacted the ice as they had done in 2007. As a result, 2008 came second to 2007 in terms of record melting of sea ice – and the North Pole remained iced up.”
http://www.independent.co.uk/opinion/commentators/steve-connor-bets-still-on-for-icefree-north-pole-949661.html
More first year ice didn’t melt because of warmer temperatures. I wonder if this is just a typo.
Re: Glenn (22:26:41) :
Unlikely, since the Independent is one of the UK’s leading warmist alarmist papers. They probably have some convoluted chain of reasoning that will ‘prove’ that warmer temperatures result in less ice melting. After all, ‘climate change’ predicts (supposedly) more unusual weather patterns, and warm temperatures resulting in less melting is certainly unusual, you have to admit. Therefore, since this is unusual behaviour, climate change must be responsible for it. Obvious, really, when you don’t think about it.
This article has a few more details about Gakkel Ridge and thermal activity:
http://news.bbc.co.uk/2/hi/science/nature/1760271.stm
The map of Gakkel Ridge reveals that the ridge is enormous. It practically bisects the Arctic. Besides that and the recent eruptions, the surveyors were very surprised by the ongoing thermal activity.
“We have completely unexpected results,” said Charles Langmuir, of Columbia University. “The ocean ridge below the Arctic is completely unique. We found 12 new volcanoes where we expected to find none, and we found unexpected and abundant hydrothermal activity.”
“Our discovery of these signals clearly show that hydrothermal vents similar to those present on faster-spreading mid-ocean ridges are present in abundance here, too” said Henrietta Edmonds, of the University of Texas.
According to Charles Langmuir the expedition “found more hydrothermal activity on this cruise than in 20 years of exploration on the mid-Atlantic ridge”.
If the animation above had a white line showing the exact location of Gakkel Ridge, I believe it would be enlightening. Could this slightly warmer water have affected the ocean currents in the region? Or the wind currents? The clouds? Could the recent eruptions have increased the reported “unexpected and abundant hydrothermal activity” over the past decade? Twelve volcanoes? How many erupted? Wow.
The melting Arctic is one of the last remaining “wheels” supporting the AGW hypothesis. I think it’s getting a little wobbly.
One more question and then back to bed. Does the topography of the ridge actually direct the prevailing currents upward to flow across the bottom of the icecap?