[Note: part of the answer is in the photo they provide with the press release below, but they don’t see it. – Anthony]
Greenland melting due equally to global warming, natural variations
The rapid melting of Greenland glaciers is captured in the documentary “Chasing Ice.” The retreat of the ice edge from one year to the next sends more water into the sea.
Now University of Washington atmospheric scientists have estimated that up to half of the recent warming in Greenland and surrounding areas may be due to climate variations that originate in the tropical Pacific and are not connected with the overall warming of the planet. Still, at least half the warming remains attributable to global warming caused by rising carbon dioxide emissions. The paper is published May 8 in Nature.
Greenland and parts of neighboring Canada have experienced some of the most extreme warming since 1979, at a rate of about 1 degree Celsius per decade, or several times the global average.
“We need to understand why in the last 30 years global warming is not uniform,” said first author Qinghua Ding, a UW research scientist in atmospheric sciences. “Superimposed on this global average warming are some regional features that need to be explained.”
The study used observations and advanced computer models to show that a warmer western tropical Pacific Ocean has caused atmospheric changes over the North Atlantic that have warmed the surface by about a half-degree per decade since 1979.
“The pattern of the changes in the tropical Pacific that are responsible for remarkable atmospheric circulation changes and warming in Greenland and the Canadian Arctic are consistent with what we would call natural variability,” said co-author David Battisti, a UW professor of atmospheric sciences.
Researchers say it’s not surprising to find the imprint of natural variability in an area famous for its melting ice. In many of the fastest-warming areas on Earth, global warming and natural variations both contribute to create a “perfect storm” for warming, said co-author John “Mike” Wallace, a UW professor of atmospheric sciences.
The natural variations in the new study related to an unusually warm western tropical Pacific, near Papua New Guinea. Since the mid-1990s the water surface there has been about 0.3 degrees hotter than normal. Computer models show this affects the regional air pressure, setting off a stationary wave in the atmosphere that arcs in a great circle from the tropical Pacific toward Greenland before turning back over the Atlantic.
“Along this wave train there are warm spots where the air has been pushed down, and cold spots where the air has been pulled up,” Wallace said. “And Greenland is in one of the warm spots.”
In previous studies, Wallace and Battisti have documented the existence of decades-long climate variations in the Pacific Ocean that resemble the well-known shorter-range El Niño variations.
This particular location in the tropical Pacific may be a sweet spot for generating global atmospheric waves. A series of studies led by co-author Eric Steig, a UW professor of Earth and space sciences, working with Ding and Battisti, showed that waves starting in the same place but radiating southward are warming West Antarctica and melting the Pine Island Glacier.
Researchers can’t say for how long the tropical Pacific will remain in this state.
“Our work shows that about half of the warming signal in Greenland comes from the predictable part – forcing of climate by anthropogenic greenhouse gases – but about half comes from the unpredictable part,” Steig said.
This makes shorter-term forecasts difficult, but helps scientists to make more accurate long-range projections.
“Nothing we have found challenges the idea that globally, glaciers are retreating,” Battisti said. “We looked at this place because the warming there is really remarkable. Our findings help us to understand on a regional scale how much of what you see is human-induced by the buildup of CO2, and how much of it is natural variability.”
The dramatic message of “Chasing Ice” remains true, authors say.
“There’s nothing in this paper that negates the message in the movie,” Wallace said. “Ice appears to be exquisitely sensitive to the buildup of greenhouse gases, more than we ever would have thought.” Natural variations could either accelerate or decelerate the melting rate of Greenland’s glaciers in coming decades, he said, but “in the long run, the human-induced component is likely to prevail.”
The research was funded by the National Science Foundation, UW’s Quaternary Research Center, the National Basic Research Program of China and the APEC Climate Center. Other co-authors are Lei Geng at the UW; Ailie Gallant at Australia’s Monash University; and Hyung-Jin Kim at South Korea’s APEC Climate Center.
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Note the photo provided with the press release, here it is in full resolution: http://www.washington.edu/news/files/2014/05/Greenland2010-5.jpg
And my enlargement of a section of it:
Note the black at the bottom of the melt pool, that’s carbon soot. That’s something the UW authors aren’t paying attention to.
As I explain here http://wattsupwiththat.com/2010/11/03/greenland-ground-zero-for-global-soot-warming/
…it has a big effect on albedo, and thus absorbed solar insolation, likely far more so than CO2 forcing, as explained here: http://wattsupwiththat.com/2013/08/13/in-the-arctic-nearby-soot-may-be-a-larger-forcing-than-co2/
UPDATE: Here is a map showing albedo change, the text is from the link below:
http://www.climate.gov/news-features/understanding-climate/greenland-ice-sheet-getting-darker
Map of changes in the percent of light reflected by the Greenland Ice Sheet in summer (June-July-August) 2011 compared to the average from 2000-2006. Virtually the entire surface has grown darker due to surface melting, dust and soot on the surface, and temperature-driven changes in the size and shape of snow grains. Map by NOAA’s climate.gov team, based on NASA satellite data processed by Jason Box, Byrd Polar Research Center, the Ohio State University.
![MODISalbedo_greenland2011_610[1]](http://wattsupwiththat.files.wordpress.com/2014/05/modisalbedo_greenland2011_6101.jpg?quality=83)
Greenland warmed before
http://sunshinehours.wordpress.com/2012/07/17/greenland-temperatures-from-stations-with-data-from-the-1800s/
Someone gave us a tiny clue some time back.
Is this the “unpredictable” part part?
Here are a few others.
I decided to try and track down that photo to see if there wre any others from 2010 by the same researcher as per the caption ‘Greenland ice canyon filled with melt water in summer 2010. Ian Joughin, UW APL Polar Science Center’
I found the page HERE. There are quite a few images. Do you have any idea what caused the dark areas on the following 2 photos might be? It’s certainly is not pristine ice.
http://bigice.apl.washington.edu/photos/Greenland2010-16.jpg
http://bigice.apl.washington.edu/photos/Greenland2010-1.jpg
There are other photos from other years on the link below – 2006 to 2011.
http://bigice.apl.washington.edu/photos.html
A Yahoo article states that “”We find that 20 to 50 percent of the warming is due to anthropogenic [man-made] warming, and another 50 percent is natural,” Ding said.”.
If this is true, I think the author may have her logic reversed because up to 80% is natural and up to half is man-made, contrary to what she says in the second paragraph:
“Now University of Washington atmospheric scientists have estimated that up to half of the recent warming in Greenland and surrounding areas may be due to climate variations that originate in the tropical Pacific and are not connected with the overall warming of the planet. Still, at least half the warming remains attributable to global warming caused by rising carbon dioxide emissions. The paper is published May 8 in Nature.”
Mosher, check out this photo. The left side of the photo is NOT pristine snow.
http://bigice.apl.washington.edu/photos/Greenland07-11.jpg
From
http://bigice.apl.washington.edu/photos_greenland07.html
Excellent point Anthony. I would draw your attention from the melt water pool to the snow in the extreme foreground of the photo: It displays all the characteristics of snow covered with dark contaminants. It is granular and riddled with cavities produced as the dark particles absorb light energy and burn down through the snow. This happens even at temperatures below freezing. Snow throughout the photo displays dark surface contamination and banding. Good find.
Steve Mosher says “…soot plays a role. thats part of the human forcing equation.”
Sure it is: there’s no soot from Canadian forest fires, is there?
http://graphics8.nytimes.com/images/2010/12/06/business/fire/fire-blog480.jpg
I see that this debris is deposited unequally in layers. These layers can correspond with atmospheric events that brought these deposits to Greenland in varying amounts. It is very plausible that as this canyon melted, the narrow bottom would become quite black from this debris (soot pollution, dust, ash, rock flour, etc). It is my guess that these layers have already been studied via ice cores and reported on.
“Our work shows that about half of the warming signal in Greenland comes from the predictable part – forcing of climate by anthropogenic greenhouse gases…”
—
If warming due to anthropogenic greenhouse gases is so “predictable,” then why didn’t any climate models predict the current 17 year pause? If it is so predictable, please predict how much global warming is going to occur over the next 5 to 10 years. Predicting what will happen by the end of the century means little because we will all be dead by then.
I would add this Icelandic volcano eruption.
http://en.wikipedia.org/wiki/2011_eruption_of_Gr%C3%ADmsv%C3%B6tn
It’s basaltic, ie, the ash it produces is dark grey to black.
Sleepalot says:
May 8, 2014 at 1:13 pm
Grimsvotn and other Icelandic volcanos erupt quite regularly: where is the analysis of the black stuff on Greenland to show that it is ‘soot’. In my view ‘soot’ is being demonised like CO2.
Show me the analysis!
Looking at the close up photo with the dark layers it would indicate some ar hundreds to thousands of years old. This leaves the question of what caused them before mans recent influance.
Grimsvotn and other Icelandic volcanos erupt quite regularly
Don’t they drift the other way? I think you want the Kamchatka volcanoes, which are also very active.
I would suggest that most of soot is transported by the jet stream from the Kamchatka’s frequent volcanic eruptions
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
2 4 2 3 2 1 4 2 3 1 4
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
2 1 1 1 1 1 2 2 3 2
http://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=0,90.20,400
In the 1970’s (I think) they floated an idea of spreading soot on the ice caps to melt them. Nothing came of the idea and we cleaned up the air so people forgot about the idea. Today we have China burning massive amounts of coal in dirty power plants and they have figured out how to cover the ice caps in soot without the costly solutions that were thought up before. It will be interesting to see if we can hold off an ice age through the process of generating power.
Thanks for the enlargement of a section of the photograph; Excellent!
“We need to understand why in the last 30 years global warming is not uniform”?
We need to understand the drivers of global temperatures, then we might see if this uniformity could possibly exist.
“Still, at least half the warming remains attributable to global warming caused by rising carbon dioxide emissions.”
Read: The models need extra CO2 to simulate that warming, and given that the models are “robust” and “skillful”, we are the only “attributable” source.
They simply want to forget the cooling BS from the 1970s but it keeps coming back. If the world cools and they blame man then how can they forget the great global warming scare of the present? They have doomed themselves.
H/t
http://stevengoddard.wordpress.com/2014/05/08/1978-government-experts-said-no-end-in-sight-to-global-cooling-polar-vortex-increasing/
This makes shorter-term forecasts difficult, but helps scientists to make more accurate long-range projections.
If they can’t the short-term forecasts right, how can they be confident of getting the long-range projections right? Is that like going east to get to the west, or north to go south?
As someone else pointed out, there is much evidence of soot or dust deposition on most of the snow in the picture, especially the foreground. You have to look at the full resolution image, not just Anthony’s close-up. There is grey runoff all over. I think Anthony is right. The soot was probably deposited all over, and when the melting began, it started to wash together into more concentrated spots, and the sun kept those particles warmer than the surrounding snow.
Mosher writes “If you want to know how much of a role soot plays you have to run a GCM. or you can just speculate and assert that it plays a major role.”
Let me rewrite that for you.
“If you want to know how much of a role soot plays you have to experiment by putting soot on the ice and measure the change of the rate of melting. Then you construct methods to measure the total amount of soot present in the environment. Then you calculate the effect complete with error margins.”
What you DONT do it whack it in a GCM because GCMs cant answer that question scientifically.
Mosher also wrote “Science: build a tool to try to understand the role of soot.”
So Steve, your first instinct to answer this kind of question is to “build a tool” ?
I would suggest your instinct regarding answering scientific questions has gone West.
Jimbo writes “I found the page HERE. There are quite a few images. Do you have any idea what caused the dark areas on the following 2 photos might be? It’s certainly is not pristine ice.”
It seems obvious to me that as snow and ice forms, it will contain various amounts of soot and dust. As it melts that soot and dust will be left/concentrated at the surface. Its very likely to be a positive feedback on the melting process. Some depths of ice and snow will have more or less soot depending on how much there was around at the time. Its quite probable much of that dust/soot will originally be volcanic in nature.
it is not just soot from diesel and coal that greatly affects the albedo of normally ice covered cold regions. The Colorado Rockies in recent drought times (and likely the pre-Columbian times) have gotten Spring-time coatings of Red dust from the 4 corners region spring-time wind storms. The red dust in the snow pack obviously greatly intensifies solar radiation absorption and thus snow pack melt. That leads to earlier more intense melt runoffs, with less flows in the summer.
The coming fall 2014 El Nino may provide enhanced winter- spring rains into 2015-2016 to suppress the aoelian red dust in the Southern Rockies. Along with simply more ElNino provided precip to the SW, the worsening drought-dust cycle may be broken by natural ocean cycle.