From the City College of New York: Extreme Melting on Greenland Ice Sheet, Reports CCNY Team
Glacial Melt Cycle Could Become Self-Amplifying, Making it Difficult to Halt
The Greenland ice sheet can experience extreme melting even when temperatures don’t hit record highs, according to a new analysis by Dr. Marco Tedesco, assistant professor in the Department of Earth and Atmospheric Sciences at The City College of New York. His findings suggest that glaciers could undergo a self-amplifying cycle of melting and warming that would be difficult to halt.
“We are finding that even if you don’t have record-breaking highs, as long as warm temperatures persist you can get record-breaking melting because of positive feedback mechanisms,” said Professor Tedesco, who directs CCNY’s Cryospheric Processes Laboratory and also serves on CUNY Graduate Center doctoral faculty.
Professor Tedesco and his team collected data for the analysis this past summer during a four-week expedition to the Jakobshavn Isbræ glacier in western Greenland. Their arrival preceded the onset of the melt season.
Combining data gathered on the ground with microwave satellite recordings and the output from a model of the ice sheet, he and graduate student Patrick Alexander found a near-record loss of snow and ice this year. The extensive melting continued even without last year’s record highs.
The team recorded data on air temperatures, wind speed, exposed ice and its movement, the emergence of streams and lakes of melt water on the surface, and the water’s eventual draining away beneath the glacier. This lost melt water can accelerate the ice sheet’s slide toward the sea where it calves new icebergs. Eventually, melt water reaches the ocean, contributing to the rising sea levels associated with long-term climate change.
The model showed that melting between June and August was well above the average for 1979 to 2010. In fact, melting in 2011 was the third most extensive since 1979, lagging behind only 2010 and 2007. The “mass balance”, or amount of snow gained minus the snow and ice that melted away, ended up tying last year’s record values.
Temperatures and an albedo feedback mechanism accounted for the record losses, Professor Tedesco explained. “Albedo” describes the amount of solar energy absorbed by the surface (e.g. snow, slush, or patches of exposed ice). A white blanket of snow reflects much of the sun’s energy and thus has a high albedo. Bare ice – being darker and absorbing more light and energy – has a lower albedo.
But absorbing more energy from the sun also means that darker patches warm up faster, just like the blacktop of a road in the summer. The more they warm, the faster they melt.
And a year that follows one with record high temperatures can have more dark ice just below the surface, ready to warm and melt as soon as temperatures begin to rise. This also explains why more ice sheet melting can occur even though temperatures did not break records.
Professor Tedesco likens the melting process to a speeding steam locomotive. Higher temperatures act like coal shoveled into the boiler, increasing the pace of melting. In this scenario, “lower albedo is a downhill slope,” he says. The darker surfaces collect more heat. In this situation, even without more coal shoveled into the boiler, as a train heads downhill, it gains speed. In other words, melting accelerates.
Only new falling snow puts the brakes on the process, covering the darker ice in a reflective blanket, Professor Tedesco says. The model showed that this year’s snowfall couldn’t compensate for melting in previous years. “The process never slowed down as much as it had in the past,” he explained. “The brakes engaged only every now and again.”
The team’s observations indicate that the process was not limited to the glacier they visited; it is a large-scale effect. “It’s a sign that not only do albedo and other variables play a role in acceleration of melting, but that this acceleration is happening in many places all over Greenland,” he cautioned. “We are currently trying to understand if this is a trend or will become one. This will help us to improve models projecting future melting scenarios and predict how they might evolve.”
Additional expedition team members included Christine Foreman of Montana State University, and Ian Willis and Alison Banwell of the Scott Polar Research Institute, Cambridge, UK.
Professor Tedesco and his team provide their preliminary results on the Cryospheric Processes Laboratory webpage. They will will be presenting further results at the American Geophysical Union Society (AGU) meeting in San Francisco on December 5 at 9 a.m. and December 6 at 11:35 a.m.
The research was supported by the National Science Foundation and the NASA Cryosphere Program. The World Wildlife Fund is acknowledged for supporting fieldwork activities.
On the Internet:
2011 Melting in Greenland report
http://greenland2011.cryocity.org
Cryospheric Processes Laboratory
Professor Tedesco Tracks Life and Death of Greenland Glacial Lake
http://www1.ccny.cuny.edu/advancement/news/Tedesco-Greenland-Glacial-Lake.cfm
Map of expedition location
Expedition Facebook page
http://www.facebook.com/pages/Cryocity/124269854300408
Expedition Twitter Feed
http://twitter.com/#!/Cryocity
Marco Tedesco profile
Hugh Pepper says:
October 26, 2011 at 9:27 am
.
….We would all be wise to fully understand these processes and the consequences which will occur as a result.(rising sea levels, desalinization of oceans, declining ocean currents
“will occur” according to the 100% faiure rate of mainstream Climate Science’s relevant predictions?
Otherwise: Ok, but why is the imprimatur always such that the “consequences” are always alleged to be so dire, with no mention of “net effect”, that we must do something really stupid right now, like effectively commit suicide or become enslaved by obvious Totalitarians and their looting cohorts, without understanding the processes and likely consequences, including the benefits, which the ipcc Climate “Science” has all but totally ignored methodologically, “or else we’re all gonna die”?
Tell me, Hugh, do you really believe, or think it’s ethically right to employ a tactic such that, simply repeating a very low value meme over and over makes it come true, or so that you can “win”?
In other words, is the claim that “perception is reality” true or ethically supportable, or is it instead the very definition of “being delusional” or of “intending to delude”?
Dave Wendt says:
October 26, 2011 at 11:32 am
“Whenever we get a post on one of these hyperbolic PRs about Greenland “melting” I like to post a link to this site”
http://tinyurl.com/yrdkl6
Yes, thanks for link.
@ur momisugly WUWT – Can this link be added to the resources page please?
“One point not mentioned in the article is how much new snow and ice is added to the glaciers. One would think it is zero or almost. Not true. The only such thing I found mentioned in an anecdote posted by a reader on Steve’s blog:
http://www.real-science.com/greenland-meltdown#comment-54428 ”
It seems that the more it snows and higher it stacks up the faster the glaciers move.
Do I get it right that weather has more effect on the glacier melting than climate? Can I say weather?
Oh no! It’s the positive feedbacks again. Must mark in my diary to panic a week on Thursday.
Professor Tedesco likens the melting process to a speeding steam locomotive. Higher temperatures act like coal shoveled into the boiler, increasing the pace of melting. In this scenario, “lower albedo is a downhill slope,” he says. The darker surfaces collect more heat. In this situation, even without more coal shoveled into the boiler, as a train heads downhill, it gains speed. In other words, melting accelerates.
I think Professor Tedesco has a better understanding of perpetual motion machines than steam locomotives. I hate these anal ogies.
It does look dangerous at first sight, however, the bigger image at their Facebook page show a climbing rope at the lower right corner, so the photographer is probably roped up. Another photo shows mr. Tedesco properly roped up at another location, so we’ll assume they are familiar with glacier safety.
Supraglacial means there was indeed a lake on top of the glacier, the lake has now drained down the moulins, hence our intrepid researchers are now peeking into the hole to see where it went.
Isn’t this just a recycled version of Hansen’s 2006 rant about moulins accelerating the loss of Greenland ice? I don’t have the exact reference in front of me, but I do recall a strong feeling of “deja vu Hansen” when readin this post.
The first episode of the BBC’s frozen planet was screened here in the UK this evening. And one of the bullet points was the sudden above glacier formation of these lakes and the equally sudden disappearance of the water when it plunges at least one mile below the surface to promote glacial slip.
It was worrying right at the start when Attenborough said he was at the North pole and the production showed rocks above the ice but after that I think it was a reasonably balanced prog….for the BBC anyway.
The photography was outstanding.
Dave Wendt;
It’s polite and helpful to use the ‘Custom Alias’ option on the TinyURL page. Here, I’ve done it for you:
http://tinyurl.com/DroughtMonitor
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Side comment:
Concerning glacier and ice sheet melt and shrinkage, the only two ways those lose mass are melting (see runoff) and sublimation (e.g., Kilmanjaro). Calving and other edge loss events just show the opposite: build-up nearer the center, forcing more ice outwards faster. So the next time you see dramatic photos of ice peeling off from glacier faces, think “Advancing ice flows!”
Hugh Pepper says:
October 26, 2011 at 9:27 am
“….We would all be wise to fully understand these processes and the consequences which will occur as a result.(rising sea levels, desalinization of oceans, declining ocean currents”
Very Freudian. If we fully understand these processes then we will get over our maniacal denial of run-away climate change. But, the logical extension of your thought is that once we fully understand and accept these consequences, then we will actually do something to prevent them. At which point, it would be good to ask how to prevent a general warming of the planet that is recovering from a previous ice age? And perhaps even ask why we would want to prevent such warming?
I agree with some of the commentors above that these ‘scientific” papers are starting to all read the same.
These people are not scientists, they are GRANTISTS
To stand on a chunk of ice that is about to fall into the abyss is not clever.
“the lake has now drained down the moulins, hence our intrepid researchers are now peeking into the hole to see where it went.”
Er, lemme guess, down? Very scientific.
/sarc
The positive feedback claim due to increased albedo of exposed ice is spurious because, as pointed out by Richard Alley, the precipitation increases with increased temperature. Very convenient for them to forget about precipitation!
http://www.ncdc.noaa.gov/paleo/pubs/alley2000/alley2000.gif
And just how does liquid water go to the bottom of a glacier where the pressure is greatest and not refreeze?
Tim Folkerts says:
October 26, 2011 at 9:40 am
The headline states:
Extreme melting in Greenland – no high temperatures required
However, the article actually says:
“We are finding that even if you don’t have record-breaking highs, as long as warm temperatures persist you can get record-breaking melting because of positive feedback mechanisms.”
and
“And a year that follows one with record high temperatures can have more dark ice just below the surface, ready to warm and melt as soon as temperatures begin to rise. “
So in fact, high temperatures ARE needed, both in the current year AND in the previous year to see the effect the article is talking about.
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AND that the amount of melt exceeds the amount of snow cover from the previous winter.
If you get a heck of a lot of nice pristine white snow the next winter that melts slowly then the “dark ice just below the surface” is covered for all or most of the following summer.
Seems the amount of precipitation would be as much of a factor as the temperature and the amount of time the temperature is above freezing.
Ain’t it fun to “hunt the fallacy” in these press releases. snicker.
John says: October 26, 2011 at 12:23 pm
That probably explains why they thanked the WWF for field support. When they’d try to melt water for cooking and drinking they were probably piling snow in a bucket, adding hot charcoal on top, then bitching about how the water looked like powerplant effluent and tasted like ash.
cotwome says:
October 26, 2011 at 9:01 am
I wonder what caused the melting from 1850 – 1902, in this image from NASA?
http://www.nasa.gov/101948main_calvingstill_1850_2003.tiff
What caused the 100 years of melting 1850-1950? The IPCC tells us it was not CO2.
After much research of the literature, I have come to the single conclusion that the pro-AGW researchers and authors severely devalue the title of “professor”. Is the title just awarded to any nincompoop academic lecturer / researcher nowadays?
“Extreme melting in Greenland – no high temperatures required”
However, the article actually says:
“We are finding that even if you don’t have record-breaking highs, as long as warm temperatures persist you can get record-breaking melting because of positive feedback mechanisms.”
and
“And a year that follows one with record high temperatures can have more dark ice just below the surface, ready to warm and melt as soon as temperatures begin to rise. “
So why has this never been observed by proxies or other means before during the past 800,000 years? How can this be even suggested what a possible record-breaking melting is, when don’t have a clue what occurred over the past 800,000 years naturally. With an ice core being able to replicate this time frame, there was plenty of ice to provide this proxy. The global climate has never shown a positive feedback above a certain threshold and whenever this was reached a major cooling followed. (past 3 million years)
The planet demonstrates a safety mechanism where too much warming can’t occur, but on the worrying side too much cooling can. (major ice ages) The planet shows global albedo controls this with especially cloud levels. Therefore never get too much warming because with rising temperatures the increasing cloud albedo prevents solar energy warming the oceans. This leads to a negative feedback and pushes the planet back into a cooling phase. After a period of cooling for many years global cloud albedo declines, increasing solar energy reaching the surface again and then the planet starts warming. There is a noticeable 30ish year warming and cooling cycle observed and likely is controlled by this mechanism.
Warm temperatures dominating could occur mainly during any season not necessarily summer. Only the summer temperatures are important with the rest of the seasons being so cold. These can lead to greater snowfalls increasing the glacier mass not reducing it, over usually extremely cold regions of the planet. Therefore even if it was possible to say a record melt occurred, a record snowfall could follow during the winter to balance things up. To sum things up, the overall mass of the glacier can increase or decline whether or not the temperatures are warmer or cooler than normal for long periods. A year with record high temperatures can also have a year of record snowfall because normally with very cold weather there is little water vapour/moisture and therefore snowfall. The majority of the time it is milder air that brings the snow.
“Wolf! Wolf! Wolf!”
“I’m not listeniiiiing…”
Yes, where is the water in the supraglacial lake Tedesco is standing in in the Summer, and given the optimal conditions, why can’t he get a picture of any water dribbling down to help the glacier allegedly “slide”, which they don’t do?
“From the City College of New York: Extreme Melting on Greenland Ice Sheet, Reports CCNY Team
Glacial Melt Cycle Could Become Self-Amplifying, Making it Difficult to Halt”
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From:
http://en.wikipedia.org/wiki/History_of_New_York_City_(prehistory%E2%80%931664)
About 75,000 years ago, during the last ice age, the area of present day New York City was at the edge of the ice sheet that stretched down from Canada. The ice sheet covered the site of the present city to a depth of approximately 1000 feet (300 m). The glaciers scraped off much of the top layers of material in the region, exposing underlying much-older bedrock, including gneiss and marble that dates from 500 million years ago.
Approximately 15,000 years ago, when the ice sheet began retreating, the glacier left behind a terminal moraine that now forms the hills of Long Island and Staten Island. The two islands were not yet separated by the Narrows, which were formed approximately 12,000 to 13,000 years ago when the waters of the Upper Bay broke through into the Lower Bay. [1]
Also from Wiki:
Modern humans spread rapidly from Africa into the frost-free zones of Europe and Asia. The rapid expansion of humankind to North America and Oceania took place at the climax of the most recent Ice Age, when temperate regions of today were extremely inhospitable. Yet, humans had colonised nearly all the ice-free parts of the globe by the end of the Ice Age, some 12,000 years ago.
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Warm is good, cold is bad.
“Power tends to corrupt and absolute power corrupts absolutely.”
CUNY – a typo surely.
Admin – if my growing exasperation with this nonsense is sailing too close to the wind with this comment then please feel free to trim my sails. I won’t take offence.
Greenland is a huge bowl with a ring of mountains brokenby some glaciers. The glaciers are overflow and subject ot the most melting. The main mass of Glreenland is not going anywhere and there overall mass is also doing nothing unusual.
What these clowns are not willing to admit is that the Medieval Warm Period must have been much warmer than now, with much more attendant melting for it to be colonized by the Vikings for so very long. Can’t do that now!
A paper easily found at CO2 Science:
Vinther, B.M., Andersen, K.K., Jones, P.D., Briffa, K.R. and Cappelen, J. 2006. Extending Greenland temperature records into the late eighteenth century. Journal of Geophysical Research 111: 10.1029/2005:
“one would expect to see southwestern coastal Greenland’s air temperature responding vigorously to the 75-ppm increase in the atmosphere’s CO2 concentration that has occurred since 1930, even if the models were only half-way correct. However, there has been no net change in air temperature there in response to the 25% increase in the air’s CO2 content experienced over that period. And this is the region the world’s climate alarmists refer to as a climatological canary in a coal mine??? If it is, real-world data suggest that the greenhouse effect of CO2 has been hugely overestimated.”