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
Well, I’ll just get right on the panicking part.
I mean really… it was such a breeze to “halt” glacial melting before, but now that it’s self-amplifying, I don’t know.
Of course we have no reference period. Everything today that has to do with melting can therefore be blamed on CO2.
Does it get any better than that?
“The model showed that melting between June and August was well above the average for 1979 to 2010.”
Pretty much all you need to know about this study.
Modelled nonsense.
GIGO.
The conclusions are reasonable: melting cycles can be self-accelerating, and probably just as self-decelerating once the conditions are right. It seems quite possible that the whole island could melt eventually, in the sense that it is no longer covered by a permanant ice sheet, even if it continues to have hard winters.
There does not seem to be strong emphasis on blaming human activity for initiating the change, nor a strong statement that it is natural. As Greenland has been slowly melting since the end of the LIA I presume it will continue until the next ice age starts, mini or major.
This work advances our understanding of how ice sheets behave, at least some of the time.
As Fairbridge once concluded that sea level rises and falls by as much as (or more) than a metre in as little as 20 years (study of Eastern Australian shoreline change over the last 8000 years) perhaps this type of self-acceleration is not all that rare.
I always get the funny feeling when reading these types of findings that the report was probably written prior to the data collecting expedition. Why is that?
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
Alarmists love them some positive feedback.
If there was increasing levels of positive feedback then why weren’t there record high temperatures?
I’d like to see their raw data. It doesn’t seem as if it would support any speculation about positive feedback caused melting. It seems as if they were desperate to publish something so that they didn’t have to admit that they wasted a year’s worth of work.
Did they figure out how much melting is due to black carbon?
Model involved. Ocean level dropping. Junk science.
“…….Combining data gathered on the ground with microwave satellite recordings and the output from a model of the ice sheet……..”
Model mentioned in study.
Enter sleep mode.
really nothing new…
just confirmation of what we already understood…
Danish researchers found that the annual Greenland ice melt was 191 til 240 billion metric tonnes a year from 2003 to 2008. http://www.dmi.dk/dmi/danske_forskere_maaler_og_vejer_indlandsisen
Not sure if there is any evidence that the melting was increased dramatically since then.
Wiki estimates the total Greenland ice sheet is 2,850,000 cubic kilometres. So dividing that mass with any number between 191 and 240 billion tons a year will yield over 10,000 years before we can inspect the whole of an ice free Greenland. By then we will assuredly have entered another ice age. Willis Eschenbach had a long article about this here some time ago coming to the same conclusions. It is amazing how this “non story” keeps surfacing again and again based on a cursory visit and a model. The Danes surely have a better understandig of what is going on there.
I wonder why there does not seem to be a sea-level rise signal from the accelerated melting?
http://sealevel.colorado.edu/
This will help us to improve models………
==================================
/snark
I wonder what caused the melting from 1850 – 1902, in this image from NASA?
http://www.nasa.gov/101948main_calvingstill_1850_2003.tiff
(7 MB file!)
Here is the full article from 2004. In this article NASA says, “Jakobshavn Isbrae holds the record as Greenland’s fastest moving glacier and major contributor to the mass balance of the continental ice sheet.”
http://www.nasa.gov/vision/earth/lookingatearth/jakobshavn.html
Sorry, I can’t put much faith in a study by someone without the common sense to NOT stand that close to the edge of a moulin. You fall in that thing, you’re done.
The averages are based on the years 1979 – 2010. Once again confirming that the Earth began in 1979.
@John Peter
“The Danes surely have a better understanding of what is going on there.”
There is a rumour they even use thermometers to determine the temperature of the Arctic!
How quaint!
If Greenland was basically glacier-free only 250,000 years ago, give or take, it can’t be all that unusual to have melting there. Self-acceleration is a very reasonable expectation. Watch the snowbanks melting in springtime. As soon as there is dry ground dust blows around changing the albedo. It may or may not change the sea level as prophesied – depends on what is happening elsewhere.
[snip – all caps – resubmit]
Have a look at this site how a couple of abandoned radar site are being swallowed by the Greenland ice cap. http://www.lswilson.ca/dye2pics.htm.
Ockham says:
October 26, 2011 at 8:41 am
I always get the funny feeling when reading these types of findings that the report was probably written prior to the data collecting expedition. Why is that?
The reason for the feeling may not be known, but the feeling exists, nonetheless. I liken it to the brain ‘needing’ a scientific sequence of events in order to properly integrate knowledge. When one reads one of these press releases, they all follow the same pattern: An assertion, a series of uncertain-language postulations, a leap of faith, and some wishy-washy conclusions, all watered down into layperson’s terms…and all some kind of link to ‘climate change’ as if it were some kind of dastardly anomaly beckoning for ‘science’ to unravel the cause. The queasy fealing is basically “I have the feeling I’ve read this before”, and as it unfolds, one is left with an empty hollowness. Climate science has become concrete-bound, making the same assertions over and over, to serve the juggernaut, while never leaving the safety of conventional wisdom. All of this, and tainted by alarmist untertones; “irreversible melting” in this case.
GIGO indeed.
From photo at top of article.
Marco Tedesco standing on the edge of one of four moulins (drainage holes) he and his team found at the bottom of a supraglacial lake during the expedition to Greenland in the summer, 2011. (Credit: P. Alexander)
So…where is the lake this is at the bottom of? A ‘supraglacial’ lake is on top of the glacier!?
In the period 1930-1950, summer temperatures of Greenland around the edges were as high to higher than today. The edges were melting as fast as now (if not faster). After that period, the glacier tongues advanced again, until the 2000’s…
Another “tipping point.” Positive melting feedback will lead to a “runaway” icecap melt and we’ll end up like Venus.
We noted a few posts ago that the Greenland ice sheet doesn’t record anything beyond the last interglacial, and the possibility that the Eemian melted it away. Might happen again, should the Holocene last long enough, fingers crossed. The Eemian was about 2 degrees warmer than ours for a couple thousand years, so it’s a question.
Once again, if positive feedbacks were dominant at any time in the last few billion years, why are we even alive?
Your title is misleading Anthony. The melting occurs because melting in a previous year leads to a darkened surface, which then enables increase melting in the next year even without “record high temperatures.” As many other studies have shown, water seeping down through fissures to the bed rock below, is greatly accelerating the disintegration of the massive ice structures on Greenland. 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)
That man in the photo looks more than a bit short of common sense. The Chunk of Ice he is stood on looks like it is about to break free at any moment.
The photographer who can see all the cracks and fissures below him was obiously not a good friend.
Hugh Pepper says:
“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)”
Thanx for your fantastic and incredible opinion. The fact that sea level rise is rapidly slowing, and the fact that oceans are not “desalinizing”, and the fact that ocean currents are not “declining” indicates that your lack of understanding of the issue is based on ridiculous, unscientific twaddle. Where do you find those provably wrong assumptions? Or do you just make them up as you go along?
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.
Hugh – Anthony picks the article, not the title. Perhaps a complaint to the authors on the offered link would be more constructive…
If I were Marco Tedesco I wouldn’t be standing where he is in the photograph.
That big chunk of ice he is on is about ready to crack off and go down the moulin.
A positive feedback usually works in both ways; so even if one exists… the mechanism they mention introduces a hysteresis. If it works that way, we could already be well into the cooling, yet the minimum sea ice extent managed to go down nearly to 2007 levels, or if you believe Bremen Uni, lower. Of course, at a certain point the hysteresis is overcome and the ensuing refreezing will be much more rapid.
@Mike Bromley the Kurd
Your feelings are correct. It is the expectation of a natural from observations to a general case conclusion about how things work.
Here is an example that is as valid an explanation of ice issues as many we have seen in the MSM:
From “The Central Eskimo”, Franz Boas, 1888 (Eastern Arctic, Canada) reported in “The Arctic Sky, Inuit Astronomy, Star Lore and Legend” by John MacDonald
“A long time ago the ocean suddenly began to rise, until it covered the whole land. The water even rose to the top of the mountains and ice drifted over them. When the flood had subsided the ice stranded and ever since forms an ice cap on the top of the mountains. Many shellfish, fish, seals and whales were left high and dry and their shells and bones can be seen to this day.”
So now you know.
The lack of short term correlation between temperature and melting is not surprising. Most melting occurs at low elevations, where ice is thin and the ground is warmer. The ground below the thinner ice has been warming since the Little Ice Age. But ice is a very good insulator, and the mile thick ice is fairly immune to secular temperature variation. But it is also immune to the effects of current annual variation.
I predict that warming will increase snowfall, piling the ice sheet so deep that it will collapse under its own weight, creating a tidal wave that will flood all the great capitals of the world. This will reduce carbon consumption, leading to eventual cooling, and so must be treated as negative feedback. –AGF
Wouldn’t looking at stream and river runoff data from North American mountain snowpacks provide a vastly better dataset? Throughout the Rockies we do record detailed weather information and water flow measurements, or wouldn’t that provide a cool enough field trip?
Meanwhile my models of Pacific plate tectonics show that a new continent formed between Hawaii and California last August. I’ve been trying to contact the business and government so they’ll know they can build a new harbor and new airport on it and make Pacific travel somewhat easier, but for some reason nobody e-mails me back. It’s a real head scratcher, as my model is quite specific abuot the location and size of the new lands. Perhaps I just need to give the place a catchier name than RUN01A7C or Modelerica.
So I’m a bit confused doesn’t the whole argument they present basically say
“It only take a very very small natural temp change to cause large scale melting and thus large scale melting is not proof of global warming”…
It least thats how i read the piece…
Hugh Pepper says:
October 26, 2011 at 9:27 am
“As many other studies have shown, water seeping down through fissures to the bed rock below, is greatly accelerating the disintegration of the massive ice structures on Greenland. We would all be wise to fully understand these processes and the consequences which will occur as a result.”
We would be even wiser to understand the processes and consequences of normal “behavior” of the Greenland ice sheet. The melting and seeping through the fissures IS part of the normal process. The other part is the formation of new ice every year. Some years, there is more new ice formed than melted. Some years there is less. Sometimes, those swings in increase or loss of ice span several years or even decades. This has been known for a long time. That’s the way I learned it in grade school decades ago. Still applies today. I love when “studies” like this are done and they really only show what is already known (or at least should have been known), yet think they’ve made some great discovery.
I won’t even get into how poor a study is that bases assumptions of future warming on such a limited time frame as satellites can provide for us and then compounds that with the use of MODELS. It is not sound science, no matter how “sciency” the wording of the results may sound.
By the way, here are a few known (and well documented) problems for the concept of unprecedented melting and/or melting rates and the massive global catastrophe they will supposedly unleash:
– The Vikings lived there when there was considerably less ice. They left only when the ice grew too much again for there continued use of the land. Now, the ice is supposedly losing some mass. Sounds cyclic to me and nothing in this “study” shows that the current period is not just on the warm end of a cycle.
– Planes that landed on the ice decades ago and were only recently found again were buried under over 200 feet of new ice that formed in the 60 years after they were abandoned.
-Based on estimates of the total volume of ice on Greenland and the currently accepted rate of melting, even if there was no new ice forming during the cold part of the year, it would take thousands of years for all the ice to melt.
Increasing melt rate of Greenland’s ice sheet = absolute catastrophe for the entire globe? Hmmm, what’s the word I’m looking for? Oh, yeah, FAIL!
Every time I see the phrase “positive feedback” in a climate paper, it is always misapplied and completely misunderstood.
The paper is wrong. The authors are idiots. Highly qualified in idiocy.
So a series of years with raised (but not continuously record-breaking) temperatures will allow melt to accelerate? I can buy that.
In which case, could a series of raised (but not continuously record-breaking) solar cycles allow temperature increase to continue and even accelerate? The Team would say No in the most strenuous terms. The analogy of the saucepan on the stove comes to mind…
I agree with jack mosevich: this is of very doubtful credibility in the absence of any sign of an acceleration in the rate of rise of sea levels.
Wouldn’t melting result in evaporation which results in cooling?
There might be a clue as to why the paper’s ‘findings’ are as they are. The last line in their statement to the press (here:- http://www.sciencedaily.com/releases/2011/10/111025163128.htm) is as follows ….
“The research was supported by the National Science Foundation and the NASA Cryosphere Program. The World Wildlife Fund is acknowledged for supporting fieldwork activities.”
“The model showed that melting between June and August was well above the average for 1979 to 2010”
Surely in mathmatical terms alone it is kind of important to have some values above the average. To not have any would mean your average was in fact your maximum.
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
It’s an interactive map of global drought conditions from The Drought Monitor at UCL in the UK. heir timescales only go back 36 months, but I’ve been checking the site for almost 2 years and can attest that for almost 5 years the prevailing condition for Greenland has been for at least half of the island, and usually more, to be shown as experiencing severe to exceptional drought. In all that time I have only come across one of these opuses that even mentioned lack of replenishment as a possible contributor to whatever catastrophic ice loss they were pimping, and that mention was mostly an oh by the way aside.
It sounds like the high level of melt was more closely related to low levels of snowfall the preceding winter than to any alleged “Self-Amplifying Feedback” They even hinted at this when they said that 2011 was tied for the highest “mass balance” even though it was only the third highest summer melt. So so the little snow from winter 2010/2011 quickly melts, then the exposed ice, having higher albedo, melts faster. Simple enough. But a headline like “Low Snowfall Increases Loss Of Greenland Ice” doesn’t really sound that startling. More along the lines of obvious.
Crispin in Waterloo says:
October 26, 2011 at 8:39 am
“The conclusions are reasonable: melting cycles can be self-accelerating, and probably just as self-decelerating once the conditions are right. It seems quite possible that the whole island could melt eventually, in the sense that it is no longer covered by a permanant ice sheet, even if it continues to have hard winters.”
You mean “plausible” not “reasonable.” One could imagine this happening, so it is plausible. For it to be reasonable, there would need be some reasonably well-confirmed hypothesis that explains it. They offered none. Models are neither evidence nor reasonably well-confirmed hypotheses.
“This work advances our understanding of how ice sheets behave, at least some of the time.”
You mean it advances our understanding of something that we can imagine happening.
Understanding and Imagination are different faculties.
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.
Thank you for that link.
@Theo
Yes, I agree with you. Given the past behaviour, it is plausible. I am not sure I need to posit a hypothesis as to how it happens though I am sure people will. It is sufficient for me to know that it melted before and that it might be melting again and that we really do not know much other than change is constant.
“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.”
I hope he knows a bit more about glacier melting than he does about steam locomotives, the coal usually goes in the firebox which heats and boils the water in the boiler to produce steam to drive the pistons and turn the wheels.
Coulda, woulda, shoulda; and here I thought the ice was actually melting.
Do these jerks never get tired of writing horror stories that would become true; if their science fiction were to become observed scientific fact.
So wake me, when the Greenland ice gets down to half its current total mass; or if the sea level gets up to the front steps of CCNY.
In the meantime; snore !!
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.
@ 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
_______
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.
__________________________________________________
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.”
Yes, ‘self-amplifying’ is reminiscent of the ‘positive feedbacks’, of which Warmists are so fond. Aside from that, Mrs. Lincoln, I’m not sure what the fuss is all about.
My understanding: It’s largely about albedo. Greenland glaciers can show a net decline if the white stuff on top melts, leaving the lower-albedo ice exposed to the merciless Arctic sun. And that can happen if
1. annual local snowfall decreases markedly;
2. or local temperatures increase significantly;
3. or some combination of the two.
And of course, the same logic could apply in reverse.
Ignoring the scary-sounding buzzword, the basic proposition sounds reasonable to me. I’m assuming that the researchers have reasonably accurate data. Am I missing the boat–or the iceberg–here?
Fixed it for you.
>:)