Ridiculous claim by Marco Tedesco: 'Darkening of the Greenland Ice Sheet is projected to continue as a consequence of continued climate warming'

Via Eurekalert, maybe Tedesco just isn’t looking hard enough, or maybe he only looks at data, as these and other photos previously published on WUWT and Mother Jones demonstrate:

Dark snow Greenland
Photo: Henrik Egede Lassen/Alpha Film, from the Snow, Water, Ice, and Permafrost in the Arctic report from the U.N. Arctic Monitoring and Assessment Programme. 2012
Dark ice is helping Greenland’s glaciers retreat. Photo by: Jason Box Originally published in Mother Jones September 19, 2014
Photo by Jason Box


Greenland darkening to continue, predicts CCNY expert Marco Tedesco

City College of New York

Darkening of the Greenland Ice Sheet is projected to continue as a consequence of continued climate warming, Dr. Marco Tedesco, a City College of New York scientist, said at the European Geosciences Union (EGU) General Assembly in Vienna today.

Tedesco told a press conference in the Austrian capital that the projection is based on a model that only accounts for the effects of warming on snow grain size and melting.

An associate professor in City College’s Division of Science and head of its Cryospheric Processes Laboratory that he founded, Tedesco is an authority on the Greenland Ice Sheet where he has conducted annual research.

He noted that a darkening of the Greenland Ice Sheet associated with increasing temperatures and enhanced melting occurred between 1996 and 2012. It was promoted by:

  • Extensively and persistently increased surface snow grain size;
  • The expansion and persistency of the areas of exposed bare ice and by the increased surface impurities concentration associated with the appearance of dirty ice;
  • Increased impurities concentrations due to consolidation with snowmelt.

Tedesco, however, added that his research had not found any evidence that points to either increased atmospheric deposition of impurities or to the number of fires over Eurasia and North America as being factors.

The EGU General Assembly 2015 brings together some 12,000 geoscientists from all over the world into one meeting covering all disciplines of the Earth, planetary and space sciences.


Maybe Tedesco lives in a cocoon and missed the “Dark Snow Project” which took this video last year:

Published on Oct 29, 2014

video taken during a 23 August 2014 maintenance tour of promice.org climate stations on the southern Greenland ice sheet. Higher on the ice sheet, the surface is not this dark. But down low, where the highest melt rates happen, this darkness amplifies absorbed sunlight, the dominant energy source for melt.

Tedesco must be either incompetent, blind, an activist or all three, because the data on northern hemisphere fires contradicts his claim of “his research had not found any evidence that points to either increased atmospheric deposition of impurities or to the number of fires over Eurasia and North America as being factors.

box-snow-8-630[1]You can watch the pattern of flow which puts particulates into the Greenland ice sheet:

I’m sorry, but I think Tedesco’s claim amounts to nothing more than “science climate activism by press release”.

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April 17, 2015 10:57 am

Can you provide a link that further explains the total fire intensity graph? In forest fire lingo ‘intensity’ typically refers to the output of an individual fire and is unrelated to the number or extent of fires over time which would seem to be the desired metric here. Thanks.

Dodgy Geezer
April 17, 2015 10:59 am

.. “his research had not found any evidence that points to either increased atmospheric deposition ….
He has been taking lessons from Sir Humphrey. I quote:
…’If only you’d had we’d have a departmental enquiry,’ he complained, ‘then we could have made it last eighteen months, and finally said that it revealed a certain number of anomalies which have now been rectified but that there was no evidence of any intention to mislead. Something like that.’ I allowed myself to be diverted for a moment. ‘But there was an intention to mislead.’ I pointed out. ‘I never said there wasn’t,’ Sir Humphrey replied impatiently. ‘I merely said there was no evidence of it.’ I think I was looking blank. He explained. ‘The job of a professionally conducted internal enquiry is to unearth a great mass of no evidence. If you say there was no intention, you can be proved wrong. But if you say the enquiry found no evidence of an intention, you can’t be proved wrong.’…

Reply to  Dodgy Geezer
April 18, 2015 6:55 pm

Thanks for that!
H beam piper. I weaned myself intellectually on Piper. He had me reading Toynbee, Mackinder, and M Wheeler at 12 and 13.
Greatest sci-fi writer ever. My dream is to make Space Viking into a movie.

Brandon Gates
April 17, 2015 11:13 am

I’m loving the computer simulation at the end of the head post.

Reply to  Brandon Gates
April 18, 2015 11:26 am

It should have some cool music to go with it.

April 17, 2015 11:24 am

I seem to recall a large volcanic eruption not far from Greenland just a couple of years ago that even grounded many Western European flights. Why isn’t that mentioned as a source for darkening Greenland?

Reply to  Nikolai
April 17, 2015 11:31 am

Eyjafjallajökull volcano on 14 April 2010. It grounded me in Malta for a week.
Iceland is to the east of Greenland, prevailing westerly winds take volcanic ash in easterly direction.
Only major airport in N. W. Europe operating at the time was Reykjavik !

Reply to  Nikolai
April 17, 2015 11:39 am

If volcanic ash is found in Greenland Ice it is most likely from St.Helen’s, Alaskan, Aleutian islands or even Kamchatka’s or Japanese eruptions.

Village Idiot
April 17, 2015 11:24 am

A graph showing rising Northern hemisphere fire intensity, and a random atmospheric circulation vid.
Well…I’m convinced 🙂

Reply to  Village Idiot
April 17, 2015 8:50 pm

Good, now go away if you have nothing of substance to contribute, troll.

John West
April 17, 2015 11:25 am

Obviously, global warming causes greater fire intensity.

Reply to  John West
April 17, 2015 12:14 pm

That will be the fallback when he is proven a fool.

Fred Harwood
April 17, 2015 11:39 am

Got some photos from 40,000 feet, Anthony, if you want them. Check your email.
[Note: Anthony is more likely to see comments like this in Tips & Notes. ~mod]

Reply to  Fred Harwood
April 17, 2015 7:31 pm

Just flew over Greenland. Color it white, as in it’s white – and cold. No dirt, just ice, snow and a little real cold rock. The surrounding ocean is rock solid too – all the way to Canada.

April 17, 2015 11:44 am

“It’s not easy facing up when your whole world is black.” This song just came on while reading this 🙂

Reply to  RWturner
April 17, 2015 12:31 pm

That’d be Sir Mick and the “Ugly Rolling Stones”

Jim G1
Reply to  mikerestin
April 18, 2015 7:16 am

The song is a classic and it is called “Painted Black”. They may be ugly, but they were great.

Reply to  mikerestin
April 18, 2015 2:01 pm

May be “Paint it Black”?

Bloke down the pub
April 17, 2015 11:50 am

If samples were taken from the surface of the ice there may be a way of determining the age of the deposits. If they were all recent then we’d have a good idea the darkening is increased by more deposition. If they have a wider spread of ages then it’s more likely that the darkening is produced by surface melt that leaves the deposits behind. I’d go and check it myself only I’ve got a bone in my leg.

Reply to  Bloke down the pub
April 17, 2015 4:01 pm

But you couldn’t claim it was global warming if you had evidence that it was simply particulates deposited on the surface.

April 17, 2015 12:13 pm

This is absurd. An analysis of the particulates would reveal the cause within eight hours .

Louis Hooffstetter
Reply to  Pat Ch
April 17, 2015 3:59 pm

Yes, but why would climatologists bother with empirical data when they can use computer models instead?
Empirical data is so constraining. Models allow you to reach whatever conclusion you wish.

Reply to  Louis Hooffstetter
April 17, 2015 4:01 pm


Bill Illis
April 17, 2015 12:20 pm

This is what happens at the melt edge of all moving glaciers after the winter snow has melted (late in summer in early in the fall).
Small debris, dust, sand, particles will migrate to the top of the ice. What they don’t understand about dark ice in this situation, is that the small debris layer on top actually acts as insulator and causes the ice to melt even slower.
But then, there is not enough drama in those issues to focus on the facts.
Greenland Summit Camp, however, looks like it will have to be raised because it is close to being buried right now in snow and ice and is probably semi-dangerous for the occupants.

Reply to  Bill Illis
April 17, 2015 12:40 pm

What they don’t understand about dark ice in this situation, is that the small debris layer on top actually acts as insulator and causes the ice to melt even slower.
Calling this out for additional effect. When you grow up in a cold climate, one of the things you learn about is how snow melts. Large piles of snow get darker and darker as the snow melts and leaves a layer of dirt on top. When the dirt gets thick enough, melting slows to a crawl.

Reply to  davidmhoffer
April 17, 2015 1:30 pm

spoil sport!!

Reply to  davidmhoffer
April 17, 2015 6:55 pm

davidmhoffer, All us country mice know this but the effect is even more dramatic where there is greater debris scattered on the snow plow piles by traffic so even the city mice, if they would look up from their computer screens and reflect on the world around them once in awhile, should have a handle on it.

April 17, 2015 12:59 pm

…maybe he only looks at data…

I’m pretty sure that I’ve never seen a climate scientist accused of this before.

April 17, 2015 1:07 pm

Couple of days ago I got ticked-off by Dr. Brown (RGB) for suggesting a 15 year link between Arctic Atmospheric pressure and Equatorial temps as a cause of N.A. hurricane probability.
Just over 3 years ago I , when even less ‘mature’, produced a graph suggesting an ‘impossible’ 62 year Arctic-Equator atmospheric pressure link, but since it strongly features Greenland’s ice darkening from volcanic ash, I thought worth re-posting..
Original comment February 28, 2012 can be found here:

Winnipeg Boy
Reply to  vukcevic
April 17, 2015 1:56 pm

IDK, that seems a bit like matching one squiggly line with another squiggly line.
Sometimes a line is just a line.

Reply to  Winnipeg Boy
April 17, 2015 2:19 pm

True climate data are just that, lot of squiggly lines; the AGW’s haven’t had time yet to change atmospheric pressure data. It is the bad data that looks like a hockey stick.

April 17, 2015 1:16 pm

Went and did a bit of research. Ive core studies sonce 1800. The present Greenland BC issue is least in the north and greatest in south. In all three cores (Humbolt, D4, Act2) BC started rising about 1850, peaked about 1920, then irregularly declined until about 1970-1980. Irregularly stable since, at about 1850 levels. So any association with AGW is weaker than tenuous. Plus, DMI esrimates Greenland gained as much ice mass annually in 2013 and 2014 as it lost annually in the previous decade.

Bruce Cobb
April 17, 2015 1:39 pm

Oh noes, it’s another arctic death spiral. We’re doomed.

Brandon Gates
April 17, 2015 1:42 pm

Maybe Tedesco lives in a cocoon and missed the “Dark Snow Project” which took this video last year:

Maybe we should not claim to be able to read the man’s mind, but rather, refer to his EGU abstract: http://media.egu.eu/media/documents/2015/28/tedesco_scientific_abstract.pdf
Using a combination of remote sensing data and outputs of a regional climate model, we show that albedo over the GIS decreased significantly from 1996 to 2012.
Pretty clearly he’s aware that the GIS ice sheet is darkening, in fact his 2015 paper contains this pretty picture:
The only words spoken in the Dark Snow Project video are Jason Box exclaiming, “The surface is SO dark!” Though, digging a little deeper, we find this statement from Dr. Box on the Dark Snow Project blog: http://darksnow.org/sky-selfie/
As part of the research, they have been using drones (Unmanned Aerial Vehicles, or UAVs) to photograph the surface from low altitude to examine the development of surface structures associated with melting. Strips of images and albedo measurements from the UAV are compared with simultaneous satellite images from the NASA MODIS sensor as an intermediate state to relate ground albedo measurements with that of the entire ice sheet. UAV photos reveal a surface riven with fractures, and drained by ephemeral rivers of melt water. The mid-summer melt surface in this area is pocked with 0.5 to 1 meter-wide (1.5 to 3 feet-wide) potholes with black grit and dust collected at the bottom. This black material is called cryoconite, and is comprised of dust and soot deposited on the surface, and melted out from the older ice exposed by melting.
Dr. Tedesco is quite familiar with the work of Dr. Box, they are in fact colleagues: J.E. Box, et al. (2012), “Greenland ice sheet albedo feedback: thermodynamics and atmospheric drivers”: http://www.the-cryosphere.net/6/821/2012/tc-6-821-2012.pdf
The Carbon Brief gives Tedesco’s comments some further context: http://www.carbonbrief.org/blog/2015/04/darkening-ice-speeds-up-greenland-melt-new-research-suggests/
Decreasing albedo
The darkening ice sheet is predominantly caused by three factors, all of which are triggered by the melting caused by rising temperatures, Tedesco says. First, changes to the size of individual snow ‘grains’, which are very small crystals of snow:
“When you have new snow, it’s very bright. As you go through melting and refreezing cycles, the grains get bigger and bigger. This creates a reduction in albedo.”
This is actually invisible to the human eye, Tedesco says, so you couldn’t tell it was happening from just looking at the ice sheet.
Secondly, as more snow melts, it exposes the ice underneath, which has a lower albedo. New snow has an albedo of about 80% but for bare ice this is more like 30 or 40%, says Tedesco.
Lastly, snow on the ice sheet contains particles of dust and soot. When the snow on the surface of the ice sheet melts, the meltwater filters down through the snow leaving the particles on the surface, and making it darker. This can include particles from many years ago, Tedesco says:
“The more melting you have, the more impurities you deposit on the surface. Not because [there are more] coming from forest fires or the atmosphere, but because you have a cumulative effect of all the impurities that were stored in the snowpack over the previous years or decades being released because of the increased melting.”

Despite tripping up a bit in the final sentence, it’s clear his message is that the increasing melt rate is the predominant driver by way of these three factors, not the ONLY driver — obviously the soot and dust had to get there to begin with … and I would think that most of the dust and soot in Greenland ice is arguably natural.

Reply to  Brandon Gates
April 17, 2015 2:18 pm

All good observations. But the various mass loss estimates for GIS are low to none in the 1990’s, something like 200Gt/year thereafter through 2012 during the pause, and then (per DMI) about 200Gt/year gain in 2013 and 2014. This suggests regional ocean mediated climate change rather than global warming. TheNEEM ice core showed that at the peak of the Eemian intergalcial, the ice was only 2300 meters thick rather than 2400 now. So it also depends where on the GIS. Ice cores show BC is mainly a southern Greenland issue. So does the circulation animation in the post.

Brandon Gates
Reply to  ristvan
April 17, 2015 10:55 pm


But the various mass loss estimates for GIS are low to none in the 1990’s, something like 200Gt/year thereafter through 2012 during the pause, and then (per DMI) about 200Gt/year gain in 2013 and 2014.

GRACE only goes through mid-2013 and only covered 10 years from 2003. I don’t know what DMI means. I’m not aware of any literature suggesting a reversal, a specific citation would be appreciated.

This suggests regional ocean mediated climate change rather than global warming.

Greenland air temperatures are quite volatile due to its geography — it correlates quite well with AMO. So there’s that. However, from Box, J. & Colgan, W. Greenland Ice Sheet mass balance reconstruction. Part III: Marine ice loss and total mass balance (1840–2010). J. Clim. 26, 6990–7002 (2013):
I can’t find a pre-print verion of Part III, but Part I is here: http://polarmet.osu.edu/PMG_publications/box_cressie_jc_2013.pdf
Annoying that the there is not a series representing the net, though just eyeballing the plot, this reconstruction is consistent with …

The NEEM ice core showed that at the peak of the Eemian intergalcial, the ice was only 2300 meters thick rather than 2400 now.

… warming in the entire system, as globally, the Eemian was roughly 2-4 K warmer than the Holocene mean, however much of that was insolation-driven:
Our sensitivity experiments show that only about 55% of this change in surface mass balance can be attributed to higher ambient temperatures, with the remaining 45% caused by higher insolation and associated nonlinear feedbacks. We show that temperature–melt relations are dependent on changes in insolation. Hence, we suggest that projections of future Greenland ice loss on the basis of Eemian temperature–melt relations may overestimate the future vulnerability of the ice sheet.
One still should be careful about short-term trends in the Arctic … as you allude, ocean/atmosphere couplings can swamp the CO2 forcing signal quite readily over annual and decadal time frames.

Ice cores show BC is mainly a southern Greenland issue.

Adds insult to injury from my perspective. Quite intuitively, that’s where the highest rates of mass loss are occurring.

Reply to  ristvan
April 18, 2015 2:25 am

Brandon Gates, DMI is the Danish Meteorological Institute (DMI) established in 1872.

Reply to  ristvan
April 18, 2015 2:30 am

Danish Meteorological Institute

Brandon Gates
Reply to  ristvan
April 18, 2015 9:53 am

Thanks, Lee.

April 17, 2015 2:00 pm

The Arctic sea ice (NOT the Antarctic sea ice!) DOES darken each summer from 15 April through about 20 August.
Curry and Perovich both confirm that the Arctic sea ice albedo DECREASES from a winter-spring high of 0.83 down to a July 15-July 30 low of 0.38 to 0.42. Lowest data plot I’ve seen is 0.36. As the Arctic sea ice begins re-freezing about August 15, the albedo goes back as fewer and fewer melt ponds are on top of the sea ice to absorb sunlight, reduce reflectivity, obviously – thus darken albedo
Greenland ice cap albedo behaves a little differently since it is much, much thicker and has many more “cracks” and crevasses underneath the surface snow. Melt water on top doesn’t tend to sit “on top” but to find cracks and seep below, leaving the older glacier ice to be visible. But you HAVE TO COMPARE “today’s daily plot of Greenland ice cap albedo to ANOTHER EARLIER SUMMER in the same place under the same weather conditions.
Cloudy days and cloudy conditions increase albedo, clear days have lower albedo measurements. The change from clouds to clear changes albedo from (for example) 0.65 to 0.58 over a four day period. Unless the “one-data-point-per-year” plot is RIGOROUSLY controlled against ALL daily and hourly effects (weather, time of day of the measurement, type of cloud cover, and day-of-year) that will affect the daily changing ice albedo – the very, very small change in Greenland ice albedo that is plotted (0.76 – 0.73) is not only misleading, but (to a point) deliberately misleading.
Which might be his intention.
Which almost certainly is his intention.

Brian H
Reply to  RACookPE1978
April 18, 2015 3:47 am

Such ‘darkening’ processes are continuous, ongoing, and in no way attributable to GW.

April 17, 2015 2:26 pm

Love that aerosol flow animation. Better than a lava lamp, and it’s reality (in a virtual sort of way).

Reply to  Dawtgtomis
April 17, 2015 3:00 pm

+1 !!!
That was miasmarising.

April 17, 2015 3:02 pm

Tedesco should cover Greenland with used CDs.

April 17, 2015 3:08 pm

I agree with this fine researcher.
I now believe that when it gets as hot as hell in Greenland, the snow and the ice will be as black as pitch (OH NO. – isn’t pitch a mixture of hydrocarbons?).

Bruce of Newcastle
April 17, 2015 3:12 pm

I suspect the rise in particulates in the Arctic is also closely linked to the rise in diesel used for transport, as logistics have switched to trucks and away from trains over the last 50 years. Also use of diesel in cars has climbed significantly as drivers have switched from gasoline. Diesel use has been especially favoured in the EU, US and China. The very mobile pm2.5 soot from trucks has only been controlled fairly recently.
Its hard to get a global diesel consumption graph: this one is the best that I could find. Its clear that diesel for transport has been rising fast in the Northern Hemisphere.
I didn’t see a characterisation study in the Dark Snow Project site. It would be useful to attempt characterisation of the type and source of the particulates in the snow at different times during the northern snow melt season. If my hypothesis is correct there will be a lot of pm2.5 soot in the particulate population.

Reply to  Bruce of Newcastle
April 17, 2015 3:42 pm

See upthread. According to GIS ice cores, there has not been an annual increase in BC since about 1920. The impressions the MSM headlines and paper abstracts leave is misleading. Now, whether recent melting has exposed more of what was previously deposited is a separate question. Probably so, as that is how annual snowmelt in ‘dirty’ Chicago, but not ‘clean’ Wisconsin farmland, works. Personal observations starting 1985. But, this first accelerated by black body absorption, then decelerates by thermal insulation, the snowmelt process. Not simple.
Concentration dependent. On my dairy farm, we ‘slow’ the net melt process by winter manure spreading before and during the melt season, even though that initially speeds melting when exposed to the spring sun. Means less net runoff, and more soil water saturation complete with fertilizing nitrogen. Farmers know these things. Least cost survival mode always.

Fred Harwood
Reply to  ristvan
April 17, 2015 4:11 pm

+10. Spring measures also verify the applications.

April 17, 2015 3:20 pm

Well, went out this AM to the local snow dumping site just 1 KM from my place. Three feet of snow covered by 2 feet of “black” crap. Last year, the snow never completely all melted. Pretty hard to do when you have 6″ of snow covered by 3′ of dirt. But I guess that goes against the climate change cults meme.

April 17, 2015 4:12 pm

Most of the images of Greenland from the air that I have seen (even on Google earth) seem to show white – “pure as the driven snow”:
Anybody can “cherry pick” photos (even from this collection)

April 17, 2015 5:06 pm

Ummmm. How much of the “dark” is cyanobacteria and algae?

April 17, 2015 6:59 pm

Quite simple:
Marco Tedesco is saying darkening of the Greenland Ice Sheet is caused by climate warming (implying a cycle of warming causing ice melt, causing darkening, hence causing more warming, more melt … and so on)
And ignoring the simpler and more obvious possibility; Darkening (from black carbon deposits) causes ice melt.

April 17, 2015 7:43 pm

Icelandic volcanos have no effect either I suppose.

masInt branch 4 C3I in is
April 17, 2015 9:14 pm

Ah. Retrograde metamorphism of glacial ice in the ablation zone (a change in the C-crystallographic axis relative to flow).
Seems much of the “Glaciological Community” yet fail in knowing let even understanding crystallography and thermodynamics of rocks, including the forms of Ice (1H).
With every photograph there is a lie that the photographer disparately (e.g. NSF funding) needs to exploit.
Ha ha 😀

Mr. Pettersen
April 17, 2015 11:17 pm

So if we ask a warmist whats best for mother nature, a thin white ice or a thick grey ice, he will not be able to come up with an answer. Talking about sea ice thickness is all important. Talking about ice on Greenland colour is most important. If albedo is the important bit then thickness doesnt mather. A layer of carpaint is less than a mm, and still the difference from black and white colour is messurable.

April 18, 2015 4:18 am

Is this blackening of ice a cumulative process?
Every year more black particles are deposited?

Reply to  bjorn
April 18, 2015 7:43 am

If the ice melt is intense to completely melt previous year, and that one year before and so on, I would say Yes. Thus, we may have 20 or more years of ash accumulation in a single layer, accelerating melting even further.
In a few hundreds or more years someone will be analysing top ice cores, and since annual markers are lost, it may conclude that thickness of accumulated ash indicates a cataclysmic fire caused by a impact of a meteorite or whatever .

Daniel Kuhn
April 18, 2015 4:52 am

“Tedesco must be either incompetent, blind, an activist or all three, because the data on northern hemisphere fires contradicts his claim of “his research had not found any evidence that points to either increased atmospheric deposition of impurities or to the number of fires over Eurasia and North America as being factors.“”
he did not say, there is no evidence, he said, he found no evidence, and you provide no evidence. you just show correlation.which is not the same as causation.

April 18, 2015 7:41 am

A picture is worth a thousand threads of biased gibberish burying a plank of reality.

April 18, 2015 8:06 am

I am sceptical about reliability of the photographs. Lifting gama by 2 revels different looking horizon.

k. kilty
Reply to  vukcevic
April 18, 2015 8:44 am

I was surprised by the darkness of the snow at first, but then realized that a lot of it comes from ruts and crevices and the shadows they produce. Then the darkness of the sky suggests a polarizing filter, which has a big impact on the surface appearance also.

Reply to  vukcevic
April 18, 2015 3:45 pm

The clouds are wrong. ?

tom s
April 18, 2015 11:58 am

And mankind will stop this geologic event with tweaking our co2 output. Ok, got it. grrrrrr……

masInt branch 4 C3I in is
April 19, 2015 11:32 am

Remember the Gold-White Black-Blue skirt?
Perception and optics play tricks on all of us, especially Jason Box and Marco Tedesco. Safe to say they god Ds in Physics class, if they ever took a class in physics.

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