Another alarmist pillar collapses – Greenland melting due to old soot feedback loops and albedo change – not AGW

From the EARTH INSTITUTE AT COLUMBIA UNIVERSITY and the “we told you so time and again at WUWT” department comes this study which not only explains the “insta-melt” in the Summer of 2012, but the ongoing melting that has been incorrectly blamed on CO2, when instead it’s all about older soot embedded in snow coming around again to enhance melting combined with weather pattern changes..

greenland-meltwater-albedo

An aerial image of Greenland shows rivers of meltwater and areas of dark ice. Greenland’s surface is absorbing more solar radiation as melting increases grain size and brings old impurities to the surface. CREDIT Marco Tedesco/Lamont-Doherty Earth Observatory

Greenland’s ice is getting darker, increasing risk of melting

Feedback loops from melting itself are driving changes in reflectivity

Greenland’s snowy surface has been getting darker over the past two decades, absorbing more heat from the sun and increasing snow melt, a new study of satellite data shows. That trend is likely to continue, with the surface’s reflectivity, or albedo, decreasing by as much as 10 percent by the end of the century, the study says.

While soot blowing in from wildfires contributes to the problem, it hasn’t been driving the change, the study finds. The real culprits are two feedback loops created by the melting itself. One of those processes isn’t visible to the human eye, but it is having a profound effect.

The results, published in the European Geosciences Union journal The Cryosphere, have global implications. Fresh meltwater pouring into the ocean from Greenland raises sea level and could affect ocean ecology and circulation.

“You don’t necessarily have to have a ‘dirtier’ snowpack to make it dark,” said lead author Marco Tedesco, a research professor at Columbia University’s Lamont-Doherty Earth Observatory and adjunct scientist at NASA Goddard Institute of Space Studies. “A snowpack that might look ‘clean’ to our eyes can be more effective in absorbing solar radiation than a dirty one. Overall, what matters, it is the total amount of solar energy that the surface absorbs. This is the real driver of melting.”

The feedback loops work like this: During a warm summer with clear skies and lots of solar radiation pouring in, the surface starts to melt. As the top layers of fresh snow disappear, old impurities, like dust from erosion or soot that blew in years before, begin to appear, darkening the surface. A warm summer can remove enough snow to allow several years of impurities to concentrate at the surface as surrounding snow layers disappear. At the same time, as the snow melts and refreezes, the grains of snow get larger. This is because the meltwater acts like glue, sticking grains together when the surface refreezes. The larger grains create a less reflective surface that allows more solar radiation to be absorbed. The impact of grain size on albedo – the ratio between reflected and incoming solar radiation – is strong in the infrared range, where humans can’t see, but satellite instruments can detect the change.

“It’s a complex system of interaction between the atmosphere and the ice sheet surface. Rising temperatures are promoting more melting, and that melting is reducing albedo, which in turn is increasing melting,” Tedesco said. “How this accumulates over decades is going to be important, because it can accelerate the amount of water Greenland loses. Even if we don’t have a lot of melting because of atmospheric conditions one year, the surface is more sensitive to any kind of input the sun can give it, because of the previous cycle.”

The study used satellite data to compare summertime changes in Greenland’s albedo from 1981 to 2012. The first decade showed little change, but starting around 1996, the data show that due to darkening, the ice began absorbing about 2 percent more solar radiation per decade. At the same time, summer near-surface temperatures in Greenland increased at a rate of about 0.74?C per decade, allowing more snow to melt and fuel the feedback loops.

A likely cause for the large shift around 1996 was a change in atmospheric circulation, Tedesco said. The North Atlantic Oscillation, a large-scale natural weather cycle, went into a phase in which summer atmospheric conditions favored more incoming solar radiation and warmer, moist air from the south. Later records show those conditions shifted in 2013-2014 to favor less melting, but the damage was already done – the ice sheet had become more sensitive. In 2015, melting spiked again to reach more than half of the Greenland ice sheet.

While new snowfall can make the ice sheet brighter again, the dark material built up during the melt years is waiting just below the surface, preconditioning the surface to future melting, Tedesco said.

The scientists also ran a computer model to simulate the future of Greenland’s surface temperature, grain size, exposed ice area and albedo. Over the current century, the model projects that the average albedo for the entire ice sheet will fall by as much as 8 percent, and by as much 10 percent on the western edge, where the ice is darkest today. Those are conservative estimates – the change could be twice that, Tedesco said.

The scientists looked into the hypothesis that soot from forest fires in China, Siberia and North America could be driving the increased darkening of the ice sheet. Using the Global Fire Emissions Database, they analyzed trends in black-carbon emissions from wildfires in those regions and Europe. While the amount of black carbon released by fires varied year to year, the scientists found no statistically significant increase during 1997-2012 to match the darkening of Greenland.

The study also raises questions about whether Greenland’s high plateau is darkening as previous reports have suggested. The scientists found no long-term trend of darkening at the top, and they suspect that the Terra MODIS satellite sensor that has detected darkening in the past may actually be degrading, as previous studies have suggested. At lower elevations, the signal is much stronger.

“It is a very good paper which provides valuable new insights about the physical processes controlling the change in reflectivity of the Greenland ice sheet and specifically its darkening over time,” said Eric Rignot, a senior research scientist at NASA’s Jet Propulsion Laboratory who studies ice sheets but was not involved with the new study. “I also find it particularly interesting that the darkening indicated earlier by satellite sensors is now confirmed to be less, which is good news for the ice sheet. Yet the darkening of Greenland around its periphery remains a source of concern because it contributes to making the ice sheet melt away faster.”

The feedback loops could be stopped with lots of snowfall and less melting, but that doesn’t seem likely given the increasing concentration of greenhouse gases in the atmosphere, Tedesco said. And while warming is expected to increase precipitation, that precipitation includes increasing rainfall, which speeds up melting. Melting is also moving to higher elevations as global temperatures warm.

“As warming continues, the feedback from declining albedo will add up,” Tedesco said. “It’s a train running downhill, and the hill is getting steeper.”

###

Co-authors of the paper are Sarah Doherty of the University of Washington; Xavier Fettweis of University of Liege; Patrick Alexander of NASA Goddard Institute of Space Studies and City University of New York; Jeyavinoth Jeyaratnam of the City College of New York; and Julienne Stroeve of University of Boulder.

The paper, “The darkening of the Greenland ice sheet: trends, drivers, and projections (1981-2100),” http://www.the-cryosphere.net/10/477/2016/tc-10-477-2016-discussion.html

78 thoughts on “Another alarmist pillar collapses – Greenland melting due to old soot feedback loops and albedo change – not AGW

    • Tom,
      I have been informed – years ago – that ‘The science is settled’.

      I need say no more.

      Auto

      • Really the Guardian are that ignorant they can publish that kind of crap and no one even notices.

        Like Susanne Goldberg’s “80% of Arctic ice has melted” or the recent ocean pH will drop by 109% according to IPCC.

        Oddly they cannot find anyone scientifically literate to check this crap before they publish it and avoid making complete idiots of themselves.

      • Don’t worry – only scientifically illiterate agenda driven idiots can tolerate reading the Grauniad.
        And, frankly, they deserve what they get.

      • I’m expecting the year when they tell us the whole ice sheet melted and prompt for action to save it. It can’t be far away, if already half of it melted.

      • “Haven’t you heard that “more than half of the Greenland ice sheet melted last summer””

        Sounds like the sort of drivel Drillbit Dana Nuttyjelly and his mate Abrahams come out with.

  1. We already know it is not just (or even CO2) and it is also not just Soot, we know it includes Ocean Currents, Winds and Storms as well as changes to the Polar Vortex.

  2. Not good. This will raise sea levels a lot.

    How can we prevent/stop this? I realize reducing CO2 isn’t the answer but we need to think about what is.

      • I just talked to a chap (about an hour ago) from Finland; northern region. He said the Temperature was currently sub zero (deg. C) I think he told me -1 deg. C

        He also said that he hasn’t seen as much snow the last couple of years, as they typically have had in that region. He didn’t offer any reason.

        G

      • G
        Weather varies, as you know.
        Plus northern Finland – -1C – in early March, is not bad.
        [On the basis that too cold is bad; a bit warmer is good.]
        And London has had a mild winter – a real plus.

        Auto – not quite sun-bathing!

      • No, this has been going on for a long time. The current melt water entering the oceans is not enough rise sea level globally.

        Coast lines are receding (moving seaward) where there is uplift and coast lines are encroaching (moving landward) where there is subsidence. Coast lines that are not subsiding or uplifting are typically not changing due to sedimentation keeping pace with sea level. That is unless local sedimentation rates have been altered by something, i.e. the removal of mangroves.

      • Reason for not having snow in Finland for example during the December is because the climate has changed, there is your explanation. Last few years have been exeptional. At the moment there is lots of snow, but hese are suppose to be the coldest months of the year. Avarage temperatures has piked after 80’s, the winter starts later and end sooner (about 12 days in average compared to end 1800). Cold periods are shorter as well. Weather patterns in summer are also unusally unpredictable. The changes are visible, I think there is nobody who doesn’t think that there is something happening. Still the denial is so strong here, that people are going trough some kind of mass dissassociative disorder around this subject.

    • The answer is to stop concentrating on co2 emissions, and to stop giving the developing world a free ride in all emissions. It would seem very likely that these dust and soot emissions are due to China, as the Western world is no longer pumping out emissions (the UK has no industry to pump anything). So the answer is not to buy any Chinese goods, until each particular factory has been certified to be soot emissions compliant.

    • .Mother Nature must quickly wake up to the fact that this random behaviour must cease.
      The behaviours need to fit a warm and fuzzy mathematical model.

  3. The study projects an accelerating decline for the Greenland Ice cap, based on the soot etc continuing to build up and thus increasing solar absorption. There must be an offsetting mechanism that refreshes the surface, as there have surely been massive soot depositions even before the present.
    There have been papers posted here indicating that during the Greenland summer, the surface melt water flushes down crevasses in the ice. Perhaps that water also carries off the surface soot and debris?

    • etudiant …. that’s what I was wondering as well. Obviously the soot had to have accumulated from somewhere at some time in the past. Same thing with summer melt seasons decreasing the albedo of the snow crystals as they change shape due to melting. It’s as if the soot will forever be embedded and there’s no way for it to wash off, and that the snow (really? it’s an ICE cap already) is doomed to perpetually melt away before the cycle can be reset. I don’t buy that.

      • The soot is coming from Wildfires in Siberia, which have increased greatly over the past decade. The fires have been caused by warmer and drier summer weather (presumably caused by CO2 global warming.) so, the soot does not wash away with the melt and does not get covered by snow, as it is replenished every summer. Hence, the unexpected temperature spiral and increased melting of the Greenland ice sheet.

  4. Tedesco has just re-discovered the Arctic “death spiral”.
    Somebody better tell Trenberth.

  5. The answer: Geoengineering with titanium dioxide to increase albedo (Put a climate change tax on Twinkies; they are a profligate waste of this crucial resource). Funny, I seem to recall back in the ’70’s when the next ice age was coming, people were advocating dumping black carbon on Greenland glaciers to stop the ice advance.

    • Anything that increases the cloudiness above Greenland would help as well. As well as promoting more snowfall in the winter to bury the soot deep enough that the next summers melt won’t expose it.

  6. For the climate alarmists, the details are hardly the issue. For instance, they are still running around worried about how warm it has been in 2015, never stopping for a moment to think that pretty much all that warmth is from a completely natural cause – El Nino. If you can ever grab their attention to explain that if the Greenland ice sheet does melt, it is more from the presence of soot from natural sources. But they won’t see it that way. They can’t. Every reason for climate warming is CO2, no matter what the details may be.

    • “If you can ever grab their attention to explain that if the Greenland ice sheet does melt, it is more from the presence of soot from natural sources.”

      You’ve got my undivided attention. Could you please explain why these natural sources waited until 1996 to take action when they’ve had the last 10 000 years in which to cause a sudden decrease in albedo? I’d be particularly interested in knowing why the Greenland ice sheet didn’t collapse when the climate was warmer than normal, say the medieval warm period for instance. If you could cover why this El Nino is causing the surface melting while previous ones didn’t, that would be great too.

  7. This paper, and several other recent papers indicate a trend that I think shows how this whole saga will pan out. I predict that the real scientists are starting to realise that climate change is rubbish, and that they will all slowly go back to doing real research. Meanwhile, there will be a fringe group who keep pushing the usual nonsense who will be propped up by the media.

    Eventually all the fuss will die out and everyone will forget it ever happened (maybe by 2030). I was hoping that one day there would be inquiries and the world would be shocked at how such a scandal could happen. But I suspect there will be no such joy.

  8. They really are behind the times. As I said on an earlier thread:

    Quote:
    Incidentally, it may well be that the early melt and retreat of Arctic ice in recent years has been caused by Chinese soot and dust, in a very similar fashion. Which would certainly explain the great difference between the Arctic sea ice retreat and the Antarctic sea ice growth. A paper was written a few years ago, explaining that all the Alpine glacial retreat since the 19th century was caused by industrial soot.
    https://wattsupwiththat.com/2016/02/25/the-warmer-the-icier

    .
    .

    But what this study does not highlight, is that if albedo is the primary regulator of ice sheets it is most probably also the primary regulator of temperature. Dirty ice sheets absorb up to 180 wm2 of extra insolation, and when the ice sheet is gone the bare land can absorb up to an extra 300 wm2. And that is a lot of extra energy absorption, during the northern summer. So the primary regulator of world temperature may well be ice-albedo, not Co2.

    And if albedo can regulate modern ice-sheet extent, it can also regulate ice-age ice-sheet extent. In which case, my paper on ice age modulation by dusty-ice albedo may well be the correct. But in this case, the dust was caused by Co2 concentrations getting so low that a large proportion of plant life died, leading to desertification and dust:

    Modulation of Ice Ages via Precession and Dust-Albedo Feedbacks
    https://www.academia.edu/20051643/Modulation_of_Ice_Ages_via_Precession_and_Dust-Albedo_Feedbacks

    R

    • ralfellis
      l think you are wrong to when you say that dust was the cause of the rapid melting at the end of the ice age.
      l believe the main cause was a large increase in warmer air flowing over the ice sheets due to the break down of blocking weather patterns that were bringing Polar air down across the ice sheets. When this blocking broke down a lot more of the warming air from the south was allowed to flow over the ice sheets. Which in turn greatly increased the amount of melting during the summer. With this increased melting the dust was then allowed to be exposed on the surface of the ice sheets. Which aided with the rapid melting of the ice sheets. Rather then been the cause of it.

  9. Well they’ve exonerated recent wildfires as the major soot source so it must be manmade. Here’s my theory: All that soot came from Viking fires during their settlement. Therefore it’s manmade or perhaps womanmade maybe even undeterminedgendermade depending on who was responsible for tending the fires. Oh, how horrible! Just another example of how humans can ruin a pristine wilderness. Of course the soot is just now being exposed because of the catastrophic release of CO2 in recent times. We’re doomed!

    sarc off now

  10. All the melting, and refreezing, and concentrating of soot etc, shows why ice cores can’t be trusted for determining dates etc, as they are corrupted by intermitant soot and ash being rearranged.

    “Glacier Girl”, One of the WWII planes that landed on Greenland in 1945 and recovered 50 years later, shows what can happen in 50 years. We have hard evidence, if the gloom and doomers would just look for it.

  11. Why the reluctance to blame the obvious soot source: China. I’ve been in China 4 or 5 times in recent years and the air is blue! 30 yrs ago, they collected water and silt from Aishihik Lake in the middle of Yukon, Canada and found coal fired soot and base metal smelting soot in this pristine lake, believed to have come from China over the arctic/Pacific. “The Conversation” piece on per capita spending in global cities for AGW adaptation the other day here at WUWT, praised China for having what looked to me a piddling 40 GBP per capita. Why are we not allowed to criticise China – I think it is because, with the USSR collapse, the Marksbrothers look to Mother China as their model. China wasn’t much of a model until they adopted capitalism which will be the ideology’s undoing eventually.

    Iceland’s volcanoes must also be blackening Greenland. I see a spectacular picture above of a guy on his knees on the Greenland Ice Sheet. You don’t suppose that he is NOT taking a sample for analysis, do you? Nah, no need to. It is just soot. That’s what everyone says! Besides we got models to replace data.

    ralfellis
    March 3, 2016 at 1:07 pm

    “They really are behind the times. As I said on an earlier thread:

    Quote:
    Incidentally, it may well be that the early melt and retreat of Arctic ice in recent years has been caused by Chinese soot and dust,..”

  12. This is my favorite toy theory on how the ice ages came to an end. Milankovich cycles, certainly. But on top of that dust and soot inclusions in the ice came to the surface and greatly augmented the melting.

  13. The change in albedo has resulted in different estimates of changes in Greenland’s Surface mass balance (SMB). In 2014 based on gravity changes, Greenland exhibited a negligible loss of ice (6 gt). So I predicted the following year that Greenland would gain ice http://goo.gl/drOS1N

    The following year the dynamics that drove my prediction were as expected, but paradoxically researchers reported Greenland had now lost more ice than in 2014. In 2015 they suggested ice mass had increased to 189 GT. But that contradicted the dynamics favoring increased ice mass and I was baffled as to why but accepted my failed prediction. http://goo.gl/wYgdUC

    But it was more moveable goalposts that caused that odd increase ice loss.

    Here is a 2015 DMI graph of the 2014-2015 changes in Greenland’s Surface mass balance: http://goo.gl/NkfshO

    The most extreme annual change in SMB happened in the 2011-2012 melt season was way below average when a high pressure system centered on Greenland. Nonetheless that still left Greenland with a 100 GT gain in surface mass for the year.

    Here is the new adjustments to the DMI surface mass balance. They suggest due to changes in their albedo algorithm, all the surface accumulation in 2011-12 had really melted away bringing SMB back to zero. http://goo.gl/M5HlXv

    The DMI researcher admitted their adjustments have not yet been peer reviewed, but were still used in a few papers,

    The difference between 182 GT of SMB between 2014 and 2015 was due to an adjustment, and who knows what the rap change in mass was.

    Welcome to the “Adjustocene”!!!

  14. Serious question. Do we not know the difference between human-caused soot and ash? Or is to be determined by further research?

  15. A layer of material on top of ice insulates it from melting. I see it on the farm all the time.

  16. So is it fair to conjecture that all of the industrial soot (not CO2) man has been pumping into the atmosphere since the 1800s, and even before, is what is preventing the earth from plummeting into the next ice age?

    And we are thus stalling and even preventing one of the most perilous threats to Earth’s current, very pleasant climate, Adam Smith’s invisible hand comes to mind.

    • Recent industrial soot from China? Ha.
      Industrial soot since the 1800s? Ha.
      Most of North America was regularly burned for 10,000 years, until a hundred years ago. Fire ecologies were well defined.

  17. And this is the first time in the history of the world that this has happened.

    /Or not.

  18. “Greenland melting due to old soot feedback loops and albedo change – not AGW”

    They aren’t saying it isn’t AGW. The feedback loops amplify the change, they don’t cause them.
    “It’s a complex system of interaction between the atmosphere and the ice sheet surface. Rising temperatures are promoting more melting, and that melting is reducing albedo, which in turn is increasing melting,” Tedesco said.

    The temperatures weren’t rising of their own accord.

    ‘The feedback loops could be stopped with lots of snowfall and less melting, but that doesn’t seem likely given the increasing concentration of greenhouse gases in the atmosphere, Tedesco said. And while warming is expected to increase precipitation, that precipitation includes increasing rainfall, which speeds up melting. Melting is also moving to higher elevations as global temperatures warm.

    “As warming continues, the feedback from declining albedo will add up,” Tedesco said. “It’s a train running downhill, and the hill is getting steeper.”’

    From the paper:
    “The drivers we identified to be responsible for the observed darkening are related to endogenous processes rather than exogenous ones and are strongly driven by melting. Because melting is projected to increase over the next decades,…”

    • Yes, exactly. The higher temps are acting as a catalyst. If warming cycles were a common occurrence, then this would’ve happened before. Instead, the “cake layer” effect of new snow, then some carbon deposits from the air, then new snow, then carbon, etc has been altered by the top snow layer getting melted due to warming, exposing darker snow underneath and setting off a chain reaction of accelerated melting.

    • “From the paper:
      “The drivers we identified . . .”

      They deserve some sort of award for using the traditional term instead of the alarmist invention, “forcing.”

  19. I wonder if they got the idea for this study after observing the condition of the last bits of snow left on the side of the roadway.

  20. Using the Global Fire Emissions Database, they analyzed trends in black-carbon emissions from wildfires in those regions and Europe. While the amount of black carbon released by fires varied year to year, the scientists found no statistically significant increase during 1997-2012 to match the darkening of Greenland

    Another way to show no link between man made CO2 and wildfires.

    • No, it doesn’t show that at all. It only shows that the darkening of Greenland between 1997-2012 was not due to black carbon released by fires. So either the darkening was caused by other carbon (other sources) or by the melting effect, which the paper concludes is the primary driver.

  21. “The North Atlantic Oscillation, a large-scale natural weather cycle, went into a phase in which summer atmospheric conditions favored more incoming solar radiation and warmer, moist air from the south.”

    Water vapour has absorption bands in the solar near infrared, that would decrease solar radiation at the surface, though the moist air from the south is probably carting soot along with.

    Increased CO2 is modeled to increase positive NAO, so no one should be blaming it for these negative NAO driven humidity event Greenland melts anyway.
    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-3-5-6.html

  22. well, it’s a theory. Let’s see if it holds water better than trace bits of plant food driving climate.

  23. “The feedback loops could be stopped with lots of snowfall and less melting, but that doesn’t seem likely given the increasing concentration of greenhouse gases in the atmosphere, Tedesco said.”

    Why? We’ve been told by the so-called climate experts that pretty much everything is attributable to an AGW-driven world, including more snowfalls. Tedesco forgets at what elevation and mean surface temperature Greenland’s ice cap is actually at. It’s very well possible that heavy snowfalls in the years to come across the surface of the island will make all of this a moot point.

    I’ve always wondered why there are certain banding patterns in old icebergs that, to me, aren’t easily explained by the collection of rocks and soil detritus as the glacier advances. If that theory were true, you’d see banding only at a singular front and at the very bottom of the glacier where it makes contact with the ground. But banding patterns are much farther up, and can be separated by small gaps or many feet of otherwise pristine compacted snow ice. So what impetus drives the advance and retreat of snow ice formation if, as suggested above in the article, decreased albedo and increased insolation absorption are inevitable?

    All seems like poppycock to me, that the REAL question these scientists should be asking is, By what mechanism does a switch from increased melting to one of increased snowfall overcome the summer ice loss? Weather patterns that allow greater cloud cover over the ice cap seems a likely beginning, with heavy snow events (as evidenced from DMI data records) increasing in frequency as a co-factor.

    Could some government agency give me $500,000 to perform a study please? Anyone? Anyone?

  24. I remember walking on old snow that was heavily pock marked because as the sun heated up the darker material it melted the snow and ice around it and the material had sunk. Dust is fine particles but the particles themselves are generally heavier than water and will therefore sink below the ice. I therefore have some doubts about the underlying thesis.

  25. Wait. Did you read the paper? It says that it’s GHG driven warming that has caused multi year ice to melt, leaving impurities on the surface. The projections in the paper are that continued increases in GHG will result in more melting and even darker ice, which will result in more melting. How can you people read a paper that confirms GHG levels are causing the ice to melt even faster than models predicted and decide that it means the *exact opposite*.

  26. Climat is and has been ever changing, so quit the crap. Greenland is on the way to stop being “Whiteland”.

  27. Old soot? They are trying to keep the connection with carbon alive. Because they are setup a world-wide taxation scheme based upon carbon taxation, IMO. These people are so efficient, they need a committe to change their minds, IMO.

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