A Sudden Surge in Melting Seen Atop Greenland’s Ice Sheet

By Tom Yulsman | June 20, 2014 1:13 pm

New research suggests that climate change may be contributing to warm-season melting in Greenland through a novel means: dust

sudden surge

A dusky, bluish-gray band dotted with blue melt ponds parallels the rugged west coast of Greenland, as seen in this image acquired by NASA’s Terra satellite on Monday, June 16, 2014. This is an area where snow atop the Greenland ice sheet is melting as temperatures warm. (Please click for a large, high-resolution version. Source: NASA)

Springtime melting of snow in Greenland spiked over the past week, adding a bit of an exclamation mark to the start of the warm season there.

Melting of snow along the fringes of the Greenland Ice Sheet as temperatures warm in the spring is perfectly normal. You can see its effects in the image above, acquired by NASA’s Terra satellite on Monday, June 16. The grayish-blue band dotted by little blue melt ponds shows where snow and maybe some ice is thawing.

This year, the melt season got off to a moderately fast start, but for the most part only in the southernmost part of the island. Then, things got “a bit more interesting,” says Ted Scambos, lead scientist for the National Snow and Ice Data Center at the University of Colorado, Boulder. (In the interest of full disclosure: Ted is a colleague of mine at CU-Boulder, where I run the Center for Environmental Journalism.)

Starting last weekend, the geographical extent of surface melting expanded from about 10 percent of the island to 40 percent. You can see the sudden surge in this graphic:

sudden surge

The extent of melting at the surface of the Greenland Ice Sheet is seen in this graphic from the National Snow and Ice Data Center. Note the spike to 40 percent. (Source: NSIDC)

It’s too soon to tell whether this is just a flash in the pan or the start of a really big melt year. There are examples in the past when “brief spikes of 30 and 40 percent occurred even though the year turned out to be fairly normal,” Scambos told me in an email message. In fact, in the image above you can see what looks like the start of a drop off in melt area.

That said, “Persistence at this level would get my attention,” Scambos says.

sudden surge

Extent of surface melting in Greenland on 6/17/14. (Source: NSIDC)

Last year, things got off to a fast start. But in the end, the extent of warm-season melting in Greenland in 2013 turned out to be fairly close to the long-term average.

In 2012, there was also a spike in melting early on. It began in late May and then subsided in June. But then melting just exploded, spreading rapidly and widely — with an astonishingly high peak in July. As an NSIDC Greenland Ice Sheet Today blog post describes it:

Greenland’s surface melting in 2012 was intense, far in excess of any earlier year in the satellite record since 1979. In July 2012, a very unusual weather event occurred. For a few days, 97% of the entire ice sheet indicated surface melting.

We’ll just have to wait and see before we’ll have a better sense of how things might go this year. In the meantime, I thought I’d also share some new research about a phenomenon that may be helping to accelerate the melting of snow atop the ice sheet during the warm season. And not just modestly.

If the new findings are correct, billions of tons of snow are either melting or sublimating every year in large measure because of a seemingly humble substance: dust.

Starting suddenly in 2009, there has been a significant drop in how much sunlight is being reflected back into space by dry snow at the surface in Greenland. This reduction in “albedo” means that the surface is darker and is therefore absorbing more solar energy — which leads to more melting of snow.

Why is this happening? Marie Dumont of the National Center for Meteorological Research in France, and nine of her colleagues, think they are on to the answer. Writing in a paper published in Nature Geoscience on June 8, she and her colleagues advance an intriguing — and unsettling — hypothesis:

. . . our analysis of remote sensing data indicates that the springtime darkening since 2009 stems from a widespread increase in the amount of light-absorbing impurities in snow, as well as in the atmosphere. We suggest that the transport of dust [by winds] from snow-free areas in the Arctic that are experiencing earlier melting of seasonal snow cover as the climate warms may be a contributing source of impurities.

Reaching this conclusion took a bit of scientific detective work.

First, the researchers documented changes in the reflectivity of Greenland snow using data from the MODIS instruments aboard the Terra and Aqua satellites. (The MODIS instrument aboard Terra acquired the data used to produce the image at the top of this post.)

Next, they used the remote sensing data to estimate how the impurity content of Greenland snow has also been changing. They found that impurities have been increasing since 2000 — and particularly between 2009 and 2013.

But could the darkening of the snow be pinned definitively on this? Or were other factors at work?

To help answer the question, Dumont and her colleagues ran simulations using a computer model called Crocus. These simulations showed that other factors by themselves could not explain what was happening. It all made sense only if impurities were factored in.

Soot, dust, and microorganisms can all reduce the albedo of snow and thereby cause it to absorb more solar energy. Soot is a powerful absorber, but recent measurements show modest amounts of it in Greenland snow, according to the researchers. On the other hand, substantial amounts of dust have been measured in at least one place on the ice cap, supporting the idea that it’s making a significant contribution to the decreased reflectivity of Greenland’s ice cap.

sudden surge

Greenland snow impurities compared to N. American snow cover in June. (Source:  M. Dumont et al, Nature Geoscience 2014)

But where might it be coming from? Here, the detective work gets even more interesting. It turns out that there is a fairly strong correlation between the rise in impurities in the snow, as measured with remote sensing, and decreases in the extent of snow cover that have been observed in North America during June. (To see the extent of that correlation, click on the thumbnail graphic at left.) This phenomenon may be “uncovering large areas of bare soil and thus enhancing dust erosion,” Dumont and her colleagues write.

What’s her best guess for a specific source? “I would say that probably mostly from the Northeast part of Canada, but this is only based on maps of aerosol optical depth,” she told me in an email message.

Optical depth is a measure of the atmosphere’s transparency, and it can be determined by satellite observations. These observations show “really high” levels of dust over that part of the Canadian Arctic, she says.

Dumont cautions that there is no direct evidence yet that earlier snowmelt has led to an increase in dust transport from the Arctic.  “That’s just an hypothesis that seems reasonable to us and for which we have some indirect evidence,” she says. “And that’s also why we underline in our paper the urgent need for more in situ measurements of impurities in snow.”

Lastly, how much of an effect might this be having on the amount of melting in Greenland? The Crocus computer model helped with that too. In the model’s simulations, a decrease in snow albedo equal to what has actually been observed in Greenland produced a 12 percent reduction in annual accumulation of snow.

If that does not seem like very much, consider that it works out to at least 27 billion tons of snow. Instead of accumulating year by year, it is sublimating or melting. And the latter, of course, contributes to sea level rise.

As the climate continues to warm, snow cover in the North American Arctic will disappear ever earlier, possibly increasing the transport of dust to Greenland. And this would obviously make the situation there worse, “accelerating Greenland surface melt and the corresponding sea level rise at a higher rate than currently predicted,” Dumont and her colleagues conclude.

  • William Whittingham

    They say nothing of air pollution – which is increasing exponentially every year.

    Always have to be cowardly blaming it on some natural thing.

    The bees dying – is a virus.

    The trees dying – is a beetle infestation

    The bats dying – is a fungus

    The aphids dying – is a mini mite suddenly springing from providence and getting under their skin.

    Look – when you put poisons and acid rain into the food chain – it is the POISONS and ACID RAIN causing the virus/infestation/fungus/bad weather.

    Not the virus/infestation/fungus/bad weather causing the condition.

    The trees became weakened by the vast increase in acid rain the last 25 years – allowing the beetles to overrun their immune systems.

    It would be nice if Science would extract its big block head from the sand – and start reporting on the true sources of all these problems – instead of blaming the melting of the Greenland Ice Cap – on “OH – because the snow melted in Canada – and there are now more trees growing there – they are spreading their bad seeds onto Greenland – causing the Greenland Ice Cap – to melt”.

    Yah right.

    • Tom Yulsman

      Mr. Whittingham: Perhaps you can show us where in the story it says anything about trees growing in Canada and “spreading bad seeds onto Greenland.” It almost seems as if you read a different story entirely.

      • William Whittingham

        Certainly – you must have missed it.

        First – they say that light blocking “particles” may be blocking the light: “dust”

        “. . . our analysis of remote sensing data indicates that the springtime
        darkening since 2009 stems from a widespread increase in the amount of
        light-absorbing impurities in snow, as well as in the atmosphere. We
        suggest that the transport of dust [by winds] from snow-free areas in
        the Arctic that are experiencing earlier melting of seasonal snow
        cover as the climate warms may be a contributing source of impurities.”

        I.e. “snow-free” areas in the Arctic.

        Then, later,

        ‘What’s her best guess for a specific source? “I would say that probably
        mostly from the Northeast part of Canada, but this is only based on maps
        of aerosol optical depth,”’

        So, the “dust”, comes from Canada. Now maybe I was making too big an assumption that by “dust” – and it coming from NorthEast Canada – means seeds and other detritus thrown off by vegitative growth (pollen, for instance). I mean – what else is “dust” actually anyway, coming from Northern Canada. Minute stainless steel particles?

        In fact, I wouldn’t dispute exactly what they are saying. The pollen, tiny vegetative matter like leaves, decayed or otherwise, getting blown onto Greenland is completely feasible. And – completely feasible as they say adding light blockage on Greenland snow.

        What I dispute is using the level 8 result of what is the source of the whole process. Why is there more vegitative growth in the Canadian Arctic in the first place? Because of the global warming melting the Canadian snow cover. The same weather effect – which is the cause of the primary melting of the same vanishing snow in Greenland!

        You might as well say – okay – after all the snow is melted in Greenland – and so now more trees are growing there – makiing more “dust”, that will blow onto England – will contribute to global warming – in England.

        At any rate – whatever possible albedo affects dust in snow on Greenland may amount to – even if it is happening as they describe – it cannot be any more than a fraction – of the direct, powerful affect, of for every square foot of snow that actually melts on Greenland itself, turning the ground from white to dark – therefore absorbing a huge amount more heat than before.

        The dust could not have caused that direct effect.

        Finally, that they may be implying that, is the basis for the whole point in the first place.

        • Tom Yulsman

          Mr. Whittingham: Please show me where in the paper the authors discuss trees growing in Canada and “spreading bad seeds onto Greenland.” You can’t. Because what you said is nonsense.

          I’ll tolerate a small measure of nonsense in the comments section, but only that — a small amount. So please keep this in mind for any future comments you may have on this or other posts. Keep them rational, logical and reasonable. No ad hominem attacks. You certainly can take issue with what I or anyone else says. But in doing so, follow these guidelines. And stay on point. Or stay away.

          • Buddy199

            Is Al back?

          • William Whittingham

            What is this place anyway – hey if this is just a pub for rednecks clucking their tongues – then go ahead – take it down.

            I’ll just put it up somewhere else and link to how you censored me.

            I assumed “discovermagazine.com” was something valid – it obviously is something more than that…

            Go ahead – “take me down” – its obviously a bunch of rednecks how no other ways to get their jollies.

            I’d thought I’d seen it all

          • disqus_atlq8Zmtsd

            Tom is well within his rights to moderate the comments on his blog assuming his supervisors give him that latitude.

            Certainly talking about tree growth when the article was explicitly talking about airborne dirt particles seems absolutely bizarre.

          • Buddy199

            Something about Tom’s low key, Mr. Rogers-friendly blog that really rattles the nuts out of the tree on a regular basis.

          • William Whittingham

            Who are you – the thought police?

            Look buddy – I already explained it twice. Let me try one more time – you can go straight to hell.

            Clear enough for you?

            (P.S. wish I had a dollar for every time some moron said what I said was nonsense)

          • Buddy199

            (P.S. wish I had a dollar for every time some moron said what I said was nonsense)

            Best Discover comment ever, by far.

          • http://blogs.discovermagazine.com Fred Weems

            Come on Tom, lighten up. You ever been around trees when they are propagating? It is an allergic person’s nightmare! The air is thick with that stuff, and it doesn’t take a genius to make the connection and by extension support the author’s point about dust (stuff) blowing in from Canada.

          • William Whittingham

            Thanks Fred – Al, Buddy, and Tom were ganging up on me – this is exactly what I meant. Plus the tone of the original article somehow hinting that “dust” on snow is a contributor to mass glacial snow melt – to be honest even thinking about it now – to use the words of the many attackers – “seems absolutely bizarre”.

            In the meantime more insults – now I am one of “the nuts that fall out of the trees”.

            How ironic but you know what – I do find that the various Disqus sites do tangibly bring out a lot of personal insulters.

            “Tinhat”. “Nutjob”. “Four-eyes”. “Pink Underwear”. “Male Prostitute” etc. All the time.

            They never respond point on point. Just character assassination.

            It’s like it’s a forum for passive-aggressives – who pretend to care about subjects but are only out to release some pentup frustration by insulting other people.

            Anyway I didn’t realize this was a “personal blog” of someone’s – which I could accept explains why someone I suppose would make the original “warning” – that I would never take by anyone on the street – but in this particular case I can forgive. I didn’t see anyone’s name in the discovermagazine.com Url so thought it was a mainstream one.

            Otherwise I never would have stepped in here…

            (Fred, Al, Buddy, Tom – just getting too weird. Where’s Bill, Ralph, and Sam…)

            (P.S. hey Buddy you should see what they say about me at the Daily Telegraph…among others there is a Queen’s Royal Proclamation to have me committed…)

          • Tom Yulsman

            Fred: This isn’t a question about “lightening up.” Read the story and the paper. The comment about trees, and pretty much everything else Mr. Whittingham said, was completely irrelevant to my post. I asked him to stay on point and instead he began making threats. So he is now gone.

        • disqus_atlq8Zmtsd

          Dust… as in airborne dirt. “uncovering large areas of bare soil and thus enhancing dust erosion,” I didn’t think that was particularly ambiguous.

          And the article certainly wasn’t implying that there is some underlying natural cause aside from the fact that it is natural for dust to increase heat absorption just as it is natural for greenhouse gases to increase heat retention.

          If man made global warming is causing increased melting in North America and that melting is causing increased airborne dust to settle on Greenland… then we have implied nothing other than that man has caused increased melting in Greenland.

          What is being described is called a positive feedback cycle. Melting causes increased dust. Dust causes increased melting. Rinse and repeat.

          This is why the idea that there is an inflection point past which global warming cannot be effectively mitigated is so concerning.

          • Tom Yulsman

            Thank you for this comment. Very clear and on point. I’ll add that the researchers themselves emphasize that what they are proposing is an hypothesis that needs further investigation. As I mention in the story, measurements on the ice in Greenland are needed to see whether dust there can, in fact, be traced back to the Arctic in Canada.

            Also, there is a potential hole in their hypothesis: The tundra in Canada is covered with low plants and shrubs. So why would earlier snowmelt there lead to greater dust production? I asked the lead author this question and she said she did know. But she said the hypothesis is based on quite a lot of indirect evidence, including satellite measurements showing a lot of airborne dust over that part of Canada in the spring — when snow has melted out.

            So again, more research is needed here. With all of the details I describe of the scientific detective work done by the researchers, I intended that this story be more about that process than about the particular findings. As an aside, this is also why I found Mr. Wittingham’s comments so off-putting. It was if he had read a completely different piece and was offering criticisms to things that neither I nor the researchers ever said. When I asked him to keep on point, he began making threats. So he is gone.

          • disqus_atlq8Zmtsd

            While shrub land would certainly be less susceptible to wind erosion than barren soil, I would think it is more susceptible than ice and snow.

            It is a good question to address, but I don’t think it represents a significant obstacle to the plausibility of the hypothesis.

  • Valjean1

    Energy is warmth. We permeate the atmosphere with energy from our wireless communication tools and toys. Thus, we create a hot water bottle to put under the gas comforter we also create. Ignoring it doesn’t make it not do what it does,

  • OWilson

    Here we go again.

    Every day we are inundated with studies that show positive feedback from the apparent certitude of the allegation, “as the climate continues to warm”.

    With all these studies, all purporting to support the AGW hypothesis, identifying positive feedback, the polar ice caps should have melted years ago, in line with their long standing predictions.

    This has not happened, of course. For the past 35 years the climate has been statistically stable, especially the last 17 years or so, according to satellite data.

    In fact, unless someone has received a postcard from Mother Nature letting them know when she will be back from her “hiatus”, there is no reason to believe her absence will not be permanent.

    • Fox

      Your first point is a straw man non-argument. All the ice caps are melting. Melting in Greenland is discussed above. Land ice in Antarctica is being lost at an increasing rate (Cryosat data). The US NSIDC shows how sea ice in the Arctic continues to drop, notwithstanding the extreme year that was 2012. Nobody is claiming that “the polar ice caps should have melted years ago”. No serious scientist ever, to my knowledge, did.

      Temperatures have only been stable over the past 17 years if you cherry-pick one El Nino year. That may well change the next time we get a strong El Nino.The *climate* is another matter. A number of studies have shown that extreme weather events are becoming more likely and are attributable to human activity. See doi:10.1029/2012GL052459 and DOI: 10.1029/2011GL050422 for just a couple of examples.

      Meanwhile, a lot of heat has been going in to the oceans. Your “hiatus” only works if you look at limited data on the atmosphere and cherry pick a point of comparison, but that is not the only place where heat goes. Water can hold much more heat because it is more dense (keeping it simple here).

      Mother may or may not have been snoozing, but She’s going to be right pissed off if you keep poking Her.

      (Edited for typo)

      • susansylvia

        If cherry-picking is required to make a case for this hiatus, then the IPCC is doing quite a bit of that themselves and, believe me, they would have the least motivation to cherry-pick numbers to arrive at a conclusion. Here is but one of many, many quotes from the IPCC’s WG I report of 2013 about the hiatus:

        “In summary, the observed recent warming hiatus, defined as the reduction in GMST trend during 1998–2012 as compared to the trend during1951–2012, is attributable in roughly equal measure to a cooling contribution from internal variability and a reduced trend in external forcing (expert judgment, medium confidence). The forcing trend reduction is primarily due to a negative forcing trend from both volcanic eruptions and the downward phase of the solar cycle. However, there is low confidence in quantifying the role of forcing trend in causing the hiatus, because of uncertainty in the magnitude of the volcanic forcing trend and low confidence in the aerosol forcing trend.”

        Since the IPCC acknowledges this trend, then I think that most AGW proponents would have to either agree that there is, indeed, a hiatus, or disagree with the organization whose data is the foundation for our worldwide efforts to reduce carbon emissions.

        Once we all agree that a hiatus is occurring, then the salient point becomes this: Why are we basing global policy about AGW on these models, if the observed temperatures of the past 15+ years are not marching in lock-step to the observed increase in carbon emissions worldwide, as the models predicted? Wasn’t this the entire premise of the alarms that were sounded in the 1990’s–that if we continued allowing carbon emissions to increase, the earth’s temperature would increase commensurately right alongside this emissions increase (demonstrated by the the so-called “hockey stick graph”) creating a crisis of epic proportion for all of humanity?? In an absurd irony, the IPCC is now reducing its estimates of the increase in the earth’s temperature in their models to more closely simulate the actual temperature fluctations in the past 15 years. I quote:

        “The discrepancy between simulated and observed GMST trends during 1998–2012 could be explained in part by a tendency for some CMIP5 models to simulate stronger warming in response to increases in greenhouse-gas concentration than is consistent with observations. Averaged over the ensembles of models assessed in Section, the best-estimate greenhouse-gas and other anthropogenic scaling factors are less than one (though not significantly so), indicating that the model-mean GHG and OA responses should be scaled down to best match observations. This finding provides evidence that some CMIP5 models show a larger response to greenhouse gases and other anthropogenic factors (dominated by the effects of aerosols) than the real world (medium confidence). As a consequence, it is argued in Chapter 11 that near-term model projections of GMST increase should be scaled down by about 10%. This downward scaling is, however, not sufficient to explain the model-mean overestimate of GMST trend over the hiatus period.”

        What they are saying is that it’s clear that their models factor in more climate sensitivity to carbon emissions than is actually the case. So they propose to revise their estimates of temperature increases by 10% to more closely match reality. But, they say, this reduction still does not account for all of the inaccuracy in their models–something else is wrong and they don’t know what it is.

        They didn’t bank on Mother Nature being able to withstand the huge increase from 3 to a whopping 4 parts of carbon dioxide per 10,000. But she can, and she is. Whether it’s volcanic activity, a reduction in aerosols or whether the earth is hiding all this heat in the ocean, the fact is that in the face of increased emissions, the earth’s temperature is holding steady, thank you very much.

        And upon these flawed and continually revised models we are basing our decision-making around the world, impacting billions of people, often for the worse.

        So AGW proponents can talk till the heavens implode about how we are experiencing record temperatures, and that the earth’s temperature is still going up, that polar ice caps are perilously close to disappearing, that droughts and wildfires and large weather events are all due to global warming. All of these arguments, whether they are true or not, will not change the fact that the earth’s temperature is not doing what was predicted by the models. Period. It is simply not possible to deny this fact regardless of what else you believe.

        This is the problem with calling climate models ‘science’ and calling people that don’t believe that climate models are science ‘idiots’. If we have to adjust our climate models to simulate more closely what is actually happening, that’s called ‘reporting’, not predicting, and the whole process is bassackwards. We can’t even reliably predict the weather beyond 10 days ahead, for Pete’s sake. What makes us think we can understand, let alone predict, what the infinitely complicated process that creates the earth’s climate will do? Well, apparently we can’t, because the world’s greatest climate scientists are having to go back and fix all their numbers that they now see were wholly inadequate to predict the future of the earth’s temperature. I think we finally have to say, “We just don’t know”. And if we reach the point of saying “We just don’t know” then the argument against global warming as a future problem becomes equally valid to all arguments for it.

        • Fox

          I can refute your bollocks in a couple of lines, The models don’t predict, they project, using a series of assumptions. One of those assumptions is usually that volcanic activity and other variable natural forcings remain constant. As one of your quotes above shows, some of those forcings changed. These included volcanoes (doi:10.1038/ngeo2098), a temporary decline in solar output (doi:10.4236/acs.2014.41008) and the predominance of La Nina conditions in the Pacific (doi:10.1038/nature12534). Once you factor those in, the models are almost spot on (doi:10.1038/NCLIMATE2310).

          As soon as those conditions change, I see no reason to assume we will not be back on track with the warming. In other words, we do know, as the papers cited above demonstrate.

          • susansylvia

            By all means, refute all you like. You still have not changed the fact that the IPCC has acknowledged the hiatus, has felt the need to revise its PROJECTIONS and does not understand why the models are all off. This was the point of my comment. You can split hairs on my terminology and talk about forcings all you want, none of that refutes my point in the least. When you can show me an IPCC report retracting what they have said in their own 2013 report, then I’ll listen. I don’t know why you would infer that the models are spot on, when the IPCC itself says they are not.

          • Fox

            I know that when the IPCC wrote its report, they acknowledged a slowdown. They were not sure why there was a slowdown. Since then research has been published that explains the slowdown. We now know why the models were off.

            I gave you the references, for crying out loud! They are in my previous post.

            This is why I think that deniers go around with deliberate blinkers – even when someone points out the evidence they pretend to be ignorant of, they continue to pretend to be ignorant of it.

          • susansylvia

            Believe me, I’ve read them. But as you know, these are small studies, again employing models to explain the hiatus from their point-of-view. None of it has anything to do with the IPCCs own research, upon which our policies are based, and we don’t “know” anything based on these studies. I’m sure if I could show studies to prove the opposite, you wouldn’t believe any of it, just as I don’t place any faith in these. If you are familiar with the term “we present a novel method” this signifies a new approach that has not yet been presented in the literature, and can hardly be considered settled science. The terms “We present a more appropriate test of models WHERE ONLY THOSE MODELS WITH NATURAL VARIABILITY . . . ARE SELECTED (emphasis is mine) from multi-model
            ensembles . . .” signify the kind of cherry-picking that you soundly criticized in your original post. So this cherry-picking is OK because it supports your belief? And thanks very much for that third study, which again proves my point beautifully. If further studies have to be carried out to explain the flaws in the IPCC’s models, I again ask, Why are we basing so much policy on those models? If all we need to do is factor in sunspot activity or volcanic eruption or PDO to make the numbers pencil, why are the IPCC models not doing so? Why are we having to look to some Joe Blow study from a few researchers at (fill in the blank) college to explain how the models could be made to work? You can list every single study like these that you find on the web and you will only prove my point because these studies will all be geared around trying to make the IPCC’s flawed models work. If there were not flawed, no further studies would be needed to alleviate all the head scratching. There is no evidence in the world at present to show us that the IPCCs models are accurate to the degree that we should place the entire world’s future planning on them. This returns us to my original point, which I stand by.

          • Fox

            If you think you can go find studies to show the opposite, then go ahead. Seriously. Cite your sources.

            No, This is not cherry picking. When deniers cherry pick they pick, for example, one year as a baseline and then compare all others to that baseline (hence the claptrap about the “pause”). You expect the modelers to factor in variables such as volcanoes and El Nino and then, when they do, you complain about cherry picking. The projections that were off were the ones that didn’t take into account certain variables that they couldn’t predict. Once they had the values for those variables, the output was accurate. Accurate figures in, accurate figures out.

            The upshot of your denialism is a refusal to take action on a specific threat, because it might not happen. I buy insurance in case of fire; I look before I cross a road. There might not be a fire, and I might not get hit by a bus, but I take sensible precautions to make sure that I don’t.

            In this case, we have an observed massive increase in melting on the Greeland Ice Sheet. Your response – to insist it’s not happening – like someone whose house burns down and, because they didn’t buy insurance, insists the house is still intact.

          • AskTheMoose

            “The projections that were off were the ones that didn’t take into account certain variables that they couldn’t predict. Once they had the values for those variables, the output was accurate”.
            I think the word you’re looking for is “hindsight”.

          • susansylvia

            One last thing, please. When you say that the models use a constant variable for dealing with volcanoes and other factors, you prove my point exactly. It is just not possible for a model to PROJECT what will happen to the climate in the future, because there are too many variables to take into account, and those variables have a way of changing. And upon these PROJECTIONS we base all of our global AGW decision making. Anybody can massage the numbers to make the model accurate, but the IPCC is not doing that. They are acknowledging their error and making corrections. It will be interesting to see just how many corrections they end making.

          • AskTheMoose

            “The models don’t predict, they project”. Classic.

  • Tom Yulsman

    Just a quick note about the comment thread below: The thread of conversation no longer makes sense because I removed the comments of one person. He had made some comments that had little to do with the research I describe above. So I asked him to keep his comments on point. Things only got worse at that point, and he began making threats. At that point I blocked him from commenting, and what he wrote previously has been removed.

    I do not pre-screen comments here at ImaGeo. I’d like to encourage lively discussion. But I do have some simple rules that I’d like everyone to stick to: Your comments should be directly relevant to the post in question; they should stay on point, be reasonably clear, and constructive; and no ad hominem attacks or threats of any kind will be tolerated. If I feel a commenter is straying too far from these guidelines, I’ll give a warning and try to nudge things in the right direction. But if a commenter persists in straying from these simple and reasonable guidelines, he or she will no longer be able to comment here. I’ve only done this two or three times, and I’d prefer not to do it again. So please, everyone, let’s keep things rational, logical, on point, and constructive.

  • http://www.gentoogeek.org Stephen Arnold

    I’m thinking about the large amount of human activity in the Athabasca oil sands region; could this not be part of the source (maybe the main part) of the loss in atmospheric tarnsparency to the east? Simply uncovering the (normal) surface a little sooner in the year seems like a less plausible reason than stripping the surface mechanically over huge areas. Thoughts?

    • Tom Yulsman

      Thanks Stephen for contributing. Speaking as a non-expert, I think this is a reasonable-sounding hypothesis. It’s also probably testable. I bet it wouldn’t be that difficult to find some indirect evidence, one way or the other, in remote sensing data.

  • OWilson

    Just a question.

    I posted a respectful and on topic reply to a quote in your article.

    The comment has apparently been deleted.

    I’m sure this must be a mistake as I know you would like to keep the debate open and transparent.

    I post in many places and this would be a first, if indeed it is censorship.

    Thank you.

    • Tom Yulsman

      I honestly don’t know what happened. I did not delete your post. But somehow it got caught in some sort of Disqus limbo. (For the record, I do not like this system, but this is what Discover uses.) I’ve brought it out of limbo; you’ll find it below. Sorry for the confusion!

      • OWilson

        Thank you kindly for taking the time.

        My respect for you has ratcheted up, for allowing rational debate of your views.

        I’ll try to find ways to agree with your points, without abandoning my allegiance to those great skeptics, Copernicus, Galileo, Einstein et. al.

  • OWilson

    The quote in the final paragraph, “As the climate continues to warm…” is what I commented upon.

    But let’s say the most reliable data we have, comes from the satellite record, and shows the climate statistically stable over the last 35 years, then the premise of the conclusion would be wrong.

    The present, “hiatus” in warming, can only be defined as such, when it actually ends. Until then, it is a current condition.

    • disqus_atlq8Zmtsd

      Using basketball as an example, if a traditionally great 3 point shooter misses 15 shots in a row, do we have to wait till he starts hitting shots again to say that it is just a cold streak?

      If past data establishes a trend, and our best projections indicate that the trend will continue in the future, it is not unfair to characterize it as a hiatus.

      It is perfectly valid to challenge those projections, but IMO it misses the boat to question the characterization without first attacking the projection.

      • MarkCValdez

        Google is paying 80$ per hour! Work for few hours and have more time with

        friends & family! On tuesday I got a great new Land Rover Range Rover from

        having earned $4151 this last four weeks. Its the most-financialy rewarding I’ve

        had. It sounds unbelievable but you wont forgive yourself if you don’t check it…
        Here ­­­­­­­­­is ­­­­­­­­­I ­­­­­­­­­started,———-,, HuL­­­uJoB.­­­C­­­O­­­M



  • Torbjorn Berglund

    Let us assume that the coefficient of absorption changes because of the dark material on the snow. As a hint, coult it possibly be interesting to know what sort of density this material has. Is it floating on salt water? What happens then with the coefficient of absorption on the oceans surface. This question may irrelevant but not all substances are soluble in salt water abd we are talking about a relatively much larger area contributing to a decrease in light reflection.

  • pearlridgeview

    I recall an article that contended that once the highly crystalline surface snow undergoes even a slight melting, that it’s albedo is significantly reduced. Loses that crystalline shine! Until a fresh snowfall gets it back up to snuff.

  • http://www.rocksalteic.com/ rock salt

    save money and live! Ask for our saltrock for melting ice (salting) by the prevented method u will be more save 80%, for edible use our quality table salt (iodized salt),and salt tablets for water hardness.



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


See More


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Collapse bottom bar