Global Sea Ice Coverage Has Fallen Off a Cliff — Impacts Likely to Be Wide-Ranging

Frozen water.

It’s an important aspect of our world. One that is essential to maintaining a stable climate and, by extension, the health of modern civilizations. Today, due to a continued warming of the globe, every form of frozen water — be it frozen water locked in glaciers, snow, or sea ice — is under threat. And we are almost daily reminded of new losses coming from these needed collections of cold.

Recently, however, one of these subsets of global ice has taken a very serious blow. For this past year, as ocean and land surfaces warmed to above 1 C warmer than late 19th Century averages, has seen a precipitous fall in the coverage of global sea ice. And we are now in uncharted territory as the Earth’s sea ice extent, area, and volume have fallen to never before seen lows.

(Sea ice area [upper right], extent [upper left], and volume [lower graphs] have all seen very serious declines that have now lasted for a full year. Since reflective sea ice is an important regulator of global and regional climates, the impacts of such a considerable loss is likely to be both long-term and wide-ranging. Image source: Global Sea Ice.)

Total sea ice area and extent have now ranged between 2 and 3 million square kilometers below the 38 year average for about a year now. That’s a region of sea ice larger than Greenland which has been removed from the face of the Earth now for the better part of four seasons. Global sea ice volume losses are now in the range of 12,000 cubic kilometers — each cubic kilometer roughly equal to a moderate-sized mountain. These are very considerable losses. But perhaps more ominous than the losses themselves is the fact that they seem to be sticking around — locking in a permanent warming-related-change to the Earth System, its weather and environment.

To be clear, there are some things that sea ice loss does not directly impact. And the first of which is sea level rise. Because sea ice already floats on the surface of the ocean and because it already displaces water, melting sea ice does little to change the level of the ocean surface directly.

(A very informative video describing ice albedo feedback. We do not, however, support some of the video’s sponsors who, unfortunately, appear to be ubiquitous.)

That said, there are many things that sea ice loss does affect. And the first is global temperature balance. Sea ice serves as both a reflective shield that throws back the sun’s heat during summer and as an insulator that locks warmer ocean waters below during winter. Remove a significant portion of the global sea ice, as we have done, and you’ll end up with oceans that both draw in more heat during the warmer months and bleed out more stored ocean heat into the atmosphere during the winter.

Such heat will be both stored and delivered exactly where it can do the most harm — in the polar regions. And, as a result, recently ice-liberated oceans will warm more rapidly in areas that are directly adjacent or close to the very large glaciers covering Greenland and Antarctica. As such, though melting sea ice has no direct, immediate impact on sea level rise, it can create an added pressure for the loss of land-bound and sea-fronting glaciers that will raise ocean levels if they melt.

(Arctic sea ice loss feedbacks produce complex and far-reaching impacts to the entire Arctic system. Image source: National Science Foundation.)

Arctic regions also face considerable added heat pressure to permafrost, boreal forests, and other carbon stores as a result of Arctic Ocean albedo feedbacks due to sea ice loss. In addition, warm pools of ocean water in the far north will aid in further destabilizing already-altered weather patterns. So sea ice loss is likely to continue to result in a worsening of the Jet Stream excursions that have already contributed to extreme weather — particularly in the Northern Hemisphere.

But perhaps the most concerning impact of sea ice loss is an alteration to seasonal temperature exchange. More heat absorbed by oceans during summer and then ventilated back to the atmosphere during fall and winter will tend to result in a lag in global cooling into the fall season even as winter will tend to warm.

(A roll-back of sea ice results in much warmer temperatures over nearby permafrost zones. This week, 81.5 F [27.5 C] temperatures are predicted for parts of the Yamal Peninsula — a region that has recently drawn attention for its newly discovered methane blow-holes. Image source: Earth Nullschool.)

Such a lag enhanced by sea ice loss is arguably already in play in the Northern Hemisphere — where increasing rates of heat exchange between the tropics and middle latitudes and the pole have already been observed. However, if Southern Hemisphere sea ice remains reduced, a similar heat exchange and polar amplification pattern is likely to begin setting up there as well.

The upshot is that the observed considerable loss of global sea ice coverage is likely to produce harmful or disruptive feedbacks in the Earth’s climate system in the near term. Stresses to the other frozen systems of the world will tend to increase as a result. Extreme weather events are at risk of worsening. Rates of polar warming could escalate. And disruptions to traditional seasonality will tend to become more apparent.

Leave a comment


  1. Spike

     /  July 19, 2017

    Another aspect of the cryosphere that caught my eye today was David Spratts tweet linking to this paper on 1.5C (within 10 yrs) and permafrost which as he says is a bit of a stunner:

    • 21 to 25 percent permafrost loss by the late 2020s to early 2030s is no joke. We are definitely on track for 1.5 C by mid 2020s to mid 2030s in the worst to best case ranges. Not likely to avoid that.

  2. thom prentice phd

     /  July 19, 2017

    Why do the 2017 lines not stop at mid-year (July). Are they projections beyond July?

  3. wili

     /  July 19, 2017

    Another great post. A bit off topic for this, but a nice reflections in light of the Wallace-Wells article discussed a few posts earlier:

    “The Planet Is Warming. And It’s Okay to Be Afraid
    Why being fearful can be part of a healthy, heroic response to the climate crisis

    Affect tolerance—the ability to tolerate a wide range of feelings in oneself and others—is a critical psychological skill. On the other hand, affect phobia—the fear of certain feelings in oneself or others—is a major psychological problem, as it causes people to rely heavily on psychological defenses.

    Much of the climate movement seems to suffer from affect phobia, which is probably not surprising given that scientific culture aspires to be purely rational, free of emotional influence. Further, the feelings involved in processing the climate crisis—fear, grief, anger, guilt, and helplessness—can be overwhelming. But that doesn’t mean we should try to avoid “making” people feel such things. Experiencing them is a normal, healthy, necessary part of coming to terms with the climate crisis.”

  4. coloradobob

     /  July 19, 2017

    Al Gore speaking to the NYT , it’s an hour long .

    Talking About Climate Change With Al Gore

  5. Greg

     /  July 19, 2017

    Oh boy.Thanks for that bedtime story uncle Robert. I was just getting distracted by all the fires everywhere…
    The volume graph speaks the most to me. Worth repeating: while ice melts, it remains at 0 °C (32 °F), and the liquid water that is formed with the latent heat of fusion is also at 0 °C. The heat of fusion for water at 0 °C is approximately 334 joules (79.7 calories) Once melted, however, water has a specific heat of 4.18 joules/gram*1degree C so the same energy it took to melt that gram of ice to water now can heat it by approximately (334/4.18) 80 degrees!

    • The present loss of albedo is probably in the range of 0.2 to 0.3 Watts per meter squared equivalent global as well. So, yeah, it’s about 6 to 10 percent on top of what we would otherwise see. Exactly what you would expect from an amplifying feedback. Also, as you mention, you’ve lost that ice inertia as well. So the extra heat can go to adding more energy to the ocean and/or making water vapor. It’s not that you’ll go from 0 to 80 F at the surface though. The energy gets spread out. But it’s still a lot.

    • Michael Hornick

       /  July 20, 2017

      It seems that not too many people seem to discuss this point. It is well worth repeating. The same energy that it takes to melt ice into a liquid (once ice reaches the temperature of the melting point) is the same amount of energy that it takes to take that same amount of now melted water at 0 degrees to 80 degrees Celsius. To me, this is a very scary fact and the fact that worries me the most about our near term future regarding the loss of ice. Much scarier than the moderating effect of ice on the planet.

      • Ice does produce a good degree of climate inertia. There’s a very real physical barrier to melting it. And once it does melt, then things can start changing much more rapidly in the climate system.

        The simple physical calculation you’ve given above is a sign that once states change, they can really create a lot of knock on changes due to all the energy that’s unleashed and redistributed. It’s not so much an issue of sea surface temperatures in the Arctic warming from 0-80 C once the ice is gone. It’s that that added surface heat, that all things being equal and stagnant would warm about 1-6 meters of ocean water to that range, instead gets re-circulated into the larger ocean or goes to work turning ocean water into water vapor. And that’s what generates considerable systemic change.

        • More importantly, once the arctic sea ice has all melted and we reach that tipping point, there is literally no going back. The amount of heat that the arctic will absorb after that point pretty much guarantees that the arctic won’t freeze again under our watch. There has never been humans on the planet without a frozen arctic and it would be ridiculous to think the earth as we know it would remain habitable for us afterwards.

          A blue ocean arctic event is THE tipping point. There will be no debate on humanity’s fate after that… our doom is assured. There is no precedent.

        • So hitting blue ocean events is a pretty bad outcome that we want to avoid if we can. That said, they are likely to start emerging as we hit 1.3 to 1.6 C warming.

          They do set off a number of very harmful feedbacks. But humans have probably lived through similar events in the Eemian when the world was 1.5 to 2 C warmer than the Holocene.

          So, for my expert perspective, while it’s not ‘the inevitable end of the world’ that you’ve described through your entirely unsupported statement, it is absolutely something that we should be concerned about and that we should do our best to prevent by halting fossil fuel burning as swiftly as possible.

          For readers here — this statement is an example of the kind of Doom that Mann rightly warned about. It runs counter to Wallace-Wells more accurate scenario, appeals to apathy, and has little or no basis in actual science. To be very clear it is highly unlikely that inevitable human extinction emerges from a complete loss of Arctic sea ice.

          This is not to downplay a set of very dramatic risks. To the point, the various knock-on systemic harms that result are considerable and will absolutely have a damaging effect on present human civilizations. These knock-on effects will not all emerge immediately and will tend to build over time. They include increasing rates of glacial melt, increasing rates of sea level rise, increasing stress to global carbon stores, increasing ocean stratification and loss of ocean health, increasing rates of ocean acidification at the poles as algae blooms proliferate, increasing risk of extreme weather events, and increasing disruptions to growing seasons. Such knock-on events would tend to follow by years to decades.

          That said, a blue ocean event is not an absolute line in the sand and we are seeing some of the milder effects of related Arctic and Antarctic feedbacks now. The net loss of albedo probably adds about 0.2 to 0.3 watts per meter squared of energy imbalance to the climate system at present. A total loss of sea ice during any season would add to that number of the related feedback multiplier effect.

        • I think this requires one additional clarifying comment. Those pointing toward inevitable human extinction following complete loss of sea ice rely on massive carbon feedbacks — primarily methane burps — to support their thesis. The issue with this is that methane burps of the size necessary to set off a hothouse event so severe it kills off all humans following the climate stress of total sea ice loss during one season at one pole is highly unlikely. It’s kind of like saying that if a few extra comets got nudged out of the Oort cloud, then they’d all inevitably hit the earth and wipe out all human life.

          The total loss of seasonal sea ice does, however, increase the risk of increasing carbon feedbacks from the Earth System. This is like adding bullets to the chamber in climate Russian roullette. So it is something we should be concerned about. It’s just that we should not pin our focus on arguments based on inevitability that have little or no support in the actual science.

          I also want to say that such arguments, though seeming similar to Wallace-Wells, are basically anti-Wells. Wells sought to spur responses and to focus on solutions. His dire warnings were more focused on end-century times and post 2100 times. And there is a very solid basis for those types of severe environmental impacts in a number of scientific studies. I’ve yet to see an actual peer reviewed scientific study that says — once the sea ice is gone, all humans are dead, it’s inevitable. This distinction between a rational warning and an irrational one is important.

        • Yes, perhaps using the word “extinction” was hyperbolic, but the point stand that there has never been large, agricultural-based human civilization without the climate that a frozen arctic provides. I guess we will find out if it’s possible to grow grains at scale with climate conditions we aren’t prepared for. Human extinction is a maybe while widespread collapse of civilization, and all its horrific consequences, is more probable.

          As far as pegging my thoughts as unscientific, your use of words like “probably” and “highly unlikely” and all the rest fall under the same microscope, you never cited and studies to counter it. My precedent is that widespread agricultural human civilization without an ice cap has never happened. You are making the unsupported claim that, given enough work, it can be done.

          I guess in the end we’ll see.

        • A more qualified second statement. One that, if you lead with, would have received a less critical response. In any case, you’ve moved the goal posts. And, no, there’s a broad scientific basis for what I’m saying in my response — foot notes or no.

          As for challenges to agriculture in 1.5 to 2.0 C temperature ranges and related seasonality disruptions. We can certainly agree on that point. And there are many scientific studies that point to losses resulting from simple heat alone, from simple loss of water to certain regions, and that do not take into account the very difficult to predict alterations in weather patterns and seasonality.

          The broad body of the sciences at this time points to rising stress to agriculture in these ranges. And it’s possible that loss of productivity will hit between 5 and 30 percent in key regions. There’s flex in global agriculture, though. And the heavily meat focused industries are very resource intensive. So stress here is collapse pressure that will require changes to keep providing food to the global system. That said, various responses can adapt to these stresses if you look at it systemically. The challenge will be dealing with worsening extreme events and planning for longer-term disruptions than we are used to. It’s going to be tough. Much tougher. But the human agricultural system is not a fixed entity and there is a path of responses available if we take them. Regions in the the Middle East, Africa, India, Brazil, Indonesia, parts of the US, parts of Australia, parts of Europe, parts of China and Russia are all likely to see rolling impacts. In other words, the stress will be global and few areas will be wholly spared. The worst impacts are likely to be close to the Equator. But higher latitude impacts can’t be ruled out. Mitigation and adaptation involves shifting away from meat production, changing land management, using heat resilient crops, using less water intensive crops, shifting water consumption away from energy and toward agriculture (shift from fossil fuels to renewables enables this), shifting more toward vertical farming, and adding a measure of indoor vertical farming as a backstop.

          As for applying ranges… Actually that’s due to a direct reading of various studies that point to different outcomes. As a result, we end up with a range of scientifically supported potential future outcomes. In other words, the various ranges that I cite come directly from scientific studies.

          Your shift away from inevitability is appreciated. The movement of goal posts without acknowledging it is not. And the failure to incorporate different scientific views by applying study-based ranges betrays on overly simplistic larger understanding of the situation.

        • Finally, and in a more broad sense, it’s worth noting that it’s normal to be afraid when faced with the harms coming from climate change. There is a degree of uncertainty and there is certainly a degree of danger that the science is unable to perfectly define. So we should certainly not say that it’s wrong to be afraid, but instead use that fear constructively — to toil for a better future and to avoid the terrible one that we get, sooner or later, if we keep burning fossil fuels til the end.

        • wili

           /  July 20, 2017

          Many good points, as usual, here, rs. Also note:

          “Arctic Sea Ice Loss Likely To Be Reversible:
          Scenarios of a sea ice tipping point leading to a permanently ice-free Arctic Ocean were based on oversimplified arguments”

          Just to be clear, though, as I understand it, they aren’t saying that it is likely that the ice loss _will_ be reversed. Just that it is likely that the loss isn’t in principle irreversible.

          We would likely need both drastic cuts in carbon emissions _and_ large scale, effective carbon sequestration very soon if we were to see any such sea ice recovery on any kind of human scale, as far as I can see.

        • Thanks for this, wili. Good addition to the conversation and an excellent reference.

  6. Andy_in_SD

     /  July 20, 2017

    Methane seep map of Mackenzie delta.

  7. Andy_in_SD

     /  July 20, 2017

    Temperature distribution changes.

  8. Jimbot

     /  July 20, 2017

    Thanks for stating the facts again so succinctly, RS. About Greenland ice sheet melting. Is it really an “if” scenario at this point?

    • At 492 ppm CO2e (2017) forcing (present forcing), we probably lose all of Greenland over the course of 300 to 1000 years depending on rates of response. That’s 2.0 to 2.3 C warming this Century and 4 to 4.6 C warming long term. That number has to come down if we’re going to save Greenland over the long haul.

      The methane portion at around 60-75 CO2e is something that we can draw down a bit if we can change agriculture and halt coal mining and natural gas production. The 407 ppm CO2 portion is more difficult to draw down. Hansen recommends changes to agriculture and land use. Others point toward an admittedly expensive atmospheric carbon capture process (but less expensive than damages caused by catastrophic climate change). All of this, of course, assumes that we halt fossil fuel burning very soon and start working on the draw-downs pretty quickly after.

      Present pathways and commitments are putting us in the range of 650 to 820 ppm CO2e (including likely Earth System carbon feedbacks) by 2100 which would be 3.1 to 4.6 C warming by that time and 6.2 to 9.2 C warming long term. That’s better than business as usual fossil fuel burning’s 900 to 1,200 ppm CO2e and 4.8 to 7 C warming by the end of this Century and 9.6 to 14 C warming long term. But it’s still not a very liveable world for human civilization and we should be doing our best to halt emissions and start drawing down atmospheric carbon as soon as possible.

      • utoutback

         /  July 20, 2017

        “All of this, of course, assumes that we halt fossil Fuel burning very soon…”
        Robert – can your quantify “very soon”? As far as the FF burning fleet of vehicles now on the road, the average age is 11 years, up from 8 years in 1995. (from Consumer Reports) Since we are still producing FF vehicles that results in over a decade before fleet turnover. That’s not good enough in my book.

        • Yes. It’s not good enough. The necessary sense of urgency is lacking. And foot-dragging is still rampant.

          In my opinion, getting to 2 C requires a near immediate peak in fossil fuel burning, followed by net zero carbon emissions before mid Century, immediately followed by net negative carbon emissions. Even under that scenario we probably pass 2 C at some point. We can draw down the fat tail of bad outcomes under this scenario, but it will require very rapid responses and very hard work.

          The present trajectory is probably around 4 C by end Century. If everyone committed to their Paris goals immediately, we could limit to 3 C. We need to continue to build on Paris pretty rapidly to hit 2 C.

      • Jimbot

         /  July 20, 2017

        Thanks RS. It seems likely to me at this point we won’t get things together soon enough to be able to prevent it.

        Elon’s got my vote, I hope he and a few others like him can pull off some kind of a miracle. A little puzzled over the effort on a plan to go to Mars however. On the other hand, maybe he can use those rockets for putting up our big sunshade umbrella 🙂

        • I wouldn’t rely on single saviors or miracle cures. The solution will come from mass movement — everyone pulling together. That said, Elon’s work on EVs and solar has been very helpful.

        • danabanana

           /  July 21, 2017

          Successfully colonising Mars is not going to happen. Its surface is not capable of sustaining life (as we know it).

        • Paul PNW

           /  July 24, 2017

          | Its surface is not capable of sustaining life (as we know it).

          Perhaps The Boring Company is not an incidental side project…

  9. Pat Spray

     /  July 20, 2017

    Ocean currents, halocline, massive discharges of freshwater from melting land ice. Also a scary scenario.

  10. Abel Adamski

     /  July 20, 2017

    An interesting twist experienced in Australia, the effect of a climate change induced change in storm direction on coastal areas

    The impact of the June event, though, was less to do with the storm’s intensity – it was about a one-in-five-year event – but rather its unusual direction coming largely from the east.

    “When you get particularly unusual waves it really causes huge changes [to the coast],” Dr Harley, the paper’s lead author, said. “The whole south-eastern Australian coastal line is in equilibrium, lined up for southerly or south-easterly storms.”

  11. Abel Adamski

     /  July 20, 2017

    An interesting article on HEAT and the human body

    • It’s definitely increasing the number of heat related deaths. And, it’s going to get worse, much worse if we don’t get a move on.

  12. Hal Lysander

     /  July 20, 2017
  13. climatehawk1

     /  July 20, 2017


  14. The sun is entering a low level energy output level not seen in 9300 years.

    • Lower solar activity might provide a negative forcing of 0.1 to 0.2 watts per meter squared. The total human forcing due to fossil fuel burning is in the range of 3 watts per meter squared at this time. Even a grand solar minimum is a drop in the bucket compared to human emissions and related impacts.

      • Robert,
        I would like to be sure I understand the figures correctly, all the figures can be confusing. Total human forcing is 3 W/m2. Is this the total final figure, that is with negative sources considered? (That is how I read it). Solar forcing (per Hansen) of about 0.5 W/m2, without human intervention, was sufficient to cause ice ages. Extrapolation is not comforting here.

  15. PlazaRed

     /  July 20, 2017

    Too much to take in at in one days reading all this information about the ice and probably lack of it soon.
    I am thinking looking at the ice map that the North East passage over Russia should be about open to shipping now, with the North West passage not far behind it. Lots of very thin ice cover in the Arctic.

    Interesting summary of the west coast fires and their effects.
    BC has over 3600 evacuated so far, probably a lot more in reality.
    One of the evacuated said in an embedded video,” so the house is gone, its insured, they will build me another one!”
    Sort of strange attitude but then it takes all sorts to make this world.
    The Canadian news video:-

  16. Jimbot

     /  July 20, 2017

    I recently read a comment ( forget where ) by a former climate science student quoting their mentor/professor who said something like ” by the time science has collected all the data to prove the case incontrovertibly it will be too late “.

    In the case of the Wallace-Wells news article, it isn’t saying much different than McKibben did with his book EAARTH, written more than 10 years ago. How’s 350 working out as a meme for an ultimate upper limit for preventing probable disaster?

    • I think has done fantastic work. And the 350 safe line is probably accurate. It’s worth noting that this is based on Hansen’s accurate assessment that harm probably starts getting locked in at levels higher than 350 ppm CO2. Hansen’s view is cautious and leans heavily on the precautionary principle. I think that’s generally the correct approach and McKibben and his organization have been very effective.

      • Jimbot

         /  July 21, 2017

        I certainly agree that has helped raise awareness.

        Being able to sell the idea that average global temperature increase may not be related to average global CO2 ( and other gases ) increase goes to show how effective the polices of defunding the education system have been.

        If there was some kind of at least 12th grade science-level understanding-of-reality consensus prevailing in the present day average person’s mental programming in this post-modern world, we could have a more sensible debate.

        That more sensible debate would be related to whether or not the situation can be reversed. Of course the only politically acceptable solution would be that we have to at least make the effort.

  17. humanistruth

     /  July 20, 2017

    Consider the intersection of two articles. Author Nancy MacLean warns of James McGill Buchanan’s ideological impact on the far right, as adopted by Charles Koch.
    And a 2014 independent research project led by applied mathematician Safa Motesharrei of the US National Science Foundation, based on a new cross-disciplinary ‘Human And Nature DYnamical’ (HANDY) model, which found that even advanced, complex civilizations are susceptible to collapse.
    The study found that Population, Climate, Water, Agriculture, and Energy can lead to civilization collapse when they converge to generate two crucial social features:
    “the stretching of resources due to the strain placed on the ecological carrying capacity”; and
    “the economic stratification of society into Elites [rich] and Masses (or “Commoners”) [poor]”.
    These social phenomena have played “a central role in the character or in the process of the collapse,” in all collapsed civilizations in “the last five thousand years.”

    The Buchanan-Koch agenda adopted by Trump and GOP leaders DIRECTLY (intentionally) ramps up both civilization-destabilizing features.

  18. Gotta brag for a minute about our new (used) battery-powered lawnmower. Cost $100, plus another $40 for a new lead-acid battery (newer models have Li-ion batteries). We’ve been breaking in the new battery, but the mower just ran for an hour, mowing fairly thick, heavy (country) grass, and still had a little juice left. Very quiet, no emissions (of course), and (yippee!) no cord (had been using 200 feet of cord at times, which required great patience … ) Love it. This specific model is a Neuton, actually made in Vermont, but there are a number of other options.

  19. Dave McGinnis

     /  July 22, 2017

    I’ve often wondered about the ‘ice albedo effect.’ True, dark water is more absorptive than ice, but those rays are quite oblique even in the summertime. On the other hand, open water is an excellent radiator since it circulates and will soon have 24 hours of darkness to radiate. Would an annual budget would show net cooling? Look at Lake Superior, it has warmed only a few degrees C in the last 15,000 years and is at 45N, not 75.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: