Melting Arctic Sea Ice

I’ve been quiet about global warming lately because I’ve decided that people won’t pay much attention until I present some ideas for what to do. But I don’t want you to think I’ve simply stopped paying attention. As you’ve probably heard, the area of the Arctic sea ice hit a new record low this year:

This graph was made using data from the National Snow and Ice Data Center. Lots of other data confirm this; you can see it here.

Here is how the minimum area of Arctic sea has been dropping, based on data from Cryosphere Today:

The volume is dropping even faster, as estimated by PIOMAS, the Pan-Arctic Ice Ocean Modeling and Assimilation System:

The rapid decline has taken a lot of experts by surprise. Neven Acropolis, who keeps a hawk’s eye on these matters at the Arctic Sea Ice Blog, writes:

Basically, I’m at a loss for words, and not just because my jaw has dropped and won’t go back up as long as I’m looking at the graphs. I’m also at a loss—and I have already said it a couple of times this year—because I just don’t know what to expect any longer. I had a very steep learning curve in the past two years. We all did. But it feels as if everything I’ve learned has become obsolete. As if you’ve learned to play the guitar a bit in two years’ time, and then all of a sudden have to play a xylophone. Will trend lines go even lower, or will the remaining ice pack with its edges so close to the North Pole start to freeze up?

Basically I have nothing to offer right now except short posts when yet another of those record dominoes has fallen. Hopefully I can come up with some useful post-melting season analysis when I return from a two-week holiday.

I’m at a loss at this loss. The 2007 record that stunned everyone, gets shattered without 2007 weather conditions. The ice is thin. PIOMAS was/is right.

The big question, of course, is how this should affect what we do. David Spratt put it this way:

The 2007 IPPC report suggested that by 2100 Arctic sea-ice would likely exist in summer, though at a much reduced extent. Because many of the Arctic’s climate system tipping points are significantly related to the loss of sea-ice, the implication was that the world had some reasonable time to eliminate greenhouse emissions, and still be on time to “save the Arctic”. The 2007 IPCC-framed goal of reducing emissions 25 to 40 per cent by 2020 and 80 per cent by 2050 would “do the job” for the Arctic.

But the physical world didn’t agree. By 2006, scientist Richard Alley had observed that the Arctic was already melting “100 years ahead of schedule”. But the Arctic is not melting 100 years ahead of schedule: the climate system appears to be more sensitive to perturbations than anticipated, with observations showing many climate change impacts happening more quickly and at lower temperatures that projected, of which the Arctic is a prime example.

Politically, we are 100 years behind where we need to be on emissions reductions.

Or carbon sequestration. Or geoengineering. Or preparing to live in a hotter world.

30 Responses to Melting Arctic Sea Ice

  1. Arrow says:

    “Politically, we are 100 years behind where we need to be on emissions reductions.”

    Good, any chances of us meeting any climate reduction goals were extremely slim even before, so if we are 100 years behind schedule they are utterly impossible now. This means we can forget about them all together and instead focus on the only proven strategy for dealing with changing climate – adaptation.

    • Danny Yee says:

      Adapting to a world 6 or 7 degrees warmer would be vastly more painful than reducing emissions would be. But I guess it’s going to be painful for someone else, or their children, so maybe you don’t care about that.

  2. Renato Iturriaga says:

    What about the maximums? In winter are we starting at the same point or is it also dropping very fast?

    • davidtweed says:

      You can sorta see from John’s first graph that although starting from lower than historical average start, it still higher than say 2007.

    • John Baez says:

      There are lots of great graphs at Arctic Sea Ice Graphs. This one answers Renato’s question:


      Click to make it larger.

      Since I was wondering about ‘extent’ versus ‘area’, I looked at the IJIS website, which says:

      The area of sea-ice cover is often defined in two ways, i.e., sea-ice “extent” and sea-ice “area.” These multiple definitions of sea-ice cover may sometimes confuse data users. The former is defined as the areal sum of sea ice covering the ocean (sea ice + open ocean), whereas the latter “area” definition counts only sea ice covering a fraction of the ocean (sea ice only). Thus, the sea-ice extent is always larger than the sea-ice area. Because of the possible errors in SIC mentioned above, satellite-derived sea-ice concentration can be underestimated, particularly in summer. In such a case, the sea-ice area is more susceptible to errors than the sea-ice extent.

      That’s not incredibly clear, but I guess the idea is that if you have a region of water surrounded by ice, it counts as part of the sea ice ‘extent’ but not the sea ice ‘area’. This explains why sea ice area is harder to measure. (But what if you have a region with lots of floes floating in water, not surrounded by ice? Presumably people try to use their best judgement.)

      • Renato Iturriaga says:

        Thanks John

        My question with the maximums was to see if in the annual natural cycle, we are seeing greater oscillation or there is a net lost of ice. In simple words: Does the earth recover in winter?

        The graph shows that the variations and dropping’s in the winter are not as drastic as in the summer, the earth to some extent, somehow, manages to return. However the appropriate unit to see if we loose ice is not area in any of its variants, it is the volume. The appropriate graph is graph number XIV in the site you recommended. (I don’t know how to upload it) In this case there is no doubt that even when they are small variations from year to year there is a clear downward trend.

      • Keith Richards-Dinger says:

        The bottom of the page http://earthobservatory.nasa.gov/Features/SeaIce/page2.php discusses the different between sea-ice area and extent. Basically, ‘area’ is the obvious, while ‘extent’ is the total area of all pixels that are at least 15% ice.

        This is clearly pixel-size dependent (e.g. as the pixel size shrinks towards zero, the extent will approach the area), so there must be some standard pixel size or standard set of pixels. The above website mentions ‘a coarse grid of pixels as large as 25 km x 25 km’.

        Not sure what all the reasons for using extent as well as area might be, but the site http://nsidc.org/arcticseaicenews/faq/#area_extent, mentions that extent is less affected by problems of differentiating open ocean water from surface melt on top of sea ice during the summer than area.

    • John Baez says:

      Renato wrote:

      However the appropriate unit to see if we lose ice is not area in any of its variants, it is the volume.

      That’s probably true. The problem is that area is something we can easily measure, while volume must be estimated through a complex modelling procedure—nobody swims under the whole Arctic Ocean measuring the thickness of the ice each month.

      For PIOMAS, this procedure is sketched very briefly here, but you’d really need to click the ‘Validation’ and ‘Publications’ links and read more to get enough information to truly understand this model. I haven’t. Especially in a world where so-called ‘skeptics’ assume the worst about any model that doesn’t confirm their prejudices, sea ice area has the advantage of being simpler to measure and check.

      But I’m not mainly worried about these so-called ‘skeptics’. People who actually care about the truth were skeptical about PIOMAS until recently, when it seems to have passed some tests. On his Arctic Sea Ice Blog, which is definitely worth reading, Neven recently wrote:

      Quite soon after the inception of this blog, data from the PIOMAS model became a prominent element in discussions on ice thickness and volume. Though corroborated by on-the-ground observations and satellite data, PIOMAS remained a model and so practically everyone was careful in not attaching too much importance to the numbers that showed a staggering decline in volume over the last decade.

      In the past two years, however, more and more evidence has been accumulating, showing that PIOMAS has it largely right.This year and last year we’ve seen total ice cover declining even when weather patterns would suggest the decline should stall. Moreover, it was recently announced that preliminary observational data from the CryoSat-2 satellite more or less confirm the PIOMAS modeled data.

      And so we move on, going deeper into the matter, and discuss things like the precipitous drop in average thickness at the end of May 2010 that was repeated in 2011 and 2012…

      CryoSat-2 measures sea ice thickness by changes in the Earth’s gravitational field:

       

      The appropriate graph is graph number XIV in the site you recommended. (I don’t know how to upload it) In this case there is no doubt that even when they are small variations from year to year there is a clear downward trend.

      Right. I hadn’t seen that graph. Here it is:


      Only I can make pictures appear in comments, but if you see a picture or graph that’s important, just right-click on it and choose ‘copy image location’, then include the URL in your comment. With my magic powers, I can then turn the URL for a jpg, gif or png file into something everyone can actually see!

      (‘Copy image location’ is the right trick on a modern Firefox browser. I imagine other browsers have similar tricks.)

  3. Frederik De Roo says:

    Politically, we are 100 years behind

    The part of the world with the highest carbon footprint has democracy, so the citizens can vote for politicians to act on climate change. It’s hard to expect politicians to have a long-term view on environmental matters if a majority of the voting public considers these problems are not a priority or maybe even thinks “apres moi le deluge” (keyboard without accents, sorry)

    Also, in a capitalist economy the consumer has a lot of power through his/her own choices how to spend money (at least once you have enough money that you have the freedom to decide how to spend it). From my point of view it then becomes everybody’s own choice if he/she doesn’t want to North pole ice cap to melt. (with respect to the remark that the change of only one lifestyle is negligible to what the majority does: yes, practically it makes no difference, but the same remark also applies to voting. But I think psychologically it makes a difference.)

  4. Jenny says:

    Darn. I was hoping you were going to present some ideas for what to do.

    Of all the unknowns with climate change, the most pressing one seems to be figuring out what it would take to change the behavior of large numbers of people. The people we really need to weigh in may be the primatologists. Or maybe E.O. Wilson.

    Where are the useful analogies? Maybe Industrial mobilization for WWII. That has many of the key elements — a clearly-defined enemy to oppose, a consensus that the group’s survival is at stake, willingness to turn a large industrial economy to the task without asking about the costs. But in the current situation, the enemy isn’t the Other, and the battlefields are everywhere, and nowhere. How do you make a propaganda poster for battling climate change?

    Another possible analogy is the response to the emergence of AIDS. I feel like we’re in the period when the diagnosis has become clear but as yet there are no viable treatments. It took a lot of palpable human misery to turn this from a “them” problem to an “us” problem.

    What does it take to change the behavior of the planet’s most invasive primate species?

    • Frederik De Roo says:

      Of all the unknowns with climate change, the most pressing one seems to be figuring out what it would take to change the behavior of large numbers of people.

      Religion? “thou shalt not burn carbon” (I’m kind of half-joking here)

    • John Baez says:

      Jenny wrote:

      Darn. I was hoping you were going to present some ideas for what to do.

      Sorry. Soon!

      Of all the unknowns with climate change, the most pressing one seems to be figuring out what it would take to change the behavior of large numbers of people.

      I agree completely. But this is one that I, as a mathematical physicist, feel poorly qualified to address. I should really start talking to more people who think seriously about this.

      That has many of the key elements — a clearly-defined enemy to oppose, a consensus that the group’s survival is at stake, willingness to turn a large industrial economy to the task without asking about the costs. ut in the current situation, the enemy isn’t the Other, and the battlefields are everywhere, and nowhere.

      Right. Primates are very good at rallying against another tribe without questioning the costs very much. But here the enemy is our own habits and systems. And in that situation, we’re amazingly good at justifying what we do until its effects become absolutely calamitous, and even beyond.

      As you probably know, Easter Island was deforested by its inhabitants, who then died out because they had no more wood to build the canoes that were necessary for their survival. Over on Google+ someone asked what the person who cut down the last tree there must have been thinking. And Toby Bartels gave the obvious correct answer: “Wow, I’m sure lucky! I got the last one!”

      It would be unfortunate if the ‘war against climate change’, when it finally comes, takes the distorted form of a war between groups of people, each blaming each other for disaster and trying to gain control of certain limited resources. But this is the kind of war we know how to fight.

      However, I have decided that it’s crucial, for me to have any good effect, to start acting more optimistic. When you talk about big problems without offering people solutions, they turn away and stop paying attention. Everyone loves an optimist. So, soon I will talk about better things we can do.

      • Jenny says:

        Great! I’m staying tuned.

        FWIW, Bill McKibben and the 350.org folks seem to have decided to make Big Oil the Other in their efforts to rally the troops. I respect McKibben, but he’s always been a problematic front man, and I’m not sure this approach is going to work.

        My gut feeling is that climate issues are about to break out of their green ghetto and become a hot topic (dear God, did I just write that?) in the mainstream. That will be an excellent moment to have something of value to add to the conversation — as in, now what do we do?

  5. I wrote some years ago here proposing, as in my work of 2006, that an aerosol layer at ~42,000 ft over the Arctic for ~4 months could halt the warming. It then rains or snows out in Fall. Cost: ~$200 million/yr.

    We have the KC-10 Extender aircraft (flight refuelers) which can be modified to spray dilute H2S or H2SO4 or SO2, depending on cloud specifics etc.

    No treaty governs such use; any Arctic nation could do it. Of course political and ethical matters bear here, but the tech can be developed in a few years to a reasonable level of reliability.

    The Russians want the sea lane across Siberia & N America open as much as possible. A compromise allowing this yet keeping ice over most of the Arctic seems plausible. The Inuit would much appreciate this, I gather.

    • John Baez says:

      Do the Inuit have enough money to put enough aerosols in the atmosphere over the Arctic to keep it cool? If they don’t yet, maybe they could get that money by going into the tar sands business!

      By the way, there’s a new paper estimating costs for putting enough aerosols in the stratosphere to keep the whole world cool:

      • Justin McClellan, David W Keith and Jay Apt, Cost analysis of stratospheric albedo modification delivery systems, Environmental Research Letters 7 (2012).

      There’s also a pop summary on Kurzweil’s website.

      The cheapest is the one you mention: using airplanes to put one million metric tons of aerosols between 20 and 30 km into the air would cost only 1 to 3 billion dollars per year.

      • Actually John, that a few illion for the planet, not just the Arctic. Indeed the Arctic is much cheaper because it’s only ~5% of the planet surface and it’s got a much lower stratosphere, ~40,000 ft, and need be done only ~4 months/yr. I worked all this out ~2006 for the KC-10. The equatorial stratosphere is much tougher and demands a new type of heavy lift vehicle to ~55,000 ft.

        • John Baez says:

          Right, I was trying to say the new paper puts the cost at $1-3 billion per year for the whole world. That’s cheap. So, I predict people will soon start taking this very seriously—and then, if no killer objections are found (as opposed to just complaints), start doing it.

  6. Part of the problem is waste heat from energy production – this guy, Tom Murphy, a physicist from UCSD, has some interesting things to say in this presentation about waste heat, amongst other things:

    http://fora.tv/2011/10/26/Growth_Has_an_Expiration_Date

    and he posits the root of the problem as economies which require economic growth, rather than steady state economies. Talk about improbable system changes! But we’ll get to a steady-state economy one way or another, either voluntarily or through systemic collapse…

    FWIW, here’s his weblog: http://physics.ucsd.edu/do-the-math/2012/02/my-great-hope-for-the-future/

  7. dickbill says:

    Great blog.
    There is this thread about global warming on ‘cloudynight’:

    http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5368480/page/0/view/collapsed/sb/5/o/all/fpart/1

    one comment linked to the work of a meteorologist who propose to inject sea water into the clouds to increase their reflectivity (albedo) and that could be a relatively cheap and clean (not as dirty as injecting volvanic ashes) way to keep the north polar cap. caveet: commenters mentioned the possible negative effects of halogens from the sea water on the ozone layer.True, but i say you have to choose the least evil, sometimes.
    Anyway, i’m not optimistic as some still refuse any action on the basis that global warming could be part of a natural cycle and that WHO are we to decide what MUST be the average temperature on Earth anyway? ‘we’ being mostly european people (i.e, species adpted for postglacial conditions) who want nice cold winters with snow for christmas. This is a serious point, and true. So…

  8. Giampiero Campa says:

    I have read somewhere that in one billion years or so the sun will shine 10% more, and that will trigger a runaway green house effect resulting in evaporation of the oceans.

    So why are we sure that this will not happen in the next millennium if we burn all available fossil fuels ? Is it because carbon dioxide will not stay too long in the atmosphere, or maybe because the forcing term will be way less than 10%, even including the release of methane from permafrost ?

    • John Baez says:

      Giampiero wrote:

      I have read somewhere that in one billion years or so the sun will shine 10% more, and that will trigger a runaway green house effect resulting in evaporation of the oceans.

      Right. People argue about when this will happen—I’ve seen estimates of 1 or 2 billion years—but at some point it’ll happen, unless we do something. And the real bummer is that when this happens, some of the H2O in the upper atmosphere will photodissociate, and the hydrogen will slowly get lost to outer space, so eventually the planet will lose a lot of its water.

      So why are we sure that this will not happen in the next millennium if we burn all available fossil fuels ?

      James Hansen believes it could, but most experts believe it’s unlikely. This paper seems to represent the consensus view:

      • Colin Goldblatt, Andrew J. Watson, The Runaway Greenhouse: implications for future climate change, geoengineering and planetary atmospheres.

      However, they write: “In the event that our analysis is wrong, we would be left with the situation in which only geoengineering could save us.”

      You should definitely read this paper, Giampiero. Me too—I just discovered it! It’s quite technical, but it tries to give a clear overview of a rather complex problem. Let me just quote some, as an appetizer:

      It is a common misconception that the runaway greenhouse is a simple extension of the familiar water vapour feedback. As the planet warms more water evaporates. Water vapour is a greenhouse gas, so this enhances the warming (a positive feedback). Accelerating this, by implication, would boil the entire ocean. Historically, this possibility was discussed by Sagan (1960) and Gold (1964), but some of the earliest modern-era climate models (Manabe & Wetherald, 1967) showed that while water vapour feedback is an important positive feedback for Earth, it is not a runaway feedback.

      In fact, the physics of the runaway greenhouse is rather different to “ordinary” water vapour feedback. There exist certain limits which set the maximum amount of outgoing thermal (longwave) radiation which can be emitted from a moist atmosphere. In the ordinary regime in which Earth resides at present, an increase in surface temperature causes the planet to emit more radiative energy to space, which cools the surface and maintains energy balance. However as a limit on the emission of thermal radiation is approached, the surface and lower atmosphere may warm, but no more radiation can escape the upper atmosphere to space. This is the runaway greenhouse: surface temperature will increase rapidly, finally reaching equilibrium again only when the surface temperature reaches around 1400K and emits radiation in the near-infrared, where water vapour is not a good greenhouse gas. Along the way, the entire ocean evaporates.

      In this section we review the physics of the runaway greenhouse in detail. Our theoretical framework follows Nakajima et al. (1992). Whilst Nakajima et al. (1992) was very formal and mathematical, our description here is more qualitative. We begin by describing three different “limits” on the outgoing longwave radiation. Whilst we find it useful to group these together under a single umbrella term we emphasize that the physical character of them is rather different. Limit 1, the black body upper limit, is the maximum radiation that any planet of given surface temperature can emit; this varies with temperature. It does not lead to a runaway greenhouse, but is included for context. Limit 2, the moist stratosphere upper limit, is the maximum amount of radiation which can be transferred by a moist stratosphere; this is invariant with temperature, so can lead to a runaway greenhouse. Limit 3, the moist troposphere asymptotic limit is the amount of radiation which a thick, pure water vapour atmosphere will emit; the radiation from any thick water-rich atmosphere will tend towards this asymptotic limit. It is invariant with temperature, so can lead to a runaway greenhouse. We then describe the changes which occur when increasing temperature in both runaway and moist greenhouses.

      Understanding the runaway greenhouse requires familiarity with many aspects of atmospheric radiative transfer and thermodynamics. Given the interdisciplinary interest in this topic, we summarise the necessary background material in Appendix A.

      • Giampiero Campa says:

        Wow, thanks a lot, this is great stuff! I will definitely read it.

        I have glanced at page 12 and things seem to be explained clearly already over there, but i want to understand Figure 5 better, so i’ll read it.

      • John Baez says:

        I read the paper more carefully today and it’s clear the more relevant scenario is not what Goldblatt and Watson call the ‘runaway greenhouse’, a runaway process where the atmosphere heats up to 1400 kelvin, when it becomes hot enough for outgoing radiation to avoid the frequencies that water vapor likes to absorb.. According to their calculations, this can’t be caused by increased CO2 concentrations, only by raising the amount of solar radiation absorbed by the Earth from its current value of 240 watts/meter2 to the larger value of 300 watts/meter2.

        What’s more relevant is what they call the ‘moist greenhouse’, in which enough of the oceans evaporate to make water vapor a major constituent of the troposphere. They estimate this could be caused by raising the CO2 concentration from its current value of 390 ppm to the much higher value of 10,000 ppm (by volume). This is apparently higher than could be achieved by burning all ‘conventional’ fossil fuels, but perhaps it’s achievable if we burn all tar sands, methane clathrates, and so on.

        • nad says:

          John wrote:

          “What’s more relevant is what they call the ‘moist greenhouse’, in which enough of the oceans evaporate to make water vapor a major constituent of the troposphere.”

          On a first glance I couldn’t find a good overview about the reflectivity of different earth surfaces, but I could imagine that if enough of the oceans evaporate then this could lead to quite an increase of the amount of solar radiation absorbed by the Earth from its current value of 240 watts/meter2 to a larger value…..where I hope that this value is not going over the above mentioned 300 watts/meter2……

          Did the authors say something on that?

        • John Baez says:

          If the oceans evaporate, I believe the whole Earth will be covered by clouds and its reflectivity, or ‘albedo’, will increase. Right now the (warming) greenhouse effect of clouds is about half their (cooling) albedo effect. However, this paper does not go into clouds in detail, and they’re quite tricky. So, as the authors point out, people should study some of these questions in more detail.

          Take a look at sections 3a), b) and c).

        • nad says:

          In wikipedia the reflectivity of the water of the oceans actually seems to be generally smaller than that of eg deserts, but I am not sure how much this image is based on measurement. So if the oceans should turn into deserts then by looking at this it seems that earth would absorb less solar radiation (i.e. it seems evaporating oceans would give by this a lowering contribution to the earth surface temperature)

          You wrote

          If the oceans evaporate, I believe the whole Earth will be covered by clouds and its reflectivity, or ‘albedo’, will increase. Right now the (warming) greenhouse effect of clouds is about half their (cooling) albedo effect.

          I only looked briefly into the sections you mentioned, they write (3a):

          Although it seems quite unlikely, a case of more widespread and larger droplet size high clouds or good gaseous absorbers in the water vapour window and a reduction in low clouds could, in principle, increase the absorbed solar radiation and decrease the radiation limit. Without better understanding whether such changes are possible, we cannot totally rule out a runaway greenhouse.

          So it seems rather that if clouds would form at higher altitudes (and if the temperature of the troposphere would rise and the earth surface temperature would stay as it is or get lower then if I understand correcty the clouds would be higher) than these may have larger droplets and thus they may actually have a lower albedo and it may eventually be so low that the greenhouse effect of clouds may get even bigger than the cooling cloud albedo effect, which would result in a runaway greenhouse. :O

      • Giampiero Campa says:

        So there have been proposals to move the earth to an outer orbit, but all considered (in light of the fact that a runaway greenhouse is going to eventually happen), perhaps it makes more sense to put a large enough body at the L1 point ? This perhaps can protect us from a runaway greenhouse, but i wonder if can work also later on when the sun is going to become a red giant, probably not …

  9. davidtweed says:

    Just to note that National Snow and Ice Data Center has declared that the summer melt season has very probably ended on 18 September with an arctic sea ice extent of 3.41 million square kilometers. That’s apparently half the average minumum over the last 30 years.

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