Arctic Melting — 2015

With help from global warming and the new El Niño, 2015 was a hot year. In fact it was the hottest since we’ve been keeping records—and it ended with a bang!

• Robinson Myer, The storm that will unfreeze the North Pole, The Atlantic, 29 December 2015.

The sun has not risen above the North Pole since mid-September. The sea ice—flat, landlike, windswept, and stretching as far as the eye can see—has been bathed in darkness for months.

But later this week, something extraordinary will happen: Air temperatures at the Earth’s most northernly region, in the middle of winter, will rise above freezing for only the second time on record.

On Wednesday, the same storm system that last week spun up deadly tornadoes in the American southeast will burst into the far north, centering over Iceland. It will bring strong winds and pressure as low as is typically seen during hurricanes.

That low pressure will suck air out of the planet’s middle latitudes and send it rushing to the Arctic. And so on Wednesday, the North Pole will likely see temperatures of about 35 degrees Fahrenheit, or 2 degrees Celsius. That’s 50 degrees hotter than average: it’s usually 20 degrees Fahrenheit below zero there at this time of year.

Here’s a temperature map from a couple days later—the last day of the year, 31 December 2015:

(Click on these images to enlarge them.)

And here, more revealing, is a map of the temperature anomaly: the difference between the temperature and the usual temperature at that place at that time of the year:

I think the temperature anomaly is off the scale at certain places in the Arctic—it should have been about 30 °C hotter than normal, or 55 °F.

These maps are from a great website that will show you a variety of weather maps for any day of the year:

Climate Reanalyzer.

How about the year as a whole?

You can learn a lot about Arctic sea ice here:

• National Snow and Ice Data Center, Arctic Sea Ice News.

Here’s one graph of theirs, which shows that the extent of Arctic sea ice in 2015 was very low. It was 2 standard deviations lower than the 2000–2012 average, though not as low as the record-breaking year of 2012:

Here’s another good source of data:

• Polar Science Center, PIOMAS arctic sea ice volume reanalysis.

PIOMAS stands for the Pan-Arctic Ice Ocean Modeling and Assimilation System. Here is their estimate of the Arctic sea ice volume over the course of 2015, compared to other years:

The annual cycle is very visible here.

It’s easier to see the overall trend in this graph:

This shows, for each day, the Arctic sea ice volume minus its average over 1979–2014 for that day of the year. This is a way to remove the annual cycle and focus on the big picture, including the strange events after 2012.

What to do?

The Arctic is melting.

What does that matter to us down here? We’ll probably get strange new weather patterns. It may already be happening. I hope it’s clear by now: the first visible impact of global warming is ‘wild weather’.

But what can we do about it? Of course we should stop burning carbon. But even if we stopped completely, that wouldn’t reverse the effects of the warming so far. Someday people may want to reverse its effects—at least for the Arctic.

So, it might be good to reread part of my interview with Gregory Benford. He has a plan to cool the Arctic, which he claims is quite affordable. He’s mainly famous as a science fiction author, but he’s also an astrophysicist at U. C. Irvine.

Geoengineering the Arctic

JB: I want to spend a bit more time on your proposal to screen the Arctic. There’s a good summary here:

• Gregory Benford, Climate controls, Reason Magazine, November 1997.

But in brief, it sounds like you want to test the results of spraying a lot of micron-sized dust into the atmosphere above the Arctic Sea during the summer. You suggest diatomaceous earth as an option, because it’s chemically inert: just silica. How would the test work, exactly, and what would you hope to learn?

GB: The US has inflight refueling aircraft such as the KC-10 Extender that with minor changes spread aerosols at relevant altitudes, and pilots who know how to fly big sausages filled with fluids.



Rather than diatomaceous earth, I now think ordinary SO2 or H2S will work, if there’s enough water at the relevant altitudes. Turns out the pollutant issue is minor, since it would be only a percent or so of the SO2 already in the Arctic troposphere. The point is to spread aerosols to diminish sunlight and look for signals of less sunlight on the ground, changes in sea ice loss rates in summer, etc. It’s hard to do a weak experiment and be sure you see a signal. Doing regional experiments helps, so you can see a signal before the aerosols spread much. It’s a first step, an in-principle experiment.

Simulations show it can stop the sea ice retreat. Many fear if we lose the sea ice in summer ocean currents may alter; nobody really knows. We do know that the tundra is softening as it thaws, making roads impassible and shifting many wildlife patterns, with unforeseen long term effects. Cooling the Arctic back to, say, the 1950 summer temperature range would cost maybe $300 million/year, i.e., nothing. Simulations show to do this globally, offsetting say CO2 at 500 ppm, might cost a few billion dollars per year. That doesn’t help ocean acidification, but it’s a start on the temperature problem.

JB: There’s an interesting blog on Arctic political, military and business developments:

• Anatoly Karlin, Arctic Progress.

Here’s the overview:

Today, global warming is kick-starting Arctic history. The accelerating melting of Arctic sea ice promises to open up circumpolar shipping routes, halving the time needed for container ships and tankers to travel between Europe and East Asia. As the ice and permafrost retreat, the physical infrastructure of industrial civilization will overspread the region […]. The four major populated regions encircling the Arctic Ocean—Alaska, Russia, Canada, Scandinavia (ARCS)—are all set for massive economic expansion in the decades ahead. But the flowering of industrial civilization’s fruit in the thawing Far North carries within it the seeds of its perils. The opening of the Arctic is making border disputes more serious and spurring Russian and Canadian military buildups in the region. The warming of the Arctic could also accelerate global warming—and not just through the increased economic activity and hydrocarbons production. One disturbing possibility is that the melting of the Siberian permafrost will release vast amounts of methane, a greenhouse gas that is far more potent than CO2, into the atmosphere, and tip the world into runaway climate change.

But anyway, unlike many people, I’m not mentioning risks associated with geoengineering in order to instantly foreclose discussion of it, because I know there are also risks associated with not doing it. If we rule out doing anything really new because it’s too expensive or too risky, we might wind up locking ourselves in a "business as usual" scenario. And that could be even more risky—and perhaps ultimately more expensive as well.

GB: Yes, no end of problems. Most impressive is how they look like a descending spiral, self-reinforcing.

Certainly countries now scramble for Arctic resources, trade routes opened by thawing—all likely to become hotly contested strategic assets. So too melting Himalayan glaciers can perhaps trigger "water wars" in Asia—especially India and China, two vast lands of very different cultures. Then, coming on later, come rising sea levels. Florida starts to go away. The list is endless and therefore uninteresting. We all saturate.

So droughts, floods, desertification, hammering weather events—they draw ever less attention as they grow more common. Maybe Darfur is the first "climate war." It’s plausible.

The Arctic is the canary in the climate coalmine. Cutting CO2 emissions will take far too long to significantly affect the sea ice. Permafrost melts there, giving additional positive feedback. Methane release from the not-so-perma-frost is the most dangerous amplifying feedback in the entire carbon cycle. As John Nissen has repeatedly called attention to, the permafrost permamelt holds a staggering 1.5 trillion tons of frozen carbon, about twice as much carbon as is in the atmosphere. Much would emerge as methane. Methane is 25 times as potent a heat-trapping gas as CO2 over a century, and 72 times as potent over the first 20 years! The carbon is locked in a freezer. Yet that’s the part of the planet warming up the fastest. Really bad news:

• Kevin Schaefer, Tingjun Zhang, Lori Bruhwiler and Andrew P. Barrett, Amount and timing of permafrost carbon release in response to climate warming, Tellus, 15 February 2011.

Particularly interesting is the slowing of thermohaline circulation. In John Nissen’s "two scenarios" work there’s an uncomfortably cool future—if the Gulf Stream were to be diverted by meltwater flowing into NW Atlantic. There’s also an unbearably hot future, if the methane from not-so-permafrost and causes global warming to spiral out of control. So we have a terrifying menu.

JB: I recently interviewed Nathan Urban here. He explained a paper where he estimated the chance that the Atlantic current you’re talking about could collapse. (Technically, it’s the Atlantic meridional overturning circulation, not quite the same as the Gulf Stream.) They got a 10% chance of it happening in two centuries, assuming a business as usual scenario. But there are a lot of uncertainties in the modeling here.

Back to geoengineering. I want to talk about some ways it could go wrong, how soon we’d find out if it did, and what we could do then.

For example, you say we’ll put sulfur dioxide in the atmosphere below 15 kilometers, and most of the ozone is above 20 kilometers. That’s good, but then I wonder how much sulfur dioxide will diffuse upwards. As the name suggests, the stratosphere is "stratified" —there’s not much turbulence. That’s reassuring. But I guess one reason to do experiments is to see exactly what really happens.

GB: It’s really the only way to go forward. I fear we are now in the Decade of Dithering that will end with the deadly 2020s. Only then will experiments get done and issues engaged. All else, as tempting as ideas and simulations are, spell delay if they do not couple with real field experiments—from nozzle sizes on up to albedo measures —which finally decide.

JB: Okay. But what are some other things that could go wrong with this sulfur dioxide scheme? I know you’re not eager to focus on the dangers, but you must be able to imagine some plausible ones: you’re an SF writer, after all. If you say you can’t think of any, I won’t believe you! And part of good design is looking for possible failure modes.

GB: Plenty an go wrong with so vast an idea. But we can learn from volcanoes, that give us useful experiments, though sloppy and noisy ones, about putting aerosols into the air. Monitoring those can teach us a lot with little expense.

We can fail to get the aerosols to avoid clumping, so they fall out too fast. Or we can somehow trigger a big shift in rainfall patterns—a special danger in a system already loaded with surplus energy, as is already displaying anomalies like the bitter winters in Europe, floods in Pakistan, drought in Darfur. Indeed, some of Alan Robock’s simulations of Arctic aerosol use show a several percent decline in monsoon rain—though that may be a plus, since flooding is the #1 cause of death and destruction during the Indian monsoon.

Mostly, it might just plain fail to work. Guessing outcomes is useless, though. Here’s where experiment rules, not simulations. This is engineering, which learns from mistakes. Consider the early days of aviation. Having more time to develop and test a system gives more time to learn how to avoid unwanted impacts. Of course, having a system ready also increases the probability of premature deployment; life is about choices and dangers.

More important right now than developing capability, is understanding the consequences of deployment of that capability by doing field experiments. One thing we know: both science and engineering advance most quickly by using the dance of theory with experiment. Neglecting this, preferring only experiment, is a fundamental mistake.

56 Responses to Arctic Melting — 2015

  1. Patrice Ayme says:

    Agreed with all, except for the naive idea that we have possible geoengineering means to fight the melting of the polar ice.

    Trying to put up a veil over polar areas (through various debris or SO2 suspended) will not work. But don’t volcanoes work? The enormous eruptions of Pinatubo, and the one, much worse of Indonesia’s Tambora in 1815, cooled the atmosphere dramatically (Tambora’s atmospheric veil caused freezing the following summer in Europe, and partial failure of crops).

    The main problem is that the melting of the Arctic and even worse, the melting of the Antarctic, is going to happen from BELOW. It is oceanic water, densest at four degrees centigrades (nearly 40 degrees F) which is seeping below, and causing the melting.

    An article just published in Science (December 2015) explains that one glacier has retreated by tens of kilometers, after being exposed to oceanic currents which are just ONE degree centigrade higher than the old normal, along the north-east tip of Greenland. Those currents are the return currents from the Gulf Stream extension which hit Spitzberg. (This particular glacier contains half a meter of global sea level rise.)

    So the real problem is not to throw a veil above the Arctic. It’s how to cool the Gulf Stream. (Note to would-be geoengineers: putting a big refrigerator between Florida and the Bahamas, will not work, for a number of reasons.)

    Measurements and a back of the envelope computation shows that the anomalous heat content so far stored in the upper 750 meters of the world ocean is about twenty times that stored in the atmosphere… And the ocean is playing catch up (the temperature of this layer is up only half that of the atmosphere; deeper parts are also warming up).

    We are coming close to a tipping point on three giant basins in Antarctica (the WAIS, Aurora, and Wilke basins): oceanic water is boring through the sills there. After the sill, the basin slope down (under the weight of the ice), deeper than the Grand Canyon. The melting of each of these basins will rise sea level by seven meters.

    Conclusion: only the outlawing, ASAP, of the burning of fossil fuels will mitigate the catastrophe. Anything else is a distraction from the task at hand.

    • John Baez says:

      I wanted to re-run the Gregory Benford interview because I believe that people will only take climate change seriously when they start thinking about all the options to fight it, and comparing them.

      Outlawing the burning of fossil fuels would do the job—but until one shows that most alternatives are worse, people won’t do this.

      I have no reason to disagree with most of what you say about the futility of Benford’s proposal. But I’d want to see some calculations on the effects of diminishing sunlight in the Arctic before feeling sure it wouldn’t help. Indeed this would cool the ice and ocean surface, not directly cool the seawater below. And of course this water gets most of its heat not when it’s in the Arctic, but in more southerly latitudes. So indeed, maybe it’s futile to reduce sunlight in the Arctic. But it would be nice to see a bit more precisely what effect it would have. A good climate scientist (not me) could do a rough calculation, not requiring a supercomputer or years of thought, that would be enough to either definitely drive the nail in the coffin of Benford’s plan… or reveal that it would have enough of an effect to be worth studying further. The plan is, after all, quite cheap.

      • Patrice Ayme says:

        The spectacular collapse of the sea ice in August 2012 was caused by an extremely violent warm, hurricane like storm which physically broke thick ice with enormous waves. There is evidence that melting is not just due to a warm sunshine, but to the secondary paroxysms of massive dynamic and potential (pressure) events. Sprinkling a hurricane with SO2 won’t do a thing.

        When the Larsen B iceshelf in the Antarctica peninsula collapsed, something similar happened: four days of near hurricane winds and a temperature of nearly 15 degrees centigrade (60 F).

        The Greenhouse Gas crisis is geoengineering (of the evil kind). Good geoengineering is hard to imagine (short of science fiction freezing of CO2 out of the atmosphere, thanks to giant thermonuclear reactors…)

        You are right; giving hope is important, indeed. And hope does exist, but it’s not in geoengineering: last generation nuclear reactors in places of little sun, and solar photovoltaic combined with hydrogen (for storage and transportation). These are existing technologies: expensive photovoltaics in satellites are twice more efficient (40%) than the cheap ones the ground. Existing fuel cell cars with 10 kilograms of hydrogen go 1,000 kilometers.

        The best hope is to push these technologies further in efficiency and safety, while deploying them massively with subsidies (while the 5.5 TRILLION dollars of yearly direct and indirect subsidies for burning fossil fuels are progressively transferred to non-carbon energy).

  2. Here’s a link to a website that copied John Baez’s article ‘Arctic Melting – 2015’ without saying who wrote it.

  3. For the sake of completeness let me mention my friend Neven’s famous Arctic Sea Ice Blog. It is the canonical place to go if you like to watch the yearly snail race of arctic ice melt. http://neven1.typepad.com/ There’s also a forum with highly learned and skilled observers of the North. Some things you read (or see) there first. http://forum.arctic-sea-ice.net/

    On geoengineering: Methinks much more important is mental engineering, as biological evolution is no longer effective. (A famous Einstein quote applies here regarding old thinking.) E.g. we need to confront Heidegger’s old rethorical question: “Why is the Earth silent at this destruction”

    As Patrice Ayme observed: “Verily, only big ideas soon enough will save intelligence from the rising seas of ecological necessity.”

  4. I very much like the phrases “Decade of Dithering” and “Deadly 2020s” which Dr Benford uses. It sure looks like things are “jostling up”, and the assessments of people like Drs Hansen and Mann and Rignot suggest there’s something in the system which is picking up pace.

    I don’t have any inherently against geoengineering, as long as proper and full risk assessments are done. However, given that countries, governments, and people cannot even get the physics of changing climate and why, I put their ability to correctly evaluate whether or not a particular geoengineering attempt should be attempted at nil. That’s really bad, in my opinion, because, being new, it might fail, and, while that can happen to any new effort, the conclusion publics might draw from the failure could be completely wrong.

    I also have some professional skepticism about how one would construct an experiment and observations series to tell whether or not such an experiment was a “success”. It seems it would need to run a long time, unless it was done at a limited scale and with full controls on the local environment.

  5. […] a recent post, after reviewing the extreme Arctic warming event of late 2015, Professor John Baez quotes an earlier interview with Dr Gregory Benford, who is arguing for a geoengineering effort to […]

  6. Despite an intention to keep this blog going, I have been so comfortably immersed in other matters that I didn’t comment on the Paris climate conference.

    But this got my attention: the Arctic 30 degrees Centigrade hotter than usual! I know the ups and downs are amplified there, but for a moment that gave me a feeling of superstitious terror. Like turning on a Geiger counter and discovering you have been invisibly drenched with radiation: the first spooky indication that something terribly wrong has happened.

    I have no sense at all for what this really means. But it occurs to me, don’t deserts show extremes of temperature too, in certain places? Very hot in the day, far below zero at night? Or maybe I am thinking of Mars…

    Update: Possibly it was due to warm air from the Atlantic that flowed into the Arctic.

    • John Baez says:

      I replied:

      It’s due to warm air moving into the Atlantic, as the maps on my blogs show. But this is not a routine event: as the Atlantic article states, “Air temperatures at the Earth’s most northernly region, in the middle of winter, will rise above freezing for only the second time on record.”

  7. Steve Wenner says:

    I read those same predictions of a 30 °C anomaly over the north pole at the end of 2015. But, it is now January 6; so, how did it turn out?

    • I was able to find this discussion and this presentation of the data. These are not definitive, as the data are preliminary, and the buoys making the measurements are not densely distributed in space. I’m looking if there are/will be satellite data available, although those might be even coarser in resolution. There is also an interview and discussion.

    • John Baez says:

      The temperature map in my article here shows temperature above freezing in the Arctic on December 31st. And on December 31st, CBC North wrote

      “We have temperatures above zero near the poles and that’s because the jet stream is bringing that warm air from the south up and along Greenland and Iceland. While storms here are normal, the strength of the storm isn’t,” Brauweiler said.

      You can see day-by-day world-wide and Arctic temperature maps here.

  8. Bruce Smith says:

    Does anyone know whether any countries with an “Arctic presence” have an official position on the desirability and/or acceptability of this kind of experiment?

    Also, do the Paris accords say anything about geoengineering?

    • John Baez says:

      I think the text of the Paris agreement doesn’t mention geoengineering. It certainly doesn’t contain the word ‘geoengineering’:

      • UN Framework Convention on Climate Change, Adoption of the Paris Agreement, 12 December 2015.

      More generally, I haven’t heard any suggestion that it discusses geoengineering.

      This article argues that meeting the goals of the Paris agreement might wind up requiring geoengineering, while not taking a position on whether this is a wise thing: maybe the goals are unrealistic:

      • Dan Farber, Does the Paris agreement open the door to geoengineering?, The Berkeley Blog, 14 December 2015.

      It cites this goal in Article 2(1)(a) of the agreement:

      Holding the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change.

      But it all depends on what “pursuing efforts” means; that’s pretty flexible.

  9. nad says:

    These maps are from a great website that will show you a variety of weather maps for any day of the year:

    John, unfortunately this is only the front page and I couldn’t
    find the arctic temperatures plots you display here. Could you please provide the direct link to the plots at climate reanalyzer?
    Thanks.

    • John Baez says:

      Sorry, I can’t find a way to post a direct link to a specific map. But it’s very easy to find temperature and temperature anomaly maps for any day of any year after 1979: go to Daily reanalysis maps.

      • nad says:

        I am sorry but I couldnt find the north pole map even not on this page.

      • John Baez says:

        I don’t know the reason for the difference between your image and mine, but I now notice that mine is a forecast, made on December 29th, of what the temperatures would be on the 31st. If you look at it, you can see that it says this:

        I believe I wrote my article after the 31st, so I’m not sure why this website would give me a forecast, but maybe they give forecasts and later replace them with measurements.

        • nad says:

          I don’t even see where on the reanalyzer page you can see forecasts, anyways John PLEASE have a look at this comment. I know two images are nothing but look at the shapes. Do you know those people at reanalyzer? Can’t they make a video with e.g. ozone being a kind of opaque-transparent overlay, so that one can compare the shapes over time?

        • John Baez says:

          I don’t know where you can get forecasts at Reanalyzer, either. As I already attempted to explain, when I downloaded the December 31st mean temperature map for the Arctic, I got a forecast. When I do the same sequence of actions now, I get the map you get, which is not a forecast.

          I tried to get a forecast for today, but I don’t seem able to get get any maps for 2016.

          Do you know those people at reanalyzer?

          No, I don’t.

          Can’t they make a video with e.g. ozone being a kind of opaque-transparent overlay, so that one can compare the shapes over time?

          They probably could if they had time.

        • nad says:

          When I do the same sequence of actions now, I get the map you get, which is not a forecast.

          Actually I am asking myself now what is the data on which this “reanalysis” is based. Like if I look at the surface air explanations I get strong doubts about the images.

          I mean which of the datasets used for the reanalysis contains measurement points close to the north pole, apart may be Ny Alesund?

        • nad says:

          The in the air website listed data sets are IGRA, GRUAN which belongs to GCOS and CHUAN so this is IGRA, this is GCOS , here are the 15 GRUAN sites and here are the CHUAN sites, which look on a first glance similar to HADCRUT 4. So in short all this data seems to have about less than 10 stations which are not really close to the north pole (i.e. greenland, norway etc.).

          I saw nowhere words about satellites which could eventually save them.

        • nad says:

          forgot to set the link to CHUAN

  10. Alex S-R says:

    The melt of the Arctic can also be slowed significantly in the short term by addressing emissions of short-lived climate forcers (SLCFs) such as methane and black carbon. Methane and black carbon have short residence times in the atmosphere, but contribute significantly to Arctic warming, so reducing their emissions would do a lot to mitigate warming in the short term. Some estimates say SLCFs are responsible for up to half of the warming experienced in the Arctic today. This approach is much, much safer than risky geoengineering approaches, which seem to me like hair-brained schemes to meddle in systems where predictability is very poor and the impact of mistakes is very high… A key difference from the early days of aviation engineering is that every time an airplane didn’t operate as intended it didn’t run the risk of screwing with the Asian monsoon and the lives of hundreds of millions of people.

    More info on SLCFs: https://oaarchive.arctic-council.org/bitstream/handle/11374/80/MM08_ACTF_SLCFsFinalSummaryReport_English_5-13-2013%20%283%29.pdf?sequence=1&isAllowed=y

    Also geoengineering schemes based on reflecting incoming solar radiation don’t address one of the other big problems with carbon pollution: ocean acidification.

  11. Martin Lewitt says:

    “They got a 10% chance of it happening in two centuries, assuming a business as usual scenario.” He is probably assuming a lot more than “business as usual”, what did he have the “climate sensitivity” knob at? If it had it at the level of the more complex models then he probably had it too high, since the models are in disagreement with the observational evidence. I believe that “business as usual” also assumes that renewables don’t achieve cost competitiveness, that is hard to believe over two centuries.

    Alarmism about methane hydrates can be dismissed for two reasons, the Arctic was much warmer during the holocene optimum, and today’s Arctic warming is nearly as much due to black carbon as to CO2. Black carbon is much less expensive to reduce with existing technology.

    • Can’t allow “models are in disagreement with the observational evidence” pass without comment: Y’can’t pass judgment on “the models” with something as simple-minded as a t-test, which the comment suggests.

      • Martin Lewitt says:

        Can you allow that the IPCC AR5 refused to give a best estimate of 3C like it did in the past, because of the divergence between model sensitivities and much lower model independent attempts to estimate the sensitivity?
        “No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies” (SPM-11, fn 16)”

        • (1) Failing to have a point “best estimate” for ECS is different than implying models are bogus because they disagree with “observational evidence”. As described elsewhere, the models forecast all possible climate futures, of which Earth’s climate traces one. As long as the trace remains within the ensemble cloud, all’s well.

          (2) The idea of representing Equilibrium Climate Sensitivity (ECS) or Transient Climate Sensitivity (TCS) as a point estimate with some kind of Highest probability Density Interval was always an oversimplified approach. First of all, any meaningful ECS is contingent upon whether it is over ocean or land, and, while the spatial mix can be done computationally, it’s not clear that the result can be interpreted as a practical matter. Second, the posterior density for ECS in any case is pretty broad, so the 95% HDI is much larger than would be guessed if the mean of that were taken and interpreted as some kind of Gaussian. Third, there can’t by definition be much mass below the mean, since it is constrained to be positive, so you’ll inevitably get a long tail, even before anyone tries to estimate it. Most of the risk is in that tail. Fourth, most people live on land. Land ECS always has a higher probability mass distribution than ocean or combined. Since policy is set for land, as a practical matter, land ECS is what should be used. Fifth, ECS is a function of global mean surface temperature, and responds non-linearly to that. Accordingly, would not expect ECS at +3C above baseline to be the same as ECS at +2C above baseline: It’s worse.

        • Martin Lewitt says:

          Is there any evidence that the trace is within the cloud of models with an ECS of 3C or higher? Very few model runs are below the trace due to the recent pause, they may well be outlier models with lower sensitivities. We should try to be aware of what we don’t know.

        • Again, I take exception to the characterization. In this case with “due to the recent pause”. At best, there was a decline in the positive magnitude of the first time derivative of surface temperature. There was no decline in the rate of increase of Earth planetary energy in atmosphere, and oceans. And, as I’ve noted elsewhere, studies which show marked discrepancies between observational interpretations (e.g., of the HadCRUT4 ensembles) and model runs also disagree markedly in the variance of observational temperatures. Since the second moment is so badly off, with no explanation, I don’t trust their first moment either.

        • Martin Lewitt says:

          Yes, the pause is in the surface temperature trend, but whether there was also a decline in the rate of heat storage into the oceans is an open question. Hansen’s energy imbalance calculations for the 1990s are about 0.2W/m^2 higher that figures reported for the 2000s, although I think he under estimated the error range on his calculations given the poor coverage during that time period. Trenberth’s hypothesis that the missing heat is being stored in the deep oceans is disputed, by several hypotheses for the hiatus. And there are attempts to claim there is no pause by rejiggering the data or attributing it to poor coverage in the Arctic or other issues. How can you claim “there was no decline in the rate of increase of Earth planetary energy”?

    • Alex S-R says:

      In the interview they’re talking about methane release from permafrosts, which isn’t quite the same as methane release from hydrates. Permafrost may contain methane hydrates, but much of the methane released from permafrost comes from the decomposition of organic matter by methanogenic bacteria, which can become active when permafrost thaws. Much of the world’s methane hydrates aren’t found in permafrost, but in marine sediments. So the issue of carbon release from methane hydrates is a somewhat different beast from the issue of carbon release from thawing permafrost.

      The IPCC estimates that thawing Arctic permafrost could release up to 350 GtC as CO2eq this century, which is way more than humanity’s entire carbon budget of ~275GtC to have a 66% chance of keeping the warming below 2C. So this is a big wildcard in the climate system, and a very big concern!

      I don’t think alarmism about methane hydrates can be dismissed as easily as you suggest. I don’t believe there’s been any mechanism proposed whereby hydrates could release a big amount of methane this century, and much of the methane they do released doesn’t make it to the atmosphere because it gets metabolized by microbiota in the water column, but over larger time scales (centuries) it could have a big warming effect. I don’t think we can just ignore the impacts of our actions because they’re far in the future. People and other living things centuries from now matter too, and deserve consideration. Plus even if the methane is metabolized in the water column and never makes it to the atmosphere, that’s still a big influx of carbon into the ocean-atmosphere-biosphere system from relatively stable storage in sediments.

      I agree on the black carbon issue though, that’s a much better way to quickly slow Arctic warming than geoengineering!

    • John Baez says:

      Martin wrote:

      Alarmism about methane hydrates can be dismissed for two reasons, the Arctic was much warmer during the Holocene Optimum […]

      I don’t think we can count on the Holocene Optimum to have tested what happens at the temperatures we’ll be seeing in the next century. There’s a lot more uncertainty in paleoclimate temperatures than current temperatures, but it’s quite possible that we’d already shot past the Holocene Optimum by 2004:


      This shows 8 reconstructions of past temperatures in color, and a kind of average in black. For details and caveats click the figure. Note the near-vertical slope since the Industrial Revolution.

      If you have some particular reason to think that temperatures in the Arctic were much warmer during the Holocene Optimum, I’d like to hear about that.

      (As someone else mentioned, it’s not just the temperature but the thickness of ice sheets that matters.)

      • Martin Lewitt says:

        The Arctic proxies indicated that the temperatures were 4C or 5C higher during the optimum. The global temperatures you plotted don’t show that because the Holocene Optimum wasn’t synchronized at the north and south poles, so they weren’t globally additive.

      • John Baez says:

        Some evidence please?

  12. Patrice Ayme says:

    Martin Lewitt:
    “Alarmism about methane hydrates can be dismissed for two reasons, the Arctic was much warmer during the holocene optimum, and today’s Arctic warming is nearly as much due to black carbon as to CO2. Black carbon is much less expensive to reduce with existing technology.”

    Methane Hydrates are all over the planet. Whereas some parts of the Arctic were warmer 5000 to 9000 years ago, overall temperatures, including the depths in the planetary ocean where the CH4 hydrates are, were colder than today. There were methane hydrates explosions and tsunamis then, and the former just started, again, last year. Expect a CH4 tsunami soon.

    Today’s Arctic warming is mostly due to tropical ocean currents warming up the ice from below (as a Science article just demonstrated).

  13. According to this graph on the US National Snow and Ice Data Center’s website, there were 14.2 million square kilometers of Arctic sea ice on 24 February 2016. On an average year over the last three decades, it would take until about 29 April for there to be this little Arctic sea ice.

    Since about 10 February, the area covered by sea ice has been noticeably below any of the last 30 years. The Arctic has experienced record-breaking temperatures of about 4° C higher than the 1951–1980 average.

    This post is an update of a previous one which reported very warm temperatures in the Arctic in early January.

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