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An update on the Arctic sea-ice

Filed under: — rasmus @ 26 August 2012

We noted earlier that the Artic sea-ice is approaching a record minimum. The record is now broken, almost a month before the annual sea-ice minima usually is observed, and there is probably more melting in store before it reaches the minimum for 2012 – before the autumn sea-ice starts to form.

The figure shows annual variations in the area of sea-ice extent, and the x-axis marks the time of the year, starting on January 1st and ending on December 31st (for the individual years). The grey curves show the Arctic sea-ice extent in all previous years, and the red curve shows the sea-ice area for 2012.

(The figure is plotted with an R-script that takes the data directly from NSIDC; the R-environment is available from CRAN)

UPDATE on the update The National Snow and Ice Data Center announced today (August 27th, 2012) that the 2007 record has now been broken by their more conservative 5-day running average criterion. They also note that “The six lowest ice extents in the satellite record have occurred in the last six years (2007 to 2012).”


343 Responses to “An update on the Arctic sea-ice”

  1. 201
    Snapple says:

    The melting of ice is a clear indication that the planet is warming, so I want to ask about an article that was supposedly published in “Nature Climate Change” (see the address at the bottom of the page) that claims tree rings prove it is getting colder. I am wondering if this is not the real “Nature Climate Change” because the link is a little different than the real Nature Climate Change site. The article is posted on a site that posts conspiracy theories about climate change, AIDS, and other scientific topics, so I wondered if something wasn’t right.
    http://www.omsj.org/reports/esper%202012.pdf

    On this article at the bottom of the page it says it is from Nature Climate Change, but the Internet Address is a bit different than the homepage of the Nature Climate Change that is affiliated with Nature.

    The article is too difficult for me to evaluate, but the OMSJ site is posted on posts attacks on climate science and even articles by John O’Sullivan.

    Can you look at this and explain to me what is going on?

  2. 202
    Snapple says:

    I have found what seems to be this article on the real Nature Climate Change site.
    http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1589.html

    I guess I am now wondering if someone will explain to me why this conspiracy site is posting this article. Is it supposed to prove that Dr. Mann is wrong?

  3. 203
    Snapple says:

    Here is a description of the tree ring article on the OMSJ site, which posts a lot of conspiracies. Maybe they have not accurately described the main point of the article. After all, most people wouldn’t be able to understand this article.

    http://www.omsj.org/issues/global-warming/scientists-calculate-global-cooling-trend#more-4779

  4. 204
    Snapple says:

    I have had a busy summer and missed some things, and I now see that RC discussed this paper. RC doesn’t agree with all of the paper, but thinks the paper makes some good points. the paper is being cherry-picked by denialists to undermine Dr. Mann.

  5. 205
  6. 206
    Snapple says:

    Thanks PD–I found that post and the discussion at Skeptical Science.

  7. 207
    Andy Lee Robinson says:

    Here’s a bit more refined update to my PIOMAS visualization of the evolution of Arctic Sea Ice volume.
    Latest data was Aug 26th 2012 – I’ll redo when September’s figures become available.
    http://www.youtube.com/watch?v=bNkyJ7eHHhQ

  8. 208
    David B. Benson says:

    Here is the citation for comments 190 & 192:
    The trends in summer Arctic sea ice extent are nonlinearly related to the mean sea ice state in CMIP5 models
    F. Massonnet, T. Fichefet, H. Goosse, C. M. Bitz, G. Philippon-Berthier, M.
    M. Holland & P. -Y. Barriat
    GRL, submitted
    http://www.atmos.washington.edu/~bitz/massonnet_etal_GRL_SUBMITTED.pdf

    Finally, the concluding equation ought to have a constant of integration, K, which allows setting t=0 arbitrarily:

    V = m/{exp(kmt+K)-1}

  9. 209
    Jim Larsen says:

    In the past we focused on sea ice extent simply because it was more easily and accurately measured, even as “everybody” acknowledged that volume was the better measure of the structural health of the ice.

    Now, volume measurement has become cheap and accurate enough to be used, but ironically at a time where volume might be becoming less important than extent. Now, functional health of the ice, as in albedo and weather maintenance, could be more important than structural health.

  10. 210
    Jim Larsen says:

    188 pohjois said, “Are you entirely sure, that when the reality is more and more divergent from the models, it should be wiser to stick to data, instead of trusting the models?

    [Response: … and your last statement is a completely nonsensical statement….gavin]”

    Yes, but his intent is blatantly obvious. Typos happen.

    Poh, great info and logic, but debating with someone who has lots more data is frustrating, eh? Ya gotta cobble together bits – such as your 16% of runs gave 0 trend. If the runs which encompassed reality also are 16% of runs, then the models are off by perhaps 100% (or 50%, depending on if you’re talking half or double) This gels with Cyrosat-2 news.

    http://beforeitsnews.com/environment/2012/08/esa-cryosat-2-data-reveals-arctic-summer-sea-ice-loss-50-percent-greater-than-expected-2445390.html

  11. 211
    Jim Larsen says:

    Man what a goof. Driving down the wrong side of the road. It’s 50% only.

  12. 212
    Rob Dekker says:

    David B. Benson,
    I think you confuse “Non-linear”, as denoted in Massonnet et al, with “exponential” as in your expression.

    Please remember that there does not seem to be any physical reason for “exponential” decline. A quadratic, or even up till 4th polynomial decline seems to have physical merit, while a pure “exponential” decline does not, as Gavin pointed out earlier.

    Needless to say that even a quadratic decline matches the initial part of a Gompertz curve that would be expected for a system in terminal decline with a “soft” landing, similar to what GCMs project for the future of Arctic sea ice, with the caviat that the time line on which this decline happens seems to be much shorter than the models project.

  13. 213
    Rob Dekker says:

    Jim Larsen,
    You are making assumptions about Stroeve et al 2012.
    Why don’t you read the paper before you draw conclusions ?

  14. 214
    Rob Dekker says:

    And may I add that you seriously overestimated the probability that the 2012 September minimum falls within the CMIP5 simulation window as presented by Stroeve et al 2012.

  15. 215
    BillD says:

    Snapple @ 201–I did not read the whole article, but note that they talk about “strong forcing at -0.31 oC per 1000 years. This goes along with the data showing that the earth’s climate was slowly cooling until recent, human-caused changes. The trends that the paper talks about are longer term and much weaker than more recent changes.

  16. 216
    Jim Larsen says:

    “Why don’t you read the paper before you draw conclusions ?”

    I read every link on this and the other thread. Now, if those didn’t include Strove – as if I’d remember the name – or if the links were to the “free” stuff like abstracts and what you request is paywalled, then I can’t comply. So yep, I did it or nope, I “can’t”.

    And I never draw conclusions – just current barely-informed opinions while whining for more info (oops, here comes one) like my oft-repeated whine about not seeing current ice-loss model results, especially driven by actual real weather.

  17. 217
    Jim Larsen says:

    And, to emulate your double-post :-) I was flailing and trying to find out what Gavin meant by “encompasses”. The number was totally fake, as I thought I made clear. I’ll be more diligent at putting (?) after such numbers.

    And the spread of models, from no ice loss at all to reality’s exponentialesque decline (call it quadratic, call it what you like, tis all the same, as any definition is by definition just a visualization of a happenstance fit), well, it throws up a red flag. Looking at reality, since 1990 PIOMAS minimum volume estimates have never risen for three years. Since we know each year’s ice is mostly an independent event (outside of thick multiyear ice, which is fast becoming extinct), the consistent decline really brings into question the models’ incredible swings between runs.

  18. 218
    Guy Rowland says:

    We’re now below 4m sq km – http://nsidc.org/arcticseaicenews/

  19. 219
    MalcolmT says:

    Here’s one for communicating the science, with special reference to the Arctic Sea Ice: http://www.upworthy.com/the-one-where-the-weather-lady-freaks-out-on-live-tv?g=2
    You might be wise to put you r coffee mug down before hitting ‘play’.

  20. 220
    Perk Earl says:

    Reply to Guy of post 218. Currently looks like it’s at 3600, over 1/2 a million square kilometers less than the 07 record melt. Might go as low as 3300. Just think of it – 1st time below 4 and we may end up at 3300?

    reply to 219: That was a great video! Really liked the part at the end when the anchor tries to change the subject to a famous couple ‘Kanoodling’ and she shoves him off his chair. Maybe this is what the deniers in DC need to get it.

  21. 221
    pohjois says:

    Gavin

    I have tried to response few days ago, but the comment didn’t get through and mail contact failed as well. So I will try to put my answer in parts, hopefully this will help to avoid spam filter.

    Regarding the first issue, I have no access to the Stroeve et al. so I
    can only take your word for that, which is more than sufficient.
    Nevertheless authors stress that Arctic ice predictions based on these
    models are “highly uncertain”, which in plain words means “of little use”.
    And this leads straight to the second issue – in the next comment.

  22. 222
    pohjois says:

    Part 2.
    When the uncertainty of estimates based on GCM models is so high, then the estimates based on simple trends observed in data should be treated as a reasonable alternative, and this is what I call sticking to data.

    This should apply in particular when these empirical models are accompanied by a reasonable argument why the GCM models are biased towards slower melt. People working with Arctic ice argue that this is due to low spatial resolution of sea models in GCMs leading to overestimates of ice thickness (Maslowski et al 2012).

  23. 223
    pohjois says:

    Part 3.
    And sticking to data:

    – the volume of Arctic ice as estimated by PIOMASS has reached this year 3.6 thousand km3,
    – the largest volume loss recorded at minimum in PIOMASS was 3.5K km3, and recently twice (2007 & 2010) the volume loss was 2.5K km3,
    – the average yearly ice loss since 1997 is 0.6K km3 (albeit with a very high standard deviation).
    Don’t you think that prediction of practically ice free Arctic (ice extent below 1M km2) before 2020 is at least equally reasonable as between 2040 and 2100?

  24. 224
    David B. Benson says:

    Rob Dekker @212 — Thank you, but

    V = m/{exp(kmt+K)-1}

    is not exponential in the sense used in a much earlier comment. Also, looking at the phase diagrams derived from model runs in the Massonnet et al. submission led me to the line of reasoning which gives the above formula.

    Note that the formula implies that the annual average sea ice volume will never become zero despite dT/dt=k continuing indefinitely. This might suggestion the original approximation to the phase diagrams is overly simplistic.

    Moreover the above formula is concave while the diagrams for the sea ice extent suggest a convex curve. (It would be helpful if someone used the existing data to determine the annualized average sea ice volume as a function of year.)

  25. 225

    Stroeve et al 2012 can be found here (open access for me):
    http://www.agu.org/journals/gl/gl1216/2012GL052676/2012GL052676.pdf

  26. 226
    Jim Larsen says:

    225 Daniel, that link goes to the AGU sign-on screen for me. My guess is you’re a member and so get to see information which, though probably 100% taxpayer funded, is not visible by mere taxpayers.

    We’re ever so lucky to have the 1%. Otherwise, we’d have to settle for paying a penny or two for information, when now we get to pay a far superior $20 plus the penny.

  27. 227
    Jim Larsen says:

    On 225, scientists, please please please include wording similar to “and inform the public through a free or extremely cheap conduit” to your grant proposals. Publishing in a peer-reviewed journal is just a requirement, not a good thing. The good thing is publishing a free or nearly free version of your results.

  28. 228
    Hank Roberts says:

    > 100% taxpayer funded

    But whose?

    Authors Kattsov and Pavlova are at the Voeikov Main Geophysical Observatory, Roshydromet, St. Petersburg, Russia, though the others are at US gov’t labs.

    Now I agree with you that the information ought to be more easily available (I assume you’ve looked via Scholar, which often lists the freely available copies along with the paywalled copies? If not, do make the effort.

    But yes, the AGU comes in for criticism about its publishing.

    To quote Some guy in Japan on that point: “… It’s a shame that the AGU hasn’t taken the opportunity to do something more radical with its recent reorganisation of its publications. Hooking up with a conventional profiteering toll-access publisher (and one with some fairly unsavoury activity in its recent history) is I suppose the easy option for a bunch of conservative greybeards, but I can’t help but think of it as a missed opportunity….”

    Yep.

  29. 229
    MARodger says:

    This Stroeve & Barrett presentation may help the discussion above.
    Versions of the p10 graphic have been doing the rounds but the p9 one for instance I’ve not seen elsewhere.

  30. 230
    Rob Dekker says:

    Jim Larsen,
    In the case of Stroeve et al 2012, I purchased the paper for $25.
    That’s not going to break the bank, but I agree with you that it is an obstacle for free exchange of up-to-date scientific info.

    Now. I do not know how much I am allowed to say about the paper, but I assume that my opinion on the paper is allowed.

    For starters, it seems to me that the analysis (of CMIP5 models on Arctic ice extent) it better than the 2007 CMIP3 results, but again is already behind reality.

    The 2012 mega-melt (some 3.6 M km^2 minimum) is in the fringes of the CMIP5 GCM results. It’s about 2 sigma’s below the mean of the ensemble runs, and if I interpret the plot correctly, the only model runs that showed a minimum as low as we will get in 2012 are the model runs that start off with an unrealistically small ice extent in the 80’s to begin with.

    So, Jim, your point was much stronger than you presented it to be. That’s why I told you to read the paper first before making your point. Sorry I came across a bit harsh.

    The more interesting part of the paper is what I think is what is NOT mentioned in Stroeve et al 2012 :

    – There is NO analysis of ice volume (scalar or field) development in the models (except for a mention that volume analysis will be done later).
    – There is NO mentioning at all about snow cover (snow anomaly) analysis, and certainly not if the observed massive snow anomalies from the past decade (including the record 6 million km^2 snow cover anomaly in June 2012) are even remotely replicated in the CMIP5 models.
    http://nsidc.org/arcticseaicenews/files/2012/07/Figure5a.png
    – There is not a single mention about ocean heat flux. Of course there is a real problem in validating ocean heat flux, but at least it would be nice to see what the simulated water temperatures are for the main influxes of ocean heat via Fram Strait and the Bering currents. We know that Fram Strait ocean water increased significantly over the decades, and we know that ocean heat flux seriously inhibits growth of thick ice during winter. Which in turn significantly affects ice volume.
    So can we at least get the results of ocean heat influx from the CMIP5 models and how that compares to observations ?

    In my opinion, the lack of GCM model results for ocean heat flux and spring/summer snow cover anomalies presented in scientific papers of IPCC model runs, as well as what seems to be a consistent underestimate of Arctic sea ice melting rates, makes GCM analysis papers like Stroeve et al 2012 much less interesting than they could be.

    Would it be possible to present such information in the “supplemental material” ?

    Meanwhile, the Arctic sea ice model that seems to gain more and more respect is PIOMAS.
    Time and again, it’s results match observations very nicely (submarine measurements, ICEsat, Cryosat 2 etc), maybe because it’s focus is so much on Arctic sea ice. I wish there was a snow-cover module and a ocean heat flux module that would be as accurately simulating reality as PIOMAS is for sea ice.

    Combining best-in-class modules with GCMs, we should be able to get at least a more accurate estimate of the expected response “trend line” of Arctic sea volume/extent given a GHG forcing source trend line, and how much “natural variability” really can divert from that trend.

    Until then, I agree with ‘pohjois’ that PIOMAS volume data by itself is the best volume data we have, and since year-after-year volume is still declining (even still accelerating), we should seriously consider an early melt-out to near-ice-free Arctic summers in this decade as a likely scenario (maybe even the most likely scenario).

  31. 231
    Chris Dudley says:

    Based on revised JAXA date, yesterday marked a fortnight of consecutive record ice loss. In the first half of that period, the ice extent loss rate was enormous compared to the prior ten years, sitting at 3.4 sigma above the mean. During the second half, the ice extent loss rate is not unusual. It ranks one above the median in the last 11 years (including this one). All of the ten prior years turned around in September, not October. 2007, the year with the latest turn around of this group ranks one below the median in ice extent loss rate for this period between Aug, 30 and Sept. 6.

    http://www.ijis.iarc.uaf.edu/seaice/extent/plot.csv

  32. 232
    Chris Dudley says:

    Rob (#230),

    PIOMAS does well matching observations because it incorporates a lot of observations in the calculation. It is not a climate model based prediction.

  33. 233
  34. 234
    Steve Fish says:

    Re- Comment by Jim Larsen — 6 Sep 2012 @ 10:18 PM:

    You say- “Publishing in a peer-reviewed journal is just a requirement, not a good thing.”

    I agree with your concern about the results of publicly funded research not being made more available to the public. However, you got this bit backwards. Actually, publishing in a peer reviewed journal is not a requirement but it is a good thing. Perhaps a typo?

    Steve

  35. 235
    Pekka Kostamo says:

    Another POW:

    The Arctic Ocean used to be another continent when it was frozen over all year. A witry continent with many peculiar attributes, but a continent nevetherless. It should not have been modeled as an ocean.

    World under the ice cover is very different also.

    The ice gone, it becomes a part-time real ocean. Unlinear dramatic change.

  36. 236
    L Hamilton says:

    Of possible interest: updated cycle plots showing sea ice area and extent changes for every month of the year (24 statistically significant downward trends), from November 1978 through August 2012.
    http://img.photobucket.com/albums/v224/Chiloe/12_Climate/2012_Cycle_Arctic.png

    Discussion of the plot at Neven’s Sea Ice blog:
    http://neven1.typepad.com/blog/2012/09/cycle-plots-of-sea-ice-area-and-extent.html

  37. 237
    wili says:

    Apologies if this has already been posted.

    asl.umbc.edu/pub/yurganov/methane/YurganovCCL.pdf

    Takeaway line (for me, at least):

    “The main conclusion of this paper is a qualitative detection of high and over the years increasing methane mixing ratios in areas coinciding with predicted locations of methane hydrates.”

    Sounds like pretty good evidence that methane hydrate release has begun and is accelerating. The main question now is what is the rate of accelerate, and will that rate be further increased by a newly ice-free (or nearly so) Arctic Ocean.

    Note that CT Arctic sea ice area continues to plunge–now at 2.298 million k^2.

    http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html

  38. 238
    Hank Roberts says:

    > qualitative detection
    means “I can smell it but not tell you how much there is”
    http://regentsprep.org/Regents/math/ALGEBRA/AD1/qualquant.htm

  39. 239
    wili says:

    Exactly. As I said, it is the exact amount (quantity) of acceleration of release that has yet to be accurately determined. Are any excursions up in that direction now investigating this?

  40. 240
    Jim Larsen says:

    234 Steve Fish said, ” Perhaps a typo?”

    That’s a nice way of putting it, and essentially correct, too! :-) Instead of “a good thing”, I should have typed ” “the” good thing” (including quotes). Of course, both are/would be good things. And, as Hank pointed out, things get complicated in a global community.

    Thanks for the data and analysis, Rob. Your $25 was well-leveraged. Ho-hum weather (at least above the ocean’s surface) giving 2 sigma results (and your initial conditions point as well) doesn’t convince me that the models are ready for prime time. I’ve long thought of it as a race between nature and scientists. Will nature get to ice-free before scientists can predict it via models?

    Here’s a 5 page article about weather forecasting and models. Forecasters get attuned to models’ quirks and adjust their forecasts accordingly. For example, it mentioned that certain events tend to cause the models to predict rain about 100 miles too far south(?), so they forecast rain further to the north.

    Interestingly, on page 4 it says, “weather is nonlinear, meaning that it abides by exponential rather than by arithmetic relationships.”, which seems to contradict the expert consensus on RC.

    http://www.nytimes.com/2012/09/09/magazine/the-weatherman-is-not-a-moron.html?_r=1&src=dayp

  41. 241

    #235, I really liked what Pekka wrote,:

    “The Arctic Ocean used to be another continent when it was frozen over all year. A witry continent with many peculiar attributes, but a continent nevetherless. It should not have been modeled as an ocean.

    World under the ice cover is very different also.

    The ice gone, it becomes a part-time real ocean. Unlinear dramatic change.”

    So true about the other continent bit, In Arctic Canada there are 2 huge Territories, one is called Nunavut, by the ancient most beautiful language of Inuit. Nunavut literally means “our land” , by extension Arctic straits, channels even Huge Hudson Bay becomes land by sea ice, land animals, wolves , Hares, foxes and Caribou called tuktu cross it as land.

    But Pekka, Inuit elders saw the change coming a long time before I did, it was quite linear.. Very slow slow change now becoming obvious by all the blue water.

  42. 242
    Chris Dudley says:

    A run of fifteen consecutive new records for lowest ice extent seems to have ended yesterday. More records may still be coming, and the data may be revised further. 2007 saw a couple of long streaks past the 9/22/05 prior minimum in the JAXA data set, one of 17 days starting 8/15/07 and one of 14 days starting 9/3/07.

  43. 243
    Superman1 says:

    IS THERE A WAY OUT?

    If we were to terminate all fossil fuel use today, the temperature increase over pre-industrial due to what we have burned already would be about 3 C. This arises from 0.8 C experienced already, about 0.7 C to be realized from CO2 in the atmosphere whose temperature consequences have yet to be realized because of lag time, and an equal increase from elimination of the fossil sulphates that have been placed in the atmosphere from fossil fuel combustion and effectively increase the albedo.

    This ignores any feedbacks, and especially methane release. We know from recent expeditions that large increase in Arctic methane emissions have been observed. Because of the potential importance of the methane contribution to temperature increase, we should be tracking methane releases continuously throughout the Arctic, ranging from near-seafloor to space. Yet, from what I have been reading, methane data is extremely sparse. We need to be blanketing the Arctic with methane and other GHG sensors; the present lack of effort is inexcusable.

    But, even without major feedbacks, the 3 C temperature increase we have ‘built-in’ from past combustion is catastrophic. From all that I have read, this level of increase without feedbacks will produce an effectively unlivable environment for perhaps billions of people. Also, from what I have read, there is little chance that temperatures would stabilize, given the observed existence of feedbacks. So, the unrealistic goal of terminating fossil fuel use today will still result in an unlivable environment. Given the decades more of fossil fuel use that faces us in reality, the unlivability will only be compounded. Is this problem solvable in theory and, if so, is it solvable in practice?

  44. 244
    wili says:

    Apologies if this has been posted here before, but here is this rather lengthy posting by Professor Peter Wadhams of Cambridge:

    “In a January 4th post on “Real Climate”, David Archer addressed those who are raising concerns about the speed of ice loss in the Arctic and the resultant potential for warming water temperatures to thaw frozen methane and release it as gas to the atmosphere. In essence, he dismissed such concern as a form of unfounded alarmism making “much ado about nothing”. In this rebuttal, I would like to respectfully challenge this dismissive stance and assert that severe dangers are arising in the Arctic which call for the full attention of humanity.

    The present thinning and retreat of Arctic sea ice is one of the most serious geophysical consequences of global warming and is causing a major change to the face of our planet. A challenging characteristic of the behaviour is that both the rate of retreat (especially in summer) and the rate of thinning in all seasons have greatly exceeded the predictions of climatic models. The sea ice cover of the Arctic Ocean, particularly in summer, has been in retreat since the 1950s at a rate of about 4% per decade which has recently increased to 10% per decade. More seriously, the thickness of the ice has diminished.

    Satellites can track ice area, but ice thickness distribution is most accurately measured by sonar from underneath the ice. Since 1971, I have been going to the Arctic in UK nuclear submarines, mapping the ice thickness using upward-looking sonar along the vessel’s track. U.S. submarines have also allowed such availability. Opening these submarines to scientific work has been a marvellous service to climate research. It was thanks to submarines that I was able to show for the first time that the ice in the Arctic is thinning (in a 1990 paper in Nature [2], showing a 15% thickness loss in 11 years), and recent work from UK and US submarines now shows a loss of more than 43% in thickness between the 1970s and 2000s, averaged over the ocean as a whole [3]. This is an enormous loss – nearly half of the ice thickness – and has changed the whole appearance of the ice cover. Most of the ice is now first-year rather than the formidable multi-year ice which used to prevail.

    The thinning is caused by a mixture of reduced growth in winter (because of warmer temperatures and more heat in the underlying water column) and greater melt in summer. A change in the direction and speed of ice motion has also played a role, with the ice departing quicker from the Arctic Basin through Fram Strait rather than circulating many times inside the Arctic.

    The summer (September) area of sea ice reached a record low in 2007, almost matched in 2011, but what is most serious is that the thinning continues. It is inevitable that very soon there will be a downward collapse of the summer area because the ice will just melt away. Already in 2007, measurements indicated that during the summer there were 2 metres of melt off the bottom of ice floes in the Beaufort Sea, while the neighbouring first-year floes had only reached 1.8 metres during winter – so all first-year ice was disappearing. This effect will become more important and will spread throughout the Arctic Basin.

    There is currently disagreement about when the summer Arctic will become completely ice-free. It depends on which model is being employed. My own view is based on purely empirical grounds, that is, matching the observations of area from satellites with observations from submarines (combined with some modelling) of thickness to give us ice volume. If we think in volume terms instead of area terms, the downward trend is more than linear, in fact it is exponential, and if extrapolated it gives us an ice-free summer Arctic as early as 2015 or 2016.

    Others have talked of later dates, like 2030-2040, but I do not see how the trend of summer ice volume can possibly permit this. Those who agree include W Maslowski, a leading ice modeller (Naval Postgraduate School, Monterey), and the PIOMAS project at University of Washington which generated the data shown below [4].

    The figure shows the minimum volume of Arctic sea ice in midsummer, based on areas observed from satellites and thickness trends inferred from submarine observations. Extrapolation leads to a zero volume in 2015. It must be pointed out that this perspective stands in direct contradiction to very complacent statements about the Arctic sea ice from the IPCC in the AR4 report of April 2007 saying the sea ice was very likely to last beyond the end of the century.

    The ice retreat is having major impact on the planet. The Arctic is the most rapidly warming region on earth (warming at 3-4 times the rate of low latitudes). It has become widely accepted that Arctic amplification of global warming is due to the albedo effect of sea ice retreat. The increased open water reduces the albedo (fraction of solar radiation reflected into space) and causes warming at high northern latitudes to be much faster than the tropics, with enormous implications for climatic instability. Secondly, the summer retreat of the ice from the wide Arctic continental shelves (particularly the East Siberian Sea) allows the shallow surface layer to warm up, bringing temperatures of up to 5 degrees C right down to the seabed.

    Quantification of this effect has only very recently been attempted, in a paper to the 2011 AGU by Hudson [5]. The startling conclusion is that the rate of warming of the Arctic from the sea ice albedo effect could double or worse, once the Arctic Ocean is ice-free in September. And it could double again, once the ocean is ice-free for half the year. But the timescale makes this all the more worrying.

    The scientific community has drawn attention to the risk of dangerous climate change if the world does not reduce greenhouse gas emissions – a worthy and critical objective. However, I wish to point toward a much more immediate problem that does not seem to be recognised among the climate change community at large: This is the problem of rapid retreat of Arctic sea ice, and likely consequence of catastrophic methane feedback.

    These rapidly warming temperatures are accelerating the melt of offshore permafrost, releasing methane, trapped either as methane hydrates or as free gas beneath the permafrost, and causing large plumes of methane to appear all over the summer Arctic shelves (observed for the last 2-3 summers by Semiletov and colleagues on joint University of Alaska – Far Eastern Research Institute cruises). Methane levels in the Arctic atmosphere have started to rise (measured by Dr Leonid Yurganov, Johns Hopkins University) after being stable for some years. As methane is a very powerful, if short lived, greenhouse gas (as much as 105 times as powerful per as unit weight of CO2 over a 10 year time horizon, though only lasting about 8 to 12 years in the atmosphere), this will give a strong upward kick to global warming.

    According to research crew leader Igor Semiletov, “We carried out checks at about 115 stationary points and discovered methane fields of a fantastic scale – I think on a scale not seen before…. This is the first time we’ve found continuous, powerful and impressive seeping structures more than 1,000 meters in diameter.” [6] He has also described how warmer temperatures are making their way down to the bottom of the shallow sea in the Arctic continental shelf areas: “When ice has gone, there are stronger winds and waves and a deeper mixing of water which causes the comparatively warm upper layer to mix with water at deeper levels. There are already studies which confirm that in some areas, bottom temperature in summer is 2 to 3 degrees above zero Celsius (freezing). As this warming spreads to a larger area, the more that shelf-based permafrost will thaw.” [7] There have been warnings that a major methane outbreak may be imminent.

    In a piece Archer co-authored in 2009 [8], he acknowledged both the significant warming power of methane and the fragile and “intrinsically vulnerable” nature of hydrates: “There are concerns that climate change could trigger significant methane releases from hydrates and thus could lead to strong positive carbon-climate feedbacks. …. Methane hydrate seems intrinsically vulnerable on Earth; nowhere at the Earth’s surface is it stable to melting and release of the methane.” In this same piece, Archer affirms another key factor: “Rapid warming well above the global average makes the Arctic hydrates particularly vulnerable to climate change.”

    Archer clearly acknowledges the vulnerability of methane hydrates to thawing in response to rising Arctic temperatures. Accelerating ice loss can only accelerate that temperature rise through the albedo effect, so we should be regarding the potential loss as an imminent and urgent crisis. Ira Leifer, from the Marine Science Institute at UCSB, describes the mechanics of a “runaway” methane feedback: “A runaway feedback effect would be where methane comes out of the ocean into the atmosphere leading to warming, leading to warmer oceans and more methane coming out, causing an accelerated rate of warming in what one could describe as a runaway train.” [9]

    Given that this “train” would be one way and feed upon itself in a way that might well be unstoppable by humanity, it would seem to be a classic case where the precautionary principle should be invoked as a justification for action.”

    ….

    R.Gates, who recently re-posted this at Neven’s Arctic Sea Ice site, added:

    “With the Met Office still officially saying 2030 for an ice free Arctic, Dr. Wadhams is quite specific in thinking 2015 or 2016. Now, who seems more likely to be correct? And if Dr. Wadhams is more correct on that score, who are you going to believe– those who say methane is not an immediate threat, or Dr. Wadhams who thinks it is very much so.

    Just food for thought.”

    http://neven1.typepad.com/blog/2012/09/signs-of-arctic-climate-change.html

    (For the record, I am not in agreement with the pro-geo-engineering folks that these positions seem to sometimes be connected with. I just want to get as clear a view of what the range and relative danger of the various imminent threats we face may be, and this takes active discussion, and especially input from such authoritative figures as Wadhams.)

  45. 245
    Hank Roberts says:

    wili, you know what we can do about the methane threat, right?

    Burn less fossil fuel. It’s really as simple as that.

    There’s no alternative that makes sense.

    Wadhams is much in the news lately, and does have some publications that show up in Scholar; here’s one using submarine data to characterize multiyear ice, saying the ice is changing structure compared to how it behaved in the past; interesting:
    http://www.sciencedirect.com/science/article/pii/S1873965212000084

  46. 246
    DP says:

    The 2030 date for an ice free Arctic must be an obsolete now. In the light of recent events surely the only way it could happen this late is for a dramatic reversal of the current trend. Is there any such thing in the pipeline?

  47. 247
    dbostrom says:

    DP: The 2030 date for an ice free Arctic must be an obsolete now.

    Sure does seem as though events are outpacing our understanding by a long mile, on the human timescale.

    Thing is, short of constructing a seamless, gap-free and correctly functioning physical model of what’s happening we’re reduced to conjecture of the innocent variety. Our present comprehension appears to be at that level despite the sincere best efforts of our most virtuous workers.

    In the postmortem of history our scientists should get due credit for delivering a reasonable and continuously refined span of time in which the Arctic would stop working as we’re accustomed to it, information way better than a sheer guess.

    Our skills for this project were a little too late to emerge. Bummer, but on the other hand it doesn’t really change anything. Hank’s universal suggestion is still valid: stop making C02.

  48. 248
    wili says:

    Hank, yes, of course, I agree. As Jurgen Randers said quite bluntly recently, we have to stop burning fossil fuels, period.

    I don’t fly, rarely drive or eat meat, rarely cool my house in summer and barely heat it in winter, and I’ve been active at nearly every level–neighborhood, family, work, municipal, state, national…–to change policies toward zero-emissions society.

    I still want to have as clear an idea as possible of what we are facing.

    Yes, I’ve seen that thing about change in nature of ice structure. Very interesting, indeed.

    On another front, do we have a clear idea what the major elements were that the earlier models missed when they were predicting an ice-free Arctic Ocean to not show up till at least 2070? (Apologies if this was covered somewhere and I missed it.)

    (reCaptcha: “and worry yet”!)

  49. 249
    David B. Benson says:

    My amateur view on methane release is similar to David Archer’s. Here is my reasoning.

    From
    http://en.wikipedia.org/wiki/File:Five_Myr_Climate_Change.png
    I estimate that methane accumulated in the arctic regions from about 2.6 mya until the first substantial interglacial around 0.4 mya (although some would have been released at the intermediate warming event about 1.1 mya). So whatever could accumulate during a 2.2 million year interval would have been released during that event (interglacial 5?). Then some methane further accumulated until interglacial 4 about 0.325 mya. That is quite a substantial warming, so methane formed even far in the past would be released. What I’m calling interglacial interglacial 3 about 0.24 mya again would release the more shallowly buried of the methane accumulated over the intervening 85,000 years. Once again methane accumulated up to interglacial 2, the Eemian, which was again a strong warming event, evaporating methane buried rather deeply.

    All that is current left is that which has accumulated since the Eemian interglacial, a mere 125,000 years worth; isn’t much there.

    There isn’t much there as far as effects are concerned by looking at the entire history of the Quaternary to notice that the only temperature spikes are the interglacials driven by orbital forcing and it didn’t warm enough to result in massive extinction events, etc.

    However if it warms more now than even during the Eemian (as appears likely, I fear) then deeper methane (if any) will be released. Those who care to might attempt to discover estimates of just how big such a resevoir might be.

  50. 250

    #246 DP “The 2030 date for an ice free Arctic must be an obsolete now”

    If you look carefully at Hadley’s model yearly minima projections. They were really off by way more than 40 years. So my question ever since 2007 super melt…… Have they found out what was wrong with the Arctic Ocean model? Its not embarrassing at all to find out the reasons of the sea ice minima model failure. In fact by finding out why we come to a better understanding of climate and weather. Does it take 5 years before they can find the flaws? 5 years is a lot of runs or computer time…. Surely they must have made some progress?


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