Gavin on why the Arctic methane alarm is implausible

Guest Essay by Dr. Gavin Schmidt, NASA GISS

Yesterday, I carried this story: An alarmist prediction so bad, even Gavin Schmidt thinks it is implausible

Today, on Twitter, Karel Haverkorn asked why. To his credit, Dr. Schmidt replied on Twitter in multiple tweets with an essay of bullet points. This marks the first time Dr. Schmidt publishes on WUWT, as well as the first essay here ever composed on Twitter.

Gavin_CH4_tweet

I’ve collated his responses below. 

Also the PETM (55 My) and Eocene small events. But no evidence under near-current temps. Outside of quaternary range of arctic temps, many fewer constraints…. Pliocene CH4 may well have been higher (but no direct evidence), multiple sources though…

Some more context on Arctic methane release story to follow:

1) Methane is an important part of the anthropogenic radiative forcing over 20thC. Human caused increase from 0.7ppm to 1.8ppm

2) Methane emissions have a direct GHG effect, and they effect atmospheric chemistry and strat water vapour which have additional impacts

3) Direct forcing from anthropogenic methane ~0.5 W/m2, indirect effects add ~0.4 W/m2. (For ref: CO2 forcing is ~1.8W/m2)

4) natural feedbacks involving methane likely to be important in future – via wetland response to T/rain chng, atmos chem &, yes, arctic src

5) monitoring and analysis of atmos conc of CH4 is very important. However, despite dramatic Arctic warming and summer sea ice loss ….. > …. In recent decades, little change has been seen in atmos concentrations at high latitudes.

6) There are large stores of carbon in the Arctic, some stored as hydrates, some potentially convertible to CH4 by anaerobic resporation

7) there’s evidence in deep time records of large, rapid exogenous inputs of carbon into climate system; leading theory relates this to CH4

8) it is therefore not silly or alarmist to think about the possibilities, thresholds and impacts for these kinds of events

9) in more recent past, there have been a number if times when Arctic (not necessarily globe) has been significantly warmer than today.

10) Most recently, Early Holocene, which had significantly less summer sea ice than even 2012. Earlier, Eemian 125kyrs ago was sig warmer

11) At neither of these times is there any evidence for CH4 emissions or concentrations in excess of base pre-industrial conditions.

12) this means that we are not currently near a threshold for dramatic CH4 releases. (Though we may get there)

13) Much of the concern re dramatic changes in Arctic methane come from one off surveys and poorly calibrated remote sensing

16) But we should not take what-if sensitivity experiments as predictions.

###

Addenddum:

Dr. Judith Curry also thinks the “methane time bomb” is implausible.

http://judithcurry.com/2013/07/25/arctic-time-bomb/

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60 thoughts on “Gavin on why the Arctic methane alarm is implausible

  1. Good old Gav. I knew he was always on our side. He don’t need no weatherman to know which way the wind blows…

  2. For goodness sake or even ffs would somebody please please inform the dorks over at CNN that there are a few folk who have a handle on it. They seem to think it suddenly came upon us, was discovered last week, and is almost certainly the cause of Hurricane Sandy, rain, cold, snow, heat, flood and drought, whatever comes first. I actually cringe every time their weather folk come on and spew utter garbage. My grandma’s corns were a better predictor.

  3. Good job Dr. Schmidt, on this one. Though I wasn’t impressed with an interview you did with NPR a few years ago, your opponent in that particular debate was weak on his atmospheric science, but good on economics. It made for a lousy interview from both sides, as you both had points to make, but couldn’t really point/counterpoint from the same platforms.

    This particular note regarding CH4 is at least hopeful that you may be more pragmatic than I believed. Thank you.

  4. Lots of typos, sloppiness, and ugly abbreviations in those bullet points; are they cut/pasted from somewhere else? If not, no excuse.

    REPLY:
    Sheesh, did you read the head post? Try writing an essay on a cell phone in small chunks and get back to us – Anthony

  5. I applaud him for posting here. I think we should make a concerted effort to remain civil and not pile on. I think the mods should be very strict on this thread.

    Welcome, Dr.

  6. ‘Dr. Judith Curry also thinks the “methane time bomb” is implausible.’ must be true then!

  7. TomR,Worc,MA,USA says:
    July 25, 2013 at 9:46 am

    Ina way I agree with you. But… If you can’t take it don’t dish it out. Over to you – Gav.

  8. Dr. Gavin Schmidt, why does nearly every adjustment of GISS warm the present and cool the past? Is it just because of chance or because you need to maintain the Global Warming scare so NASA can continue to cash in 1.2 bn USD a year in federal Climate Scare money?
    TIA.

  9. “16) But we should not take what-if sensitivity experiments as predictions.”

    Dr. Gavin Schmidt, should we then also ignore the IPCC projections, as they are not predictions?
    If not, why not? Has the theory of Antropogenic Global Warming ever made a prediction? If so, where? Was it confirmed or falsified? If the latter, was the theory reworked? Is there a complete list of predictions of the theory of Antropogenic Global Warming? If so, where?

    TIA.

  10. “But we should not take what-if sensitivity experiments as predictions”

    NOW he say this?!?!?

  11. Dr. Gavin fails to realize, there is a need in some quarters for alarming predictions. If he fails to satisfy this need aggresively enough, others will. Perhaps honest men like Tol would spit on my speculation, but I think there is a parallel between this situation and the business with the 97% consensus paper & the conflict between Nuticelli and Cook on one side and guys like Richard Tol and Mike Hulme on the other.
    Careful when creating monsters, as everyone knows. They’ve got a bad habit of ignoring the commands of their creators after a while and wandering off to devastate the nearby population.

  12. Well, well, well.

    The hyper-alarmists sensing defeat looming ever closer turn up the rhetoric volume to which the merely alarmist respond with catastrophe denial.

    PS: It’s twitter responses, not an intentional WUWT post by Gavin.

  13. Yes well, I’m worried that it might be true. When Al Gore steps in and discounts it, I’ll really be worried it is true.

  14. If Gavin Schmidt were serious about addressing this issue, he would publish his thoughts in a coherent essay on the GISS website versus a incoherent rambling on Twitter…but, alas, he is NOT serious about rebuking his fellow CAGW alarmists.

    (see item #8 above – clearly doesn’t want to ruffle any feathers…)

  15. Now, if he would just use that exact same logic and apply it to climate change……….

    16) But we should not take what-if sensitivity experiments as predictions.

  16. TomR,Worc,MA,USA says:
    July 25, 2013 at 9:46 am (Edit)
    I applaud him for posting here. I think we should make a concerted effort to remain civil and not pile on. I think the mods should be very strict on this thread.

    Welcome, Dr.

    ——————–

    What he says.

  17. Likely just a ‘fell good’ PR campaign as part of a push for the GISS Directorship.

  18. Nice to see a climate alarmist take down an alarm from another alarmist.

    Feels like we’re getting somewhere.

  19. Most people overestimate the capacity for a normal person to overcome the objections of their personal and professional peer groups in the name of “the Truth.” Don’t ever expect someone like Gavin to take a stand that hurts, even if deep down he might want to.

  20. Antarctic Methane (CH4) levels over the last 800,000 years. It is nearly 3 times higher today than at any of these peaks over the time period (which have been as much as +2.5C warmer globally at various times, and at least +8.0C in the Arctic during the last peak in the graph in the Eemian interglacial at 130,000 years ago).

    The individuals who wrote the latest Methane apocalypse story had the fundamental duty to point this out to the readers as it is now Gavin’s duty to try to set the record straight.

    This story is making it into international news reporting and many, many people are going to be left with a fake false impression of reality (and some kids actually lose sleep over these apocalypse musings). If that is what climate science is going to be about, then there should be a law against it or something.

  21. His comments are sound.

    It’s funny how scientists can suddenly think sceptically when the predictions are in a testable timescale.

    I blame String Theory for letting academics think untestable waffle has different rules. They don’t.
    The rules used here are universal for all hypotheses.

  22. John West says:
    July 25, 2013 at 10:23 am
    “PS: It’s twitter responses, not an intentional WUWT post by Gavin.”

    I know, But Dr. Gavin Schmidt will get around to finnd and read this, I’m sure. And he won’t answer me. But he will read my questions. And he will know the answers.

  23. I think a question that needs to be asked more often, is, if we do everything possible to reduce our “carbon footprint” (and our economy goes into a “death spiral”, reducing carbon emissions even more), then how long will it be until we notice a change in the climate?

  24. Thanks Anthony. Dr. Schmidt is most correct in his tweets and it is good to see this acknowledged.

  25. 9) in more recent past, there have been a number if times when Arctic (not necessarily globe) has been significantly warmer than today.

    10) Most recently, Early Holocene, which had significantly less summer sea ice than even 2012. Earlier, Eemian 125kyrs ago was sig warmer

    11) At neither of these times is there any evidence for CH4 emissions or concentrations in excess of base pre-industrial conditions.

    12) this means that we are not currently near a threshold for dramatic CH4 releases. (Though we may get there)
    ————————–

    Early Holocene had recently inundated the frozen tundra of the ESAS plain, this impenetrable barrier to clathrate release is no longer intact, so one cannot deduce that the early Holocene proves anything. The Eemian is not “significantly” warmer but rather is only a few degrees warmer in the arctic, this is equivalent to about 1C of additional warming on a planetary average (the arctic is warming 2.5 to 3.5 X faster and once we reach ice-free arctic summers there will be a step-change in temperatures, a steep rise.

    However, the Eemian was caused by a Milankovich cycle, its process was much much slower in scale, it also had super abundance (compared to today) of land and sea based biomass carbon sequestration organisms, which would be able to mitigate the release of natural carbon on a slower time scale.

    Finally, during the Eemian, there was a natural feedback mechanism that successfully turned the climate before the largest potential CH4 release could occur, this AMOC fluctuation produced a resurgence of the last glacial cycle once we went past the peak of the Northern Hemisphere Milankovich cycle.

    To contend that these events provide any doubt to the potential for catastrophic CH4 release from the ESAS within the next 100-200 years under current warming scenarios is simply wrong.

  26. Dr. Gavin Schmidt. Welcome warm congratulations and a big thank you, for common sense, integrity and scientific approach.on this Arctic methane subject. Please straddle the middle line between warmist and skeptic more often and maybe revisit some of the GISS adjustments for good or bad, now your ex-boss Mr. Hanson has departed.

  27. I see, so the WUWT’ers welcome Gavin into the fold as a trusted source… when he tells them what they want to hear. It’s not a menu, folks — in for a penny, in for a pound.

  28. Dr. Schmidt, welcome to WUWT. Does this mean you’re prepared to also rethink some other things? For example, might you consider ending the rank censorship that takes place under your leadership at your Real Climate blog, and get rid of the Bore Hole? What message did you send when you petulantly and childishly refused to appear on set with a CAGW critic during that John Stossel TV interview a few months back? Have you ever noticed that WUWT has no problem linking to your site and to even more shamelessly propagandistic CAGW sites (like “SkepticalScience”) while you refuse to link to WUWT? What do you think that means?

    Do you appreciate that those you seek to persuade may instead see in your behaviors, editorial choices and control mechanisms, something of a totalitarian, or perhaps even an entire category of study that concludes with certainty before it really understands, that values political aims over objective truth, that’s besot with an intolerant mindset that brooks no criticism? Just askin’ …

  29. Sally people here know it’s not a menu; this is why they call bullshit on bullshit, yet are prepared to acknowledge when someone gets it right even if they are supposedly ‘on the other side’.

    The point is, this is science; and properly conducted there’s no place for taking sides. Science is about data, facts, and empirical truths.

  30. Sally,
    Dr. Schmidt is still a researcher with a PhD. He had to demonstrate some level of either intelligence or perseverance to achieve that. The post above at gives a glimmer that he can follow the empirical data where it leads. Making some speculation on my own part, this may be as was alluded to by ‘Sunup’ that Dr. Hanson’s departure removes some political pressure within NASA-GISS to actually use data to find answers.

  31. Thanks, Anthony. It’s interesting to see his remarks collated as bullet points like that. It reads well.

    I give Gavin high marks for honesty and clarity. I find no fault with his response. It is considered, supported by observations, and is a good summation of what I see as the current state of knowledge about the odds of a catastrophic methane release.

    I would only add that his edifice is built on on sand. The sand in this case is the simplistic idea that the change in temperature of the earth is a linear function of the change in total forcing. I know of no other complex natural system for which that kind of linear input-to-output relationship holds true, and I see no evidence for that in the observations of the climate.

    w.

  32. jai mitchell says: July 25, 2013 at 12:44 pm

    LOL, take it up with Dr Schmidt … they’re his tweets. Mann, you’re shallow !

  33. jai mitchell says:
    July 25, 2013 at 12:44 pm
    “Early Holocene had recently inundated the frozen tundra of the ESAS plain, this impenetrable barrier to clathrate release is no longer intact, so one cannot deduce that the early Holocene proves anything. The Eemian is not “significantly” warmer but rather is only a few degrees warmer in the arctic, this is equivalent to about 1C of additional warming on a planetary average (the arctic is warming 2.5 to 3.5 X faster and once we reach ice-free arctic summers there will be a step-change in temperatures, a steep rise.

    However, the Eemian was caused by a Milankovich cycle, its process was much much slower in scale, it also had super abundance (compared to today) of land and sea based biomass carbon sequestration organisms, which would be able to mitigate the release of natural carbon on a slower time scale.”

    Finally an expert! Please, Dr. Mitchell, I have two questions I need answered:
    – What caused the Younger Dryas?
    – What causes the Bond cycles?

    TIA

  34. Gavin Schmidt,

    Thank you for participating here, albeit initially by a rather abrupt / casual collages of Tweets.

    Please come post articles here that do some heavy lifting in some of your fundamental work related to the basis of significant (i.e. dangerous) AGW from burning CO2. That is a sincere request. It would add to an open and independent dialog about the ongoing issues in the young area of climate science. WUWT has a good venue for it.

    John

  35. Best bit of science I’ve actually read from Gavin without mumbo jumbo malarkey twisting findings into a cagw spin or responses delivered with self superior condescension.

    Actually that bit of cell feed above by Gavin doesn’t deserve the backhanded compliment in my first sentence above. It’s just that Dr. Schmidt has a long cagw religious history he needs to correct.

    One step forward adhering to common sense and science is very welcome! We look forward to more open honest science from you, Dr. Schmidt!

    Especially since I plan to never return to that poisonous propaganda site realclimate.bogus; (bogus is a definitely intended replacement serving as a descriptor rather than an url type).

  36. John Whitman has a far nicer sentiment than mine. My only quibble is that if Dr. Schmidt plans to post a major CAGW leaning bit of science at WUWT; I ask that Dr. Schmidt break the publication into smaller portions so scientific points, data or code receives proper attention without fracturing the thread into a clamorous row.

    Good comment John!

  37. ATheoK on July 25, 2013 at 5:11 pm said,

    @John Whitman on July 25, 2013 at 4:58 pm

    John Whitman has a far nicer sentiment than mine. [. . .]

    Good comment John!

    – – – – – – – – –

    ATheoK,

    Thanks for your kind words.

    I have been critical of Gavin Schmidt, but am enthusiastic about the possibility of his participation in open and independent dialog at WUWT on his scientific works.

    John

  38. Good to see Dr. Schmidt here, even if it’s only as a series of tweets.

    A while back, there was a Scientific American poll – mostly about whether Dr. Curry was a saint or a dupe, but there was a question: “Should climate scientists engage with skeptics or does it just give ‘em credibility.?” This question got an amazingly positive response – well beyond any attempt to “game” the poll. Seems like a good idea to me, and I’m glad to see a little of it here. Us skeptics might help out be being a little more “engageable”.

  39. Just so I can be clear, Anthony: is this actually a “guest essay” by Gavin? I mean, did he consciously contact you and propose it as an essay? If so, fine. If not, well, it would be misleading.

    REPLY: I contacted him, he didn’t object – Anthony

  40. The main absorption peak for methane is at a wavelength of about 3.3 microns. At this wavelength the radiant flux from the Sun is of the order of 85 times greater than that from an Earth at 15 degrees Celsius. This must result in about 85 times as much infrared radiation from the Sun, at 3.3 microns wavelength, being sent back into space by the absorption and re-radiation from methane molecules in the upper atmosphere as could be re-radiated into the lower atmosphere for infrared radiation sourced from the warmed Earth. Furthermore as the Sun’s radiation is re-emitted into space before reaching the Earth’s surface, that surface will be colder than the assumed 15 degrees Celsius and thus will release even less radiation at all wavelengths.

    To conclude, more methane in the atmosphere means a colder Earth, not hotter.

  41. Titan has a 5% methane atmosphere. How much warmer should it be then say… a neighboring moon that has no atmosphere?
    Fortunately there is a neighboring moon. It’s called Hyperion. And better, Titan and Hyperion have almost matching albedo which means pound for pound they both absorb and convert the same amount of sunlight into infrared (ie:surface temperature).
    So we can do a direct comparison between their surface temperatures and the difference will be the global warming potential of methane. Right?

    According to the wikipedias, Hyperion’s surface temperature is 93 K (−180 °C)
    TItan’s surface temperature at the Huygens crashsite (equator) 93.7 K (−179.5 °C).

    http://en.wikipedia.org/wiki/Hyperion_(moon)

    http://en.wikipedia.org/wiki/Titan_(moon)

    Where is it? Where’s the warming?

    Bevan”s comment @ July 26, 2013 at 12:17 am, I’m guessing is based on the physical chemical properties of methane as produced in a lab here on Earth. I don’t think it’s an accident that against all reports of methane as a GHG by people such as Gavin Schmidt, when it’s observed in the wild places of our solar system, methane acts in the manner described by Brevan.

  42. I think this:

    http://scottishsceptic.wordpress.com/2013/07/25/wikipedia-warming-becomes-climate-change/

    has alot to do with the resent slight tilt toward reality by Gavin Schmidt.

    Scottish says that “…the number of active editors (@Wikipedia) have plummeted, those who do contribute clearly have no knowledge of the climate.

    They haven’t enough voluntary manpower to police their global warming hokem at wikipedia anymore. That will flat change a moonlighting NASA computer tech’s religion, I think.

  43. 9) in more recent past, there have been a number if times when Arctic (not necessarily globe) has been significantly warmer than today.
    10) Most recently, Early Holocene, which had significantly less summer sea ice than even 2012. Earlier, Eemian 125kyrs ago was sig warmer
    =============
    Early Holocene, 8k years ago, a drop in the bucket time wise. A much warmer Arctic, but the polar bears survived. A time when the first evidence of agriculture and the beginnings of our modern civilization first appear. Yet we continue to hear fantasy stories about how bad warming would be for civilization.

    Contrast that to 80 thousand years ago when genetic evidence shows that humans were all but wiped out during the ice age that followed the Eemian. Genetic markers show that the worldwide human population was likely reduced to a few hundred individuals. Will we fare any better if we are not able to prevent the next ice age? Perhaps the only thing that will prevent our mass extinction is the CO2 from fossil fuels.

  44. jai mitchell says:
    July 25, 2013 at 12:44 pm
    Finally, during the Eemian, there was a natural feedback mechanism that successfully turned the climate before the largest potential CH4 release could occur, this AMOC fluctuation produced a resurgence of the last glacial cycle once we went past the peak of the Northern Hemisphere Milankovich cycle.
    ===============
    What was that natural feedback mechanism that “successfully” turned the climate, even though CO2 levels were significantly increased during the Eemian as the oceans warmed? Though it is hard to see how one can call turning the climate back into an ice age as “successful”.

    Your agenda is clear. You see a return to ice age conditions as “natural” and thus a good thing. The collapse of civilization and the billions of deaths that would result worldwide are the solution to overpopulation. It would be sunny every day, with forests of unicorns and butterflies.

    Funny how there was natural feedback in the Eemian to counter the rising CO2 from the warming oceans. We are told by climate scientists that most certainly know better, that rising CO2 will lead to natural feedback due to increased moisture that will increase the warming and prevent a return to ice age conditions.

    Now we hear that the natural feedback mechanism works to counter the warming due to rising CO2 as occurred in the Eemian. Someone needs to tell the IPCC and the climate modellers they have it all wrong.

    Like the say, the truth goes on forever, but a lie always has an end. The truth has no contradiction. A lie always at some point contradicts itself, revealing that it is a lie.

    The natural feedback mechanism that allowed the Eemian to return to ice age conditions in spite of rising CO2 levels directly contradicts the hypothesis of positive water feedback as theorized by the IPCC, climate science and the global climate models. The contradiction reveals the lie.

  45. 7) there’s evidence in deep time records of large, rapid exogenous inputs of carbon into climate system; leading theory relates this to CH4

    8) it is therefore not silly or alarmist to think about the possibilities, thresholds and impacts for these kinds of events
    <<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>
    It’s quite a stretch: from “evidence” to “leading theory” and, from thence a claim of robust science which is “not silly or alarmist”. Gavin Schmidt needs to do better than this if he is to convince a scientist who likes good, old fashioned scientific rigor (and there are still lots of these around). But, scientific rigor is the first casualty in this climate business.

  46. We’re about 11k years into the current interglacial, about the fifth one in the last 400k years, and that’s way past the average length of the peak of those interglacials. If The Eemian and the early Holocene and apparently interglacials in general are good enough evidence of the pattern of climate change for the warmists why aren’t they more concerned with our impending descent into another glaciation more than the potential warming over the next hundred or more years? That’s a 10-11 degree centigrade drop we’re staring at. A few degrees rise in temperature is merely a stay of execution.

  47. Bevan says:
    July 26, 2013 at 12:17 am
    “The main absorption peak for methane is at a wavelength of about 3.3 microns”

    Very nice; that should correspond to a color temperature of about 1200 K or 900 deg C.
    ( Wien’s displacement law)
    Methane should be great in capturing and re-emitting radiative heat of furnaces then.

  48. Interesting new evidence the Jai postings are an autoresponder that is biased to respond to comments that don’t follow the alarmist talking points list. Somebody will need to tweak the code to become aware of context as this kind of “friendly fire” is likely to continue. Perhaps there are some climate model coders out there who are having some fun with their faulty algoreisms while waiting for the observed data to get in line with modeled data.

  49. If Jai posts are automated then report the IP to Google spam and other spam block lists. If other websites, blogs and forums report it the responder will get added to an rbl list and posts blocked by services such as http://www.projecthoneypot.org/

    KPO:
    Why not stop watching CNN? I only watch them in airports.
    —-
    Or watch it with the sound turned off, then you can laugh at the faces they pull.

  50. Man Bearpig says:
    July 26, 2013 at 12:11 pm
    “If Jai posts are automated then report the IP to Google spam and other spam block lists. ”

    Nonsense. He once even answered me.

  51. An interesting quote from Neven on the weather for future reference Anthony

    That’s 10 days from now. The forecast will change.

    Posted by: Neven | July 24, 2013 at 13:38
    The Naming of Arctic Cyclones | Main | Arctic time bombs »
    Second storm Gac2013There’s another storm brewing in the Arctic,

  52. @tom 9.39 am
    The only reason the put CNN on in airports is that by the time you finished watching you haven’t thought about flying you are to p’d off

  53. papertiger says:
    July 26, 2013 at 2:48 am

    Thanks for the wonderful data from the moons of Saturn.

    On Gavin’s engagement here, however indirect, please reply if you feel slighted, Dr. Schmidt, but I quit commenting on your RealClimate, which you maintain at my tax dollar expense during “working” hours, when, in response to another commenter’s request for the names of scientists who questioned the “consensus, settled” conclusion of Warmunistas, I provided dozens, you, Dr. Schmidt, told me that such lists weren’t allowed.

    Is bureaucrat Gavin now trying to appear more like a real scientist, given the looming possibility of a return to the scientific method at GISS?

    FU, Dr. Schmidt, & the nag you rode in on, namely the raving lunatic Dr. Hansen.

  54. @jai Mitchel

    “To contend that these events provide any doubt to the potential for catastrophic CH4 release from the ESAS within the next 100-200 years under current warming scenarios is simply wrong.”

    ++++++++++

    The key word there is ‘scenarios’. The ‘scenarios’ are bunk. That is what the graphs show. There are not believable ‘scenarios’ and thus no believable ‘potential’ nor ‘catastrophic CH4 release’.

    I have read a number of your posts recently and they amaze. Your unique parascientific approach is likely to mislead. Without getting into details, please try to keep up:

    The models are junk,
    Their predictions are bunk.
    The ship of methane catastrophe has sunk.

    Perhaps there is a ‘potential catastrophe’ were the world warming ‘as predicted’. It is not, and won’t.

    ‘Potential catastrophe’ averted.
    Rejoice, for heaven’s sake.

  55. jai mitchell says:
    …………….
    Again, I will point jai mitchell here. He seems to be living in fairy wonder land. An Arctic ocean that is ice free for more than a millenium in summer is not in better shape than todays Arctic sea ice.

Comments are closed.