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Unforced variations: July 2015

Filed under: — group @ 3 July 2015

This month’s open thread. How about a focus on cimate science this time? Data visualizations anyone?

273 Responses to “Unforced variations: July 2015”

  1. 1

    Has anyone taken a look at my RCM tutorial? I’d be grateful for any input.

    http://bartonlevenson.com/Climatology.html

    Click on the link that says “RCM Tutorial.”

  2. 2
    patrick says:

    Solar Impulse Hawaii landing briefing has begun. Streaming here, choose your widget:

    http://www.solarimpulse.com/widget-energy

    I like the energy widget. RTW is default. Pilot emotions widget is still connected.

  3. 3
  4. 4
    patrick says:

    The data visualizations at the top are a great tool brilliantly executed, an example of moving the bar in climate science communication, involving data and design. I note Methodology. And the Acknowledgements:

    Many thanks to Kate Marvel and Gavin Schmidt of NASA-GISS.

    Gavin’s tweets on this are very helpful in particular–and a great observation of what’s going on:

    https://twitter.com/ClimateOfGavin/status/614397288614637569

    Data visualization, animated and not, is part of a developing genre that includes data sonification and animations of all sorts. NASA has played a leading role in making it an increasingly effective tool.

  5. 5
    patrick says:

    Solar Impulse Day 5 Briefing I:

    https://www.youtube.com/watch?v=cBj4AXtqwXQ

    Prince of Monaco talks to pilot. The control room is in Monaco. Batteries. Weather. And especially: flight profile for landing.

    That’s now, on the livestream.

  6. 6
    O says:

    BPL, I skimmed through it. Quite a lot of work went into this. I wouldn’t be too concerned about fit to
    a standard atmosphere, it is a 1-D model, with constant sunlight, whereas the real atmosphere is many coupled 1-D models, and the solar input is time and space variable. I once did a highly simplified 1-D model (no clouds, simple “grey opacity” but had day/night variation. The lower atmosphere tends to convect during the afternoon/evening, but the lowest layers cool at night, leading to a low level inversion. I suspect this diurnal variation might be important for getting the details right. Add in different 1-D models representing different latitude bands. How to couple the latitude models?

  7. 7
    Steven Emmerson says:

    This is the third time in a week that I’ve encountered that animated Bloomberg graphic. Either I’m in an echo chamber or it’s having an impact.

  8. 8
    Alastair McDonald says:

    What do you think about this interview with Prof Peter Wadhams?
    https://www.youtube.com/watch?feature=player_embedded&v=8xdOTyGQOso
    I agree with him that, in the main, climate scientists seem to be in denial regarding the fate of the Arctic sea ice and its affect on global climate :-(

  9. 9
    Hank Roberts says:

    This suggests a rather interesting solution to our overshoot problem:

    https://upload.wikimedia.org/wikipedia/commons/f/f1/Human_welfare_and_ecological_footprint_sustainability.jpg

    Note that a country meeting the minimum criteria for sustainability could also be viewed as a country highly susceptible to stripmining, since sustainability requires leaving a whole lot of resources untouched because you’re “living off the interest” rather than “eating the seed corn” AKA borrowing against the future.

    Hmmmm.

  10. 10
    patrick says:

    “I was at the UN Monday and we were talking about climate change.” –Solvay CEO

    “This is not just an achievement in energy. This is an achievement in clean tech–and that’s why we have so many people supporting us.” –Bertrand Piccard

    “It [the 5-day fuel-less flight] was like a retreat.” It’s not just the aviation [that is an experiment in energy management], it’s a chance for me to experiment with managing my own energy. –Andre Borschberg

    They are big thinkers and perfect spokespersons with fresh ideas. They will surprise you.

    The flight of the Solar Impulse is particularly historic because of the connection between Piccard’s family and Solvay, and because of the association of Solvay with science. Just check the now-interactive photo here from the 5th Solvay Conference, and select your scientist:

    https://en.wikipedia.org/wiki/Solvay_Conference

  11. 11

    O 6,

    Thanks for looking at that for me. You may be the only person who did.

    For a three-dimensional model, you’d need to add air motion across columns, and conserve mass, energy, momentum, and moisture. It gets complicated.

  12. 12
    Joe says:

    The Bloomberg graphic is excellent! I have a question about the orbital influence on the mean surface temperature. What surprised me about the data was that there were year-to-year fluctuations. As a non-specialist in the field, I’m cognizant of the role of eccentricity, obliquity and precession. For such a short time interval as shown in the data, I would have expected a flat line very close to zero. Instead, one can see a 40 year cycle even in the time series. An FFT shows that there also 4, 26, and 11 year cycles as well. Even though these effects are very small, they are larger than I would have thought. I’d appreciate it if someone could give an overview of why the orbital effects aren’t zero. Thanks!

    [Response: The results shown are the average results of 5 simulations where the only thing changing is the orbital forcing (or the volcanoes, or GHGs etc.). That means that the natural, internal variability of each individual run (‘the weather’) is included. In the limit of an infinite number of simulations, the weather would exactly cancel out and you’d get the smooth (slow) change you expect, but with a finite sample, there will also be some residual weather noise. For a strong driving function (like GHGs over the 20th C, or for volcanoes), the signal is much stronger than the residual weather noise, and so you can see the change clearly. For the smaller forcings (like orbital), you can’t see it (in the surface temperature metric at least). – gavin]

  13. 13
    Russell says:

    While trying to deny the reality of present warming, Mark Steyn has discovered convincing evidence of The Medieval Cooler Than Now Period.

  14. 14
    Omega Centauri says:

    BPL at 11. Sorry my handle got chopped off, in my previous comment. I hope others are at least taking a look at your work, there is quite a lot there.

    Back to my ideas on deficiencies of 1-D models: I already mentioned having simply averaged the solar input. Imagine the simplest possible time varying model, we have a black surface which directly faces its star. Fifty percent of the time the starlight is occulted by some mechanism. I choose units such that the Steffan Boltzmann constant is unity, as is the average solar intensity. The solar intensity when we can see the star is two. Assume that the surface has negligible thermal storage capacity. When lit the temperature is the fourth root of 2, when in the dark it is absolute zero. Average the two temperatures, and the result is a tad under .6, whereas if you used the average intensity you would expect a temperature of 1. So at least in the extreme case, the surface average is much lower than what one would expect from simply averaging the illumination intensity.

    Now consider your 1-D atmosphere: during daytime (or at least the afternoon), the temperature profile will follow the lapse rate up to a given height. At night, the radiative balance at the surface is strongly negative. If there is no wind, the only sources of heat at the surface are conduction from
    stored heat in the ground, and downwelling IR from the sky. The radiative imbalance will be substantially negative like roughly (100-200 watts/meter**2). So the ground and the lowest layers of the atmosphere cools to well below the lapse rate, whilst the mid levels of the atmosphere will barely notice the lack of sunlight. So the actual nighttime surface temperature will substantially decouple from the temperature of the bulk of the atmosphere. Now consider a windy night, stress from wind sheer can be tapped by turbulent eddies, maintaining some vertical mixing of the air, so the temperature of the lower atmosphere will be much closer to the adiabatic lapse rate than the windless example. The standard atmosphere will tend toward a weighted average of these two cases (plus effects due to transport from neighboring sites). I can’t see any way from first principles that these important effects can be incorporated into a 1-D model. So there are real limits to the utility of such models, adding physics will not be able to overcome these limitations.

  15. 15
    patrick says:

    Here’s the Solar Impulse Hawaii landing video. Bertrand Piccard, who will pilot the Hawaii to Phoenix leg of the global flight is at 1:57:09. Both pilots together are at 5:07:50:

    https://www.youtube.com/watch?v=xvmX8SAzfZM

    “The project was carried by the people who believe that that’s the way to go. …The most important decision was the decision to leave [take-off from Nagoya].” –Pilot Andre Borschberg

    The entire flight and the years of development of the aircraft and team is a paradigm of cutting-edge energy production and energy management.

    The flight is directly connected to the FutureIsClean social media campaign to act for a clean future at COP 21 the UN Climate Change Conference.

    http://futureisclean.org/

  16. 16
    John Mashey says:

    Yes, visualizations are excellent. I add that to my favorites, including NOAA’s excellent History of atmospheric carbon dioxide from 800,000 years ago until January, 2014.
    The “breathing Earth” effect is especially striking.

  17. 17
    Kurt says:

    Gavin, thanks for the answer to Joe’s question about orbital forcing and the simulations used in the Bloomberg infographic. That had been puzzling me as well.

  18. 18

    #8 Alastair,

    I disagree with Prof Wadhams, I had thought his entry for SIPN was a benchmarking exercise, from that recent interview I now think he’s serious. I find this rather hard to understand, current conditions do not support a massive loss this year. It is hard to see how such a radical change in winter volume that would permit a crash will happen within a few years. I very much doubt it will happen this decade, I have a bet for £1000 with someone that Cryosphere Today won’t go below 1M km^2 for any day by 2022.

    Following the 2010 volume loss event, PIOMAS April volume for the Arctic Ocean stuck at around 19k km^3 in the years 2011, 2012, 2013, 2014. This is the volume expected for a nominal sea ice thickness of around 2m thick, and 2m thick is about the thickness expected for ice thickening from open water over current levels of winter cold.

    What I’m pretty sure is happening is that the thickness-growth feedback is opposing the long term trend of loss of sea ice, and leaving aside the current increase in volume (which is weather driven), we face a slow transition to a seasonally sea ice free state, not a fast crash.

    More detail in this blog post.
    http://dosbat.blogspot.co.uk/2015/05/the-slow-transition.html

  19. 19
    Pete Best says:

    The Peter Wadham video here (https://www.youtube.com/watch?v=p-qdbICw2f8) is a good on and a long one. He is Cambridge UK so I guess has the experience and the gravitas to be listened to although on occasion he has been deemed somewhat fringe on these forums at times.

  20. 20

    Omega: Average the two temperatures, and the result is a tad under .6, whereas if you used the average intensity you would expect a temperature of 1. So at least in the extreme case, the surface average is much lower than what one would expect from simply averaging the illumination intensity.

    BPL: The difference is from the fact that most of the Earth is tilted away from the sun due to planetary curvature, so receives less illumination per unit area by Lambert’s cosine law. You’re starting from a plane that is flat-on to the sun. To get the average on a hemisphere, you’d need to weight by latitude, keeping in mind that the area of a latitude band is proportionate to 1 – sin θ where θ is the mean latitude (the approximation is better the narrower the bands).

  21. 21
    Hank Roberts says:

    Dr. Wadhams will eventually be correct, but apparently again not this year.
    See Stoat on the subject

  22. 22
    Mike says:

    I watched the Wadhams video and found it pretty alarming, so it’s good to hear that he is considered to be “on the fringe” on this website.

    It seems like it would be a bad thing to have an ice free arctic because it would then lead to the methane release described in this article:

    http://www.nature.com/scitable/knowledge/library/methane-hydrates-and-contemporary-climate-change-24314790

    http://www.nature.com/scitable/content/ne0000/ne0000/ne0000/ne0000/24332092/NatureKnowledge_figure-01-1-_a_1_2.png

    If the ice free arctic is set to occur as a slow transition rather than an abrupt crash, that would be greatly appreciated because I am getting old and might expire before the ice cover.

    I have been a little worried about the kelvin waves, the warm weather blob in the Pacific, etc, but am reassured by Chris Reynolds @#18.

    Chris, do you have earlier predictions regarding ice mass loss and how those predictions and models have turned out versus the observations? It would be great to know that we will not need to embrace geo-engineering as Wadhams feels will be needed to reduce the CO2 in the atmosphere.

  23. 23
    Chuck Hughes says:

    Chris Reynolds:
    July 4th, 2015 at 2:38 AM
    #8 Alastair,
    I disagree with Prof Wadhams, I had thought his entry for SIPN was a benchmarking exercise, from that recent interview I now think he’s serious. I find this rather hard to understand, current conditions do not support a massive loss this year. It is hard to see how such a radical change in winter volume that would permit a crash will happen within a few years. I very much doubt it will happen this decade, I have a bet for £1000 with someone that Cryosphere Today won’t go below 1M km^2 for any day by 2022.”

    I don’t think we’ve ever accurately predicted anything happening as soon as it has. It seems to me we’re always off by orders of decades as to how soon and how bad things will get. Of course I am not a scientist but the only thing keeping the ice from completely disappearing in the Arctic is Greenland. From the satellite images I’ve looked at Greenland is keeping all the ice from washing out into the North Atlantic. We’re in an El Nino event, there’s a lot of heat in the Pacific ocean that seems to be making its way Northward. I just think that if it weren’t for all that land keeping the Arctic ice in place it would already be gone. Of course there’s area, volume, extent and quality so it depends on what paramaters we’re talking about. At some point in the near future I think for all intents and purposes the Arctic Ice may as well be gone for all the good it will be doing. I guess some ice is better than no ice but after a certian point I doubt it will matter. Just my opinion.

  24. 24
    Jef says:

    There will always be amazing innovations profiled in the MSM which allow the top 10% or whatever % to live like Gods on earth.

    The reality is we ALL live on 1 finite planet and we are at a point in history where everyones gain is everyones loss.

  25. 25
    Omega Centauri says:

    BPL. The point of my extreme example was not be be realistic, but to illustrate that time averaged surface temperature with time varying illumination can significantly differ from what you’d expect from using average illumination. With more realistic illumination profiles the effect won’t be quite as strong, but could still be significant. I’m also trying to make the point that 2D and 3D effects can
    be necessary for some types of important physics to arise, ignore these effects and don’t be surprise if the best possible 1D model only poorly matches the standard atmosphere.

  26. 26
    James McDonald says:

    Kate and Gavin, thank you for the excellent visualization. I’ve linked to it in several discussions online.

    I do have a quibble, though: it is hard to see the methodology or data sources, making it difficult to respond to challenges to it.

    I wasn’t aware, for example, that you added weather from 5 simulations.

    Did I miss something obvious (in which case, mea culpa), or is there a background page somewhere explaining all of it?

    Thanks in advance…

  27. 27
    Killian says:

    #9 Hank Roberts said This suggests a rather interesting solution to our overshoot problem:

    https://upload.wikimedia.org/wikipedia/commons/f/f1/Human_welfare_and_ecological_footprint_sustainability.jpg

    So, somebody was questioning my 10% of current consumption estimate, which would put us dead center of the sustainability criteria.

    Some of us already know about Cuba… and the role Permaculture played/plays there. Crashed after fall of Sov. Union, but death rate didn’t increase. Hmmm…. despite avg. weight falling 20 lbs. for a few years… Hmmm…

    But what the heck do they/we/I know?

  28. 28
    Marco says:

    Pete Best #19, I think the figure below shows why Wadhams is considered not just “somewhat fringe”, but just plain “fringe”:

    http://neven1.typepad.com/.a/6a0133f03a1e37970b01b7c7a6bef4970b-pi

  29. 29

    My drought paper has been accepted.

    “Accuracy Check on Predictions of Near-Term Collapse” will appear in the British Journal of Science.

    This will be my third article in a peer-reviewed science journal, and the first dealing directly with climate science.

  30. 30

    Worst possible news: I just learned “British Journal of Science” is a scam journal. Boy, do I feel stupid.

  31. 31
    Killian says:

    So, what’s wrong with my math? Results seem counter-intuitive, but everything seems correct. To get an estimate of SLR at 5- and 10-year doublings, I used the following equations in Excel, then repeated 85 times to equate to SLR for 2100 CE (brackets show the actual starting numbers):

    10-year doubling
    =SUM((B3[3.3]*0.061605)+B3[3.3])

    Result: @ .5 meters total.

    5-year doubling
    =SUM((B3[3.3]*0.127002)+B3[3.3])

    Result: @ 85 meters total.

    I know exponents are powerful, but good lord! Seems 84.5 meters difference from just 1 doubling of the doubling? What am I doing wrong?

  32. 32
    Killian says:

    Ah, re; SLR above, should add that I divided result by 1000 to get .5 and 85 meters. Realized I should just start with 0.0033. :-)

  33. 33
    Richard Mercer says:

    I was wondering if Real Climate or someone else has a post critiquing the following article and paper. I came across a link to it in the comments section of a Facebook post by Skeptical Science.

    Posted at The Hockey Schtick denier blog.
    ( I consider a site that has a post titled – “The Pope’s Encyclical Exposes the Real Agenda Behind Global Warming”, as a “denier” blog.)

    It refers to the following paper, Published online in Atmospheric and Climate Sciences, Dec. 2014 by

    “Do Increasing Contents of Methane and Carbon Dioxide in the Atmosphere Cause Global Warming?”
    ——

    New paper finds increased CO2 or methane will have ‘essentially no effect’ upon global temperature or climate

    “A new paper by USC Professor Emeritus of Geology, Dr. George Chilingar (with three co-authors), finds that increasing levels of the greenhouse gases CO2 & methane will have “essentially no effect” upon global temperatures or climate.”

    [Response: Chilingar’s ‘work’ is a total nonsense. He doesn’t have the faintest clue how radiative transfer works – this has come up previously (and I think even featured in Randy Olson’s GW mockumentary ‘Sizzle’). – gavin]

  34. 34
    Alastair McDonald says:

    Chris (#18),

    I learnt the hard way that a bet on Arctic sea ice is only a measure of one’s confidence in an event, not its certainty :-(

    AIUI, the PIOMAS is based on a model, not on measurements, and so may not be accurate. I find it hard to believe that the thickness of the ice has steadily increased since 2012 so I distrust the PIOMAS estimates. Of course, after a large melt such as 2012 there will have been a lot of fresh water about, which would have frozen more easily. I am guessing that the 2012 fresh water has now been flushed out through the Fram Strait. See this map of the drift track of the buoys http://psc.apl.washington.edu/northpole/DriftTrackMap.html

    Recently it has been argued that July melt ponds are good indicators of September ice extent and this picture from the North Pole webcams seems to suggest that the melt ponds are forming stongly this year: http://psc.apl.washington.edu/northpole/NPEO2015/2015cam2_1.jpg and http://psc.apl.washington.edu/northpole/NPEO2015/2015cam1_1.jpg So I suspect there could be another record like in 2007 and 2012

  35. 35
    flxible says:

    > “Some of us already know about Cuba… and the role Permaculture played/plays there. Crashed after fall of Sov. Union, but death rate didn’t increase. Hmmm…. despite avg. weight falling 20 lbs. for a few years… Hmmm…”

    Some of us know the actuality of the Cuban situation, Urban Agriculture born of desperate hunger, NOT permaculture, and still quite dependent on imported staples, with the reason folks there lost weight due to having a very limited diet. . . Hmmm indeed.

  36. 36
    John Mashey says:

    BPL: sorry to hear that
    All: Always check at Jeffrey Beall’s Website, which has good lists of dubious journal’s and publishers.

  37. 37
    Killian says:

    #34 Alastair McDonald said AIUI, the PIOMAS is based on a model, not on measurements, and so may not be accurate. I find it hard to believe that the thickness of the ice has steadily increased since 2012 so I distrust the PIOMAS estimates.

    I used to love PIOMAS, but IIRC they redid their algorithm a couple years back and the numbers have seemed inflated since then. To wit, while the raw numbers for 2015 right now are pretty high overall – meaning in the 2013-2014 range, looking at the ice up close and personal-like tells a different story. I see weakness over virtually the entire ice mass, and certainly over quite a bit of it.

    Much of the ice is what I like to call “popcorn,” i.e., clearly identifiable clumps of ice floes amidst “mush,” i.e. grayish stuff clearly not stable ice. Overall, looks like popcorn in thick soup.

    185th day 2015

    185th day 2014

    Look at the top third of the images, particular the upper left. There is considerably more weakness in the ice than last year, yet extent, area and volume are in the range of ’13 and ’14? I’m not buying it. Working on my analysis now. At the end of the day, we all know transport via Fram is the single biggest short term variable. It was high till about three weeks ago and has been reletively week the last three weeks before getting a bit of a push this last week for a few days. If the export returns to spring levels, could see a loss of a lot of ice.Given the integrity of the ice is much in question, could be a very interesting summer.

  38. 38
    Digby Scorgie says:

    Did Nostradamus predict climate change? I don’t know if this qualifies as a “focus on climate science”, but I have a story about it that readers might find amusing, that is, if you like your humour black. (That reminds me: Please humour my British English.)

    Nostradamus published his enigmatic oracles over four centuries ago. They have intrigued and baffled people ever since. I’ve always considered them no more than an interesting curiosity. And it was out of sheer curiosity that in the early 1980s I bought a slim booklet by Geoffrey Houghton-Brown that ventured a history of the period from 1981 to 1999, as deduced from the oracles. I reckoned that 20 years would not be too long to wait in order to judge the accuracy of this future history.

    Well, as you have no doubt already guessed, the predicted history turned out to be hilariously at odds with the reality. But that is not the end of the story. In a final section of his booklet the author presents a few interpretations of oracles that purport to refer to events beyond the middle of the twenty-first century. They made absolutely no sense to me at the time and probably not to the author either. Now they do. They read suspiciously like commentary on the likely consequences of unabated global warming. The following are the relevant quotations:

    “Before the universal conflagration shall happen so many great inundations that there shall scarcely be any land left that shall not be covered with water.” “The world shall be so diminished, and the people so few, that there will not be enough found to till the ground.” “Also, before and after these inundations in many countries there shall be such scarcity of rain, and such a deal of fire, and burning stones falling from the skies, that nothing unconsumed shall be left, and this shall happen a little before the great conflagration.” There will then be “a thousand years of peace”, after which “the wars will begin again”.

    Ouch! Of course, I’m not suggesting that anyone should take this story seriously. Nevertheless, if those who reject climate science cannot abide the scientific method, perhaps they’ll be more amenable to ancient mysticism. The message, after all, is the same in both cases.

  39. 39
    Chuck Hughes says:

    Dr. Wadhams will eventually be correct, but apparently again not this year.
    See Stoat on the subject – See more at:

    At what point does it no longer matter if there’s an ice cube left in the Arctic? Will our situation change drasticly from what it is now if we go for a week or two without ice in the Arctic, or is it just that it will be a landmark event? I’m sure there are a lot of people who would like to accurately predict the Arctic’s demise. I even noticed that someone had bet $10,000 as to when it might happen. I think we all know it will happen eventually so why does it matter if it’s this Summer or next? Aren’t we screwed either way?

    A better bet would be ‘when will humans decide to react to the situation?’.

    Any takers?

  40. 40
    James McDonald says:

    Re: 26, nevermind. I found the methodology section by scrolling down past the bottom of the last slide.
    (I’m not sure why that didn’t work the first time I tried it, but it does now…)

    All is good.

  41. 41
    jgnfld says:

    Unless there is a lot of ejection of multiyear ice through the Fram Strait, I think you’ll find it unlikely that the NW Passage will be all that open this year. There is a lot of thin ice elsewhere. Most people at the Sea Ice Prediction Network are predicting a min around 5 million km^2. Low, but not record low. See http://www.arcus.org/sipn/sea-ice-outlook/2015/june

    Prepare to see a lot of “arctic ice recovery” articles this fall in denier blogs. Joy of all joys!

  42. 42
    wili says:

    Concerning Wadhams and ‘fringe,’ it should be kept in mind that sometimes the ‘fringe’ is right. If anyone had predicted beforehand the kind of losses seen in Arctic sea ice extent and area in 2007 that actually occurred, they would have been way beyond ‘fringe’–none of the models at that point were anywhere close to the reality that quickly ensued.

    I would hope that here, at least, we would avoid disrespecting scientists of longs standing because we don’t agree with their learned judgments. Let’s leave that for the denialist sites, shall we?

    Wadhams has about as much and as long experience observing Arctic sea ice as anyone on the planet. I take his point to be mostly qualitative and not (yet) quantitative…the _nature_ of the ice he seas in the Arctic now is just so far different than anything that used to exist dominantly there before, that he thinks that we are essentially a weather event (a few weeks of very warm weather with lots of sun…) away from a virtually (under 1 million k^2) ice free Arctic sea. I personally find that unlikely, but I’m not going to dismiss this scientist’s judgment out of hand (much less disrespect the man himself) just arguing from incredulity. And even arguing from statistics doesn’t quite address his position, since those deal with quantities not qualities of the ice.

    Having said that, on the other hand, the best of the quants folks have been the most accurate in their predictions recently.

    Mike at #22 asked: “Chris, do you have earlier predictions regarding ice mass loss and how those predictions and models have turned out versus the observations?”

    He may not want to blow his own horn here much, but, iirc, it was Chris who by far most accurately predicted the partial recovery of 2013. I gave and give him great kudos for that achievement, and I certainly don’t think his views can be lightly dismissed, especially given that track record.

    But if I may be permitted a third hand (or to return to my prior one), things just recently have looked particularly primed for a rapid melt. Here’s jdallen from neven’s Arctic sea ice forum just a bit ago:

    “As you said elsewhere, Neven, it does look like 2014 with heat; lots of it. I recall last year around this time we were pretty disturbed by how things looked as well, and there was some discussion whether or not we were going to see a 2012 – level melt off. Thankfully (I and others were wrong, and…), weather came to the rescue of the pack.

    “Napkin-back” calculation suggests enough heat left after albedo loss to strip off 6CM of ice a day, more or less. Bottom melt will be bonus.

    Now it’s just grinding out the time – just under half a meter of ice a week, more or less, as long as these conditions persist.

    Lots of ice all across the Arctic is currently below 1.5M in thickness; possibly over half of it.

    If this pattern persists, by the end of July we should see most of the pack as a discontinuous bowl of MYI ice cubes trying to resist the pounding its getting.”

    Time will tell.

  43. 43
    wili says:

    I would love to hear a discussion on the validity (or lack thereof) of the science behind this…troubling conclusion:
    http://theleap.thischangeseverything.org/a-hard-deadline-we-must-stop-building-new-carbon-infrastructure-by-2018/

    “A Hard Deadline: We Must Stop Building New Carbon Infrastructure by 2018”

    This is based on author Steven Leahy’s calculations from this study by Socolow and Davis: http://iopscience.iop.org/1748-9326/9/8/084018/

    What are the chances that we will stop production of all new coal plants, ICE cars and trucks, ff-heated homes and schools…by 2018?

    Or, to quote the title of a recent AGU talk (iirc): “Are We F’ed?”

  44. 44
    Mal Adapted says:

    Digby Scorgie:

    There will then be “a thousand years of peace”, after which “the wars will begin again”.

    A classic theme in science fiction, memorably instantiated by Walter Miller’s A Canticle for Leibowitz. I read it in my early teens, and it has shaped my own vision of humanity’s future ever since.

    “You know the forest tribes? How they venerate their ancestors?”

    The gray eyes of the robber flashed angrily for a moment.

    “We despise our ancestors,” he barked. “Cursed be they who gave us birth!”

    “Cursed, cursed!” echoed one of the shrouded archers on the hillside.

    Not wanting to be cursed by my descendants, I decided not to have any.

  45. 45
    Dan H. says:

    Killian,

    I agree that Fram is the single largest influence. The weakness witnessed over the past few weeks can be attributed to a cold North Atlantic and Greenland. If this persists, it may continue to hinder melting through the Strait, leading to a higher minimum.

    http://nsidc.org/greenland-today/

  46. 46

    #31–I’m a Bear of Very Little Math, but am also always up for a learning exercise.

    Sanity checking, then…

    Famously, doubling time can be “…approximated by dividing 70 by the percentage growth rate.” So:

    Td = 70/Gr

    Which means that:

    Td*Gr = 70, or Gr = 70/Td.

    Actually, 69 is a more accurate approximation, so let’s use it. The growth rates are then roughly:

    5-year: 13.8% annual growth rate
    10-year: 6.9% annual growth rate

    That will let us calculate future growth in SLR increase, given this:

    The formula to calculate future [SLR] given current [SLR] and a growth rate is:

    Rf = Rp * (1 + i)eN

    Where:

    Rp = Present SLR
    i = Growth Rate
    N = Number of Periods

    So the 10-year case is:

    3.3 x (1.069)e85 = ~959 mm, or 0.959 meters.

    The 5-year case is:

    3.3 x (1.138)e85 = ~195,257 mm, or 195.257 meters.

    The numbers are different than in the original comment, but the shape of the result is not, so I doubt anything is wrong with K’s formula. (I suppose the difference has to do with the exact approximations used in the two methods–K’s version looks to use ~6.1% and 12.7%, which I would think enough to account for it.)

    The main takeaway, though, is probably that a 5-year doubling time has little relation to reality in this case.

    “Anyone who believes exponential growth can go on forever in a finite world is either a madman or an economist.”
    – Kenneth Boulding

    http://www.cairco.org/reference/exponential-growth-doubling-time-rule-70

  47. 47
    Chuck Hughes says:

    So you thought you’d seen the last of coal??? Not so fast!

    http://www.vox.com/2015/7/7/8908179/coal-global-climate-change

    How do you turn this around?

  48. 48
    Chuck Hughes says:

    I think this has already been reported here but China’s reported drop in emissions apparently wasn’t accurate.

    http://www.vox.com/2015/5/22/8645455/china-emissions-coal-drop

  49. 49
    sidd says:

    I have been mulling over the rise in blocking events and persistent weather systems. While i tend to believe that Francis and Vavrus are on to something, there is another idea that might (or not) prove fruitful. When studying systems close to critical points there is a phenomenon called critical slowing down. In the classic Ising model this is seen in the relaxation times going to infinity as correlation lengths diverge. It occurs in many other systems as well. A naive measure of a relaxation time might come from the recovery after perturbation. I dont’ see much evidence of this in things like response of surface temperature to volcanoes. Another approach might be to define some kind of correlation length and see if it increases. (Teleconnections, anyone ?) I have thought of attempting the latter, from something like ERA, but i haven’t yet. Also i imagine there are others who have thought this through better than me. Perhaps Tsonis has something.

    The nature of any putative critical point could be a state with a single hemispherical atmospheric cell or a rearrangement of ocean circulation or arctic ice free state or more unpalatable things like a Canfield ocean.

    sidd

  50. 50
    Richard Mercer says:

    Thanks Gavin @33