Unforced Variations: Dec 2013

This month’s open thread. It’s coming to the end of the year and that means updates to the annual time series of observations and models relatively soon. Suggestions for what you’d like to see assessed are welcome… or any other climate science related topic.

354 comments on this post.
  1. Jeb:

    Interested in status of latest estimate of when irreversible tipping point thresholds of various cascading feedback loops of global warming might be exceeded…

  2. John Mashey:

    1) I strongly recommend Bill Ruddiman’s new book, Earth Transformed.

    It’s been nearly 10 years since Plows, Plagues and Petroleum was written, and between further research by Bill, colleagues and various other groups who got interested, I think the book is a very coherent, thorough, makes-sense history of The Holocene.

    It is unusually multi-discplinary, drawing on rice paddy archaeology, agricultural history, charcoal records and various other areas, and is a dandy example of real science in action:
    a) Interesting hypotheses, with some loose ends or inconsistencies. Real scientists push back, hypotheses get refined. Error bars get shrunk.

    b) Other scientists get interested and either gather new data or revisit existing data to see how it bears.

    c) Hypotheses get more consistent and coherent, and in this case tend to do away with “climate has changed naturally for millenia before the industrial revolution” as a sole explanation. In particular, the evidence for human contribution to the Little Ice Age has firmed, as well as effects of human wars on methane emissions.

    Anyway, the book is out and is quite readable. Even at $57 (publisher sets prices, and it has ~200 color photos/illustrations, which costs), it is well worth having or at least get a library to get it. I’m told there will be an eBook version in a month or so, ~$30. Some Amazon resellers claimed to have used copies cheaper, but they were claiming that 8 months before the book came out, so I’m not sure if those are real.

    2) For anyone attending AGU, Bill’s giving the Tyndall Lecture on this, “Early Agriculture: Land Clearance and Climate Effects” GC43B Thursday Dec 12, 2:40-3:40 in Moscone West 2022.

    Actually, that’s a great room to be in, since the immediately preceding talk is:

    GC43E Stephen Schneider Lecture
    Moscone West, Room 2022, 1:40 P.M.
    What Should a Climate Scientist Advocate For?
    The Intersection of Expertise and Values in a Politicized
    Presented by Gavin A. Schmidt, NASA/GISS, New York, USA

  3. MARodger:

    Sean @289 Unforced Variations – Nov 2013.
    You reference your big opus magnus @229 in last month’s thread, the one that is almost 1,300 words long. I have been told by web-meisters that after about 800 words the blog-reader’s eyes begin to glaze over. That is probably the reason (or one of the reasons) why your comment @229 it didn’t precipitate a big(ger) discussion.
    You should try to condense you message down into a more manageable length. Hey, you might then even identify the contradiction within your message.
    And do be mindful that while a troll knows he is being annoying because he does it on purpose, to the recipient of the annoyance there is no difference between a troll and an annoying jerk. Acceptable collateral damage? Well, you are, by your own admission within your comment @229, happy with folk on a site carrying out troll whacking.

  4. Jim Shewan:

    Recently watched a video by Andrew Dessler explaining the pysics of the greenhouse effect. Very clear and easy to understand but I have a question concerning the effect of an atmosphere that warms with height on a hypothetical planet. In this case extra co2 causes cooling. This all all clear enough on the hypothetical planet but I was wondering if this is the reason for the cooling of the stratosphere.

  5. AbruptSLR:

    I would like to see a discussion of the likelihood that factors traditionally viewed as slow response feedback factors (such as Arctic albedo, or high methane emissions permafrost degradation) may actually become faster response feedback factors.

  6. john byatt:

    with the new year model update, any chance including a small section on what impact the Cowtan and Way 2013 findings would have,

  7. sidd:

    Would admin on this site consider making https available ? Self signed cert is fine, don’t have to give the (almost certainly compromised) cert signing authorities any money.

  8. Hank Roberts:

    for Jim Shewan, there are several threads at RC over the years, which the search box (upper right corner) will find for you — people have struggled with this explanation. At one point this was recommended as a good explanation: http://www.atmosphere.mpg.de/enid/20c.html

  9. Sean:

    Dear MARodger I know of cases where after about 8 words the blog-reader’s eyes begin to glaze over.

    Anyway, I’m reminded of the time when Lennon first met Yoko at her art exhibition. he had to climb up a step ladder, grab hold of the magnifying glass hanging by a thread to see a single word she had written onto the ceiling.

    That’s my answer. Not sure what the question was. Cheers

  10. Sean:

    Dear MARodger, alt reply #2. Unforced Variations Dec: 2013 “Suggestions for what you’d like to see assessed are welcome… or any other climate science related topic.”

    Moderator may have been asleep at the keyboard.


  11. Jon Kirwan:

    To: John Mashey… I looked at that link. I guess I’m a little confused, though. I find the following two ISBNs for the same book? (1464107769 and 1429255250) I looked both up at the library of congress and they both say paperback and 2013. But different ISBN numbers. One of them says its the 3rd edition, the other doesn’t say. Your link is just for one of these ISBNs. (I also found a different link showing a publication date of 2014!)

    Anyway, is the edition the 3rd edition and the ISBN you linked to? Or the other one I found? Or? (Don’t want to order an older edition.)

    Sorry I’m confused here. And thanks.

  12. Hank Roberts:

    Be careful what you cite:

    Science 29 November 2013: Vol. 342 no. 6162 pp. 1035-1039
    DOI: 10.1126/science.342.6162.1035
    News Focus

    China’s Publication Bazaar
    Mara Hvistendahl*

    Science has exposed a thriving academic black market in China involving shady agencies, corrupt scientists, and compromised editors—many of them operating in plain view. The commodity: papers in journals indexed by Thomson Reuters’ Science Citation Index, Thomson Reuters’ Social Sciences Citation Index, and Elsevier’s Engineering Index.

  13. Hank Roberts:

    Oh, here’s why to be careful — when scientific papers are for sale, fraud’s easy and profitable.

    Pacific Gas and Electric got caught buying a fake paper not long ago, to try to swing the judge in a lawsuit.

    That one became rather famous among those who find this sort of thing cautionary:


  14. Fred Moolten:

    Jim Shewan (4) – The point about CO2-based cooling in an atmosphere that warms with height is basically correct, and is the explanation for CO2-based stratospheric cooling in our own atmosphere. The mechanism is well described in basic geophysics texts such as those by Hartmann, Pierrehumbert, and others. In our stratosphere, upper level warming is due to ozone absorption of solar radiation. At stratospheric temperatures, however, emission to space is primarily in the infrared spectrum. CO2 increases emissivity in the infrared, facilitating cooling, but absorbs sunlight only minimally, and so there is no commensurate warming. In essence, stratospheric CO2 acts as an escape valve to space for ozone-induced heating. If the stratosphere contained no ozone and did not warm with height, extra CO2 would warm it rather than cool it.

    [Response: Actually I disagree with the last sentence. The gradient of temperature or the presence of ozone are not relevant. For contrast look at the mesosphere where CO2 is also a cooling factor despite neither of these factors are present. It’s more useful to think of the stratosphere and above as being radiatively heated/cooled in specific bands (as opposed to a more general absorption/emission in the troposphere – mainly due to water vapour). CO2 is an important absorber all the way up, and as concentrations increase, upward LW in the CO2 band is increasingly absorbed (then thermalised and transmitted to other molecules). Looking down from the stratosphere, you will increasingly see less and less upward LW in that band as CO2 concentrations increase. Since emission in the stratosphere (and above) goes up with increasing CO2, there is a clear flux divergence in the CO2 band (more out, less in) and so there is cooling. The mechanisms that form the other part of the upper atmosphere heat budget don’t really matter. – gavin]

  15. Fred Moolten:

    Gavin – We’ve had this discussion before. Raypierre has an excellent quantitative description in his book, and includes the conclusion that CO2 would warm the stratosphere in the absence of ozone heating. Dennis Hartmann also describes the same mechanism, involving CO2-based dissipation of ozone-absorbed heat. Readers might want to visit either of those texts for a more quantitative assessment. I should add, of course, that extra CO2 in the stratosphere does absorb some IR from below, but this is small compared to the extent to which it increases IR emissions, because most of the heat it dissipates comes from ozone.

    [Response: I should check that out indeed. But the issue is not what other absorbers are present. It could be solar, SO2 or whatever, and the temperature gradient is not relevant either (though both issues will make a difference to any realistic calculation). The conclusion that CO2 would warm the stratosphere in the absence of O3 needs to be looked at carefully to see what the actual assumptions are (is CO2 the only strat absorber? how is the stratosphere maintained? is that a grey-body calculation? or wavelength dependent? etc.). – gavin]

  16. KR:

    One of the draft AR5 figures (the one reworked due to baseline errors, mind you) showed HadCRUT4 variability for the 2-sigma bounds around the model mean rather than model variability. Would something like that (GISS variability, for example) be worth graphing against the models?

    [Response: Uncertainty in the observations is very different from the uncertainty due to possible weather variations that might have happened but didn’t (the dominant term in the near-future model spread). But it is important to know what that uncertainty is of course. Thanks. -gavin]

  17. Fred Moolten:

    Gavin – I agree that a temperature gradient is not relevant. Rather, I would argue that it’s the presence of an exogenous (non-CO2) heat source. The way I visualize it is this: CO2 warms its surroundings as a result of its IR absorption and cools them via IR emission, so that in the absence of other heat sources, increased CO2 raises temperature to a level that stabilizes as a result of the increased emissions. Imagine, however, that in this situation, one suddenly warmed the surroundings by another mechanism that had little or no effect on IR absorption by CO2. The ability of CO2 to warm its surroundings would be unaffected, but because of the temperature increase, its emission level would increase, and hence its ability to cool. With sufficient exogenous heat, cooling would outweigh warming. Regarding the texts I mentioned, the concepts are discussed on page 332 of Hartmann’s “Global Physical Climatology”, and page 215 (bottom) of Pierrehumbert’s “Principles of Planetary Climate”.

    I didn’t know anything about the mesospheric effect at the time of your last comment, but I’ve looked into it a little bit since then, and I gather that there is non-CO2 heating there involving ozone as well as a variety of chemical reactions.

  18. John Mashey:

    I’m not sure about the others (this from iPhone in coffee shop, which thinks ISBN’s are phone # :-)), but:
    1) The link I gave to WH Freeman website is correct, the book only just came out last month, it is definitely first edition (although Bill has several other books, of which one might have 3rd edition).
    2) I’m not sure about 2013 vs 2014, although I’ve sometimes seen that before with books published near end of year.
    3) I don’t understand the odd entry at Amazon.

    Anyway, the link I gave is the right source.

  19. Chris Colose:

    I’m quite sure gavin is correct regarding stratosphere cooling in the absence of a solar absorber aloft.

    The whole issue is that any level above what is often called the “effective radiating level” (say, at ~255 K on Earth) should start to cool as atmospheric CO2 increases, since the layers above this height are being shielded more strongly from upwelling radiation…except not quite, because convection distributes heating higher than this level, the stratosphere marks the point where convection gives out and there is high static stability. You can still get a stably stratified layer in an atmosphere devoid of an absorber aloft, even if a temperature inversion does not develop. The spectral-dependence of CO2 matters as the cooling needs to be limited to a limited wavenumber region, as planetary energy balance remains satisfied by an increase in emission at fairly transparent wavelengths and decreased in emission at fairly opaque wavelengths. This stratospheric cooling is independent of the ozone heating…without ozone, we’d be talking about a cooling upper atmosphere.

  20. Sol Candel:

    I’m interested to know what the effect on global temperature averages is by glacial and ice melt water. An enourmous amount of near zero degree water mixed into ocean currents would surely have some measurable global effect. Has anyone reasearched this phenomena?

  21. John Mashey:

    re: #2 on Ruddiman book
    Someone had asked elsewhere, so I say more.

    a) There was a lot of legitimate argument early on about comparisons of the Holocene with other interglacials, alignment, etc. I think that’s been pretty well resolved, in more detail in the book, but the meat of it is in 2011 paper Can natural or anthropogenic explanations of late-Holocene CO2 and CH4 increases be falsified?
    See especially Figures 2 and 6.

    b) A big change from ~2005 is that people couldn’t believe there were enough humans early to clear enough land or do enough rice paddies to have noticeable effects on CO2 and CH4. It turns out (the subject of big chunks of the book and the Tyndall Lecture), that early agriculture tended to have a much larger acreage footprint per person than people assumed. On the CH4 front, there is a better integration of rice paddy archeology and it fits.

  22. Fred Moolten:

    Hi Chris (#19) Raypierre points out that in the absence of solar absorption by stratospheric ozone, added CO2 would warm all layers. This makes sense. Consider the alternative explanation – there exists a hypothetical level below which extra CO2 warms and above which it cools. Just below this “transition” layer, then, as CO2 is added, the temperature rises. At this point, we have more CO2 and a higher temperature. What will happen? It seems logical to me that the answer is not that less IR is emitted upwards above the “transition” layer, but rather more. It really doesn’t matter where this layer is, it would be physically implausible for it to send less IR radiation upward. Above this layer, there is also more CO2. The combination of more CO2 and increased IR from below must inevitably mean more warming rather than more cooling, unless there is some additional mechanism to accelerate cooling in excess of warming. In any case, I think the descriptions given in the text sources I cited above provide a better and more detailed explanation, but I think my comment gives a good general idea.

    [Response: There is a fundamental difference btw the stratosphere and the troposphere because of the presence of massive amounts of water vapour – implying that the LW absorption is far more (spectrally) widespread than in the stratosphere. If you are modelling the GHE using a single grey body absorber that is not wavelength dependent, then you have warming throughout the whole atmosphere. But it is precisely the spectral nature of the absorber (in this case) that drives the real stratospheric (and higher) cooling. – gavin]

  23. Pete Houlihan:

    I need recommendations for the best 30 to 60 minute introductory documentaries to the physical aspects of climate change. It should have info about patterns of climate change and a discussion of forcings. The audience is mostly first year undergraduate biology students. The documentary must be available on YouTube or Vimeo.


  24. Ray Ladbury:

    Hi Sol,
    I’ve done this calculation in the dark and distant past. I think that GRACE last estimated ice loss at about 500 billion tonnes per year. Multiply by the latent heat of water, and you will have some estimate. You will also find that it is tiny compared to the global energy flux.

  25. Gordon:

    @Sol #20 and Ray #22. I found the 500 B tons per year number also. 500 B tons = 5*10^17g. Assuming a 10 degree temperature difference between the temperature of the runoff and the average temperature of the ocean that would be 5*10^18 cal or 2*10^19 J/yr. From the graph of ocean heat gain a couple months ago in RealClimate, we know that the oceans have gained about 20*10^22 J since 1979 or about 5*10^21 J/yr. So glacial runoff might counteract 1% of ocean warming. More than I might have thought but not really significant unless my calculations are wrong.

  26. Gordon:

    RealClimate, we know that the oceans have gained about 20*10^22 J since 1979 or about 5*10^21 J/yr. So glacial runoff might counteract 1% of ocean warming. More than I might have thought but not really significant unless my calculations are wrong.

  27. TomB:

    Could you comment on the recent articles about the reduction in sunspot activity possibly negating the effect of global warming and even putting us into another Little Ice Age.

    [Response: Sure: Low Solar Activity Won’t Slow Climate Change. -mike]

  28. Gordon:

    So I have been studying climate change as a personal interest for a couple years. I am particularly interested in paleo climate reconstructions and spent several hours studying the Wolcott paper earlier this year. So I thought I was understanding the whole thing pretty well and then along comes this Rosenthal paper on Pacific Ocean heat content over the past 10,000 years.

    The Wolcott paper was fascinating in the detail but not that surprising in the big picture; warming from the early Holocene to the inter-glacial optimum about 5000 years ago and then slow but steady cooling culminating in the LIA. However, the most remarkable thing (to me anyway) is that the global average temperature hasn’t varied much more than 1C over its entire range. So what I expected to see in the ocean temperature record was a pattern lagging the land temperatures and even less volatile. But the intermediate water temperature (IWT 500-900M) seems to have no lag and a lot more volatility in terms of actual temperature change than the surface temperatures. The Northern Hemisphere (I assume from the green color in Fig 2C of Rosenthal) IWT has dropped by 4 degrees in the last 6000 years. During the Holocene optimum at a time when Wolcott shows less than 0.2C of variability, Rosenthal shows an upset in NH IWT that has the temperature rising 2C in about 500 years. The SH (again assumed) is only slightly less bouncy.

    Am I the only one that finds this perplexing? Doesn’t most of the forcing move from air/surface to deep ocean? How can the surface temperature be stable and the deeper water temperature be so volatile? The IWT graphs don’t show any AGW but that might be because the proxies don’t work up to the present. By my calculations, the current warming of the IWT only amounts to maybe 0.1C, but I think I am off on that as Rosenthal (Fig 4) shows the Pacific IWT catching up to the Holocene maximum in a couple centuries at the rate we are going. So how much has the global IWT increased in the last 50-100 years?

    Just hoping someone can shed some light on all of this for me. I am surprised I haven’t seen any discussion of Rosenthal in this or other climate forums.

  29. Jon Kirwan:

    To: John @18: Thanks. That title appears to go back more than a decade. You say it is just in the last month and that the one you linked is 1st ed. So my confusion, I suppose, is warranted. Focusing on your ISBN exclusively, I’ve ordered a copy. The bookseller swears to me that the ISBN is just exactly the same as from your link AND that inside the book it says “2014” as the pub date. No idea why, there. But that’s what the communication from them today tells me.

    Ordered. I guess I’ll find out.


  30. wili:

    I recently ran across this piece: http://www.climatecodered.org/2013/11/parts-of-australia-reaching-threshold.html

    That had the following quote from Mark Maslin, professor of climatology at University College in London:

    “We are already planning for a 4°C world because that is where we are heading. I do not know of any scientists who do not believe that.”

    I was just curious to know if that is a judgment shared by the scientist who frequent this blog, moderators and commenters. Thanks ahead of time for any feedback.

  31. Sean:

    [edit – blaming the mods for your own words is a little sad. More than that, it is tedious. Stay substantive, don’t be so belligerent and maybe we can all just get along – gavin]

  32. John Mashey:

    Jon: great!
    I have seen strange things in book databases before.
    this is a bit strange, Jan 9, 2019

    Perhaps odder was one that Deep Climate found in 2010: Wegman’s book on the Wegman Report.
    In mid-2010, that appeared as:
    ‘Controversy in Global Warming: A Case Study in Statistics, December 21, 2007.’

    Both DC and I tried to buy a copy from various booksellers who claimed to have it in stock. Every time I tried to order it, status changed to “out of stock” or “not yet published.”

    Amazon now says 2020, and
    “This item has not been released yet and is not eligible to be reviewed”
    However, I got a review in a year ago…

  33. MARodger:

    Gordon @28.
    The Rosenthal et al paper is pay-walled so making discussion by us mere mortals rather difficult. Those with access have passed comment, for instance here and here. Rosenthal et al appears to be classed as interesting but raising lots of questions, perhaps too many questions. And in such situations I think the actual questions you raise will be heavily dependent on where you’re coming from.

  34. john byatt:

    #30 more here today on ABC http://www.abc.net.au/worldtoday/content/2013/s3903815.htm

  35. Geoff Wexler:

    Re: stratospheric cooling. I hope Gavin won’t mind me ‘starting from the beginning’. This will seem too elementary for some readers. I want to know if it is more or less correct. I am not going to consider what might happen without the UV heating.

    As I see it, the problem can be understood in local terms. In this particular respect it is simpler than that of the more obvious case of tropospheric warming which depends on what happens elsewhere (see later).

    Warm substances, including greenhouse gases, emit more energy than cold ones at all wavelengths for which they absorb (Planck). On the other hand their absorption is independent of temperature.

    If you add more greenhouse gases the absorption and emission will both rise but for different reasons. To help with understanding it often helps to throw things away e.g. the upper or lower boundaries. I am not going to consider such subtleties as the surface budget fallacy.

    Tropospheric case. Assume that the heating is entirely from below. disregard direct solar heating from above e.g. by UV.

    Stratospheric case. Assume that heating is entirely from above. Disregard the ground*.

    Replace day/night variations with a constant average day ; and start with energy balance and steady state.

    Assume that the added greenhouse gas is not ozone. Consider CO2. Then the heating from above caused by the absorption of incoming ultra-violet light by the O3 is unaltered, whereas the energy loss caused by the emission from the CO2 is raised. This creates an energy imbalance which causes cooling.

    It is not essential, but for completeness, it might be worth following the energy accounting to include the so-called Planck feedback? The familiar version of this can be re-stated by considering the energy balance at ground level. An energy surplus there gives rise to warming which causes a rise in infra-red radiation leading to more energy loss at the top of the atmosphere and hence a trend back into energy balance (negative feedback). A similar effect occurs in the stratosphere, except that the negative energy imbalance now causes a cooling which causes less energy to be emitted by the CO2 (see para.3 above). This gradually reduces the energy imbalance to zero.

    People seem to think that the warming of the troposphere is the simpler case and so it does not get much attention. Cooling by greenhouse gas emission will still rise but this will now be opposed by non-local effects. The land and sea warm , the infra-red from them increases and the oxygen, nitrogen and water vapour all carry more heat upwards by convection. It is only a small intuitive step to conclude that the net effect is warming throughout the region for which the UV absorption can be neglected. Can be checked by computer.
    *. In this respect, and in this respect only, the problem is analogous to the addition of insulation (at floor level) of a loft subject to normal solar heating of the roof. In my first (but not my second) RC attempt, to simplify this discussion, I suggested this flawed analogy.

  36. Geoff Wexler:

    Re: Intuition and tropospheric warming.
    (Penultimate sentence in my last comment)

    I would prefer …… throughout most of the region…

  37. Paul S:

    Gordon – this is essentially a copy of a comment left at another blog but is relevant to your question:

    It’s not necessarily the case that relative trajectories of OHC and surface temperature have to be congruent over these long timescales. I’ll give an example using the MPI-ESM-P model simulation of the past millennium. This plot shows thermosteric sea level change over that period, which would strongly correlate with OHC/ocean temperature, and this plot shows surface temperature evolution.

    In the first plot, relating to ocean temperatures, it is clearly warmer about 1000 years ago but current temperatures are clearly warmer at the surface.

    Note that this shouldn’t at all be considered an accurate simulation of what was shown in the Rosenthal paper*. Much the same trend can be seen in the control run for this model so it’s the result of “drift”. Other models produce drift of opposite sign. The point is simply that finding a warmer ocean around the medieval period shouldn’t have much weight in debate about relative surface temperatures.

    *On the other hand, I guess the processes involved in what we call “model drift” could be broadly similar to those which produce Holocene length trends like those seen in the Rosenthal et al. paper.

  38. wili:

    Thanks, john (@#34)…I guess :-(

    I would still like to hear from any scientists in the room how widespread this understanding of things is.

  39. Fergus Brown:

    I have been keeping an eye on antarctic melt this past few weeks and note several substantial ‘chunks’ now free-floating, according the the AMSR2 images. Can’t find up-to-date sat images. I emailed eric to ask about this but got no reply (no blame attached).

    I just want to know whether this is ‘usual’ or if 100 mile+ chunks of sea ice at 62 S are nothing of note. Any feedback?

  40. tokodave:

    Here’s some good news from over at Skeptical Science:
    Cowtan and Way, 2013 is now open for business:http://www.skepticalscience.com/open_access_cw2013_update.html

  41. Sean:

    @31 That’s rubbish Gavin. If you are the moderator, then you are biased, selective, inconsistent, irrational, unfair, participate in ad hom yourself, allow whacko denier posts just so you can comment on them, slap them down, insult them, and look good clever and a hero in front of your audience. [edit – more of the same removed.]

    My work is done.

    [Response: Yup. Try not take things so personally, you’ll be happier for it in the end. – gavin]

  42. John Mashey:

    I wonder if this Sean is the same one who participated at Jo Nova’s on the Salby affair, never once saying anything useful. One never knows with anonymous commenters, but there does seem to be a similarity of style, as for example:

    ‘This “university” should have its public funding pulled and their charter as a university revoked.Its president should be fired, along with the department head who colluded in this. Salby should sue for breach of contract, seeking special damages for what was clearly not a good faith contract negotiation and rather intended only to deprive him of his voice and career; he should also file criminal complaints with the police for the thefts and harassment.’

    ‘Agreed – there seem to be a whole host of laws this university is guilty of being in breach of – more than enough to justify some terminations for cause of some top level academics and administrators.’

    ‘john, don’t you have some climate skeptic in your university’s physics department to go harass and otherwise not do your job of making photocopies for him?’

    ‘“Only those with no moral compass would suggest otherwise.”You have captured climate cult activist John Brookes to the “T”…’

    ‘What kind of banana republic are you Australians running down under? Sorry but i am now striking Australia off of my list of tourism destinations. Will also avoid hiring any graduates of the Australian university system.’

    ‘You should have asked instead for the dean of junk science – he is always in…’

    July 14 (a day or two after the NSF roof fell on Salby)
    ‘Oh? Has the Dean of the engineering school spoken out against his biased Luddite peers? No? OK, then degrees from this uni are staying on my no-hire list.’

    ‘Aren’t you late for your appointment at the euthanasia clinic Catamon?’

    If it is the same Sean, I’m sorry, Gavin, but I doubt anything will make him feel better :-)

  43. Fred Moolten:

    Geoff Wexler (35, 36) – I’ve already commented too much on this, but I’m reluctant to see your request go unanswered, so I’ll say that although you make some simplifying assumptions, I think you’ve stated the underlying principle correctly. I agree that a Planck response to surface and tropospheric warming and to stratospheric cooling is what limits the temperature change in each case.

  44. Phil Mattheis:

    now for something completely different,
    and especiallyfor Sean,
    as alternative to RC that may more directly meet his needs:
    (from our friends at Monty Python)

  45. Phil Mattheis:

    More data on impact of changing local weather patterns, maybe putting more personal ground-based perspective to melting arctic ice:
    (captcha: thanks ideafun)

  46. Geoff Beacon:

    Just out. Hansen et. al. Assessing ‘‘Dangerous Climate Change’’: Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature

    From the abstract

    Cumulative emissions of ~1000 GtC, sometimes associated with 2°C global warming, would spur “slow” feedbacks and eventual warming of 3-4°C with disastrous consequences. Rapid emissions reduction is required to restore Earth’s energy balance and avoid ocean heat uptake that would practically guarantee irreversible effects.

  47. Sean:

    @42 “if this Sean is the same one” No.

  48. Tony Weddle:


    Do you think it’s possible that almost all climate scientists also think that economic growth can go on for the rest of this century? Isn’t that what all of the RCPs assume? I find that assumption untenable, given the rate of environmental degradation and the fact that most of the marginal increase in fossil fuel production is from the harder to produce sources.

    So the comment that all climate scientists think we’re heading for a 4 degree warmer world may be true but based on a questionable assumption. Not that 4 degrees isn’t possible without economic growth, of course.

  49. Richard Hawes:

    Dearest Sean, we do thee implore,
    To go away, and Blog No More.
    But if temptation prove too great,
    To Go Away, at any rate.

  50. Kevin McKinney:

    #41–One can only hope. That Gavin and company didn’t start boreholing this tendentious junk long ago is testament to moderator patience.