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Unforced Variations: February 2012

Filed under: — group @ 1 February 2012

This month’s open thread. Current topics are focused on the laughingly bad Daily Mail article by David Rose, the fallout from the Wall Street Journal’s latest regurgitation of why no-one should ever do anything ever. And perhaps someone might want to audit some of David Whitehouse’s arithmetic and reading comprehension…

Or anything else. Within reason.

399 Responses to “Unforced Variations: February 2012”

  1. 251
    Dan H. says:

    I think this is what you want. Try this link for a recent GISS map.

  2. 252

    For those interested in flywheel technology–

    It seems that Beacon Energy, which went bust in the wake of the Solyndra affair, found a ‘white knight’:

    Good news, I think. Beacon has a real-world technology, earning actual revenue by stabilizing the grid, seemingly with good long-term prospects. But development costs have been high. Can they “get over the hump?” At least they’ll have a chance to try, and some (hopefully more robust) financial backing in doing so.

  3. 253

    #251–No, Dan that is not what he wanted. That is baselined to 1998-2006, which is fairly goofy.

  4. 254
    Hank Roberts says:

    Oh, dear, Dan H., you’ve done it again.
    You’re linking an unexplained copy of someone else’s image at a known denial site and handwaving to claim it answers someone’s question.

    That particular spun image is all over the denial sites if you do an image search. You can do better than be a tube piping stuff you find in without thinking.

    Look up the original source.
    Read the caption and the context.
    People who post unattributed copies with their own claims are quite likely trying to delude people who don’t think critically.
    Ask them where they got the original.
    If they won’t tell you — ask why not.

  5. 255
    dbostrom says:

    …when comes the time to write up and report the results, these otherwise smart folks regress to office automation software.

    Constant supplies of “free” or heavily discounted software to clueless administrators will have that effect.

    Of course it’s not really “free” software unless publishers making these “donations” eschew taking tax deductions for their purported munificence. Otherwise, each “free” copy of Office or whatever proprietary version of mundanity is on offer is a self-printed coupon which may be submitted to our government as a means to resign from the social contract that helped to produce the human talent required for creating the software in the first place.

    This sort of thing is rampant here in Washington; Microsoft’s reputation as a benefactor to the state is high even as our educational infrastructure crumbles for lack of a fraction of the contributions they’re managing to dodge. Here we don’t have an income tax, so the self-printed tax exemption coupon thing is replaced by other sorts of exemptions.

    Public college and university budgets here have been cut to the tune of 40-50% in the past 3 years. Meanwhile Microsoft executives take the stage with the Governor and university officials, lamenting these cuts and exhorting legislators to magically fix the problem, even as Microsoft agilely avoids all responsibility for helping to ameliorate this problem.

    Presumably in the future the company will fasten its feeding tubes on graduates from other states with less of a parasitic burden, as the supply of graduates in Washington dries up.

  6. 256
    SecularAnimist says:

    Dan H wrote: “Try this link for a recent GISS map.”

    Dan H. tries to put one over on “DP” by suggesting that he’s linked to a map created by NASA GISS.

    But that is not a “GISS map”. It’s a map created by someone using the “climate4you” website — perhaps by Dan H., or perhaps by Ole Humlum, the maintainer of the “climate4you” website.

    Humlum is a denier who has signed on to a statement which asserts “the case for alarm regarding climate change is grossly overstated. Surface temperature changes over the past century have been episodic and modest and there has been no net global warming for over a decade now … there has been no increase in damages from severe weather-related events. The computer models forecasting rapid temperature change abjectly fail to explain recent climate behavior.” Other signatories include Craig Idso, Richard Lindzen, Patrick Michaels and Roy Spencer.

    Humlum’s errors and egregious cherry-picking have been documented at SkepticalScience.

    It’s one thing for Dan H. to “contribute” such denialist fare to the discussion here. It’s quite another thing for Dan H. to misrepresent the work of a well-known denier as the product of NASA GISS.

  7. 257
    Ric Merritt says:

    Ron R, re squabbling between bluebirds and sparrows: A while back (10 years??) The New Yorker published “A Scrap of Sky”, a gorgeous sonnet by George Bradley on that very subject, so much so that I memorized it.

    I fear that reproducing it here would be too far OT, plus probably a copyright violation, but for those who enjoy bluebirds, poetry, or both, it is worth looking up.

  8. 258
    flxible says:

    Shame on DanH@251 for yet again referencing a denialator sites unexplained and unreferenced mis-interpretations of data instead of encouraging folks to investigate for themselves, all the while attributing the misinformation to real scientists. Humlum’s “climate4you” is climate for Dan.

  9. 259

    Re: Dan H. “Despicable” is the word to use for the mendacity of certain deniers.

    A suggestion: Require Dan H. to make an honest start by owning up to and explaining his laughable misunderstanding of the PDSI, as detailed on Tamino’s blog.

    Otherwise, send his comments straight to the bore hole.

  10. 260
    Hank Roberts says:

    Sigh. climate4you Humlum fake image.

    Desccribed as using ‘data from the GISS database’:

    “All the above diagrams are constructed using data from the GISS database.”

    Faked by changing the baseline to the latest highest years:

    “the period 1998-2006 is used as reference period….”

    1998 is a denial favorite comparison point, and claiming trends based on time spans a favorite deception. Bunk on bunk.

    To paraphrase the rest of the ‘climate4you’ explanation:

    Any comparison to a few years starting in 1998 will therefore appear as low or cool, and it will be impossible to decide if last year’s surface air temperatures are increasing or decreasing. Comparing with this very recent period is done to enhance the deception.

    — No cite
    — Deceptive source
    — Offered as helpful in response to someone’s question

    Dan H., for shame. BAD.


  11. 261
    dbostrom says:

    Otherwise, send his comments straight to the bore hole.

    Some are already being pumped in, but like a composting toilet it seems the bore hole can only digest “matter” at a certain maximum rate.

  12. 262
    Meow says:

    @246: The sciencedaily summary misrepresents the paper via the (unqualified) italicized statement:

    The study…claims that the rapid deployment of low-greenhouse-gas-emitting technologies (LGEs) will initially increase emissions as they will require a large amount of energy to construct and install. These cumulative emissions will remain in the atmosphere for extended periods due to the long lifetime of CO2, meaning that global mean surface temperatures will increase to a level greater than if we continued to use conventional coal-fired plants.

    Actually, the paper claims that, depending upon the technology, there will be ~1 yr to ~15 yr periods during deployment of low/no-carbon electricity generation tech [1] where CO2 emissions (and thus global temperatures) will be somewhat greater than they would be for continued use of coal. Supp. materials Fig. S3 shows the estimated years of “excess” deployment emissions, and Fig. S7 shows the resulting excess radiative forcing (in uW/m^2/GW and degrees C/GW deployed). Note the gigantic uncertainty ranges for renewables.

    [1] Excepting hydro, which has an uncertainty range of 0-62 years (????)

    CAPTCHA: people ingLIn

  13. 263
    Ray Ladbury says:

    So, did anyone remember to sweep up the ashes of Dan H.’s credibility? I mean we should probably put them in a box…or at least a vacuum cleaner bag so he can carry them home.

  14. 264
    David Miller says:

    Dan H. once had credibility?

    Darn, I read RC at least daily and I quite missed that.

  15. 265
    David B. Benson says:

    SRJ @250 — Empirical observation is easy (and enjoyable): buy a cool bottle and also a warm bottle of your favorite carbonated beverage; open both. Which expresses the more carbon? Taste both; which tastes the more carbonated?

  16. 266
    Ron R. says:

    Ric, I found that poem on this site (along with lot of others).

    A lovely poem. I especially like these lines:

    “Has hope and optimism to the marrow,”

    “So beauty comes again each spring and tries to stay,
    And so does drab determination thrive.”

    Can I pen one?

    The bluebird does have it’s enemies.
    The swallows and the sparrows.
    All beautiful things do.
    But I love the swallow
    and the sparrow too.

    Thank goodness that little glowing scrap of sky stepped back from the brink of extinction.

    [Response:You might be interested in this–Jim]

  17. 267
    Hank Roberts says:

    So for the benefit of search engines:

    This is NOT a recent GISS map, we were being misinformed.

  18. 268
    Hank Roberts says:

    hat tip to commenter Zorawar at John Baez’s Azimuth

    “The 85% energy wasted figure probably comes form the “Energy Flow” diagrams the government produces (in archaic units), e.g.

  19. 269
    Hank Roberts says:
    Changes in seasonal land precipitation during the latter twentieth-century
    Key Points
    Seasonal precipitation changes can be attributed to external climate forcing
    Pattern of change is consistent across 3 independent observational datasets
    Multi-model mean trends tend to underestimate the observed trends

  20. 270
    Leland Palmer says:

    Hi All-

    Here’s a nasty correlation between temperature increase in the Arctic and the location of the ESAS:

    From Shakhova:


    (Hit the small orange download button, not the large green animated one, which is a commercial link)

    (From page 24)
    Observed warming on the ESAS (March-April-May; MAM, 2000-2005 versus 1970-1999, NOAA) is the strongest in the entire Arctic and the region is now 5°C warmer compared with average springtime temperature registered during the 20th century;
    B) Circum-Arctic map of sub-sea permafrost (shown in purple) (ACIA, 2005). This compilation suggests that most (~ 80%) of the relict submarine permafrost is predicted on the ESAS;

    This suggests a causal relationship, between methane release from the hydrates and local average temperature increases. Looking at the 2011 average data from NASA GISS:

    NASS GISS 2011 – Hot Spot over the ESAS

    Chances are, this will be condemned as unscientific, by the habitual pundits on this site. But temperature increases over the ESAS are certainly not inconsistent with moderately large scale methane release in 2011 from the ESAS.

  21. 271
    Ron R. says:

    Thanks Jim. I’ve read a bit Jeffers in the past. While not available at my local library I’ll keep an eye for it.

    I also like Thoreau and Muir and Abbey. A old melancholy favorite is Loren Eiseley.

    It seems that a love of the natural combined with a disaffection with organized religion has figured into much of environmental verse.

    [Response:Good poetry is similar to good science in some respects. We could use a few more people who can do both.–Jim]

  22. 272
    Ron R. says:

    I should say, between organized religion on one side and cold, scientific reductionism on the other.

  23. 273
    John E. Pearson says:

    [Response:Lake Erie has been essentially ice free all winter, which is highly unusual.–Jim]

  24. 274
    John E. Pearson says:

    There just wasn’t enough ice,” said Shannon Meister, a spokeswoman for Winterfest, who said parts of Lake Manawa revealed not just dubious ice, but open water. “In past years, it’s been debatable, but this year it was no question.”

    And some said they had no intention of missing out on remaining fishing days and worried aloud that climate change or the causes of this season’s warmth — a jet stream that sat farther north than usual and a relatively small snow cover — might somehow signal the beginning of the end of a sport that has spanned generations.

    I wonder how many of Michelle Bachman’s constituents will have to start saying these sorts of things before she starts parroting them.

  25. 275
    Susan Anderson says:

    dumb question: What is ESAS in this context. Everything I can find assumes I know, but as far as I can see it’s

    Exploration Systems Architecture Study

    which is not a physical area.

  26. 276
    Rick Brown says:

    Susan – it’s East Siberian Arctic Shelf, I believe

  27. 277
    Leland Palmer says:

    Yes, sorry Susan.

    From Shakhova, about the significance of the ESAS methane hydrates (East Siberian Arctic Shelf):

    The ESAS is the most extensive and the shallowest shelf of the World Ocean
    • The East Siberian Arctic Shelf (ESAS) is 2.1×106 km2 area (~25% of the Arctic Shelf, ~8% of the total area of the World Ocean’s continental shelf;
    • ~75% is shallower than 50 m (mean depth of the continental shelf is 130 m); this provides very short conduit for methane to escape to the atmosphere with almost no oxidation.

    So, it’s a big area of shallow undersea methane hydrates, which is heating rapidly. Shakhova claims that there are about a trillion tons of hydrate there, along with another 700 billion tons of free associated methane.

    There appears to me to be a correlation between the extensive methane venting Shakhova and Semiletov observed there and average temperature increases over all of 2011 as reported by NASA GISS (Goddard Institute of Space Sciences) for the local area around the ESAS.

    It could be a coincidence, but this correlation keeps showing up, and it is consistent with methane releases in the area.

    Chances are, in my opinion, it is not a coincidence, and what we are seeing with the hot spot in the NASA data is mostly local warming caused by methane release from the hydrates. There could be some albedo effect thrown in, with less ice cover reflecting less sunlight into outer space, and other more random factors, of course. But it looks to me like the methane releases are having a significant enough effect that they are affecting the yearly average temperatures. November, December, and January of 2011-2012 seemed to show very large temperature anomalies consistent with methane release from the hydrates, known to be large during those months.

    So, for the first time, in the last decade but especially in 2011 we’re starting to see this theoretical prediction of localized greenhouse heating from methane releases from the hydrates come true, I think.

    If you want to make your own maps, here is the link to NASA GISS:

    NASA GISS Surface Temperature Map Maker

    Pick temperature anomalies, select the time period you want, and select polar projection for a similar map.

  28. 278
    Hank Roberts says:

    > It could be a coincidence, but this correlation keeps showing up

    And the wacky-woo anti-vaccine parody-science site huffpost is on it:

    I noticed in the Heartland stuff one of their writers moved to Huffpost recently. Seems to me like PR winding up for the leap from “can’t happen” to “too late” — or at least to “geoengineering now drill baby drill that methane”


    But perhaps I’m too cynical.

  29. 279
    Hank Roberts says:

    The guy moving from Heartland to Huffington is named Greenwood, by the way.

    Came across that wondering why credit unions’ national association has been funding Heartland’s “FIRE” program. It’s their push against acceptance of climate change risks by the financial and insurance industries, which is a big issue for regulation of financial institutions.

    Heartland wants “risk-based” insurance — based on only what’s already known to have gone wrong in the past, not on what’s likely to go wrong with business as usual continuing. Look up how well that has worked out for other industries, it’s been a big “conservative” notion for a while.

    More coverage of Huffington Post’s new “Science” duck:

  30. 280
  31. 281
    Leland Palmer says:

    Hi Hank-

    Don’t think it’s possible to be too cynical, these days.

    Seriously, though, I thought that the “Methane in the Twilight Zone” series of articles was great, and would not condemn the author just for publishing on the Huffington Post.

    We don’t have to drill for methane. Plumes of methane are bubbling up through the ocean. The oil corporations wanted to present the world with an accomplished fact, in the Arctic, and now they have done so, I think.

    The question now is what to do about the methane plumes, and is is possible to do anything significant about them at all?

    I suggest we start laying underwater electrical cables to the sites, and start capturing the methane, burning it using oxyfuel combustion to generate electricity, and then deep inject the resulting CO2 into any deep fractured basalt layers we can find in the area. Some of the sites seem to be pretty close to shore, and it might be possible to directly export the methane from there by pipeline. Then, of course, there is the possibility of exporting it as liquified natural gas (LNG).

    If we let the oil and gas corporations do it, they won’t capture and deep inject the resulting CO2 from methane combustion, I think. So, maybe Obama should get together with other countries, and at midnight some night just go in with the military and nationalize the multinational oil and gas corporations. Then, using the equipment and experience of the oil corporations, we go up to the Arctic and clean up some of their mess, generating useful electricity at the same time.

    It’s too late, though, chances are.

    Still, there are concentrated hot spots where most of the methane is coming out, and it may be possible to capture some or most of it from those hot spots. We can’t get all of it, but maybe we can capture and do carbon neutral remediation on some of it.

    Ancient Chinese curse- “May you live in interesting times”. These do seem like interesting times, sad to say.

  32. 282
    Leland Palmer says:

    About the correlation between surface temperature anomalies over the East Siberian Arctic Shelf (ESAS) and the months of highest methane release- every month of 2011 seems to be a reasonable fit to this correlation.

    From NASA GISS (Goddard Institute of Space Sciences)

    August 2011 shows a slight correlation between ESAS location and temperature anomaly, possibly due to methane release.

    September 2011 shows a moderate correlation.

    More to come…

  33. 283

    #281–All of which seems to me like a rush to throw tons of money at several, er, undeveloped technologies, in an attempt to solve what may very well be a non-existent problem.

    Sorry, Leland, but I don’t think you’ve made your case.

    I say we get on with the serious work of mitigating CO2 emissions.

  34. 284
    Leland Palmer says:


    October 2011 shows very strong heating over the ESAS, just when methane release would plausibly be increasing.

    November 2011 also seems to show a strong correlation.

    December 2011 and January 2012 also show strong correlations between months of high methane release and temperature anomaly over the ESAS.

    Add them all together, and these hot spots generate a nearly perfect correlation between ESAS (East Siberian Arctic Shelf) location and temperature increases for all of 2011, likely due to methane releases from this area.

    Really, this seems beyond coincidence. As predicted, it looks like large scale methane releases are occurring, and are large enough to show up on the surface temperature maps.

  35. 285
    Leland Palmer says:

    Hi Kevin-

    Mitigating methane and CO2 are not mutually exclusive. Electricity generated by capturing and burning methane from the hydrates would reduce CO2 generated by conventional fossil fuel use…if the methane was burned using oxyfuel combustion and the resulting CO2 deep injected. But the real threat is from the methane, of course, because of its high greenhouse potency, and because it will eventually oxidize into CO2 in the atmosphere anyway, and then we will be stuck with that secondary CO2 for thousands of years.

    So far as making my case goes, I don’t really worry about that. I just tell the truth as I see it.

  36. 286
    Leland Palmer says:

    Just to be complete:

    December 2011 shows a really nasty correlation between surface temperatures and East Siberian Arctic Shelf (ESAS) location, possibly due to methane release from ESAS hydrates.

    January 2012 also shows a strong hot spot over the ESAS.

    It looks to me like this is happening. Methane release from the hydrates is likely a new fact of life, and now we have to try to figure out how to deal with this terrible mess.

  37. 287
    Ron R. says:

    A thousand apologies. I just discovered from comparing pictures of swallow species that I apparently misidentified the species of swallow that has been taking up residence with us. Although we have had cliff swallows, the ones famous for their long migration from Argentina to San Juan Capistrano, nesting under the eaves of our house in the past, these are evidently tree swallows not cliff swallows.

    I will endeavor to be more accurate in the future.

    [Response:You’re fired :)]

  38. 288
    Craig Nazor says:

    Concerning the comment at 273:

    I grew up along the shores of Lake Erie in the ’50’s, ’60’s, and early 70’s, close to the Pennsylvania border. The lake ALWAYS froze out at least a half mile from shore, frequently out to the horizon, at least once or twice in the winter. My grandparents would tell stories of when, in a cold, bygone winter, the lake would freeze all the way to Canada, and wolves could be seen crossing the ice. Everyone says that now the winters are much milder, and summers are getting wetter.

    [Response:Interesting. I’ve read reports of deer swimming across the open water between the islands in the western basin. Just went looking (again) for historical ice cover data and it’s a nightmare tracking it down. Here’s the latest views of the western basin.–Jim]

    Also, as I noticed when I visited back home in the spring recently (and discussed with my family), the trees are consistently leafing out one month earlier than in the early 70’s.

    These are easy observations to make, and hard ones to deny!

    recaptcha says: Geoppea much?

    Well, not recently…

  39. 289
    Anonymous Coward says:

    For the record, there is no evidence of abnormally large methane releases. Methane alarmists have made this up based on qualitative newspaper accounts.
    All the quantitative _local_ measurements I’ve seen are within 3% or so of status quo. Even if methane spiked a bit in some locations, you’d still have no evidence that it’s unprecedented.
    And you’d need a hell of a lot more methane to cause signifcant warming anyway!

    Gotta love this by the way: “at midnight some night just go in with the military and nationalize the multinational oil and gas corporations.”
    How to tell parody apart from the real thing?

  40. 290
    Ron R. says:

    [Response:You’re fired :)]

    Wouldn’t be the first time.

  41. 291
    dhogaza says:

    Ron R:

    “these are evidently tree swallows not cliff swallows.”

    Yes, tree swallows are earliest north american swallow species to begin migrating north in spring. Funny, when I saw your earlier posts I wondered if perhaps you were seeing tree swallows, but they don’t look at all like cliff swallows so didn’t bother asking. Since you went to the bird books, now it’s obvious you’re a neophyte birder. Maybe this experience will lead you to learn more and more about our avian friends! :)

  42. 292
    SRJ says:

    David B. Benson @ 265
    I think you misunderstood my question. First, when I asked for empirical evidence I was hoping to get suggestions for some peer reviewed papers.
    Secondly, what I asked was not about how the carbon dioxide content of bottled beverages is affected by temperature.
    Trying to restate my question:
    From radiative physics it follows that a doubling of CO2 gives a warming of ca. 1 Celsius, without any feedbacks. With the feedbacks from the water vapor, the ice-albedo, the clouds , and the lapse rate the warming of a CO2 doubling is expected to be higher, Wikipedia mentions a range of 2.6–4.1 °C estimated from models (Wiki is quoting Rahmstorf, Stefan (2008). “Anthropogenic Climate Change: Revisiting the Facts”. In Zedillo, E. (PDF). Global Warming: Looking Beyond Kyoto. Brookings Institution Press. pp. 34–53).
    My question is, what observational evidence is there for these feedbacks? Only from actual observations, not from model calculations?

  43. 293

    #287–Just be careful if you run into a strange bridgekeeper. . .

  44. 294

    #292–SRJ, I’ll rush in where (perhaps) angels fear to tread.

    First, note that mechanisms operating as climate feedbacks are often observable over short timescales as factors influencing weather. For example, numerical forecasting–ie., darn near all forecasting these days–must calculate radiational warming or cooling if it is to arrive at a temperature forecast. It does so using the pretty the same mathematical/computational tools as climate models do, with regard to things like water vapor content (absolute humidity), albedo, and of course the relevant bits of the atmospheric circulation. So there’s a validated physical basis for how these factors affect energy flows within the atmosphere. That doesn’t answer the question of how their evolution over time is affected by CO2 levels, of course, but it does say that these factors are going to affect climate sensitivity if they are at all dependent upon CO2 levels in any way.

    From there, it is a logical step to use modeling techniques to investigate climate sensitivity directly, and of course that has been done (and continues to be done.) That’s not ’empirical’ in the way you mean it, but I hope my first paragraph highlights the fact that atmospheric modeling in general does have strong evidentiary–indeed, operational–basis. It’s not just ivory-tower hypothesizing.

    However, there’s a whole other approach to the question, which is to use paleo-climatic proxy data to infer sensitivity. If we can see that CO2 levels changed at certain points in the paleo record, what did temperature do? This approach can be (and often is) combined with modeling studies, since that allows a detailed probing of what feedbacks may have been at work, and how strong they were over various timescales. Here’s a small sample:

    Hope that bears some relation to what you want to know.

  45. 295

    I suppose that I should quickly add that the general record of the last 3-4 decades also suggests that some of the hypothesized effects do occur in the real world, insofar as we have raised CO2 levels significantly, and observe at least two of the feedback parameters responding as expected: there is, in fact, a robust rising trend in absolute humidity, and there is a falling planetary albedo, particularly in the Arctic, and particularly in the early fall. We’re in the process of observing just how those changes affect the planetary system now. . . but of course that’s something that evolves over decadal timescales and greater.

    Of course, every decade of BAU sees a CO2 increase of around 6% (if my mental arithmetic can be trusted.) Equilibrium could take quite a while, going on like that. . .

  46. 296
    Ron R. says:

    dhogaza @ 291. “Yes, tree swallows are earliest north american swallow species to begin migrating north in spring.”

    I’m embarrassed to have confused them.

    Still they did show up 39 days earlier than last year. These houses have been up for several years now, last year being the first time I actually noted their arrival here. As far as I remember they arrived in early spring the other years as well.

  47. 297
    Ron R. says:

    Kevin McKinney: Just be careful if you run into a strange bridgekeeper. . .

    Don’t think I’ve ever used this overused acronym before but, LOL. :-D

  48. 298
    David B. Benson says:

    SRJ @292 — Ah, climate sensitivity. There is a study of the Pliocene with Gavin Schmidt as one of the authors which suggests that the so-called earth system climate sensitivity is quite high. As for estimating the Charney (fast feedback) climate sensitivity, I recommend papers by Annan & Hargreaves and papers referencing that body of knowledge.

    I had thought you were interested in the fact the ocean CO2 content waxes and wanes with temperature, hence the bottled beverage experiment.

  49. 299
    Chris Colose says:


    Keep in mind that “observational” evidence to diagnose climate sensitivity can come in the form of using actual 20th century data (in a couple of different forms), or it can come from using proxy data that is applied to reconstruct past climates. In both cases, the usefulness of applying this evidence to interrogate the question (in the absence of physical models) is actually quite limited.

    For the 20th century, you might think that you can naively link the total radiative forcing applied on the Earth system with the observed temperature change to know the sensitivity. In fact, we have very poor understanding of the total applied radiative forcing. Because estimating the ‘true’ climate sensitivity depends on understanding this forcing, you end up with a relatively wide distribution for possible values that are all consistent with the modern climate.

    People have also looked at the linkage between surface temperatures and the top of the atmospheric radiation budget with satellites, which in theory could tell you something about how efficient the Earth is at restoring itself to a new equilibrium. In a highly sensitive system, the temperature responds much more to a certain radiative perturbation. But you can also think about it as saying that the radiative response by the Earth is less efficient at coming back to equilibrium. The problem, however, with these approaches is that it requires global coverage, datasets that are long and accurate enough, in addition to properly recognizing that it is possible to have changes in net radiation that give little insight into the sensitivity problem (such as the response after an El Nino event).

    People have also looked at the response to volcanic eruptions. The problem here is that the response to a volcanic eruption is very short-lived and is not necessarily linearly related to the equilibrium climate sensitivity. For example, the peak cooling of a volcanic eruption in system 1 might change only slightly from that in system 2, even if system 1 and 2 have radically different equilibrium sensitivities. You can also isolate individual feedback responses (for example, it was confirmed after the Pinatubo eruption how the water vapor concentration would change, lending confidence to our understanding of a positive water vapor feedback). This, however, does not strongly constrain the response to the whole system on decadal timescales to a CO2 forcing.

    Turning to the paleoclimate record, there are intervals in the past that have a good enough signal-to-noise ratio that they are useful targets for answering the question. The Last Glacial Maximum comes to mind as a time period that was in equilibrium and featured large enough forcing/temperature change relative to the current day. Indeed, there are a number of papers that have given best estimates of the total forcing and the total temperature change, and you do get a useful range of results. But the problem here is that when you apply this result to the future, you are inherently making an assumption that the feedbacks of interest apply linearly from the LGM to modern as they do from modern to 2xCO2. If you think that assumption is not very good, then you cannot advocate using the observation-only approach.

  50. 300
    Anonymous Coward says:

    #292 SRJ
    Your question is self-contradictory. It will only result in confusion.
    Climate sensitivity is a model property. You can not say anything about it without models or untenable assumptions (see Chris Colose’s comment).
    All that observational evidence can demonstrate is that feedbacks are indeed operating.
    People who claim climate sensitivity is low are either using models or making stuff up.
    For references to peer-reviewed papers, consult the IPCC reports.