Climate sensitivity constrained by CO2 concentrations over the past 420 million years

Posted by William M. Connolley on April 2, 2007
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Nature has Climate sensitivity constrained by CO2 concentrations over the past 420 million years (subs req, of course). Its interesting for two reasons: firstly as yet another way of getting the same range for climate sensitivity (they get 2.8 oC as a best guess). And secondly as an antidote to the septics who assert no correlation of CO2 and T over geological time. Not that the match presented here is perfect, but it does exist.

[Update: FP has a link+pix for those without direct nature access -W]

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Comments

  1. #1 Lubos Motl
    2007/04/02

    I think that you have completely lost contact with climate science. Not just skeptics, but literally hundreds of millions of ordinary people including former alarmists, already know that there’s a correlation but the causation behind this correlation goes the other way around, and thus this correlation doesn’t measure response of T on CO2 concentration but the response of gas concentrations (not just CO2) on temperature via the temperature-dependent ability of oceans to absorb these gasses.

    [Linkspam removed -W]

    [Lubos - you've lost the plot (as ever). Do take a look at the paper in question. Its not about ice cores but about geological time. And do you really belive that there aren't any wako septic geologists out there that deny a CO2-T relation over these timescales? -W]

  2. #2 Fergus Brown
    2007/04/02

    Lubos; I kind of admire your persistence, but only in the most abstract of ways. Are you still insisting that CO2 is not a forcing? If stuff like this was understood as the nonsense it is, it wouldn’t matter, but your attempt to confuse the issue can fall on ignorant ears, so must be countered with sense. CO2 is a forcing; true or false?
    Regards,

  3. #3 John L. McCormick
    2007/04/02

    Folks, This is for real.

    The New York Times just reported the US Supreme Court handed down its opinion on EPA regulating CO2;

    see link which includes link to the entire opinion:

    http://www.nytimes.com/aponline/business/AP-Scotus-Greenhouse-Gase.html

    The story leads off with the following:

    WASHINGTON (AP) — The Supreme Court ordered the federal government on Monday to take a fresh look at regulating carbon dioxide emissions from cars, a rebuke to Bush administration policy on global warming.
    In a 5-4 decision, the court said the Clean Air Act gives the Environmental Protection Agency the authority to regulate the emissions of carbon dioxide and other greenhouse gases from cars.

  4. #4 oku
    2007/04/02

    I wrote something about that a few days ago. The link to the paper (without subscription) and a graphic is within.

  5. #5 Lubos Motl
    2007/04/02

    The link was not a spam but on the contrary a chance for you to increase the link quality of your blog by orders of magnitude. The page you erased is the #1 hit on Google for many combinations of words involving co2, temperature, lag, correlation, inconvenient-truth, al-gore, etc. Try e.g. co2 lag temperature

    If you go to much longer timescales, I deny the correlation myself. The key correlation known at sub-billion-year time-frame is between the cosmic rays and temperature. See the Global Swindle documentary. The shorter-term wiggles of CO2 and temperature are still correlated, like in ice core records, but the precise relationship in this correlation keeps on changing over hundreds of billions of years.

    Whatever timescale we consider, I insist that you don’t understand – or admit – the actual direction of the causal relationship.

    Best
    Lubos

  6. #6 James Annan
    2007/04/03

    It’s also interesting to see just how chronic the standard of reviewing must be to let something like this get published. Bits of that paper are palpable nonsense, starting off with the 2nd sentence. Even by the standards of climate science it is truly astonishing.

    But despite this it does, as you say, provide some more (rather weak) support for a middle of the road value for S, so it’s not entirely useless.

  7. #7 Wag the Dog
    2007/04/03

    Lubos Motl wrote: “The key correlation known at sub-billion-year time-frame is between the cosmic rays and temperature. See the Global Swindle documentary.”

    Citing a completely debunked polemical hatchet job is hardly going to win anyone over to your side. Given your reference to billion year time scales I assumed you are refering to the Shaviv and Veizer paper “Celestial driver of Phanerozoic climate?, GSA Today, 13 (7), 4-10, 2003 whose billion year plot of cosmic rays almost exactly mirroring temperature featured prominently in the Swindle. This work was critiqued by Rahmstorf et al. “Cosmic Rays, Carbon Dioxide and Climate” in January 2004 in Eos, Transactions of the American Geophysical Union. The cosmic ray model seems to have been phase shifted and over-tuned to such an extent that the cosmic ray plot now fits the original meteorite proxy data even less than the smoothed temperature reconstruction. Most dubious. Rahmstorf also noted Royer’s work as it relates to Veizer’s:

    A critique of the CO2 and temperature reconstructions used in [Shaviv and Veizer, 2003] will be published by Royer et al [in press], who correct Veizer’s d18O record for the effect of changing pH. This effect has been demonstrated in culture [Spero et al., 1997] and explained theoretically [Zeebe, 1999; Zeebe, 2001]. The result is a corrected climate record that no longer follows the cosmic ray model but correlates well with the Geocarb III CO2 reconstruction.

  8. #8 guthrie
    2007/04/03

    “Take this plane to Cuba!”

    On the Scotsman newspaper, we have some washed up old scientist called Richard Courtney claiming it is all down to changes in cloud cover.
    http://thescotsman.scotsman.com/international.cfm?id=506652007

    He is so stupid he has repeated the cooling since 1998 canard. Has anyone else bumped into him before, and why isn’t Lubos citing him as an expert?

  9. #9 Wag the Dog
    2007/04/03

    Royer’s previous work as it relates to climate sensitivity to CO2 and implications for the Shaviv-Veizer cosmic ray theory:

    The uncorrected Veizer temperature curve predicts long periods of intense global cooling that do not agree with independent observations of paleoclimate, especially during the Mesozoic. When corrected for pH effects, however, the temperature curve matches the glacial record much better.

    The global temperatures inferred from the cosmic ray flux model of Shaviv and Veizer (2003) do not correlate in amplitude with the temperatures recorded by Veizer et al. (2000) when corrected for past changes in oceanic pH. Additional problems with this correction have been shown by Rahmstaff et al.(2004). Changes in cosmic ray flux may affect climate but they are not the dominant climate driver on a multimillion-year time scale.

  10. #10 James Annan
    2007/04/03

    AFAICS, Courtney is one of the wanabees at the bottom end of the climate sceptics ladder. He’s got a sourcewatch page which I suppose is one step higher than having only a wikipedia page :-)

  11. #11 Luboš Motl
    2007/04/03

    Dear James, what kind of people are reviewing these papers? Is it old guys or young guys? Are you reviewing a lot of papers, or do you think that those who review most of them are less smart than you are?

    Best
    Lubos

  12. #12 guthrie
    2007/04/03

    Courtney is amusing, because of the way his right wing free market connections don’t seem to clash with his bein ga trades union person as well.
    He keeps banging on about how we know so little about clouds, and that Co2 warming is negligible, and also that:

    “I pointed out that from the mid 1980s to the end of the 1990s changes to cloud cover were measured to have had between 2 and 4 times more effect on climate than all emissions of greenhouse gases from all human activities since the industrial revolution.”

    They have yet to come back with some evidence.

  13. #13 Steve Bloom
    2007/04/03

    Lubos’ contrarianism is so pure that he can’t resist undermining himself by questioning James’ competence to support Lubos’ own position. He is, as he says, entertaining in some unique ways (although maybe I wouldn’t think so if I knew more Czechs, since based on that recent stuff from Peerless Leader it could be that it’s some sort of national tendency).

    BTW, James, am I correct that your comment was a snark about their reference of Hegerl et al rather than a substantive criticism? Just curious.

  14. #14 Luboš Motl
    2007/04/03

    Dear Steve Bloom, if you think that all Czechs are bright and independent geniuses like Klaus and your humble correspondent, I am afraid that such a generalization could be a little bit too excessive. ;-)

  15. #15 James Annan
    2007/04/03

    Lubos,

    I have no idea who refereed it, but it’s pretty clear that the Nature editors don’t think I’m fit to read their pearls let alone comment on them. I guess (and hope) that the reviewers must have been geoscientists rather than those with experience in probabilistic estimation.

    Steve, the problem I have with it is no snark on references but rather that the whole manner of their probabilistic calculations seems just bizarre, and although it’s vague and brief enough that I can’t tell exactly how wrong it is, the number of clumsy inaccuracies in their wording make it seem improbable that it is because their brilliance is way over my head…

    Furthermore, it’s not actually clear what they have done to account for changes in ice sheets, but it looks like they have included this as part of the CO2 response, which makes their definition of climate sensitivity incompatible with the rest of the world. That might not matter hugely given that most of this interval was warmer than present, but it’s hardly an encouraging sign.