Paleo tagging past climate sensitivity

I find this paper (PDF) interesting, but it still does not address the temperature/CO2 800 year time lag seen in ice core records. h/t to Leif Svalgaard – Anthony

Fossil soils constrain ancient climate sensitivity
Dana L. Royer 1

Department of Earth and Environmental Sciences, Wesleyan University, Middletown, CT 06459

Global temperatures have covaried with atmospheric carbon dioxide (CO2) over the last 450 million years of Earth’s history (1). Critically, ancient greenhouse periods provide some of the most pertinent information for anticipating how the Earth will respond to the current anthropogenic loading of greenhouse gases. Paleo-CO2 can be inferred either by proxy or by the modeling of the long-term carbon cycle.

Fig. 1. Constraints on climate sensitivity for the globally warm Cretaceous and early Paleogene (125–40 Mya). (A) Tropical sea surface temperature (SST) records (15–29). Boxes represent studies with high sampling density. The red band corresponds to estimated tropical SST under an atmospheric CO2 concentration of 1,000 ppm and a climate sensitivity (ΔT2×) of 3°C per CO2 doubling. Temperatures above this band probably represent times when climate sensitivity exceeded 3°C (see text). (B) Atmospheric CO2 records (compilation from ref. 2). Dashed lines correspond to present-day CO2 (387 ppm; A.D. 2009) and 1,000 ppm CO2. Records from the boron proxy are excluded because they are likely unreliable (30); records from the goethite and nahcolite proxies are excluded because they are not yet widely applied.

For much of the geologic past, estimates of CO2 are consistent across methods (1). One exception is the paleosol carbonate proxy, whose CO2 estimates are often more than twice as high as coeval estimates from other methods (1). This discrepancy has led some to question the validity of the other methods and has hindered attempts to understand the linkages between paleo-CO2 and other parts of the Earth system. In this issue of PNAS, Breecker and colleagues (2) break important new ground for resolving this conflict.

The paleosol carbonate proxy for atmospheric CO2 is based on the analysis of carbonate nodules that precipitate in soils in seasonally dry to dry climates. These nodules incorporate carbon from two sources: atmospheric CO2 that diffuses directly into the soil and in situ CO2 from biological respiration. Because the stable carbon isotopic composition of these two sources is distinct, the concentration of atmospheric CO2 can be inferred if the concentration of soil CO2 and the isotopic compositions of the two sources are known (3). Atmospheric CO2 estimates scale directly with soil CO2 concentration: If the soil term is wrong by a factor of two, the inferred atmospheric CO2 will be off by a factor of two.

Estimates of soil CO2 concentration for fossil soils have been based on measurements taken during the growing season in equivalent living soils. However, Breecker et al. (2, 4) demonstrate convincingly that the window of active carbonate formation is restricted to the warmer and dryer parts of the growing season. Carbonate formation is simply not thermodynamically favorable during cooler and wetter seasons. Critically, biological productivity and respiration are low during these dry periods. As a result, soil CO2 concentration during the critical window of active carbonate formation has been overestimated in most soils by a factor of two or more (2).

What does this mean? CO2 estimates from the paleosol carbonate proxy can be cut in half (or more). Doing so snaps the paleosol-based estimates in line with most other approaches (2) (Fig. 1B) and produces the most precise view to date of Earth’s CO2 history. We are now better equipped to answer some important, basic questions. For example, what is the quantitative relationship between CO2 and temperature? That is, for every doubling of CO2, what is the long-term (103–104 years) equilibrium response of global temperature (termed here climate sensitivity)?

Most assessments of climate sensitivity for the present day hover around 3°C per CO2 doubling (5), although if the longterm waxing and waning of continental ice sheets are considered it is probably closer to 6°C (6). Less is known about climate sensitivity during ancient greenhouse periods, simply because having poles draped in forest instead of ice represents a profound rearrangement of climate feedbacks.

Records of CO2 and temperature are now sufficiently robust for placing firm  minimum constraints on climate sensitivity during parts of the Cretaceous and early Paleogene (125–40 Mya), a well-known globally warm interval. Indeed, owing to the logarithmic relationship between CO2 and temperature, the geologic record is ideally suited for establishing minimum thresholds. This is because, to accommodate a declining sensitivity, other boundary conditions of the Earth system need to shift exponentially, for example, unreasonable oscillations in atmospheric CO2. Policywise, establishing a basement value for climate sensitivity is a critical step for addressing our current climate crisis (5).

With few exceptions, CO2 during the Cretaceous and early Paleogene was<1,000 ppm (2) (Fig. 1B). Global mean surface temperature is very difficult to establish for these ancient periods. However, temperature change in the tropics today scales at roughly two-thirds the global change (5, 6).

If we assume a similar relationship in the past and a climate sensitivity of 3°C perCO2 doubling, a rise in atmospheric CO2 to 1,000 ppm results in a 3.6°C warming in the tropics (relative to a 280-ppm baseline).

Given that tropical sea surface temperatures range from 27° to 29°C today, tropical temperatures exceeding 30.6°–32.6°C  (red band in Fig. 1A) during the Cretaceous and early Paleogene likely correspond to a climate sensitivity >3°C. This threshold was commonly surpassed during the Cretaceous and early Paleogene (Fig. 1A). For times when CO2 was <1,000 ppm, the tropical temperature threshold for a 3°C climate sensitivity would shift to correspondingly cooler values.

Further, there is abundant evidence for flatter latitudinal temperature gradients during greenhouse periods (7, 8), meaning, again, that the tropical temperature threshold used here is probably a maximum. Together, it is clear that during the Cretaceous and Paleogene climate sensitivity commonly exceeded 3°C per CO2 doubling.

Although further work is needed, the geologic evidence (2) (Fig. 1) is most consistent with long-term, future climate change being more severe than presently anticipated (5). Also, global climate models tuned to ancient greenhouse periods commonly have emergent climate sensitivities of <3°C and they fail to simulate the shallow latitudinal temperature gradients (9). Thus even for times with little ice, there are important positive feedbacks that are presently not captured adequately in climate models. Processes for warming the high latitudes without a change in CO2 include more vigorous heat transport (10, 11), more widespread stratospheric clouds in the high latitudes (12), and climate feedbacks from polar forests (13). and their study highlights the value of a clearly resolved paleo-CO2 record. However, a limitation is that they uniformly apply a “best guess” value of 2,500 ppm for soil CO2 concentration.

They recognize this as an oversimplification and is an area for future work. Better modeling of the term, perhaps through independent proxy (14), may result in a further tightening of the paleo-CO2 record.

1. Royer DL (2006) CO2-forced climate thresholds during the Phanerozoic. Geochim Cosmochim Acta 70:5665– 5675.

2. Breecker DO, Sharp ZD, McFadden LD (2010) Atmospheric CO2 concentrations during ancient greenhouse climates were similar to those predicted for 2100 A.D. Proc Natl Acad Sci USA 107:576–580.

3. Cerling TE (1991) Carbon dioxide in the atmosphere: Evidence from Cenozoic and Mesozoic paleosols. Am J Sci 291:377–400.

4. Breecker DO, Sharp ZD, McFadden LD (2009) Seasonal bias in the formation and stable isotopic composition of pedogenic carbonate in modern soils from central New Mexico, USA. Geol Soc Am Bull 121:630–640.

5. IPCC (2007) Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge Univ Press, Cambridge, UK).

6. Hansen J, et al. (2008) Target atmospheric CO2: Where should humanity aim? Open Atmospheric Sci J 2: 217–231.

7. Bice KL, Huber BT, Norris RD (2003) Extreme polar warmth during the Cretaceous greenhouse? Paradox of the late Turonian δ18O record at Deep Sea Drilling Project Site 511. Paleoceanography 18:1031.

8. Bijl PK, et al. (2009) Early Palaeogene temperature evolution of the southwest Pacific Ocean. Nature 461: 776–779.

9. Shellito CJ, Sloan LC, Huber M (2003) Climate model sensitivity to atmospheric CO2 levels in the Early-Middle Paleogene. Palaeogeogr Palaeoclimatol Palaeoecol 193: 113–123.

10. Korty RL, Emanuel KA, Scott JR (2008) Tropical cycloneinduced upper-ocean mixing and climate: Application to equable climates. J Clim 21:638–654.

11. Ufnar DF, González LA, Ludvigson GA, Brenner RL, Witzke BJ (2004) Evidence for increased latent heat transport during the Cretaceous (Albian) greenhouse warming. Geology 32:1049–1052.

12. Abbot DS, Tziperman E (2008) Sea ice, high-latitude convection, and equable climates. Geophys Res Lett 35:L03702.

13. Beerling DJ, Nicholas Hewitt C, Pyle JA, Raven JA (2007) Critical issues in trace gas biogeochemistry and global change. Philos Trans R Soc Lond A 365:1629–1642.

14. Retallack GJ (2009) Refining a pedogenic-carbonate CO2 paleobarometer to quantify a middle Miocene greenhouse spike. Palaeogeogr Palaeoclimatol Palaeoecol 281:57–65.

15. Bice KL, et al. (2006) A multiple proxy and model study of Cretaceous upper ocean temperatures and atmospheric CO2 concentration. Paleoceanography 21: PA2002.

16. Bornemann A, et al. (2008) Isotopic evidence for glaciation during the Cretaceous supergreenhouse. Science 319:189–192.

17. Forster A, Schouten S, Baas M, Sinninghe Damsté JS (2007) Mid-Cretaceous (Albian Santonian) sea surface temperature record of the tropical Atlantic Ocean. Geology 35:919–922.

18. Forster A, Schouten S, Moriya K, Wilson PA, Sinninghe Damsté JS (2007) Tropical warming and intermittent cooling during the Cenomanian/Turonian oceanic anoxic event 2: Sea surface temperature records from the equatorial Atlantic. Paleoceanography 22:PA1219.

19. Moriya K, Wilson PA, Friedrich O, Erbacher J, Kawahata H (2007) Testing for ice sheets during the mid-Cretaceous greenhouse using glassy foraminiferal calcite from the mid-Cenomanian tropics on Demerara Rise. Geology 35:615–618.

20. Norris RD, Bice KL, Magno EA, Wilson PA (2002) Jiggling the tropical thermostat in the Cretaceous hothouse. Geology 30:299–302.

21. Pearson PN, et al. (2001) Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs. Nature 413:481–487.

22. Pearson PN, et al. (2007) Stable warm tropical climate through the Eocene Epoch. Geology 35:211–214.

23. Schouten S, et al. (2003) Extremely high sea-surface temperatures at low latitudes during the middle Cretaceous as revealed by archaeal membrane lipids. Geology 31:1069–1072.

24. Tripati A, et al. (2003) Tropical sea-surface temperature reconstruction for the early Paleogene using Mg/Ca ratios of planktonic foraminifera. Paleoceanography 18:1101.

25. Wagner T, et al. (2008) Rapid warming and salinity changes of Cretaceous surface waters in the subtropical North Atlantic. Geology 36:203–206.

26. Wilson PA, Norris RD (2001) Warm tropical ocean surface and global anoxia during the mid-Cretaceous period. Nature 412:425–429.

27. Wilson PA, Norris RD, Cooper MJ (2002) Testing the Cretaceous greenhouse hypothesis using glassy foraminiferal calcite from the core of the Turonian tropics on Demerara Rise. Geology 30:607–610.

28. Wilson PA, Opdyke BN (1996) Equatorial sea-surface temperatures for the Maastrichtian revealed through remarkable preservation of metastable carbonate. Geology 24:555–558.

29. Sexton PF, Wilson PA, Pearson PN (2006) Microstructural and geochemical perspectives on planktic foraminiferal preservation: “glassy” versus “frosty”. Geochem Geophys Geosyst 7:Q12P19.

30. Pagani M, Lemarchand D, Spivack A, Gaillardet J (2005) A critical evaluation of the boron isotope-pH proxy: The accuracy of ancient ocean pH estimates. Geochim Cosmochim Acta 69:953–961.

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128 Responses to Paleo tagging past climate sensitivity

  1. anna v says:

    From what I see they assume that CO2 drives temperatures.
    Then start interpreting.

    This meas they ignore completely the 800 year lag in the ice core records.

    What if they assumed that rising and falling water levels control temperature , with varying H2O proportional to the area, a much more important green house gas? Or change in areas of tropical forests, which would again change H2O.
    Considering the land changes in the periods covered this is another exercise in GIGO, imho.

  2. I find this paper (PDF) interesting, but it still does not address the temperature/CO2 800 year time lag seen in ice core records.
    The paleo data is not fine-grained enough to show what follows what. The data does show that a much higher CO2-content was rather normal, and that the SST was ~5 degrees higher than today.

  3. Robert says:

    “Although further work is needed, the geologic evidence (2) (Fig. 1) is most consistent with long-term, future climate change being more severe than presently anticipated (5). Also, global climate models tuned to ancient greenhouse periods commonly have emergent climate sensitivities of <3°C and they fail to simulate the shallow latitudinal temperature gradients (9). Thus even for times with little ice, there are important positive feedbacks that are presently not captured adequately in climate models."

    Wow. Who says there's no debate over AGW? There's a vitally important debate going on, only in its most important aspects it's not between "happening" and "not happening" but rather between "happening" and "Let's-recite-the-21st-Psalm happening."

    Props to Mr. Watts for featuring something that directly challenges his take on the subject. I can see now why the blog wins awards.

    Obviously just one paper, needs confirmation, etc., but nicely dovetails with other research. I'd like to address this point:

    "it still does not address the temperature/CO2 800 year time lag seen in ice core records."

    Natural cycles seem most often to start with a weak change in solar forcing. After a certain point, positive feedbacks take over, among them, very importantly, CO2.

    Imagine a vase on the top of a stand. As long as you leave it alone, nothing. But push on it, even with one finger, it will tip over and then fall. Positive feedback takes over, in the form of gravity. You can see how gravity works by measuring how long the object takes to fall, just as you can measure the greenhouse effect of CO2 in the climate record, even though in both cases the initial "nudge" is different from the force being measured.

  4. Stephan says:

    From SVOR
    ““The [computer model] simulations rule out (at the 95% level) zero trends [in global temperatures] for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate.”
    taken from official NOAA doc s se SVOR website
    would this not automatically terminate AGW re jones statements no statistical warming since 1995?

  5. To my surprise, here I find myself in agreement with Mr. Svalgaard.

    Most of the premises in this article are based on “proxies,” “estimates,” and “assumptions,” not at all verifiable. But the conclusions are, suddenly, “clear” and “robust” enough to “establish a basement value for climate sensitivity as a critical step for addressing our current climate crisis, policywise.”

    I smell a paleofish.

  6. anna v says:

    Re: Leif Svalgaard (Feb 15 21:43),

    I wonder if there is somebody who has calculated how much CO2 will boil out of the oceans if they were 5 degrees warmer than now .

    I think it is hubris to believe that one can extract CO2 sensitivity from these paleo data, when there is water water everywhere.

  7. Doug in Seattle says:

    Its really quite amazing what you can do when you assume the IPCC and Jim Hansen are correct. In both cases the sensitivity of CO2 is estimated based on GCM models rather than empirical data.

    I wonder what results the authors would have got had they assumed different sensitivities.

  8. chuck says:

    Natural cycles seem most often to start with a weak change in solar forcing. After a certain point, positive feedbacks take over, among them, very importantly, CO2.

    What about the fact that CO2 is less soluble in warm water? That has to be factored out along with the contribution of water vapor and clouds, which are likely to depend not only on temperature but also on ocean currents and the locations of the continents. I don’t see any indication that that was attempted. What is shown is a possible correlation, the causation part doesn’t look to be settled at all.

  9. Dave Wendt says:

    Looking at their nice little graph, it appears that at most points the range of CO2 values is is 600 to 700 ppm and temps range about 10C. Plus we can’t know if the CO2 is driving the temps or vice versa. I’d have to say that it’s time to change the initials from PNAS to POS.

  10. a jones says:

    Interesting. Quite so.

    But what it tells us I am not so sure.

    It does say that CO2 levels vary with temperature.

    Since we do not know whether those CO2 levels led or lagged the temperature change we can say nothing beyond high CO2 levels are associated with warmer temperatures.

    That is hardly controversial, if the oceans control the CO2 in the atmosphere, and given their vast bulk and huge reserves of dissolved CO2, that is more or less what we would expect to see.

    Whether the CO2 levels in the atmosphere have any significant effect on global temperature is a moot point.

    Even more questionable is whether burning fossil fuels can significantly affect the CO2 levels in the atmosphere: given the scale of the natural variation.

    But whilst the science in this paper as to CO2 levels and temperature appear to be serious the interpretation placed on the relationship is highly dubious.

    And without any foundation in either the reported data or speculative assumptions as to the magnitude of the supposed effects of changes of atmospheric CO2 on global temperatures.

    In short the data, whilst possibly better than we had before, does not support the momentous conclusions placed upon it. The data only tells us what we knew before, if to a better degree of precision.

    Kindest Regards

  11. NickB. says:

    I still cannot accept the logic that non-CO2 variation kickstarts massive changes in climate but then CO2 takes over. Much like the warming from 1910 to the 1940s… we don’t know what caused it but the nexr round, oh yeah, *that* one was CO2

    Don’t get me wrong, I understand the allure of “it’s a simple physics problem” but complex systems are never quite that easy. Still looks like an answer in search of a problem I think

    BTW Leif, thanks for setting me straight on solar activity earlier, I hadn’t seen your post when I submitted. Good to see you around again!

  12. Phillip Bratby says:

    “Policywise, establishing a basement value for climate sensitivity is a critical step for addressing our current climate crisis”. What crisis would that be? The crisis that has emanated from Climategate showing AGW has no foundation? A future funding crisis if nobody believes the scary projections?

  13. rbateman says:

    Which came first: The temperature rise or the C02 released ?
    What is the ultimate source of the C02 levels in play, the oceans or the planetary interior (volcanic)?
    The question of volcanic activity levels releasing C02 and other gases must be answered, or we will continue to bat the oceanic ball back & forth.
    Plants don’t create C02, they use it. Animals eat plants and release 02.
    Geology sequesters in sediments. Limestone formations bring Calcium into the equation, and Calcium supply into question.
    Oceans can hold C02 in absorbtion, but how long does it take for geology to place it out of reach of warming ocean cycles?
    I think we would be better served to define the levels of vocanic activity during the Geologic Ages, then see how much the oceanic cycles work with what is in play.

  14. Carl Chapman says:

    The assumption is positive feedback causing sensitivity. The author quotes 3 degrees centigrade per doubling of CO2, which as about 3 times the first order rise. How can a positive feedback cause 3 times the effect, without going off to infinity? The feedback would have to be finely balanced.

    If the primary effect of doubling CO2 is a 1 degree rise, and the feed back factor is x, then the second order effect is x degrees. The third order feedback is x squared, then x^3, x^4 etc
    The final rise is then r = 1 + x + x^2 + x^3 + x^4 ….
    Solving that gives r = 1/(1-x).
    A feedback of 0.5 gives r = 2.
    feedback = 2/3 gives r = 3, which is what the article assumes.
    feedback = 3/4 gives r = 4

    feedback = 9/10 gives r = 10.
    So the feedback has to be very finely tuned. Less than 2/3 gives CO2 global warming is no big deal.
    2/3 would be barely believable if you assumed CRU and Gistemp were gospel.
    ¾ would be so high the effects would already be dramatic.
    9/10, we’d be fried or frozen long ago.
    There is absolutely no evidence that feedback is exactly 2/3. If it was, the temperatures couldn’t have fallen since 1995, as Phil Jones now admits they have.

  15. Mike D. says:

    Polar forests instead of ice caps? Bummer, man.

  16. stumpy says:

    Translation = We spent lots of time and money, made lots of dodgy assumptions and dont know any thing more than we did before.

    I find the paper a little troubling, the issue of temperature co2 lag is V important and key to the papers conclusions. The papers assumes there is a linear relationship between co2 and temperature, which there is, but the relationship is reversed to what they assume. The relationship is due to the sea warming and then outgassing co2 and vise versa (a very well established relationship), it has not been demonstrated that co2 has had any part in past warming in any way given the large lag (see the IPCC AR4) and only climate models provide any support for this, but they based on circular reasoning as they assume co2 causes warming, hence invalid.

    So I would argue the entire papers is pointless and wrong, but confusing correlation and causation they provide support for the IPCC claims of a 3 degree sensitivity but include enough get out clauses to show the results is so uncertain, its of no use whatsoever, but when sucked into the IPCC report, it can be misrepresented to mislead those who have not taken time to read or understand the paper. They also fail to mention all of the uncertainties in past paleo records.

    Also the assumption that the equator has a linear relationship to temperatures globally is foolish, given the IPCC state that the poles are greatly affected by temperature change whilst the equator has remained fairly constant or cooled during previous warm periods (IPCC AR4). This again invalidates their work.

    Poorly justified assumptions and reversed relationships do not equal reality! A complete waste of tax payer money!!!

    However, perfect to mislead policy makers!

  17. Richard Telford says:

    “it still does not address the temperature/CO2 800 year time lag seen in ice core records”
    There are numerous papers that explain the lag between orbitally-forced climate change and the CO2 rise which was initiated by the warming and led to further warming. It would be far more surprising if CO2 preceded orbitally-forced climate change!

  18. Leo G says:

    Anthony, you are to be congradgulated for staying curious. It is only old minds that are settled.

    Bravo!

  19. jorgekafkazar says:

    Fiction and fact from Sam’s almanac.

  20. tty says:

    The very high temperature estimates based on TEX86 are essentially just guesses as there is no way to verify them from modern sediments. I find them very doubtful since they are never corroborated by e. g. d18O which are based on known physics.

  21. Cement a friend says:

    Great, they pick one of the methods for obtaining CO2 proxies and say the other methods are wrong. If they consider consensus, should they have not discarded the method which is giving anomalous results? Of course, they would not have had preconceived ideas about global warming would they ?
    Also, where does the idea of temperature increase from doubling of CO2 come from- models which have been proved to be inaccurate.
    I wonder who peer reviewed this was it Mann, Jones, or Hansen who is mentioned in the references?

  22. Rabe says:

    @Robert:

    That’s reasonable. When a vase standing at a tipping point is tipped and releases such a big energy impulse it really must be possible using that energy difference to drive a perpetual motion machine.

  23. old construction worker says:

    Leif Svalgaard (21:43:28) :
    ‘I find this paper (PDF) interesting, but it still does not address the temperature/CO2 800 year time lag seen in ice core records.
    The paleo data is not fine-grained enough to show what follows what. The data does show that a much higher CO2-content was rather normal, and that the SST was ~5 degrees higher than today.’

    Or they are saying the Ice Core Data is “wrong”. There is no “lag time”.

  24. Robert says:

    Rabe: “That’s reasonable. When a vase standing at a tipping point is tipped and releases such a big energy impulse it really must be possible using that energy difference to drive a perpetual motion machine.”

    Wow. Not content with rejecting the theory of AGW, apparently you reject the law of gravity. At least your attitude towards science is consistent.

  25. Tom P says:

    Carl Chapman (23:08:23) :

    “There is absolutely no evidence that feedback is exactly 2/3. If it was, the temperatures couldn’t have fallen since 1995, as Phil Jones now admits they have.”

    Temperatures on any measure have increased since 1995:

    http://www.woodfortrees.org/plot/uah/from:1995/plot/wti/from:1995/trend/plot/rss/from:1995/plot/hadcrut3vgl/from:1995/offset:-.15/plot/gistemp/from:1995/offset:-.24

    Jones stated this increase was not statistically significant. That’s hardly an admission that temperatures have fallen since 1995. Their rise could be consistent with some measure of positive feedback.

  26. JER0ME says:

    Over at unreal climate they have fully explained the temperature/CO2 800 year time lag:

    http://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores/

    This is an issue that is often misunderstood in the public sphere and media, so it is worth spending some time to explain it and clarify it. At least three careful ice core studies have shown that CO2 starts to rise about 800 years (600-1000 years) after Antarctic temperature during glacial terminations. These terminations are pronounced warming periods that mark the ends of the ice ages that happen every 100,000 years or so.

    Does this prove that CO2 doesn’t cause global warming? The answer is no.

    The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2, as far as we can tell from this ice core data.

    From studying all the available data (not just ice cores), the probable sequence of events at a termination goes something like this. Some (currently unknown) process causes Antarctica and the surrounding ocean to warm. This process also causes CO2 to start rising, about 800 years later. Then CO2 further warms the whole planet, because of its heat-trapping properties. This leads to even further CO2 release. So CO2 during ice ages should be thought of as a “feedback”, much like the feedback that results from putting a microphone too near to a loudspeaker.

    You see, it’s obvious. It was CO2 wot dunnit, even though it was not in the room at the time. We believe it turned up afterwards and finished the dirty deed. We’ve even got proof. Well, not proof exactly, but we are pretty sure. It must be CO2. Trust us, please…..

  27. Richard Telford says:

    tty (23:34:20)

    A calibration curve for TEX86 for temperatures above those found in the modern ocean has been derived from culture experiments, see Schouten et al 2007 Towards calibration of the TEX86 palaeothermometer for tropical sea surface temperatures in ancient greenhouse worlds. http://www.ldeo.columbia.edu/~peter/Resources/Seminar/readings/Schouten_TEX86Calibration-tropics_OG%2707.pdf
    Oxgen isotopes are not without their difficulties – to estimate temperature from the d18O of calcite, you need to know the d18O of the water.

  28. kadaka says:

    Robert (21:56:42) :
    (…)
    Imagine a vase on the top of a stand. As long as you leave it alone, nothing. But push on it, even with one finger, it will tip over and then fall. Positive feedback takes over, in the form of gravity. (…)

    Preliminary testing completed. Small test group of randomly-selected empty vases, all with circular reasonably-flat bottoms, with a rounded edge going from bottom to side (main body). Light pressure from a single finger did not result in tipping over. Upon removal of pressure, vases returned to sitting flat on test surface, normally after briefly wobbling back-and-forth. Going from basic physics, assuming insignificant momentum (slow and steady application of pressure with negligible velocity during movement), the vase would not be expected to fall over unless the center of gravity was allowed to move beyond the point of contact near the base. [From contact point on rounded edge, figure the size of a circle measured from vase axis, project that perpendicularly to the test surface (will yield an ellipse given the tilt of the base). The center of gravity projected perpendicularly to the surface cannot go beyond the edge of the ellipse.]

    Further, the vases exhibited a tendency to roll away from the tip of the finger then resume sitting flat (as above), or as flat as possible if the finger was still in contact with the vase. Sometimes the vases would not tilt, but were pushed along while still sitting flat (they slid).

    Initial results indicate that the mere act of pushing on a vase with a single finger will not automatically result in the vase tipping over and falling. When the vase tilts instead of slides, gravity will act to keep the vase upright and yield a force acting against the pressure from the finger, up to where the center of gravity moves beyond the point of contact, i.e. the tipping point. Gravity also acts to allow the vase to slide instead of tilt. When enough pressure is applied during a tilting condition to cause the vase to tip over, gravity will then act to place the vase in a new equilibrium state that ceases the influence of the finger on the vase, i.e. it tips the vase away from the finger.

    Therefore pushing the vase with a single finger does not guarantee it will tip over and fall. And since gravity acts to counter any effect from the finger, it cannot be considered to yield a positive feedback.

    Physics 2, Robert 0.

    No further testing is indicated as necessary. Unless one wishes to consider the anecdotal reports that a frequent cause of vases falling off of stands is the stands being disturbed (moved, bumped) and verify that a vase “left alone” on a stand can also fall.

  29. anna v says:

    Re: Richard Telford (Feb 15 23:24),

    “it still does not address the temperature/CO2 800 year time lag seen in ice core records”
    There are numerous papers that explain the lag between orbitally-forced climate change and the CO2 rise which was initiated by the warming and led to further warming. It would be far more surprising if CO2 preceded orbitally-forced climate change!

    These numerous papers are thermodynamically wrong and should be scrapped.

    Time to show the free energy oven: once more.

    The confusion comes by mixing two physical bases: quantum mechanics and thermodynamics. Thermodynamics appears as a limit in quantum statistical mechanics but if the systems are mixed, double counting happens, as the oven linked above shows.

    There is no way in thermodynamics, which is a physics system that works extremely well in macroscopic systems, for example in combustion engines, to filter green house gases on an individual basis. In the thermodynamic equations a deltaX of one green house gas is indistinguishable from another, except in how much the heat capacity is changing. And the deltaX coming from H2O is much larger in quantity and in effect.

    If there were a mechanism by which a small change in a greenhouse gas would induce runaway warming it would have happened with water vapor at the first orbital change, mllions of years ago, and we would not be here now typing.

  30. Richard says:

    Robert (21:56:42) : Obviously just one paper, needs confirmation, etc., but nicely dovetails with other research. I’d like to address this point:

    “it still does not address the temperature/CO2 800 year time lag seen in ice core records.”

    Natural cycles seem most often to start with a weak change in solar forcing. After a certain point, positive feedbacks take over, among them, very importantly, CO2.

    Imagine a vase .. blah blah..

    Thanks Robert I think we know what positive feedbacks are.

    More CO2 .. more water vapour.. more warming… so the AGW hypothesis goes

    Question: – why does this not carry on? What stops it? Why do temperatures eventually start plunging even as CO2 continues to rise? Why are warm interglacials brief and glacial periods long?

    Nature does not seem to behave as the theory goes.

  31. D Mayhew says:

    Policywise, establishing a basement value for climate sensitivity is a critical step for addressing our current climate crisis (5).

    What crisis?

  32. John Wright says:

    “Thus even for times with little ice, there are important positive feedbacks that are presently not captured adequately in climate models.”

    Just a semantic niggle and I don’t know if it’s relevant here (although I think it does reveal a certain mindset): a model can take observed facts into account and perhaps give a new slant on them, but I don’t see how it can “capture” anything, let alone “important positive feedbacks”.

  33. anopheles says:

    I’m having a little difficulty seeing how these guys can measure CO2 sensitivity long long ago, but today we can’t agree on what it is when we can see everything that is going on, TSI, clouds, albedo, ice coverage, SSTs. Indeed we can’t even agree on whether the concept of CO2 sensitivity is a sound one except in isolation.

    I think we can all agree, more research is needed. Funny how all papers end that way.

  34. Mark Hladik says:

    As previously mentioned, there does not seem to be much control for the location(s) of the continental land masses at this time. Antarctica was barely impinging upon the south geographic pole, there was no isthmus of Panama (so the “Atlantic” and “Pacific” were virtually the same ocean), and oceanic/atmospheric circulation patterns were substantially different from the ones we see today.

    Most of the paleogeographic reconstructions I have seen have a high degree of confidence that the Arctic was largely ice-free year-round, but again, was it CO2 or was it something to do with circulation patterns of that time period?

    O/T : Anthony or Moderator — – —

    There is a website I visit occasionally, very strongly in the IPCC camp, which has some great data, charts, etc. My suspicion is that they [whomever 'they' might be] do not realize that much of their archive directly refutes their belief in AGW. If ‘they’ should figure out, these valuable data might be lost. Without violating copyright laws, and what-not, is there a way for WUWT to capture at least some of their data, and preserve it for posterity?

    Best wishes to all, and Thnx,

    Mark H.

    Reply: Your question is unanswerable without details, such as what website? ~ ctm

  35. cal says:

    Robert

    As Carl Chapman has already pointed out, the concept of significant positive feedback is an unlikely and unsupported concept. The fact is that that the worlds climate has been relatively stable over many millions of years despite major events that have pushed it to extremes of temperature. It as has always recovered. Your vase analogy is not a good one; the earth is more like one of those wobbly toys that always bounces back to upright eventually.

    Also I suggest you check the climate records in detail before you repeat the mantra that the climate first warms as a result of orbital factors and then the increasing CO2 amplifies the effect. The ice core records show that after a period of warming the temperature begins to fall again whilst the CO2 concentrations are still rising. In some cases the temperature anomoly has dropped all the way back to zero before CO2 concentration begins to fall significantly. Rapidly falling temperatures whilst CO2 levels are at a maximum is not consistent with positive feedback unless the primary drivers completely overwhelm the feedback. If this is the case we should be looking for what makes these orbital effects so powerful.

    The same is true when the earth is in the depths of an ice age. CO2 concentrations are at a minimum and albedo at a maximum and yet the earth recovers!

    Indeed if I were to look at the graphs without any knowledge of what the plots related to I would say that the line representing CO2 was consistent with negative feedback!

  36. The Truth Will Make You Puca says:

    How did/does Gore get away with claiming that CO2 causes warming in ‘an inconvenient truth’ by just splitting the two lines in the ‘graph’ to hide the fact that temperature rises first and then CO2 conc? Why wasn’t he hounded and vilified by the media for such an obvious attempt to mislead? I really can’t understand it at all.

  37. AlanG says:

    WRONG. The authors of this paper have left out one of the major differences between 120 Mya and today – the position of the continents which change because of continental drift. If warm currents can get to the poles, which they could in the past, the poles (and average global temperatures) would be much warmer than when polar ocean currents are blocked as they are today. The two barriers today are the Americas which extend from the Arctic nearly to the Antarctic and Siberia down to South Africa.

    Leaving aside any changes of atmospheric pressure or to plant life via evolution, assigning higher paleo temperatures entirely to paleo CO2 as the authors do will give a higher sensitivity to CO2 if any of the temperature difference is due to other causes (such as continental drift). I think I’m right here. If Leif or Anthony knows any of the authors perhaps they would care to comment.

  38. Mark Hladik says:

    Howdy Charles,

    Sorry to be so vague. Most likely you know the website:

    http://www.globalwarmingart.com

    I made a ‘paper and pencil’ composite of three of the graphs from their archive, then did some TI- 30 Solar processing on it (so as to not offend Mr. Gore) and found interesting cross-correlations.

    Looking forward to your input,

    Mark H.

    Reply: Oh…That’s “Hano”‘s site. Interesting backstory here. He has different content licensed with various restrictions, much under a GNU free use. Just check the copyrights on what you want and make sure you adhere to any restrictions on any redistributions. He is pretty clear. ~ ctm

  39. Chris Wright says:

    As they refer to ‘our current climate crisis’, it’s pretty obvious where they’re coming from.
    Although the ice cores cover a much small time scan ( around 600,000 years) they’re probably the best data source that shows the natural relationship between temperature and CO2. As far as I’m aware, they very clearly show a roughly 800 year lag, and it has not been possible to demonstrate that CO2 had any effect on the climate at all over this 600,000 year period.
    Unless there is evidence to the contrary, it seems likely that the relationship demonstrated by the ice cores will be true over much longer periods. Therefore, if any scientists assume that their data demonstrates CO2 driving the climate they’re going to need proof that it was not the other way around.#
    Unless they provide proof that the temperature changes were driven by CO2, any conclusions about CO2 forcing based on their data are worthless.
    Science should be based on proof and not on blind faith.
    By the way, as far as I’m aware, the NOAA, on their web page, still states specifically that the ice cores show that the temperature was driven by the CO2 (it says something like ‘As the CO2 goes up, the temperature goes up’, virtually a direct quote from Gore). Either the NOAA is unaware of the 800 year lag or they’re still trying to ‘hide the decline’.
    Ironically, I would think the ice cores provide one of the strongest arguments against AGW, as they appear to show that CO2 has essentially no effect on the climate.
    Chris

  40. wayne says:

    anna v (22:08:14) :
    I wonder if there is somebody who has calculated how much CO2 will boil out of the oceans…

    CO2 solubility in water data from brown.edu
    radiusEarth and sea% from wikiPedia
    Assuming warming top 1 meters from 17C to 22C
    CO2 vented =
    4/3**(^3 – (-1)^3) * 70%
    to * (0.001845 – 0.001590)
    = 9.1e+13 kg

  41. wayne says:

    anna v (22:08:14) :
    Well the formatter didn’t like the sharp brackets around units in the equation. The data & answer survived.
    (Knew better than that!)

  42. guidoLaMoto says:

    Note from Fig 1 that (a) estimates of [co2] vary so wildly at any given time, even among those taken by similar methods, so as to be meaningless, and (b) estimates of temps seem to occur at times where fewest co2 estimates are made. So how can you correlate one with the other in any meanigful way?

  43. rbateman says:

    anna v (00:39:31) :

    If there were a mechanism by which a small change in a greenhouse gas would induce runaway warming it would have happened with water vapor at the first orbital change, mllions of years ago, and we would not be here now typing.

    The next planet in towards the Sun from Earth immediately comes to mind.
    On the other end of the spectrum, we have the runaway cooling case of Mars.
    If we had spent more $$$ on Mars exploration instead of the $$$ wasted on chasing climate disaster theories, we’d not be in here typing about the latter. There is still the spectre of Life on Ancient Mars yet to be resolved.
    So we might be typing about how Life on Mars failed to maintain the biosphere/atmosphere.

  44. wayne says:

    Hey, they found the leak!
    So that’s where that linear co2 is coming from. :)

    Scientists Discover Liquid Carbon Dioxide ‘Champagne’ Bubbles At Hydrothermal Vent
    - ScienceDaily
    http://www.sciencedaily.com/releases/2005/01/050104114942.htm

  45. Spector says:

    RE: Carl Chapman (23:08:23) : “The assumption is positive feedback causing sensitivity. The author quotes 3 degrees centigrade per doubling of CO2, which as about 3 times the first order rise. How can a positive feedback cause 3 times the effect, without going off to infinity? The feedback would have to be finely balanced.”

    I think you are confusing closed-loop gain with open-loop gain. A closed loop gain of three with positive feedback is obtained with a net open loop gain of 2/3 (0.666…) with a basic forward gain of unity. The final closed loop gain of three is the result of an infinite series of the form 1 + 2/3 + 4/9 + 8/27 + 16/81 + ….

    Yes, the feedback would have to be finely balanced, however to be dangerous, the linear feedback gain would have to increase as the CO2 concentration increases to match the decreasing rate of temperature rise per each additional ppm increase in CO2 concentration. This decreasing sensitivity is implied by the logarithmic doubling relationship.

  46. Lonnie Schubert says:

    AlanG:

    Nothing new. Christopher R. Scotese has had the data posted for years:
    http://www.scotese.com/

    My favorite quote: “During the last 2 billion years the Earth’s climate has alternated between a frigid “Ice House”, like today’s world, and a steaming “Hot House”, like the world of the dinosaurs.”

    from here: http://www.scotese.com/climate.htm
    and check the graph. Note that the high point in the early Eocene is where the bio folks tell us primates and grass eaters got their hold in life’s web.

    Warmer is beter.

  47. Leonard Weinstein says:

    Earth’s surface plate drift moves land in and out of the polar regions over geologic times. Whenever the land area is large enough near the poles, glacier formation lowers sea level and results in lower temperatures and even ice ages. Add to this the planetary variation in tilt and orbit, Solar activity, and periods of massive volcanic activity (Siberian traps, etc) and biological activity, and the drivers for temperature change are many. As the temperature changes, rock erosion, sea water release of CO2, and variation in biological activity change the atmospheric CO2 level. There is NO evidence the CO2 itself caused any significant temperature change, but it is clearly logical that temperature change results in a change in CO2 level. Positive feedback is assumed, but totally without proof, and in fact seems to be falsified with present direct data. It has also been observed that the small temperature rise over the last 150 years is mainly due to higher low temperatures, not higher high temperatures. This also removes the claim of extreme high temperature problems as a result of the warming.

  48. tty says:

    Richard Telford (00:30:07) :

    From the paper you cite:

    “…however, the crenarchaeol regioisomer in the GDGT distribution obtained from the incubation experiments is substantially less than in sediments deposited in exceptionally warm oceans of the geological past, so our laboratory results cannot be directly used to convert TEX86 values from these sediments into temperature.”

    So as I said, the TEX 86 / temperature correlation is decidedly shaky.

  49. Tamara says:

    I have a hard time with this study because it starts with the assumption that there is a baseline concentration of 280ppm CO2. The history of the Earth has been to SEQUESTER CO2, not release it. From a starting atmosphere that was dominated by CO2, with no free oxygen, the concentration fell to less than 0.02% at the end of the last glaciation. Without the activities of man, digging up peat bogs, burning fuels, processing carbonate rocks, very little CO2 would be released into the atmosphere. The historical record shows that our currently cold world releases very little CO2 on its own. There is no equilibrium state. If temperatures were to remain at the very cold pre-Industrial level with no increase in CO2, is it not possible that we might find ourselves living in a nutrient-starved desert?

  50. Bill Illis says:

    There is a lot of data selection and confusing graphs in this paper. That is the signature of all of Royer’s papers.

    The pedogenic carbonates/paleosols/fossil soils CO2 estimates have always produced widely varying estimates (Royer changes the name each time he uses them).

    Look at the data in the chart for around 65 to 70 million years ago. The revised fossil soils CO2 estimates range from Zero to 750 ppm with the majority being lower than 280 ppm. Previously, these estimates ranged from Zero to 1,500 ppm at this time period (2,950 ppm at 75 million years ago).

    They should just quit using this method, it is not reliable. Any CO2 estimate that produces Zeros and unrealistically low estimates consistently should be discontinued (there will be at least 12 estimates below 100 ppm with this newer method now).

    It is no wonder that Royer wants to restate these CO2 estimates, they do not match the temperature record at 3.0C per doubling.

    Here is all of the CO2 estimates over the whole record from Fossil Soils/Pedogenic Carbonates as used in the IPCC AR4 (I believe they were collated by Royer).

    http://img708.imageshack.us/img708/4313/co2fossilsoilsar4.png

    as documented here: figure6.1top

    ftp://ftp.ncdc.noaa.gov/pub/data/paleo/ipcc2007/

  51. JT says:

    This paper says, “If we assume a similar relationship in the past and a climate sensitivity of 3°C perCO2 doubling, a rise in atmospheric CO2 to 1,000 ppm results in a 3.6°C warming in the tropics (relative to a 280-ppm baseline).” Note the word “assume”. But Dr. Jeffrey Glassman, in

    THE ACQUITTAL OF CARBON DIOXIDE
    http://www.rocketscientistsjournal.com/2006/10/co2_acquittal.html

    has shown that the 800 – 1000 year time lag in the Vostok ice cores and the overall shape of the temperature and CO2 curves is entirely consistent with temperature being the driver of CO2 concentration, and that there is no evidence in the Vostok cores that CO2 drives temperature at all. I have looked for a reasoned refutation of Glassman’s thesis on the web and have not found one.

  52. Ivan says:

    Leif Svalgard: “The paleo data is not fine-grained enough to show what follows what. The data does show that a much higher CO2-content was rather normal, and that the SST was ~5 degrees higher than today.”

    And that proves – what?

  53. Roger Knights says:

    wayne (02:51:49) :

    anna v (22:08:14) :
    Well the formatter didn’t like the sharp brackets around units in the equation. The data & answer survived.
    (Knew better than that!)

    A “printable” left angle bracket is made with these four characters in succession:

    &
    lt
    ;

    For a right angle bracket, use “gt”

  54. Jean Parisot says:

    As the time baseline extend back, the 800 years of precede or lag becomes invisible due to the error margin in the time domain. Until the recent ice core data is explained – this paper has a fundamental problem – one could look at the paleo-data and rationally identify CO2 as a lagging indicator of warming. As one could do today.

  55. J.Hansford says:

    Still seems chicken or egg stuff to me….. Warming first then CO2…. Or warm because of CO2.

    No very clarifying…

  56. JonesII says:

    Am I at WUWT?:

    If we assume a similar relationship in the past and a climate sensitivity of 3°C perCO2 doubling, a rise in atmospheric CO2 to 1,000 ppm results in a 3.6°C warming in the tropics (relative to a 280-ppm baseline).

    The Holy Church of Global Warming.

  57. Trysail says:

    For your glossary:

    PNAS= Proceedings of the National Academy of Sciences

  58. son of mulder says:

    Carl Chapman (23:08:23) :

    Taking your feedback exercise a stage further consider 1880 with a temperature anomoly of -0.2C on http://www.cru.uea.ac.uk/cru/data/temperature/nhshgl.gif and 0.5C in 2000 both are points at a local peak of temperature so not a cherry pick. Assume CO2 grew from 280 ppm (pre industrial?) in 1880 to 360ppm in 2000 according to http://www.esrl.noaa.gov/gmd/ccgg/trends/#mlo_full What value of x,r do you calculate. I make x to be about 0.48 and r=1.92 (assuming the flat last 10 years means no more warming from pre 2000 addition of anthropic CO2). I assumed warming due to CO2 alone (before feedbacks) as ((1/ln(2))*ln(C2000/C1880) = 0.363 so doubling CO2 would give 1 deg C as you used. C2000 is CO2ppm in 2000.

  59. AlanG says:

    Lonnie Schubert (04:46:46) : Thanks for that link to Scotese. His hot/cold flip flop certainly doesn’t fit with linear temp/CO2

  60. Richard Telford says:

    anna v (00:39:31)

    The absurd cartoon you link to bears no resemblance to the way that anybody thinks that the climate works.

  61. Wondering Aloud says:

    Once again starting with the assumption that CO2 drives temperature than try to make the record suggest a large sensitivity. Very telling is the repeated use of the idea of degrees change per doubling as if a second doubling would have an equal effect.

    I am very disappointed, the built in bias is so large I have trouble taking it seriously and they may have something of interest buried here

  62. Dave in Delaware says:

    anna v (22:08:14) :
    I wonder if there is somebody who has calculated how much CO2 will boil out of the oceans…and wayne (02:48:21) :

    My estimates suggest that warming the oceans from 27-29 DegC range to 30.6°–32.6°C range could reduce the CO2 solubility by a relative 10% to 15%.
    How much CO2 is that? Well, it looks to me like it could pretty much account for the CO2 range shown in the diagram B. In other words, warming the surface & intermediate ocean levels (from any source) could account for all of that CO2 without AGW forcing.

    Details:

    I started with the CO2 – Water solubility per Glassman to get an approximation of the CO2 lost as the water warms.

    This table shows the grams of CO2 in 100 g water at various temperatures. The percentage columns show the remaining CO2 relative to the 27, 28 or 29 Deg CO2. So the interpolated CO2 value for 32.6 would be about 86% versus a 27 Deg starting point, and would be 91% vs a 29 Deg baseline. For the sensitivity of this estimate, I suggest 10% to 15% loss is a reasonable approximation.

    DegC__g/100g_________ vs 27___vs 28___vs29
    27_____0.137 100.0%
    28_____0.133 97.1% 100.0%
    29_____0.129 94.6% 97.4% 100.0%
    30_____0.126 92.0% 94.7% 97.3%
    32.6____0.118 interpolated 86.2% 88.8% 91.2%
    35_____0.111 80.9% 83.3% 85.5%

    How much CO2 is that relative to estimated Ocean and Atmospheric material balances?
    From Holmen, 2000 we get estimated CO2 in Surface + Intermediate Ocean to the order of 7600 Gt CO2 (as Carbon)
    and for atmospheric CO2 of 380 ppm, the estimate is about 750 Gt CO2 (as Carbon)

    If 10 to 15% of the 7600 Gt is released to the atmosphere, that would be an additional 760 to 1100 Gt CO2, which could change the
    380 ppm (at 750Gt)
    to 760 ppm (at 750+760 Gt)
    up to about 960 ppm (at 750 + 1100 Gt).

    To my eye, that CO2 range up to 960 ppm pretty much accounts for the ‘dotted line’ area for Atmospheric CO2 (ppm) as shown in graph B.

  63. NickB. says:

    JT (06:40:08)

    The only response I have seen is here:

    Does this prove that CO2 doesn’t cause global warming? The answer is no. The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2, as far as we can tell from this ice core data.
    http://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores/

    Like I said earlier, this line of thinking still seems to be an answer in search of a problem.

  64. Spector says:

    RE: J.Hansford (07:03:51) : “Still seems chicken or egg stuff to me….. Warming first then CO2…. Or warm because of CO2.”

    As water vapor ['dihydrogen monoxide'] is *the* primary greenhouse gas in the atmosphere, it might be more instructive to attempt to track or estimate past changes in the H2O concentration of the atmosphere and perhaps more importantly, the stratosphere…

    http://www.scientificamerican.com/article.cfm?id=is-water-vapor-in-the-stratosphere-slowing-global-warming

  65. David Middleton says:

    Global temperatures have covaried with atmospheric carbon dioxide (CO2) over the last 450 million years of Earth’s history (1).

    Dr. Royer references his own paper (Royer, 2006) for this claim. Veizer’s and Shaviv’s reply to Royer’s previous assertion of Phanerozoic and temperature covariance (Royer et al., 2004) pointed out that this covariance was obtained through a pH adjustment to oxygen isotope data; which brought the temperatures into line with the pale-CO2 levels. The pH adjustment was derived from CO2. So, Royer used CO2 to calibrate temperatures to CO2…

    The analysis of Royer et al. (2004) assumes an unrealistically high pH correction. First, it neglects the ice-volume effect, which changes the relation between d18O and dT. Second, this large pH correction implies high temperatures for seawater even during times of extensive glaciations.

    Moreover, the analysis of Royer et al. (2004) consists of bootstrapping, by introducing a correction to dT that
    is an implicit function of RCO2. It is then not surprising that a correlation between dT and RCO2 is obtained.
    This would be the case irrespective of the RCO2 model utilized.

    Then Royer suggests that the deviation of paleosol (pedogenic carbonate) derived CO2 from other methods of CO2 derivation, somehow brings those other methods into question…

    One exception is the paleosol carbonate proxy, whose CO2 estimates are often more than twice as high as coeval estimates from other methods (1). This discrepancy has led some to question the validity of the other methods and has hindered attempts to understand the linkages between paleo-CO2 and other parts of the Earth system.

    In the case of Royer’s 2004 paper on Paleocene-Eocene Thermal Maximum (PETM) CO2 levels, he showed that pedogenic carbonates actually yielded CO2 levels that were 4-5 times as large as those derived from fossil plant stomata indices. Yet Royer insists that pedogenic carbonates yield “the most precise view to date of Earth’s CO2 history.” Plant SI data can actually be calibrated to the modern instrumental record and can be empirically tested; yet Royer would reject these data in favor of the data that supports his hypothesis of Phanerozoic covariance of CO2 and temperature.

    This leads Royer to the absurd conclusion that “for every doubling of CO2″ is “is probably closer to 6°C”; rather than the maximum of 2°C that can be derived from CO2 and temperature data since 1880. And the 2°C can only be achieved if every bot of warming since 1880 is the result of an enhanced greenhouse effect from anthropogenic CO2.

    What could possibly lead Dr. Royer to continually torture the data until it says what he wants it to say?

    Maybe it has something to do with him being an environmental activist… Ask a Professor: Dana Royer, Earth and Environmental Science.

  66. NickB. says:

    @ John Wright (01:08:34) :
    Just a semantic niggle and I don’t know if it’s relevant here (although I think it does reveal a certain mindset): a model can take observed facts into account and perhaps give a new slant on them, but I don’t see how it can “capture” anything, let alone “important positive feedbacks”.

    The contrary of what you just said is really the logical failure at the heart of the GCMs – so I think it is very important that we do not fall into the same bad way of thinking. Careful use of observed data is very useful for supporting/refuting theories (like feedbacks), but in and of itself can’t make theories. As discussed on another thread recently, this is where Economics (specifically Econometrics) seems to be a much better evolved and mature discipline than climate science.

    You can tease correlations out of data sets all day long, but those correlations have to then be underpinned by a theory that can then be proven or falsified through observation or experimentation. All of that must be done *before* you even think about plugging that relationship into a more complex model and consider it to have any predictive power based on solid science.

    It might just be a “semantic niggle”, but it is important.

  67. p.g.sharrow "PG" says:

    It appears to me that the paleosol carbonate proxy, is proved to be useless. The chart offered above shows this proxy is all over the place in results and the author says the results need adjustments to make them fit in. Shades of Mann and Jones, we don’t need more of this. BS (bad science) poor premis both in chemistry and physics.

  68. RockyRoad says:

    From Robert:

    “Imagine a vase on the top of a stand. As long as you leave it alone, nothing. But push on it, even with one finger, it will tip over and then fall. Positive feedback takes over, in the form of gravity. You can see how gravity works by measuring how long the object takes to fall, just as you can measure the greenhouse effect of CO2 in the climate record, even though in both cases the initial “nudge” is different from the force being measured.”
    —————
    Reply:
    So Robert, you’re saying it took 800 years for the CO2 vase to fall, yet in the meantime the contents within the vase were flowing out, causing the forcing?

    Your analogy doesn’t hold water.

    Because not only is there an 800-year lag of CO2 w/ warming, but also a similar lag following cooling. You’re saying there’s something that nudges the vase so it stands upright?

    Again, your analogy doesn’t hold water.

  69. ThinkingBeing says:

    People here keep trashing the paper because it doesn’t give a 5 minute sound bite proof that AGW/GHG exists/doesn’t exist.

    Quick point of fact: Prior to the paper, there was an issue where a particular paleoproxy for CO2 levels did not jive with other proxies. This paper provides a correction that eliminates that problem with a meaningful, logical reason for it. It then points out how, once that particular detail is adjusted, other inferences (which were previously hard to reconcile) can be made.

    That’s all. No more, no less. It’s one guy, one scientist, whose job is to work with paleo-data (and he’d have that job with or without AGW, people, he doesn’t need a climate crisis to keep his post). He did something useful, which incrementally increases our knowledge of the climate.

    That’s all! If it doesn’t say what you want it to say… so what?

    The fact that you all want him to talk about CO2 being a driver or a feedback, or providing proof about time lags, and all that other nonsense is like standing up in the middle of a theater and complaining that you want caviar instead of popcorn. It’s silly, embarrassing, and unproductive.

    Read the article, learn, and move on.

  70. son of mulder says:

    Carl Chapman (23:08:23) :
    son of mulder (07:59:50) :

    And further to the above 2 posts imagine halving the amount from 280 ppm of atmospheric CO2 and halving it again. Keep doing this for 8 times and you get down to approx 1 part CO2 and 273 deg K. I’m sure at some point other factors would cut in but drawing the graph of temp vs CO2 ppm the go forward effect of CO2 and feedbacks gets less and less per unit of added CO2. It would take something quite dramatic to change the go forward graph into a runaway. What?

  71. Steve Keohane says:

    Tamara (05:49:36) : Not to worry, humans are a tiny spec of the respiring biomass on this planet, even with all our excesses we contribute about 3% of the CO2, or 2ppm/yr. If we disappeared CO2 would not change significantly.
    This study is interesting by finding a way to cut previous CO2 in half, making modern CO2 levels more significant, clever. That seems to be the sole innovation, the rest is the usual CAGW/IPCC slop.

  72. Kwinterkorn says:

    I am biased against AGW, so I choose to believe the following:

    The Interglacial and other paleo-warmings are completely unrelated to CO2 with respect to causation or feedback. Most CO2 production on earth is due to respiration of organisms: bacteria, fungi, etc. When it warms for non-CO2 reasons, these organisms thrive and covert C and O2 to CO2 at a higher rate—so atmospheric CO2 rises, lagging warming, and then falls, lagging cooling.

    Of course my “belief” is not science, even if it is based on “scientific conjecture”. Neither is the warmist belief in positive feedbacks of other types causing rising CO2 which then accelerates warming. In fact, compared to other parts of science, climatology is in its infancy and no self-respecting scientist should hold to any particular “beliefs”. My god, we cannot even measure the current “global temperature” with accuracy, yet some are pretending that paleo-proxies for temperature and atmospheric CO2, etc. are sufficient for scientific conclusions about climate sensitivity to rising CO2. Shame on these people for calling their work “science”.

    KW

  73. Rational Debate says:

    @ Robert (21:56:42) :…………Natural cycles seem most often to start with a weak change in solar forcing. After a certain point, positive feedbacks take over, among them, very importantly, CO2.

    Speculation.

    Imagine a vase on the top of a stand. As long as you leave it alone, nothing. But push on it, even with one finger, it will tip over and then fall. Positive feedback takes over, in the form of gravity. You can see how gravity works by measuring how long the object takes to fall, just as you can measure the greenhouse effect of CO2 in the climate record, even though in both cases the initial “nudge” is different from the force being measured.

    There’s a massive logical problem with speculations/conclusions of this nature. If positive feedback takes over, then how can the increase ever possibly stop? The world would continue heating, or at least hit a high point and then stay there. That’s the entire nature of a positive feedback.

    I see this sort of statement all over the place, but have yet to see anyone propose a mechanism that would explain how historically we’ve had far higher CO2 levels, and yet temperatures do not continue increasing, or even hit a maximum and remain there – no, temperatures fluctuate, and return to far colder conditions.

    Anyone who propounds CO2 as a positive feedback that is robust enough to overcome existing negative feedbacks, must also be able to explain logically how the system can then cycle back to colder temperatures in the face of their tipping point CO2 positive feedback.

    Otherwise, it seems to me that the very idea of a positive feedback CO2 ‘tipping point’ is pretty much disproved right on the face of it. (which was, I believe, the whole point of Rabe’s perpetual motion machine – grin)

  74. Rational Debate says:

    @ JER0ME (00:30:05) : Over at unreal climate they have fully explained the temperature/CO2 800 year time lag:
    ==========================

    That’s the same logic problem with the ‘real climate’ explanation too – if CO2 dun-it, then whatever allowed the process to stop and temperatures to cool again, in the face of highly elevated CO2 levels?

  75. Robert says:

    “Thanks Robert I think we know what positive feedbacks are.”

    The evidence would suggest many of you don’t. You yourself don’t seem to understand the difference between a positive feedback and an explosive change. And some of you are having trouble understanding gravity.

  76. son of mulder says:

    And on the topic of CO2 rise lagging temperature rise by 800 years. When the temperature starts to fall we have 800 years of rising CO2 and falling temperature. What makes that CO2 different from anthropic CO2? CO2 going up for 800 years while temperature falls.

  77. Kwinterkorn says:

    Re Dave in Delaware’s CO2 release from warming water calculation:

    It looks like you have made an assumption that the ocean is currently saturated with CO2, so that warming promptly results in CO@ being “pushed” out of solution and into the atmosphere. Is the ocean “saturated” at current CO2 levels? And if not, won’t the CO2 stay in solution at near current levels until warming-induced decreased solubility results in saturation?

    KW

  78. NickB. says:

    @ Richard (00:47:43)
    @ Robert (10:05:16)

    Don’t mean to step into a minefield here but, just sayin, there might be a language issue at play, and it might be best to have a quick read here to clear things up: http://www.drroyspencer.com/2009/04/when-is-positive-feedback-really-negative-feedback/

    In particular:

    “climate researchers have ‘redefined’ positive feedback. We borrowed the concept from electric circuit theory, which was elucidated back in the 1940s. And, yes, all of you engineers are right…in your terms, the climate system IS dominated by negative feedback. The Earth DOES lose extra energy to outer space when it warms, which then stabilizes the climate system against perturbations.

    But in the climate research world, the dividing line between ‘positive’ and ‘negative’ feedback is not whether extra energy is gained or lost with warming, but whether the increase is greater (or not) than the ‘temperature-only’ increase in infrared energy loss with warming.”

    Maybe it’s not quite accurate, but I have always thought of feedbacks in the climate world as amplification (positive) or compression (negative) if that helps at all(?)

    …and of course, if I’m off please set me straight :)

  79. tty says:

    Robert (10:05:16) :

    “And some of you are having trouble understanding gravity.”

    Indeed we have. Nobody understands gravity – except you apparently.

  80. George E. Smith says:

    Well with all this paleoproxy temperature and CO2 “data”, and Dana Royer’s assertion of a “climate Sensitivity” number of 3 deg C per doubling (that seems to be the IPCC guess); I wish the author would actually publish a plot of Temp vs Log(CO2), to demonstrate where that 3 deg C per 3X comes from; rather than simply asserting such a number and thereby implicitly endorsing the notion that T is proportional to Log (CO2), something I have yet to see demonstrated with peer reviewed data; like a graph.

    My understanding is that IPCC says that 3 deg C could actually be 1 or 10 deg C. If so, the demonstration of any logarithmic; or other, mathematical function connecting those two variables would be most surprising.

    Why not construct a model to fit the data, rather than try to shoe horn the data to fit a model.

  81. David Middleton says:

    Robert (10:05:16) :

    “Thanks Robert I think we know what positive feedbacks are.”

    The evidence would suggest many of you don’t. You yourself don’t seem to understand the difference between a positive feedback and an explosive change. And some of you are having trouble understanding gravity.

    If Earth’s atmosphere was inclined toward positive climate feedbacks, run away greenhouse warming would have long ago turned Earth into an uninhabitable inferno. The Earth could not have experienced ice ages in the Ordovician and mid-Mesozoic if elevated CO2 levels led to run away warming fed by positive feedback mechanisms. ..

    Phanerozoic CO2 v Temp

    The geological and meteorlogiocal records show that Earth’s atmosphere is dominated by negative (or neutralizing) feedback mechanisms.

    The so-called greenhouse effect of water vapor, CO2, CH4 and other trace gases enable the atmosphere to retain more heat that would otherwise be possible. This keeps the Earth’s lower atmosphere about 30 to 40°C warmer than it would be without a greenhouse effect.

    However, if the Earth’s atmosphere had no negative (or neutralizing) feedbacks, the greenhouse effect would make the surface temperature 100 to 140°C warmer than it currently is.

    Atmospheric circulation (AKA weather) is one giant negative feedback system.

  82. David Middleton says:

    George E. Smith (11:21:53) :

    Well with all this paleoproxy temperature and CO2 “data”, and Dana Royer’s assertion of a “climate Sensitivity” number of 3 deg C per doubling (that seems to be the IPCC guess); I wish the author would actually publish a plot of Temp vs Log(CO2), to demonstrate where that 3 deg C per 3X comes from; rather than simply asserting such a number and thereby implicitly endorsing the notion that T is proportional to Log (CO2), something I have yet to see demonstrated with peer reviewed data; like a graph.

    My understanding is that IPCC says that 3 deg C could actually be 1 or 10 deg C. If so, the demonstration of any logarithmic; or other, mathematical function connecting those two variables would be most surprising.

    Why not construct a model to fit the data, rather than try to shoe horn the data to fit a model.

    Easier said than done…

    I used an equation that Bill Illis posted some time ago to do just that…

    T = 2.73ln(CO2)-15.85

    I then calculated a low frequency temperature trend from ice core CO2 data back to the mid-1800′s and plotted that along with HadCRUT3…

    Model CO3 vs HadCRUT3

    It’s not a bad fit.

    If all of the warming since the mid-1800′s is the result of anthropogenic CO2, the maximum warming that could result from a doubling of pre-industrial CO2 is ~2°C.

    Now… Since we know that half of the warming since the mid-1800′s is due to natural climate oscillations, solar activity and other non-anthropogenic forces… And that the other half of the warming since the mid-1800′s is due to instrumental problems, operator bias, UHI, fraud and other non-CO2 related anthropogenic activities… We’re left with no enhanced greenhouse warming.

    Therefore we can conclude that the Earth’s climate is relatively insensitive to CO2 fluctuations between 275 and 4,000 ppmv.

  83. David Middleton says:

    The Spam filter may have just grabbed my last post.

    [Yes. It's posted now. ~dbs]

  84. Spector says:

    Just for reference, I do not believe we need fear a thermal runaway due to CO2 released from the oceans because this would require double the amount of CO2 to be released for each basic CO2 doubling-temperature step increase (nominally, I believe, one degree Celsius) before you could have a thermal run-away effect caused by CO2 released from the ocean.

  85. Robert says:

    “If Earth’s atmosphere was inclined toward positive climate feedbacks, run away greenhouse warming would have long ago turned Earth into an uninhabitable inferno. The Earth could not have experienced ice ages in the Ordovician and mid-Mesozoic if elevated CO2 levels led to run away warming fed by positive feedback mechanisms. ..”

    Again, the problem is that you are equating the presence of positive feedback mechanisms with inevitable “runaway warming.” Those are two entirely different things. There are numerous feedbacks — some positive, some negative, some short-term, some long-term. The interplay between them is what determines the length and depth of the warming (or cooling) (plus other influences like man-made forcing, or an asteroid impact, slight changes in the earth’s orbit, etc.)

    The lack of a “Venus syndrome” on Earth in no demonstrates a lack of net positive feedbacks to warming on human timescales (hundreds to thousands of years). It implies (and we have evidence of this) that over the very long term negative feedbacks move into the ascendant and return the climate system to a cooler equilibrium.

  86. AnonyMoose says:

    The graph doesn’t have anything labeled “paleosol carbonate proxy”. I can go look up the details, but the text should discuss what is in the graph. Or is that graph an unrelated illustration?

  87. David Middleton says:

    @Robert (11:55:51) :

    Actually the lack of any evidence of past positive feedback mechanisms is what casts doubt on the model-based predictions of future positive feedback mechanisms.

    The perfect example is Jimbo Hansen’s 1988 climate model. Hansen’s worst case scenario nailed the actual atmospheric CO2 trend over the next 20+ years…

    Hansen CO2 Model

    While the actual warming that occurred over the same period undershot Hansen’s best case scenario…

    Hansen Temp Model

    Hansen CO2 scenarios…

    “Specifically, in scenario A CO2 increases as observed by Keeling for the interval 1958-1981 [keeling et al, 1982] and subsequently with a 1.5%/yr growth of the annual increment.”

    “In scenario B the growth of the annual increment of CO2 is is reduced from 1.5%/yr today to 1%/yr in 1990, 0.5%/yr in 2000 and 0 in 2010; thus after 2010 is constant, 1.9 ppmv/yr.”

    “In scenario C the CO2 growth is the same as scenarios A and B through 1985; between 1985 and 2000 the annual increment is fixed at 1.5 ppmv/yr; after 2000, CO2 ceases to increase, its abundance remaining fixed at 368 ppmv.”

    CH4 and other trace gases inexplicably stopped rising some time ago and actually followed paths closer to scenario’s B & C… But CO2 is the “Big Kahuna”. Even if CH4 has 20X the greenhouse effect of CO2. 1800 ppb is 0.46% of 390 ppm…20 X 0.46% = 9.2%. At most, CH4 accounts for only about 10% of the greenhouse effect of CO2 in Earth’s current atmosphere.

    So, according to Hansen’s 1988 predictions, the global temperature anomaly should be about 90% of the way from Scenario “C” to Scenario “A”… ~0.97°C. In reality, the annual global temperature anomaly is about half of what Hansen predicted for a similar rise in CO2.

    In most branches of science, when experimental results falsify the original hypothesis, scientists discard or modify the original hypothesis. In the wacky world of Warmistas the initial conditions of the experiment are simply redefined with flux adjustments.

  88. keith in hastings UK says:

    Re:Robert (11:55:51)

    So, you’re postulating +ve feedback of CO2 effects on temp in the geological short term – a few hundred or thousand years – which is then overmastered by powerful but incredibly slowly reacting -ve feedback, which forces temps down even while CO2 levels continue to climb for 800 – 1000 years or so, before CO2 concentrations follow the temp down…?

    Ingenious, but do you really believe this? What turns off the strong negative feedback ie “chooses” the target temperature? Any idea what the feedback mechanisms might be? The sceptic position is simpler: CO2 has only a small effect, and the climate variations come from other sources… I dont buy your view at present, and still see the ice core cooling phase data as a “killer” for AGW via CO2.

  89. Mike Borgelt says:

    Seems to me that a fossil soil expert has found a way to link his filed of research to AGW in order to get funding. Nothing to see here folks…

  90. George E. Smith says:

    “”” David Middleton (11:46:00) :

    George E. Smith (11:21:53) :

    Well with all this paleoproxy temperature and CO2 “data”, and Dana Royer’s assertion of a “climate Sensitivity” number of 3 deg C per doubling (that seems to be the IPCC guess); I wish the author would actually publish a plot of Temp vs Log(CO2), to demonstrate where that 3 deg C per 3X comes from; rather than simply asserting such a number and thereby implicitly endorsing the notion that T is proportional to Log (CO2), something I have yet to see demonstrated with peer reviewed data; like a graph.

    My understanding is that IPCC says that 3 deg C could actually be 1 or 10 deg C. If so, the demonstration of any logarithmic; or other, mathematical function connecting those two variables would be most surprising.

    Why not construct a model to fit the data, rather than try to shoe horn the data to fit a model.

    Easier said than done…

    I used an equation that Bill Illis posted some time ago to do just that…

    T = 2.73ln(CO2)-15.85

    I then calculated a low frequency temperature trend from ice core CO2 data back to the mid-1800’s and plotted that along with HadCRUT3…

    Model CO3 vs HadCRUT3

    It’s not a bad fit. “””

    So just how many octaves of CO2 did you cover in your plot. If mid 1800s CO2 was 280 ppm and now we haver 388.09 ppm.

    That’s a ratio of 1.3857 : 1, or not even 1/2 of an octave.

    So now use the same data, and assume instead a straqight line linear elationship between CO2 and temperature for that same period.

    Is that fit any worse than your log function ? I somehow doubt it.

    But try that same log function you gave over the roughly five octaves of CO2 going back 600 million years; and tell us if you still get a pretty good fit.

    But just why are you trying to fit the data to a log function; what physical process is suggestive of it being a log function.

    We know for example, that the Watts per square metre “forcing” due to surface emitted LWIR being absorbed by CO2, varies by more than a factor of ten over the earth surface, simply due to the change in surface temperature from the coldest to the hottest surface locations.

    And I doubt that anyone has sampled the “climate sensitivity” value over a sufficient sample of the earth surface to even compute what a global average might be; and whay would such a value average out to produce a global logarithmic function.

    Just because the sensitivity to cO2 change diminishes as you add more CO2, is no justification for saying the function must be logarithmic.

    I think Anthony actually put up a Log function plot soem time ago using recent history data, and the portion of the log curve that was applicable was as linear as any drawn straight line.

    Ln(1+x) =x-(x^2)/2+ …. near enough to linear given the short data range.

  91. Dave in Delaware says:

    sorry .. this got to be a rather long answer, hope it helps

    re Kwinterkorn (10:30:37) : Re Dave in Delaware’s CO2 release from warming water calculation:

    It looks like you have made an assumption that the ocean is currently saturated with CO2, so that warming promptly results in CO@ being “pushed” out of solution and into the atmosphere. Is the ocean “saturated” at current CO2 levels? And if not, won’t the CO2 stay in solution at near current levels until warming-induced decreased solubility results in saturation?

    Good question -Why do I think that the oceans are at or near saturation in CO2?

    Well, CO2 is highly soluble in water, and given the right conditions, the physical process to drive toward saturation should be relatively fast. There are those that claim the oceans are absorbing CO2 and others that claim the oceans are degassing CO2. I believe both are probably correct, depending on temperature and other conditions at a given location. If you read down through the chemistry information, there is much more CO2 tied up in the oceans than in the atmosphere, and I my belief is the right conditions release some CO2 to the atmosphere.

    Some Air Ocean data that suggests this may be happening on a macro ocean scale. Dr Roy Spencer did a review of Sea Surface Temperature (SST) changes in comparison to Mauna Loa CO2 readings. Atmospheric CO2 Increases:Could the Ocean, Rather Than Mankind, Be the Reason? by Roy W. Spencer 1/25/2008
    http://wattsupwiththat.com/2008/01/25/double-whammy-friday-roy-spencer-on-how-oceans-are-driving-co2/

    He says – “The large interannual fluctuations in Mauna Loa-derived CO2 “emissions” roughly coincide with El Nino and La Nina events, which are also periods of globally-averaged warmth and coolness, respectively.”

    Chemistry (and what it tells us about saturation and equilibrium)
    Once CO2 dissolves into water, some stays as CO2, but most forms other ionic species, which is handy because we can then get some idea of ‘close to saturation’ from pH readings. Those pH readings suggest that even in the relatively short life times of rain drops, they absorb enough CO2 from the air to be at or near saturation. (supports the idea of relatively fast)

    In sea water, there is the further complexity where the CO2 ions interact with the dissolved minerals. In fact, most of the ocean CO2 is tied up in those other ‘buffered’ entities. So if a bit of the ‘free’ CO2 is stripped out to the atmosphere, the equilibrium shifts to replace it from the plentiful ‘buffered’ species.

    Here is more on CO2 in sea water, with author and link for further reading on this.
    The quotes below are excerpts from http://www.seafriends.org.nz/issues/global/acid.htm
    Dr J Floor Anthoni (2007)

    “As CO2 dissolves in water, the water becomes mildly acidic (clean rain water has a pH=5.6) …

    “This behaviour of CO2 also applies to sea water, but here the situation is much more complicated due to the buffering effect of limestone.

    “CO2 ‘binds’ with water like: CO2 + H2O H2CO3 H+ + HCO3- H+ + H+ + CO32-

    “In this equilibrium equation the double arrow means ‘in balance’ (equilibrium) or that the chemical reaction can move both ways.

    “Of the four ‘states’ that CO2 can assume, carbondioxide CO2 is a mere 1%, bicarbonate HCO3 is 93% and carbonate CO3 8% . But the total amount of carbon dissolved in the oceans is just short of 40,000Gt (Pg) compared with less than 700Gt in the atmosphere. The sea is a massive carbon dioxide reservoir, in balance with an even more massive limestone reservoir of 40,000,000Gt carbon in marine sediments . ”

    “This equation is a gross simplification of the seawater system because seawater has many more elements that are likely to play a role. One of these is Calcium (Ca2+) which ‘binds’ with CO3 like: Ca2+ + CO32- CaCO3 to form limestone as in corals and shells.”

    The author goes on to show that “…the sea has a vast oversupply of calcium.”

  92. Douglas Haynes says:

    It is difficult to conclude from an examination of the CO2-T relationships in the Eemian in the Vostok ice core that CO2 exerts any definitive positive feedback on T; the data also indicate that the increases in atmospheric CO2 concentrations caused by oceanic CO2 degassing with T increase will be of the order of 30ppmv with a 3degree C global mean surface temperature increase.

    At the onset of the Eemian, atmospheric CO2 concentration increase from ~170ppmv to ~ 270ppmv, but this LAGS a T increase of 10 degrees C by ~ 800 years. Interestingly, the DeltaT-CO2 concentration relationships indicate that there is ~ 10ppmv CO2 increase per 1 degree C increase (Henry’s law gas behaviour relating to dissolved oceanic CO2). CO2 then PLATEAUS at 270ppmv, whist T then DECREASES from its maximum of 2 degrees C (above current global mean surface T’s), whilst CO2 concentrations remain at their plateau of ~ 270ppmv. CO2 concentrations then drop from their 270ppmv “plateau” to 230ppmv ~ 1000 years AFTER T drops to ~ -4 degrees C!

    Where is the positive feedback signal here between rising CO2 concentrations and T’s?

    The ice core data also indicate that CO2 concentrations will increase by ~ 10ppmv per 1 degree C T increase. In other words, the data indicate that a 3 degree C T increase globally should increase CO2 concentrations by ~ 30ppmv (above the anthropogenic component added).

    For sources of data, go to http://www.ferdinand-engelbeen.be/klimaat/eemian.html

    There are also primary data sources listed in Ferdinand Engelbeen’s descriptions, graphs of the ice core data, and a rebuttal of some criticisms of the validity of these data.

  93. ThinkingBeing says:

    Rational Debate –

    Positive feedbacks do not need to be runaway, particularly when they are logarithmic (as many/most are). Each feedback gives you less than you added to begin with, or may be bounded by some limit (such as how much ice is available to melt).

    In the case of CO2, for example, you have to double CO2 to get 1 degree of warming. Each degree of warming may also add 10 ppm of CO2. So if you start at 280 ppm CO2 and double to 560 ppm CO2, you get 1 C of warming, and with that another 10 ppm of CO2. But you can see that that extra 10 ppm of warming doesn’t get you anywhere close to another 1 C of warming…. more like another 0.001 C of warming.

    The biggest positive feedback in the system is H2O, which will increase with rising temperature (everyone knows it’s more humid in summer than winter), but not in a runaway fashion. You’ll get H2O that gives you another 1 C of warming, and that will in turn give you another 0.5 C of warming, which will in turn give you another 0.25 C of warming, etc. It’s a convergent series.

    There are also some negative feedbacks that will counteract the positive feedbacks (like, hopefully, increased cloud formation, which will reflect sunlight before it hits the earth and warms the ground).

    So, double CO2 and you get 1 C of warming from that, plus another 2-4 C of warming from all of the combined positive feedbacks and negative feedbacks, combined.

  94. Robert says:

    Dave wrote:

    “There are those that claim the oceans are absorbing CO2 and others that claim the oceans are degassing CO2. ”

    It’s fairly easy to deduce which way the arrow is pointing:

    a = Mass of the atmosphere: 5 x 10^18 kg

    b = Human CO2 emissions: 2.7 x 10^13kg (est. 2004)

    b/a x 10^6 (to convert to ppm) = 5.4ppm/year

    This is parts per million by mass, not volume, so to avoid confusion we should calculate the percent change:

    5.4ppm/582ppm = 0.9% increase in CO2 per year.

    But in reality what we observe is closer to half that:

    388.63/386.92= 1.0044 = 0.44% increase in CO2/year

    So unless the CO2 is escaping the planet somehow, about half of our emissions are going into carbon sinks, mostly the ocean.

  95. Frank says:

    The above commentary written by Royer is intended to publicize the implications of a research article appearing in the same issue of PNAS written by Breecker et al titled: Atmospheric CO2 concentrations during ancient greenhouse climates were similar to those predicted for A.D. 2100. That article can be obtained from co-author Sharp’s website at: http://epswww.unm.edu/facstaff/zsharp/homepage/hompage-v6_website/files/Download/breecker%20pnas.pdf

    Breeker has been investigating whether the assumptions used in calculating atmospheric CO2 levels from deltaC13 isotope ratios in calcium carbonate “fossil soils”. Breeker has published one earlier paper showing that calcium carbonate is incorporated into soil at ONE site only under conditions that are warmer and drier than the average climate for the site. Applying the corrections derived for this one site to all other sites, lowers the previous estimates of atmospheric CO2 by 1.5-4.0X. According to Breeker and Royer, Breeker’s corrections bring soil-based estimates of CO2 into better agreement with other techniques. (Breeker acknowledges relying on data provided by Royer to come to this conclusion, so their analyses are not completely independent.)

    The question is whether it is appropriate to apply Breeker’s correction to all other sites used to estimate CO2 levels from soil carbonate isotope ratios. A quick glance at Royer’s graph shows that numerous soil measurements made around 65 MYA give suspiciously low carbon dioxide levels when Royer’s correction is applied. So, perhaps in a fews years, Breeker’s research will have been replicated at a number of different sites under varying atmospheric concentrations of carbon dioxide by a number of different workers. Then we will know how much faith to place in the above putative change in our understanding of past atmospheric levels of carbon dioxide. Their relevance to the climate sensitivity of our current world – with polar ice caps and an isthmus of Panama – will still be questionable.

    (Of course, none of this has anything to do with the first 800 years of melting at the end of the last ice age or many of the other distractions mentioned above.)

  96. Spector says:

    I believe there is a principle known as Henry’s Law that states “At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.”

    I think the amount of CO2 dissolved in the ocean is proportional to the CO2 concentration in the atmosphere and inversely proportional to the average temperature of the water.

  97. David Middleton says:

    @George E. Smith (13:07:16) :

    I was just pointing out that you can actually derive a maximum sensitivity that is a lot less than 6 C. Any sensitivity greater than 2 C per doubling from pre-industrial levels would have caused more warming than the HadCRUT3 temperatures show. Since HadCRUT3 probably exaggerates the instrumental era warming by as much as 0.5 C… The sensitivity can’t even be 2 C.

    If CO2 actually varied from 280 to 400 ppmv during pre-industrial times (and since the end of the Pleistocene) as plant stomata indices and chemical analyses suggest… The climate is almost totally insensitive to CO2 variations between about 275 ppmv and 4,000 ppmv.

  98. David Middleton says:

    ThinkingBeing (14:32:28) :

    Rational Debate –

    [...]

    So, double CO2 and you get 1 C of warming from that, plus another 2-4 C of warming from all of the combined positive feedbacks and negative feedbacks, combined.

    There is absolutely no evidence of past or present net positive feedbacks… None.

    If there were, the Earth would have already experienced run-way greenhouse warming several times from the Cambrian to the Paleogene.

    If there were net positive feedbacks, HadCRUT3 would show a heck of a lot more warming over the last 150 years and the satellite data would show a steadily increasing temperature rather than no change prior to 1995 and after 2000. All of the warming in the satellite era occurred in one five year period.

  99. George E. Smith says:

    “”” ThinkingBeing (14:32:28) :

    Rational Debate –

    Positive feedbacks do not need to be runaway, particularly when they are logarithmic (as many/most are). Each feedback gives you less than you added to begin with, or may be bounded by some limit (such as how much ice is available to melt).

    In the case of CO2, for example, you have to double CO2 to get 1 degree of warming. Each degree of warming may also add 10 ppm of CO2. So if you start at 280 ppm CO2 and double to 560 ppm CO2, you get 1 C of warming, and with that another 10 ppm of CO2. But you can see that that extra 10 ppm of warming doesn’t get you anywhere close to another 1 C of warming…. more like another 0.001 C of warming. “””

    Where are you getting your numbers from ? The above paper says the “Climate sensitivity” is 3 deg C per doubling, which is about what the IPCC claims. So what is the source of your 1 deg C. Spencer and Christy argue that their data shows way less than even one deg of warming per doubling.

    Unfortunately the mean global temperature depends on a whole lot more factors than just CO2 abundance; for one thing CO2 is just another component of the total atmospheric GHG most of which is water. In fact, I don’t believe that for most of the earth’s atmosphere, that H2O is ever less than CO2, even over the dryest deserts. Maybe at really high altitudes, when the temperatures are way below freezing. the H2O vapor may end up less than the CO2 but then you have an even bigger problem, because all the excess H2O that is not vapor, is in the form of clouds, giving a very strong negative cooling feedback.

    When a cloud passes in front of the sun, you get a shadow zone the size of the cloud, with a penumbral edge due to the 0.5 degree angular diameter of the sun; and nobody ever observed it to suddenly get warmer on the surface in that shadow zone.

    On the other hand the LWIR emission form the surface; possibly diminished because of the temperature drop in the shadow, is at least a Lambertian emission pattern (for flat water) and more likely closer to isotropic for a normally rough surface; so the LWIR surface emission is a very diffuse source, compared to the 0.5 degree beam source for the incoming solar radiation.

    So only a small fraction of the surface emitted LWIR, will strike that cloud, and be intercepted by water or ice absorption. The optics always favors a net cooling of the surface. Yes the atmosphere may warm due to both absorbed sunlight, and GHG intercepted LWIR (mostly H2O); but the lower mass of the warmed atmosphere layer, makes it a poor surface warmer.

    And in particular, most of the returned LWIR will impinge on water (73% of the surface), and be sborbed in the top 10 microns or so. This will reult in a warmed surface film, and prompt evaporation, which conveys a whole lot of latent heat into the atmosp[here, and ultimately the higher atmosphere (where the clouds form); and that process dumps the latent heat out (around 5435 Cal/gm) plus another 80 cal/gm if it is cold enough to form ice crystals, instead of water droplets.

    Doesn’t strike me as a surface warming of any major extent.

    The warmists argue that the high clouds warm the surface, by absorbing LWIR, while not stopping much sunlight; so the higher the clouds the more the surface warming. Surprisingly; they say this happens, regardless of the relative humidity of the intervening air mass; so they evidently attribute all the surface warming to the LWIR returned from the clouds; but none of it comes from LWIR emitted from the water vapor warmed atmosphere. Somehow I doubt that is realistic.

    The surgface temperature and relative humidity of the intervening atmosphere under those high clouds, is more likely to be the source of those clouds, and not the result of those clouds.

    So I do not believe clouds are ever a positive feedback warming influence; given of course that I am talking climate, and not weather, so don’t give me that last night’s high cloud thing.

    It doesn’t make any sense, that the higher and colder, and less dense that a cloud layer is, the more it warms the surface by emission of LWIR back to the surface.

  100. Robert says:

    “There is absolutely no evidence of past or present net positive feedbacks… None.”

    Exactly! Except for the mountain of evidence of net positive feedbacks.

    Tiny orbital changes altering solar forcing by less than 0.1 Watts/m^2 have led to swings of as much as 5C (http://en.wikipedia.org/wiki/Milankovitch_cycles). Utterly impossible without net positive feedbacks in the short term.

  101. Smokey says:

    Robert (18:07:31),

    Both George E. Smith and David Middleton have probably forgotten more about physics than you will ever learn, your being a sociologist or whatever. But I must say, your cut ‘n’ paste skillz make it easy to take realclimate propaganda and dump it here.

    I’ll help you out here, by explaining the situation – without cutting and pasting what other folks say: click1, click2

    See? CO2 absorbency operates on a logarithmic scale. So you can relax.

    Burning all of the known reserves of fossil fuels would not double atmospheric carbon dioxide. Nor would it make the oceans acidic. And as anyone can plainly see from the links above, even a lot more CO2 would make only a negligible difference.

  102. Rational Debate says:

    Just a minor note up front… several people replying to “ThinkingBeing” left my screen name in their reply – probably because that’s how the text happened to be from “ThinkingBeing’s” reply to my earlier post – but I hope folks realize that our positions are quite different.

    So, now to make it even more confusing, I’m replying to:

    ThinkingBeing (14:32:28) : -removed myself here, GRIN- Positive feedbacks do not need to be runaway, particularly when they are logarithmic (as many/most are). Each feedback gives you less than you added to begin with, or may be bounded by some limit (such as how much ice is available to melt).

    Several points here. First, if you go back to my post, I stated right up front: “If positive feedback takes over, then how can the increase ever possibly stop? The world would continue heating, or at least hit a high point and then stay there. That’s the entire nature of a positive feedback.” A significant part of the reason I used that phrase was because of the logarithmic CO2 curve.

    Now, I don’t know if all of the ‘climate scientists’ adhere to the logarithmic standpoint or if some don’t and claim a ‘runaway’ system, but I’d assume the latter since there are claims all over the place about how Venus’s atmospheric composition and temperature, far far higher than our temperatures, are because of runaway greenhouse warming from CO2.

    Which segue’s right into my next point. The AGW claim is that there is a net system positive feedback occurring right now, directly or indirectly, because of CO2. That CO2 is the ‘driver,’ so to speak. In other words, that within the current system (e.g., our solar system and all of the various feedbacks within it on or off the earth), increasing CO2 is causing increasing temperatures.

    That this net positive feedback will continue in the near future to the tune of somewhere between an additional 2 to what? 10 degrees? Pick your numbers, it really doesn’t matter to my point. I don’t recall seeing what those same proponents claim would happen if CO2 continued to rise beyond the upper temperature they’re predicting, but again, that’s relatively moot to the point.

    That point being the same logic flaw from my original post – net system positive feedback as being described by ‘climate scientists’ is that as CO2 increases, the temperature continues to increase at least to that upper number. In which case, even if it stopped there because of the logarithmic nature, there is nothing that would be able to drop the temperature back down from that upper temperature. As the temp started to drop, you would be right back in a net positive CO2 feedback mechanism that got you there to begin with, so the temp should stay at that level (or continue higher if it isn’t a self-bounding situation, logarithmic, etc.).

    The logic as its being claimed simply cannot reconcile with Earth’s history, unless some other theory is proposed for what could possibly account for temperatures to ever come down below that upper number. That theory would have to also account for how suddenly CO2 is no longer the driver of a net positive system feedback. I’ve yet to see anyone propose anything along those lines, yourself included. All that you’ve stated merely gets the temperature increase to stop once it hits an upper number that is at least several degrees warmer than present day temperatures.

    So, by the current AGW theory of CO2 being the driver of a net postive system feedback, either the Earth turns into Venus (minus a teensy smidge for distance), or far back in our history we would have hit temperatures at least several degrees warmer than present day and stayed there without any mechanism to account for little ice ages or even present day temperatures.

  103. David Middleton says:

    @Robert(18:O7:31)

    That’s not a feedback in the sense of the enhanced greenhouse hypothesis.

  104. Robert says:

    David (20:01:36)

    What do you mean? If I were unclear, I am saying that small changes in solar forcings have, according the the climate record, triggered large changes in temperature, far larger than can be accounted for by the solar forcing itself. This implies that there are positive feedbacks (such as melting ice) that can and do operate on the climate system. It does not imply that GHGs are among those feedbacks; that’s a separate issue.

    Do you disagree with this?

  105. Glenn Tamblyn says:

    My understanding from what I have read from several sources about the 800 year lag in CO2, and ‘runaway’ warming is as follows. It is about the balance of 4 forces

    1. Milankovitch cycles impose a small, 0.1 w/m^2 or so, warming/cooling cycle

    2. CO2 and perhaps to a lesser extent Methane provide a warming effect but the logarithmic nature of this effect means that this tapers off. Further concentration increases provide a diminishing returns effect. And the main source of extra CO2 is release from the oceans. And the time lag of 800 years or so reflects the overturning time of the oceans currents. Surface waters may release their CO2 relatively quickly, but the real impact comes as deep water is raised to the surface and continues to supply new water to feed release. And the same process in reverse drives CO2 absorbtion during the cooling phase.

    3. As warming proceeds the Albedo (Reflectivity) of the planet changes. White reflective ice is replaced by dark water, dark rock and relatively dark vegetation. And this proceeds in a very non-linear way. An Ice sheet 2 km thick can thin to 100m and the albedo hasn’t changed, Then the last 100 m goes and it is bare rock. The extent of winter sea ice remains unchanged until it has thinned enough to become weak enough to break up at the edges during the summer melt then it can decline rapidly. Vegetation takes time to fully colonise bare rock. But once the transition is complete then the albedo can’t keep changing. Vegetation, rocks and water can only be so dark. Ice can only be so white

    4. Water vapour changes magnify the warming/cooling effect from all other causes. However, the amount of water in the atmosphere is governed by temperature. So unless there are other factors contributing to a temperature changes, water vapour cannot continue that change on its own.

    So the sequence is something like this. In the depths of an Ice Age a Milankovitch event starts a minor warming. Ice retreat starts at the edges changing Albedo a bit, followed by some vegetation growth on the exposed ground. Methane release from melting permafrost at the margins starts to add to the warming effect. But this doesn’t show up much in the Ice Core records because its warming impact while it exists as Methane is a couple of orders of magnitude higher than CO2 molecule for molecule. So it has a bigger warming whammy briefly before it then oxidises and converts to a minor amount of CO2 that barely registers in the cores. More water vapour due to the heating magnifies the warming a bit more. CO2 starts to outgass from the oceans because at a higher temperature they can’t hold as much CO2 in solution but only slowly. A modest positive feedback has started. Then overturning of the oceans a few hundred years later starts to accelerate the effect, bringing more CO2 laden water to the surface. More warming and we start to see a real rise in CO2 in the cores. Then, after perhaps several 1000 years, the warming and the total size of the ice involved means that the collapse of the ice sheets starts to accelerate. The warming effect of CO2 is starting to taper off as the logarithmic law kicks in. Albedo change may now be a bigger driver. And Water vapour is still doing its thing, magnifying the change. Eventually the change from Ice Age to Interglacial is complete. And then the effects of Albedo change taper off radically. And CO2 may still be climbing buts its temperature impact is declining due to the logarithmic effect. And with no other things driving it, Water vapour’s contribution falls away as well. Temperatures are nearly stable although CO2 is still coming out of the oceans.
    So, a positive feedback but self limiting. Not a runaway.

    Then the reversal starts. Again, a reversal of the Milankovitch cycle starts the decline. With less warming from the sun, this starts to counteract the residual warming from the still rising CO2 levels which are driven by the concentration imbalance that still exists between the deep oceans and the air. So temperature rise stops even though CO2 levels keep rising for a bit. Once the cooling due to Milankovitch beats the warming due to CO2, temps start to drop. And Water vapour then changes sides and starts to magnify the cooling. And unlike the warming phase where there were long lag times before albedo change had a big impact, waiting for all the ice to melt, now more snowfalls at lower latitudes / altitudes have an immediate effect. A couple of metres of snow has the same albedo effect as 2 kilometers of ice cap. So this time albedo change leads the charge. Also, as climate cools, vegetation declines. This decomposes and releases CO2 which helps to keep CO2 levels elevated as the cooling proceeds. Eventually the cooling temps mean CO2 uptake into the oceans can increase. CO2 uptake by the oceans starts to get ahead of CO2 release from dying vegetation and CO2 levels start to drop, adding to the cooling. But it is several hundred years again before overturning of the oceans really starts to draw CO2 down into the depths and make a real impact on atmospheric concentrations. Now the big chill is on in earnest as we plunge down into the Ice Age. Lots of relatively thin ice over large areas drives temps down aided by H2O. Then as CO2 declines, the logarithmic effect works in reverse, driving the cooling even faster. So what stops the decline? Well the Milankovich effect drops away. And how far the ice can spread depends on land shapes – ice simply can’t spread too far to low latitudes over ocean. So eventually this limits ice spread no matter how cold things get. So the Albedo driver tapers off again. Then CO2 alone can’t keep driving temps lower alone and this tapers off and we are back where we started.

    The depth and severity of Ices Ages seems to depend on land shape. You need at least one continent at the poles to allow major ice build up, and it seems to be that you need a major north/south continent to block east west ocean currents as a contributor as well. So our current period of glacial cycles began about 30 million years ago when Antarctica was down in the south and the Isthmus of Panama closed. A previous major glacial period during the mid Carboniferous may have started when the supecontinent of PanGaia had its lower half near the south pole and was so big that it stretched well into the northern hemisphere. And it ended when Pangaia broke up. Gondwana remained near the south but Laurasia moved north and the return of currents through the seaway in between ended that glacial period.

  106. David Middleton says:

    @Robert

    “Do you agree with this?”

    Maybe.

    When the input of energy into the system changes, atmospheric and oceanic processes might amplify or mute those changes. There are lines of evidence to support this sort of hypothesis.

    However, there is no evidence whatsoever of unremarkable changes in atmospheric CO2 causing any sort of cascading positive feedback loop.

    And the rise in atmospheric CO2 over the last 5O years is wholly unremarkable. If the plant stomata data and chemical analyses are correct, it`s not even anomalous.

  107. Spector says:

    To me, it seems easier to imagine an ocean cooling feedback event when the cooling of a warm sea absorbs or sucks more CO2 out of the atmosphere that all natural sources can produce and lowers the greenhouse warming by one degree every time the CO2 concentration in the atmosphere is halved until the ocean has cooled to its temperature of maximum CO2 solubility.

    Even in this case, however, I believe the role of CO2 would have to be secondary to some other primary forcing factor because of the logarithmic nature of the CO2 greenhouse effect.

  108. David Middleton says:

    @Spector (10:09:04) :

    Since the “greenhouse” warming effect of increasing CO2 on temperature is logarithmic… The cooling effect of CO2 depletion is much greater per ppmv than the warming effect is

    All other things being equal (and they never are)…

    A doubling of the current CO2 level from 388 to 776 ppmv could cause maximum of 1.89 C of warming. Atmospheric and oceanic circulation would mute this warming to a large extent.

    A halving of the current CO2 level from 388 to 194 ppmv could cause -1.89 C of cooling. Atmospheric and oceanic circulation would not be able to mute the cooling effect. The lower atmosphere would simply lose heat. Cooler oceans would be able to take more CO2 into solution… This would lead to accelerated cooling… Causing more CO2 to go into solution… This could actually lead to a cascading feedback loop of cooling.

    However, we know from the geological record that runaway negative feedback loops haven’t happened before either.

    CO2 depletion is a far greater threat to humanity than greenhouse gas emissions ever possibly could be. 2C of cooling would lead to famine on an unimaginable scale. 2C of warming would cause a lot of problems; but people can move.

  109. Spector says:

    RE: David Middleton (12:25:29) “… runaway negative feedback loops haven’t happened before either.”

    Runaway heating or cooling are both manifestations of *positive* feedback.

    An example of negative feedback would be an effect that would cause the atmosphere to cool in response to forced warming or cause it to warm in response to forced cooling. This is why negative feedback is usually used to stabilize the gain of electronic amplifiers.

  110. Robert says:

    “A doubling of the current CO2 level from 388 to 776 ppmv could cause maximum of 1.89 C of warming.”

    If only. Actually, a doubling of CO2 is likely to cause 4+ degrees of warming, according to the very paper we are discussing.

    “2C of cooling would lead to famine on an unimaginable scale. 2C of warming would cause a lot of problems; but people can move.”

    I agree that any radical change in the climate is likely to be to our detriment. That being the case, the safest thing to do is to leave it as close to possible as the state we found it in (280ppm). Those are the levels that have been safe for the last 10,000 years of human history. Until we understand the climate system much better, they are the only levels that can be considered “safe” in the long run.

    I like to use the analogy of a person alone on an alien spaceship who wanders into the life support control room. The room is full of buttons and levers and our traveler understands none of it. What is the only reasonable course of action we can recommend to him? Isn’t it: “Don’t touch anything”?

    Practically speaking, we are going to see continued warming for our lifetimes, even if we bring CO2 down to 350ppm. The name of the game is to try and keep that warming as slow and limited as possible; to stay as close to the conditions that have been safe over the last 10,000 years.

  111. @ Spector (14:18:24) :

    I know… But it just sounds “funny” to refer to an amplification of cooling as a “positive” feedback. Kind of like “negative economic growth” sounds funny.

    Technically speaking… Negative feedback loops can’t run away at all and they happen all the time.

    The endless conflict between grammar and science… ;-))

  112. DirkH says:

    Positive feedback exacerbates an effect; negative feedback dampens it. I’m being simplistic here; feedbacks can involve time delays and very often have a frequency dependency and a frequency dependant phase shift so a feedback can in fact be negative for one part of the spectrum and positive for a different part, leading to resonance effects. This would materialize itself in oscillations, like the PDO. Which in turn leads to intermittent ica age/meltdown panics.

  113. Spector says:

    Dave Middleton (15:10:56) : “Kind of like ‘negative economic growth’ sounds funny.”

    I am sure you have heard the phrase “vicious circle” in regard to the Great Depression. That was a classic example of a positive-feedback runaway event in the field of economics.

  114. anna v says:

    I want to add a PS to why the errors in the energy budget ( energy in energy out) are really unknown and could be bigger than the claimed effect of CO2 in Watts/m^2.

    They treat the earth as a black body, to convert temperatures to watts/m^2

    1) the earth is a gray body with emissivities from 1 to .7 of the black body constant.
    2) they measure the sea surface temperature, true, so that gray body calculation in an energy balance would pass muster.
    3)Have you seen anybody measuring ground temperature? Forrest canopy temperature? Sahara sand temperature? They use the temperatures 2m up from surface stations and do black body radiation? I know for sure that the temperature on sand is over 50C while the air temperature is below 40C ( try to walk on sand barefoot in greece in the summer). One can fry eggs on the sand in Sahara, but the air is what? 45C? 50C? On land it is the surface temperature that radiates according to T^4 and a gray body constant.

    example. 40C in the air and 50C on the sand: there is 13.5 more flux going out for the 50C temperature. So if one budgets as if it is black body with the air temperature, that is 537watts/m^2 for 40C versus (assumed 50C) sand temperature 604 watts/m^2. Thats a lot of watts to be off, even though the Sahara is a small part of the globe and even though it is not a black but a gray body.

    I have not seen 3) discussed anyplace. I can easily see systematic errors of the order of 2Watts/m^2 in the energy budget.

  115. Rational Debate says:

    Re: Robert (15:09:16) :

    “2C of cooling would lead to famine on an unimaginable scale. 2C of warming would cause a lot of problems; but people can move.”

    I agree that any radical change in the climate is likely to be to our detriment. That being the case, the safest thing to do is to leave it as close to possible as the state we found it in (280ppm).

    Hi Robert,

    The point is that a 2C decrease in global temperatures would have vastly worse impacts throughout the world than a 2C increase. Which means that we have a lot more incentive to try to avoid or at least prepare for that eventuality than for a comparable warming. You went on to say:

    Those are the levels that have been safe for the last 10,000 years of human history. Until we understand the climate system much better, they are the only levels that can be considered “safe” in the long run.

    Again, speculation. Even the levels that existed for the past 10K years are debatable. A few examples, see: http://www.sciencemag.org/cgi/content/full/286/5446/1815a where the article authors argue that historical CO2 levels may have been as high as ~360ppm. http://www.sciencemag.org/cgi/content/abstract/284/5422/1971 “well above 300ppm” Then there are the possible problems with ice cores significantly underestimating CO2 levels, and if I recall correctly, also being poor proxies for the relatively near past (holocene).

    You are also making what may very well be a grossly incorrect assumption that pre-industrial levels of CO2 were 280ppm. That value is, as I understand it, highly debatable. Apparently pre-industrial CO2 levels were commonly, and likely accurately, measured well into the 400+ppm range. The 280ppm value would seem to have been from pretty heavily cherry picked data.

    As to ‘…safest…leaving it in the state we found it in…’ I would strongly argue that while it may be ostensibly ‘safest’ to remain in approximately the state we are currently in – as we are currently better off now by far than in pre-industrial mini-ice-age days (your 280ppm) – it isn’t necessarily ‘better.’ I also suspect plants would argue that we’re far better off now, and would be even better yet with significantly higher CO2 levels. I’m certainly happier with warmer temps than more ice and snow myself. –grin–

    Plants aside, In order to determine if we would be ‘better,’ I believe we have to do some cost/benefit type of analysis. For example, one may certainly be ‘safer’ in a completely temperature controlled padded 6ft x 6ft room with all nutritionally balanced meals delivered – but the cost sure isn’t worth it. Even ‘safety’ itself has to be defined in this sort of situation. Is a hypothetically slightly more ‘stable’ climate ‘safer’ if it comes with reduced lifespans, significantly reduced standards of living, reduced nutrition and health?

    Safety cannot be the only consideration. One must consider the costs of trying to stay even at present day levels of CO2, let alone trying to actually reduce levels, if either scenario is even possible. If the costs to world standards of living, life-spans, nutrition, etc. are too high, then its surely not worth trying to halt CO2 levels on the possibility that maybe it will be somehow ‘safer’ when we’ve no idea if in reality things really would be any safer.

    All of these factors mean that we had better be pretty darned sure that we base ANY decisions on good, solid, verified science. Which we very clearly do NOT have at this point in time.

    Lastly, your spaceship…

    I like to use the analogy of a person alone on an alien spaceship who wanders into the life support control room. The room is full of buttons and levers and our traveler understands none of it. What is the only reasonable course of action we can recommend to him? Isn’t it: “Don’t touch anything”?

    Ah, but there’s a few flies in the ointment here. The more apt analogy is that our intrepid spaceman has been on the ship for awhile. He’s managed to figure out ways to take a few measurements over time, but there are flaws with his methods and the accuracy and usefulness of what he’s measured are highly questionable. Even so, he’s managed to convince himself that changes over time might mean disaster, maybe HE actually changed things, just by being there. He convinces himself that he’s got to quit burping, or its going to destroy the delicate balance of the life support system on the spaceship, that MUST be what has caused some of the values he measured over time to change. He wanders into the control room, and is just sure that SOMETHING in here MUST be able to help him sequester his burps and save the system!! So he starts messing around with the buttons and levers….. and he confines himself to a single tiny closet to try to minimize his influence on the ship. Doing something must be better than doing nothing, right? After all, he’s just trying to return things to the way it was before he started doing all that burping, and all that wandering about breathing on things, none of which the system could possibly be designed to handle.

    Little does he know he’s either playing with fire or just making his own life utterly miserable, because he doesn’t have any real knowledge of the systems involved, of what his measurements mean or how they’re not accurate enough to even be meaningful.

    But then of course, any really GOOD spaceship would have all those levers and buttons safety interlocked, so he can’t really hurt the system after all by acting without sufficient knowledge – we hope. Perhaps what’s really better and safer, is to keep on having the best life he can, within reason, while trying to develop the science of ‘spaceship’ which is in its infancy, until he has some solid idea of just what he’s really measuring and what the ramifications are – or aren’t.

  116. David Middleton says:

    Robert (15:09:16) :

    If only. Actually, a doubling of CO2 is likely to cause 4+ degrees of warming, according to the very paper we are discussing.

    The “peer reviewed paper” is wrong. If it was right, we would have had more warming since 1850 than the HadCRUT3 series shows.

    Without positive feedbacks, a doubling of pre-industrial CO2 cannot cause more than 2C of warming. It actually can’t even cause half of that, because the net feedbacks are negative.

    I agree that any radical change in the climate is likely to be to our detriment. That being the case, the safest thing to do is to leave it as close to possible as the state we found it in (280ppm). Those are the levels that have been safe for the last 10,000 years of human history. Until we understand the climate system much better, they are the only levels that can be considered “safe” in the long run.

    If mankind had never discovered fire, atmospheric CO2 would be between 330 ppmv and 390 ppmv. If you back all of the anthropogenic CO2 emissions since 1700 out of the atmosphere, you get 330 ppmv. Plant stomata data (Kurchner et al., 1995, Wagner et al., 1999, Kouwenberg, 2004, Wagner et al. 2004 and 2005, Kurchner, 2008) and chemical analyses (Beck, 2007) tell us that since the beginning of the Holocene up until the start of the instrumental record, atmospheric CO2 has routinely fluctuated between 280 and 390 ppmv. The chemical analyses point to CO2 levels in excess of 400 ppmv within the last 200 years.

    If Mann and the other Hockey Stickers are correct, a reduction of atmospheric CO2 to 280 ppmv would return Earth’s climate to Little Ice Age conditions – Almost as bad as a 2C decline in global temperatures.

    If the climate reconstructions that honor the low frequency component of the data are correct (Esper et al., 2003, Moberg et al., 2005 and Loehle, 2007), a reduction to 280 ppmv would have a negligible effect on the Earth’s climate.

    There are no “middle ground” reconstructions. There are Hockey Sticks which suppress the low frequency signal from ice & sediment cores and boreholes… And there are reconstructions that honor the data. There is no “happy middle ground” between the two.

    I like to use the analogy of a person alone on an alien spaceship who wanders into the life support control room. The room is full of buttons and levers and our traveler understands none of it. What is the only reasonable course of action we can recommend to him? Isn’t it: “Don’t touch anything”?

    I personally like to use science (geology in particular) and mathematics to understand how the Earth’s climate behaved in the past to determine whether or not modern climate changes and atmospheric CO2 are anomalous. They are not anomalous.

    Practically speaking, we are going to see continued warming for our lifetimes, even if we bring CO2 down to 350ppm. The name of the game is to try and keep that warming as slow and limited as possible; to stay as close to the conditions that have been safe over the last 10,000 years.

    Scientifically speaking, we are going to see a slight to moderate cooling trend over the next 2-3 decades… Then a slight to moderate warming trend over the subsequent 2-3 decades. This ~60-yr cycle will continue for the next 100 to 500 years. Then the ~1,500-year (Dansgaard-Oeschger / Bond) cycle will turn negative and the Earth will return to Little Ice Age conditions. At some point down the road, this interglacial will end and the Earth will return to Upper Pleistocene glacial conditions. At some point a bit further down the road, the Quaternary ice age will end and the Earth will return to its normal, warmer state (~22C avg. surface temp. vs. the current ~15C).

    Anthropogenic CO2 emissions will not affect this process in any statistically significant manner.

    Furthermore, there is no economically possible pathway to reduce the atmospheric CO2 level from 388 ppmv to 350 ppmv. An 80% reduction in CO2 emissions by 2050 (“80 by 50″) would require us to reduce our per capita CO2 emissions to levels not seen since the 1860′s… And it would only result in a 2050 CO2 level of 435 ppmv vs a “business as usual” 2050 CO2 level of 471 ppmv.

    Could “80 by 50″ be achieved without destroying the global economy and killing billions of people? Maybe… But the price tag would be astronomical… The High Costs of Copenhagen

  117. David Middleton says:

    A very good discussion on the differences between the “Hockey Sticks” and the correct reconstructions can be found in J. Esper et al. / Quaternary Science Reviews 24 (2005) 2164–2166

    So, what would it mean, if the reconstructions indicate a larger (Esper et al., 2002; Pollack and Smerdon, 2004; Moberg et al., 2005) or smaller (Jones et al., 1998; Mann et al., 1999) temperature amplitude? We suggest that the former situation, i.e. enhanced variability during pre-industrial times, would result in a redistribution of weight towards the role of natural factors in forcing temperature changes, thereby relatively devaluing the impact of anthropogenic emissions and affecting future predicted scenarios. If that turns out to be the case, agreements such as the Kyoto protocol that intend to reduce emissions of anthropogenic greenhouse gases, would be less effective than thought.

    Oh… And… Esper and Moberg are not skeptics, deniers, denialists or whatever the current pejorative is…

    This scenario, however, does not question the general mechanism established within the protocol, which we believe is a breakthrough.

    Despite the fact that their own work devalues “impact of anthropogenic emissions”, they still accept the AGW premise.

  118. Robert says:

    “The “peer reviewed paper” is wrong. If it was right, we would have had more warming since 1850 than the HadCRUT3 series shows.”

    Not at all: feedbacks aren’t instantaneous. We won’t know until the system reaches equilibrium exactly how much warming the CO2 increase has set us up for.

    Most of your post is like that: a series of (mostly erroneous) assertions with no sources and no evidence. If you want to support the claim that there will be a cooling trend for 2-3 decades, or that anthropogenic GHGs won’t affect the climate significantly, I’d be happy to take a look. Without evidence, they are no more notable than any random claim that flies in the face of the evidence in hand: that the Earth is 10,000 years old, or cell phones cause cancer.

  119. Rational Debate says:

    Robert (09:02:54) :

    …….Not at all: feedbacks aren’t instantaneous. We won’t know until the system reaches equilibrium exactly how much warming the CO2 increase has set us up for.

    Citation/source please showing the net feedback lag.

    or that anthropogenic GHGs won’t affect the climate significantly,

    Citation/source please showing evidence that anthropogenic GHGs will affect climate significantly.

  120. David Middleton says:

    @Robert (09:02:54) :

    CO2 has a residence time in the atmosphere of about 5-10 years (Revelle & Suess (1957), Sundquist (1985), Segalstad (1989), Essenhigh (2009). Any warming caused by the current atmospheric CO2 and its combined feedbacks has pretty well already occurred.

    Furthermore, two thirds of the data for pre-Mauna Loa Observatory CO2 levels (plant stomata and chemical analyses) show that CO2 has routinely fluctuated between 280 and 390 ppmv…

    Plant SI vs Ice Core CO2

    CO2 From Chemical Analyses

    Even if the ice core CO2 data are correct, the Earth has not warmed in response to the increasing CO2. The Earth started to warm from the Little Ice Age in about 1600. CO2 did not start to rise until about 1860…

    Moberg (2005) and Ice Core CO2

    No positive feedback loops occurred during previous CO2 spikes. The Earth doesn’t all of the sudden start responding differently to atmospheric CO2 just because some of it is the result of fossil fuel burning.

    The only “pipeline” in which future warming is hiding is in the oceans… And they have been losing heat content since about 2003…

    NODC Ocean Heat Content Anomaly

    As far as the twenty to thirty year alternating cooling and warming trends go… Just look at the HadCRUT3 in relation to the PDO phase…

    HadCRUT3 vs PDO

    The PDO has been negative since about 2003. Over the last 100 years, the Earth has not warmed when the PDO was negative.

    The future 20-30 years of slight to moderate cooling was also predicted by Mojib Latif at the World Climate Conference last September.

    The 30 or so years of cooling are on slide three of Latif’s presentation… LINK

    Latif attributes the cooling to the North Atlantic Oscillation (NAO).

    Here’s an enlarged version of Latif’s 30 years of cooling… LINK

    Of course, the funny thing is that Latif chose to ignore the natural climate oscillations after the upcoming 30-yr cooling period, despite the fact that he attributed at least half of the prior century’s warming to those same oscillations.

    For a more realistic view of the potential warming and cooling effects, I would recommend this Don Easterbrook paper…

    Solar Influence on Recurring Global, Decadal, Climate Cycles Recorded by Glacial Fluctuations, Ice Cores, Sea Surface Temperatures, and Historic Measurements Over the Past Millennium

  121. David Middleton says:

    Here’s the Moberg reconstruction without the CO2…

    Moberg (2005) and UAH

    The MLO CO2 curve kind of obscures the temperature curve in the image from the previous post. I tied the UAH data into the end of Moberg (which he calibrated to the Hadley instrumental data).

    The late 20th and early 21st centuries are no warmer than the Medieval warm period. If CO2 was 280 ppmv in the MWP (as the ice core data suggest)… The 108 ppmv rise to today’s CO2 level has made no difference at all. The current warm phase of the ~1500-yr cycle is almost exactly as warm as the prior Holocene warm phases of the ~1500-yr cycle.

    The ~1500-yr cycle should be painfully obvious in the oxygen isotope-derived temperatures from the GISP2 ice core…

    GISP2

  122. Glenn Tamblyn says:

    @David Middleton (11:33:24)

    The NOAA Graph for Ocean Heat ontent is based on the most recent paper by Levitus et al. This only deals with heat in the top 700m of the ocean. Von Scuckmann et al 2009 looks at data down to 2000m for 2003 onwards and shows heat content still rising.

    (Revelle & Suess (1957), Sundquist (1985), Segalstad (1989), Essenhigh (2009) on CO2 residense time are outligher papers, not suppourted by other scientists.

  123. David Middleton says:

    @Glenn Tamblyn (13:20:35) :

    If both Levitus and Von Schuckman are correct, the oceans are gaining heat from 700m to 2000m and losing heat above 700m. How could this happen if the oceans are being warmed by an atmosphere that is being subjected to an enhanced greenhouse effect?

    If Revelle & Suess (1957), Sundquist (1985), Segalstad (1989) and Essenhigh (2009) are the outliers, then what, pray tell, constitutes the main body of peer-reviewed scientific literature on CO2 residence time?

    The atmosphere contains about 750 Gt C.

    The total annual carbon sources to the atmosphere:

    Oceans: 100-115 Gt C
    Decay of organic matter: 50-60 Gt C
    Plant respiration: 40-50 Gt C
    Fossil fuels: 5.3 Gt C
    Land use: 0.6-2.6

    Carbon Cycle

    Total sources: 196-233 Gt C

    750/196 = 3.8
    750/233 = 3.2

    Carbon sinks annually take up all but 3-4 years worth of the annual sources. The residence time can’t be a whole lot more than 4 years. Otherwise, CO2 would be accumulating in the atmosphere a heck of a lot faster than it currently is.

    Furthermore, the total anthropogenic component is less than the margin of error of the natural sources… A lot less than the margin of error.

  124. Glenn Tamblyn says:

    @David Middleton (17:21:01)

    “If both Levitus and Von Schuckman are correct, the oceans are gaining heat from 700m to 2000m and losing heat above 700m. How could this happen if the oceans are being warmed by an atmosphere that is being subjected to an enhanced greenhouse effect?”

    It is accepted that the last decade has seen a slowing of warming, I suggest due to a combination of factors – deep solar cycle minimum, reduced stratospheric water vapour levels, increased aerosol levels due to growth of Asia, possibly a reduced effect from the NAO. So heat flux into the top 700m layer has reduced due to these effects.

    But the heat flux from 700m to lower levels is driven by the temperature gradient between these levels, not what is happening above. All that is required for this to produce the result observed is the net flux into the 700m layer from above is less than the net flux from 700 to layers below. But the total heat of the entire ensemble has increased.

    So a reduction in warming, but not cooling. And all this under the conditions I have mentioned. What happens as Asia continues its attempts to clean up its aerosol emissions and we return to the next solar maximum in 5-6 years. A return of more vigorous warming?

  125. David Middleton says:

    Glenn Tamblyn (22:55:37) :

    It is accepted that the last decade has seen a slowing of warming, I suggest due to a combination of factors – deep solar cycle minimum, reduced stratospheric water vapour levels, increased aerosol levels due to growth of Asia, possibly a reduced effect from the NAO. So heat flux into the top 700m layer has reduced due to these effects.

    The cyclicity that it fairly apparent in the temperature data would suggest that the major cause is climate oscillations (PDO, NAO, AMO, etc.). All of which are probably manifestations of the ENSO. The ENSO itself might be driven by solar fluctuations… It could even be related to upper mantle convection. I don’t even have a good guess as to what drives the ENSO.

    But the heat flux from 700m to lower levels is driven by the temperature gradient between these levels, not what is happening above. All that is required for this to produce the result observed is the net flux into the 700m layer from above is less than the net flux from 700 to layers below. But the total heat of the entire ensemble has increased.

    I doubt that the upper 700m of the oceans are losing heat to the next deeper 1300m.

    I haven’t read Von Schuckman, beyond the abstract, but I seem to recall reading that it was only based on the Argo data. Whereas, Levitus used both Argo and XBT data. Furthermore, I think the correction to Levitus which produced the negative flux since 2003 was published about a year after Von Schuckman.

    NASA, NOAA and other groups have been constantly trying to figure out the best way to integrate the Argo and XBT data since 2005-2006 after NASA reported a sudden cooling of the oceans in 2003. A report they later retracted.

    If the climate is in the process of a major transition, like the “Great Pacific Climate Shift” of 1976-1977, it would seem to not be too much of a logical jump to assume that ocean heat content should be acting “funny”.

    So a reduction in warming, but not cooling. And all this under the conditions I have mentioned. What happens as Asia continues its attempts to clean up its aerosol emissions and we return to the next solar maximum in 5-6 years. A return of more vigorous warming?

    I don’t think that the solar minima and maxima act that quickly on climate. They have to be translated through the atmosphere and oceans to drive the multitude of climate oscillations. And I doubt that Asian aerosols are causing the current warming hiatus or slight cooling any more than Euro-American aerosols caused the slight cooling from ~1942 to ~1976… Or that European black carbon caused the warming from ~1908 to ~1942.

    It really stretches credulity to think that these anthropogenic effects are oscillating on such a regular schedule… A schedule that happens to coincide with the phases of the AMO, NAO, PDO, ENSO, etc.

    As a far as “a of more vigorous warming”… It will happen. But it will happen about 20-30 years from now. If people should be worried about climate change, they should be worried about how much it might cool over the next 20-30 years. If the solar minima are really instructive about climate change and we are in a Dalton-style minimum, it’s going to be getting quite a bit colder. If we get 1 or 2 Pinatubo’s over the next couple of decades, it’ll be even colder.

    We have a lot more people to feed now than we had back in 1815;

  126. Spector says:

    I wonder if anyone has ever analyzed the plant remains from the initiation of the last ice-age to see if there was any evidence of global CO2 starvation. I am sure that it would be fairly easy to get grant money for such a study.

  127. David Middleton says:

    @Spector (11:11:52) :

    There is quite a lot of evidence of CO2 starvation during Pleistocene glacial episodes… Carbon starvation in glacial trees recovered from the La Brea tar pits, southern California

    CO2 starvation becomes an issue for many plants at less than 200 ppmv, particularly C3 plants.

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