Successful Predictions of Climate Science

guest post by Steve Easterbrook

In December I went to the 2012 American Geophysical Union Fall Meeting. I’d like to tell you about with the Tyndall lecture given by Ray Pierrehumbert, on “Successful Predictions”. You can watch the whole talk here:

But let me give you a summary, with some references.

Ray’s talk spanned 120 years of research on climate change. The key message is that science is a long, slow process of discovery, in which theories (and their predictions) tend to emerge long before they can be tested. We often learn just as much from the predictions that turned out to be wrong as we do from those that were right. But successful predictions eventually form the body of knowledge that we can be sure about, not just because they were successful, but because they build up into a coherent explanation of multiple lines of evidence.

Here are the successful predictions:

1896: Svante Arrhenius correctly predicts that increases in fossil fuel emissions would cause the earth to warm. At that time, much of the theory of how atmospheric heat transfer works was missing, but nevertheless, he got a lot of the process right. He was right that surface temperature is determined by the balance between incoming solar energy and outgoing infrared radiation, and that the balance that matters is the radiation budget at the top of the atmosphere. He knew that the absorption of infrared radiation was due to CO2 and water vapour, and he also knew that CO2 is a forcing while water vapour is a feedback. He understood the logarithmic relationship between CO2 concentrations in the atmosphere and surface temperature. However, he got a few things wrong too. His attempt to quantify the enhanced greenhouse effect was incorrect, because he worked with a 1-layer model of the atmosphere, which cannot capture the competition between water vapour and CO2, and doesn’t account for the role of convection in determining air temperatures. His calculations were incorrect because he had the wrong absorption characteristics of greenhouse gases. And he thought the problem would be centuries away, because he didn’t imagine an exponential growth in use of fossil fuels.

Arrhenius, as we now know, was way ahead of his time. Nobody really considered his work again for nearly 50 years, a period we might think of as the dark ages of climate science. The story perfectly illustrates Paul Hoffman’s tongue-in-cheek depiction of how scientific discoveries work: someone formulates the theory, other scientists then reject it, ignore it for years, eventually rediscover it, and finally accept it. These “dark ages” weren’t really dark, of course—much good work was done in this period. For example:

• 1900: Frank Very worked out the radiation balance, and hence the temperature, of the moon. His results were confirmed by Pettit and Nicholson in 1930.

• 1902-14: Arthur Schuster and Karl Schwarzschild used a 2-layer radiative-convective model to explain the structure of the sun.

• 1907: Robert Emden realized that a similar radiative-convective model could be applied to planets, and Gerard Kuiper and others applied this to astronomical observations of planetary atmospheres.

This work established the standard radiative-convective model of atmospheric heat transfer. This treats the atmosphere as two layers; in the lower layer, convection is the main heat transport, while in the upper layer, it is radiation. A planet’s outgoing radiation comes from this upper layer. However, up until the early 1930’s, there was no discussion in the literature of the role of carbon dioxide, despite occasional discussion of climate cycles. In 1928, George Simpson published a memoir on atmospheric radiation, which assumed water vapour was the only greenhouse gas, even though, as Richardson pointed out in a comment, there was evidence that even dry air absorbed infrared radiation.

1938: Guy Callendar is the first to link observed rises in CO2 concentrations with observed rises in surface temperatures. But Callendar failed to revive interest in Arrhenius’s work, and made a number of mistakes in things that Arrhenius had gotten right. Callendar’s calculations focused on the radiation balance at the surface, whereas Arrhenius had (correctly) focussed on the balance at the top of the atmosphere. Also, he neglected convective processes, which astrophysicists had already resolved using the radiative-convective model. In the end, Callendar’s work was ignored for another two decades.

1956: Gilbert Plass correctly predicts a depletion of outgoing radiation in the 15 micron band, due to CO2 absorption. This depletion was eventually confirmed by satellite measurements. Plass was one of the first to revisit Arrhenius’s work since Callendar, however his calculations of climate sensitivity to CO2 were also wrong, because, like Callendar, he focussed on the surface radiation budget, rather than the top of the atmosphere.

1961-2: Carl Sagan correctly predicts very thick greenhouse gases in the atmosphere of Venus, as the only way to explain the very high observed temperatures. His calculations showed that greenhouse gasses must absorb around 99.5% of the outgoing surface radiation. The composition of Venus’s atmosphere was confirmed by NASA’s Venus probes in 1967-70.

1959: Burt Bolin and Erik Eriksson correctly predict the exponential increase in CO2 concentrations in the atmosphere as a result of rising fossil fuel use. At that time they did not have good data for atmospheric concentrations prior to 1958, hence their hindcast back to 1900 was wrong, but despite this, their projection for changes forward to 2000 were remarkably good.

1967: Suki Manabe and Dick Wetherald correctly predict that warming in the lower atmosphere would be accompanied by stratospheric cooling. They had built the first completely correct radiative-convective implementation of the standard model applied to Earth, and used it to calculate a +2 °C equilibrium warming for doubling CO2, including the water vapour feedback, assuming constant relative humidity. The stratospheric cooling was confirmed in 2011 by Gillett et al.

1975: Suki Manabe and Dick Wetherald correctly predict that the surface warming would be much greater in the polar regions, and that there would be some upper troposphere amplification in the tropics. This was the first coupled general circulation model (GCM), with an idealized geography. This model computed changes in humidity, rather than assuming it, as had been the case in earlier models. It showed polar amplification, and some vertical amplification in the tropics. The polar amplification was measured, and confirmed by Serreze et al in 2009. However, the height gradient in the tropics hasn’t yet been confirmed (nor has it yet been falsified—see Thorne 2008 for an analysis)

1989: Ron Stouffer et. al. correctly predict that the land surface will warm more than the ocean surface, and that the southern ocean warming would be temporarily suppressed due to the slower ocean heat uptake. These predictions are correct, although these models failed to predict the strong warming we’ve seen over the antarctic peninsula.

Of course, scientists often get it wrong:

1900: Knut Ångström incorrectly predicts that increasing levels of CO2 would have no effect on climate, because he thought the effect was already saturated. His laboratory experiments weren’t accurate enough to detect the actual absorption properties, and even if they were, the vertical structure of the atmosphere would still allow the greenhouse effect to grow as CO2 is added.

1971: Rasool and Schneider incorrectly predict that atmospheric cooling due to aerosols would outweigh the warming from CO2. However, their model had some important weaknesses, and was shown to be wrong by 1975. Rasool and Schneider fixed their model and moved on. Good scientists acknowledge their mistakes.

1993: Richard Lindzen incorrectly predicts that warming will dry the troposphere, according to his theory that a negative water vapour feedback keeps climate sensitivity to CO2 really low. Lindzen’s work attempted to resolve a long standing conundrum in climate science. In 1981, the CLIMAP project reconstructed temperatures at the last Glacial maximum, and showed very little tropical cooling. This was inconsistent the general circulation models (GCMs), which predicted substantial cooling in the tropics (e.g. see Broccoli & Manabe 1987). So everyone thought the models must be wrong. Lindzen attempted to explain the CLIMAP results via a negative water vapour feedback. But then the CLIMAP results started to unravel, and newer proxies demonstrated that it was the CLIMAP data that was wrong, rather than the models. It eventually turns out the models were getting it right, and it was the CLIMAP data and Lindzen’s theories that were wrong. Unfortunately, bad scientists don’t acknowledge their mistakes; Lindzen keeps inventing ever more arcane theories to avoid admitting he was wrong.

1995: John Christy and Roy Spencer incorrectly calculate that the lower troposphere is cooling, rather than warming. Again, this turned out to be wrong, once errors in satellite data were corrected.

In science, it’s okay to be wrong, because exploring why something is wrong usually advances the science. But sometimes, theories are published that are so bad, they are not even wrong:

2007: Courtillot et. al. predicted a connection between cosmic rays and climate change. But they couldn’t even get the sign of the effect consistent across the paper. You can’t falsify a theory that’s incoherent! Scientists label this kind of thing as “Not even wrong”.

Finally, there are, of course, some things that scientists didn’t predict. The most important of these is probably the multi-decadal fluctuations in the warming signal. If you calculate the radiative effect of all greenhouse gases, and the delay due to ocean heating, you still can’t reproduce the flat period in the temperature trend in that was observed in 1950–1970. While this wasn’t predicted, we ought to be able to explain it after the fact. Currently, there are two competing explanations. The first is that the ocean heat uptake itself has decadal fluctuations, although models don’t show this. However, it’s possible that climate sensitivity is at the low end of the likely range (say 2 °C per doubling of CO2), it’s possible we’re seeing a decadal fluctuation around a warming signal. The other explanation is that aerosols took some of the warming away from GHGs. This explanation requires a higher value for climate sensitivity (say around 3 °C), but with a significant fraction of the warming counteracted by an aerosol cooling effect. If this explanation is correct, it’s a much more frightening world, because it implies much greater warming as CO2 levels continue to increase. The truth is probably somewhere between these two. (See Armour & Roe, 2011 for a discussion.)

To conclude, climate scientists have made many predictions about the effect of increasing greenhouse gases that have proven to be correct. They have earned a right to be listened to, but is anyone actually listening? If we fail to act upon the science, will future archaeologists wade through AGU abstracts and try to figure out what went wrong? There are signs of hope—in his re-election acceptance speech, President Obama revived his pledge to take action, saying “We want our children to live in an America that isn’t threatened by the destructive power of a warming planet.”

78 Responses to Successful Predictions of Climate Science

  1. John Baez says:

    I too went to the AGU Fall Meeting, saw Ray Pierrehumbert’s fascinating and entertaining talk, and wanted to blog about it. But Steve Easterbrook beat me to it and did a better job than I could have! Everyone interested in climate science or global warming should check out his blog here:

    • Steve Easterbrook, Serendipity.

    And everyone should watch Ray Pierrehumbert’s talk!

    • Marvin J. Greenberg says:

      Although Easterbook’s list of predictions was informative, the last sentence of his piece endorsing Obama does not belong on your blog, John, unless you too have become politically biased and not scientifically objective. Also, he exaggerates the results by using the vague word “many” while he has only listed a few, as Arrow pointed out.

      • John Baez says:

        I wouldn’t have included that last sentence myself, and I’ll be more careful about politics in guest posts in the future. But I don’t feel the need to delete it. I wouldn’t say it’s “endorsing” Obama. It’s just saying that his pledge to take action is a sign of hope. If you prefer that little action be taken, don’t worry: so far it’s just talk.

      • Marvin – that’s not me talking about Obama, it’s how Ray ended his talk. I find it fascinating (from a sociological point of view) that many of the big keynote talks at the AGU end with some speculation about how the science might should (or should not) get translated into policy, and the role of politics in that process. My political science colleagues would point how how naive most of these are.

        • Marvin J. Greenberg says:

          Well, Steve, then I object to your reporting how Ray ended his talk with his political opinion. That opens the door to everyone who comments here expressing his/her political opinion. We have enough of that on many other websites. I doubt that’s what John Baez wants to present on his website.

          Let me refer people to just one article that shows how complicated is this issue of climate change, so that jumping to alarmist conclusions at this time is not so intelligent.

          New estimates from a Norwegian project on climate calculations indicate that the warming associated by increased atmospheric CO2 concentrations is less than previously assumed.

        • I’m sorry, Mr. Greenberg, this sounds more like you are polticizing here. Facts are sometimes inconvenient. Inconvenience can be factual as well as political. There is realitiy, and then there is politics, ego, and worldviews. As the saying goes: You are entitled to your own opinion, but not your own facts.

      • “Scientifically objective”: What does that mean? I’m serious: How would you objectively measure whether it was present or not?

      • @Greenberg … Guess there must be some depth limit on the replies here … But your invocation of the Norwegian report shows tremendous lack of scholarship. The principals behind that report regret its release, because it is premature and not peer reviewed. It was a press release, not an official publication. Yet, apparently, some people jump at the opportunity to highlight these kinds of reports because it suits their viewpoint. Huh.

        Climate sensitivities come in all over the place: See

        Click to access knutti08natgeo.pdf


        • Marvin J. Greenberg says:

          @hypergeometric “The principals behind that report regret its release, because it is premature and not peer reviewed. It was a press release, not an official publication.”

          You gave no reference for your claim that the principals regret the release of their findings. And if they do regret the release because it is premature, that does not imply that they are withdrawing their findings that the warming associated to increased atmospheric CO2 concentrations is less than previously assumed!

          @hypergeometric “some people jump at the opportunity to highlight these kinds of reports because it suits their viewpoint.”

          You are one of those people, sir.

        • @Greenberg from 8 February, 2013 at 4:37 am: Link on the Norwegian press matter,

          However, the entire deal with sensitivity is written up nicely at:

          in part moved by the current kerfluffle. Typical of the good work done in this area is that co-authored by Prof Baez’s friend,
          Dr Nathan Urban, along with Professor Andreas Schmittner and others: “Response to Comment on ‘Climate
          Sensitivity Estimated from Temperature Reconstructions
          of the Last Glacial Maximum'”, 14 SEPTEMBER 2012 VOL 337 SCIENCE, pp 1294ff. Check it’s references for the primary papers and their supplementary materials which permit the dedicated reader to reproduce the results.

          Professor Baez blogged about this paper, too, at:

          Prof Baez interviewed Dr Urban at, e.g.,

          By the way, the to and fro regarding the Schmitter-Urban-Shakun-Mahowald-Clark-Bartlein-Mix-Rosell-Melé paper is a great example of how science is really done and good scientific criticism handled. In particular, a criticism of the work was voiced by Fyke and Eby, but, then, quoting Schmittner, et al’s rejoinder:

          “In a much-appreciated collaboration with Fyke and Eby, we have estimated the effect of dust forcing by calculating temperature anomalies from simulations in (2) with amodel with similar ECS2xC (3.4 K) as that used in (1). Adding these anomalies to the model results in (1) (thick blue line in Fig. 1) results in too-cold temperatures over most of the tropics.”

          It goes on, but the point is that both groups are trying to get to the heart of a difficult, complicated problem, modeling the data as available and as consistent with physical law.

          This is very much in contrast with the style and feeling of controversies regarding anthropogenicity or not which play out elsewhere, and are more like attorneys going at each other in courtrooms. Even their language is legalistic.

          Apologies for not having a direct link to the SCIENCE paper, but their search engine is broken this morning. A trip to the library will produce such, or copies can be obtained online with an AAAS membership. Can buy individual copies as well.

  2. Marvin J. Greenberg says:

    Henrik Svensmark has proposed that galactic cosmic rays (GCRs) could exert significant influence over global temperatures. The theory goes that the solar magnetic field deflects GCRs, which are capable of seeding cloud formation on Earth. So if the solar magnetic field were to increase, fewer GCRs would reach Earth, seeding fewer low-level clouds, which are strongly reflective. Thus an increased solar magnetic field can indirectly decrease the Earth’s albedo (reflectivity), causing the planet to warm.

    There are arguments pro and con about his theory. The cloud seeding part got support from the CERN experiment.

    Henrik Svensmark, Torsten Bondo and Jacob Svensmark (2009). “Cosmic Ray Decreases Affect Atmospheric Aerosols and Clouds”. Geophysical Research Letters 36: L15101. Bibcode 2009GeoRL..3615101S. doi:10.1029/2009GL038429.

    M.B. Enghoff, J. O. Pepke Pedersen, U. I. Uggerhøj, S. M. Paling, and H. Svensmark (2011). “Aerosol nucleation induced by a high energy particle beam”. Geophysical Research Letters 38: L09805. Bibcode 2010AGUFM.A33F0232E. doi:10.1029/2011GL047036

    More generally, this piece is fascinating:

    “Evidence of nearby supernovae affecting life on Earth”

  3. Arrow says:

    So is the track record of 8 correct to 5 incorrect predictions supposed to inspire confidence in climate science?

    Also what is sorely missing from this list are correct quantitative long term predictions of global average temperature. Without them why should anyone take future temperature forecasts (on which all the apocalyptic scenarios are based) seriously?

    • John Baez says:

      Arrow wrote:

      So is the track record of 8 correct to 5 incorrect predictions supposed to inspire confidence in climate science?

      Heh. Come on—every science generates lot of papers containing incorrect predictions. What matters is the papers that become accepted by the scientific community! Most of the correct predictions on this list have been widely accepted for a long time, while all the incorrect ones have been embraced by ‘climate skeptics’.

      Also what is sorely missing from this list are correct quantitative long term predictions of global average temperature.

      I guess you didn’t watch the video of the actual talk.

      • Arrow says:

        That could be the hindsight bias. Most of the correct predictions have been accepted for a long time because they were confirmed long time ago, but were they widely accepted at the time of publication?

        No, I haven’t seen the video of the talk, though I have scanned it now and can’t find anything particularly relevant to my point. Do you refer to the “world is warming compatibly with predictions of GHG theory” slide? That is hardly a concrete prediction.

        You can see the kind of predictions I have in mind – only shorter term – discussed here (an alarmist blog, so spun accordingly, but the graphs speak for themselves):

        Note that only Hansen et al, 1988 temperature prediction is what I would call medium term (25 years) and it fails spectacularly, already running 0.5 deg C warmer than reality. The other 3 predictions are short term at this point (around 10 years) and despite the fact the errors didn’t have that much time to accumulate they are all already clearly off track. The IPCC AR4 has significantly steeper warming trend than reality, and both the predicted ocean heat content and arctic sea ice are significantly overestimated.

        So the track record of detailed medium term and even short term climate model predictions is already really bad (and the models I mentioned were endorsed by the community) and yet we are expected to trust climate science predictions for the middle and the end of this century?

      • About reporting failures as well a successes, it reminded me of this great lecture:

        (even if i don’t think it really applies because we have models that seems to explain well both the failures as well as the successes, so in a sense failures can be now counted as successes, because they are explained by the same models, but still …)

    • Arrow: You can’t do the 5/8 thing, because you’ve no information about how this sample was selected (i.e. no way of mapping the sample back to the population). It’s fair to say that Ray picked a set that he thought would make a good talk. Don’t draw any other conclusions about the numbers.

      Quantitative long term predictions are not possible in climate science because of the complexity of the system. An output from a model is never a prediction, it’s a scenario. Read this excellent (and mildly skeptical) paper to get a sense of what the models are and the role they play in the science:

    • correct quantitative long term predictions of global average temperature

      As I told Andy Revkin recently: Still stuck with blah, blah, blah: Predictions of apocalypse not precise enough!

      1) You need to get used to qualitative thinking (as e.g. in stuff involving the exponential function).

      2) The qualitative results of climate science are old enough and well-established enough.

      3) Forget climate sensitivity in theory’s sense for a moment and behold the sensitivity of the bio-geo-physical system (e.g. rapid arctic summer ice melt, practically done and gone as early as 2012 (ask the empiricists e.g. at Neven’s blog)). There is your qualitative evidence. It makes no difference if you predict Greenland ice gone in 2300 or 2078.

      Models based on natural law are something entirely different to criticize than economist models.

      • Arrow says:

        It’s not that “predictions of apocalypse” are not precise enough, they are not convincing.

        And I don’t know what you mean by bio-geo-physical sensitivity but I know that rapid arctic summer ice melt of 2012 was a complete non-issue unlike countless REAL problems like poverty, hunger, diseases, wars, crime and so on.

        • “…they are not convincing.” But not convincing to whom? It’s easy to take any area of science and refuse to be convinced by it. Big Bang Theory? Not convincing. Evolution? Not convincing. Relativity? Not convincing. Genome sequencing? Not convincing. See, I could play this game all day long.

          The honest thing to do is to go and learn the physics of climate change properly. Take some courses. Read some textbooks. Study hard. Then ask yourself whether you’re convinced.

          Climate science is hard, because climate is a complex system. Virtually every scientist who has invested the time to study it deeply is convinced that continuing along the emissions path we’re on will have widespread and dangerous impacts on much of human society. I’ve interviewed more than 50 climate scientists, and chatted informally to many more. They disagree over some of the details, but there’s no disagreement over the big picture.

          Occasionally you hear of a climate scientist who takes a contrary view. But that’s the nature of science – scientists like to be contrary whenever possible. I find it truly remarkable that climate science has so few contrarians – there’s about half a dozen of them, among thousands of publishing climate scientists worldwide. That’s the mark of a field with a very mature theoretical foundation.

        • Arrow says:

          Steve, “Predictions of climate apocalypse” are not convincing to anyone who takes scientific method seriously enough. Evolution, relativity and genome sequencing have countless experimental evidence to back them up. Big bang theory makes extremely long term (14 billion years!) and detailed quantitative predictions – see CMB spectrum. “Predictions of climate apocalypse” are based on climate models with bad to non-existent track record, can you see the difference?

          You yourself agree above that “quantitative long term predictions are not possible in climate science because of the complexity of the system,” but that is precisely what “predictions of climate apocalypse” rest on. The difference between barely-noticeable 1 degree warming by 2050 and dangerous 5 degree warming is quantitative. If climate sensitivity is 1-2C per CO2 doubling the whole anthropogenic global warming will be a non-issue. The Hansen 1988 model I mentioned above assumed it was 4C, it run spectacularly too hot, so as you can read in the link now “consensus” revised it downward to 3C and models still run too hot compared to reality, I fully expect it to be revised further down.

          Qualitative predictions of the sort “it will get hotter” are next to useless and certainly do not warrant massive interventions into global energy economy.

          As to your arguments from authority, it is difficult to get a man to admit something, when his salary depends upon his not admitting it.

        • I know that rapid arctic summer ice melt of 2012 was a complete non-issue

          1) Frankenstorm Sandy. The empiricists at Nevens blog saw it coming. The polar jet stream grabbed Sandy and smashed it into New York

          2) Moscow buried in snow. Russia experiences a gigantic lake snow effect.

          The Arctic is just one aspect of bio-geo-physical sensitivity. But it is directly visible and can be studied even by artists (who might even be better in reading cloud dynamics).


          Another important bio-geo-physical detail (alas invisible) is ocean acidification. This is the litmus test of human-made catastrophe: The oceans can’t buffer away the acidity due to the rapid (unnatural) rise of CO2. Since more than a billion humans depend on ocean protein, this is not a non-issue.

          For a visible biological feedback have a look at tree mortalitity in the U.S. (bark beetle, drought, fire).

        • P.S. How climate can affect poverty, hunger and war can be studied in Syria these days. See also Darfur some years earlier. One cause of the Egyptian revolution was rising prices of bread. We will see more of this, guess why.

        • I suggest, sir, that you have not gotten deeply enough into the details to make any such inference. We are playing with forces of incredible size here. I know your time is limited, but I encourage you to go through Dr Baez’s series on the matter here, or take Dr Archer’s course at Open Climate 101,

    • Matt McIrvin says:

      This is kind of like saying that because so many people insisted that the Sun goes around the Earth, and they were all wrong, this degree of wrongness casts doubt on Copernican astronomy as well and therefore suggests that the geocentrists were actually right. I could refute a lot of things that way!

  4. Domenico says:

    I am thinking a crazy idea (I don’t make here proof of concept),
    A complete real simulation of a planet meteorology.
    I think that can be possible to use a centrifuge to simulate the gravitation gradient until the space (if the rotation is right).
    It is not an Earth simulation, but if you use artificial mountain, right gas, little seas, solar simulation lamp in quick rotation; then you can built the numerical planet simulation, and it is possible to verify the reality on the artificial model.
    Are there artificial clouds and lightning? Is it possible to make experimental meteorology on field?
    If this work you can change the initial condition (for example the CO2 concentration, vegetation,…) and to prove that the human race can destroy the planet (science fiction?).



    • Frederik De Roo says:

      Are there artificial clouds and lightning? Is it possible to make experimental meteorology on field?

      See e.g. Eurochamp-2

      I think that can be possible to use a centrifuge to simulate the gravitation gradient until the space (if the rotation is right).

      I think you can only get the gravitation gradient near the surface right (i.e. the first order of the expansion) and actually you would have to simulate a radially reversed earth.

      • Domenico says:

        I am thinking a sealed rotating cylinder with a geophysical model of a planet (like mountains, seas and rivers, and some lichen) in the inner surface.
        The friction between air layers have a point of equilibrium, after a phase of vorticity, and there are problems only for the layer near the center (rarefaction produce less friction, and I am thinking to include the ionization of the high atmopshere): this is not a problem if the numerical model is the model of the rotating athmosphere, which include the pertubation of the Earth’s gravity; i cannot evaluate in this moment the time necessary to obtain the stationary state.



    • Domenico says:

      I think that a correct model of Earth meteorology is necessary to change the point of view of many scientists, but the industries (that lose money with a different green politic) can change the vision of the people, because they can use advertising, lobbying to fit the change.

      The ozone depletion is near to the solution because there are not more industries that loses money for its solution; but there are scientists that said that the ozone depletion have a natural cause!

      So the problem is convince people of democratic countries, and politicians, which is a bet that is not convenient (destroy the planet for money): it is possible to change the industries to make money with green economy, and the old industries can be helped (that fight against the change) to enter in the new green economy.

      The theory of the greenhouse effect must be used to convince the people; for example I think that the Beijng politicians believes, now, that humans are causing climate change, and I think that the Hurricane Sandy, Katrina have changed the persuasion of people.



  5. Timothy says:

    Why is global warming assumed to be bad?

    While the evidence that global warming is occurring is quite convincing, involving theory, models, and evidence, all discussion about global warming assumes that it is a negative effect that needs to be stopped. However, the common predictions I’ve heard are not so bad.

    An example of this is the prediction that sea levels will rise. While this is damaging to some current infrastructure, the period of change is on the same level as the life time of most constructions (a few decades). Also, we know from the geologic record that sea levels have fluctuated significantly in the past.

    Most other predicted effects of global warming are similar. They predict changes to land use patterns, but it is not obvious that these changes are even net negatives. All most all negative effects assume static land use patterns despite historical evidence that these can change significantly on the same time scales as the predictions.

    Obviously, many experts in this field disagree with the position stated above. What information are they working on which I am probably missing?

    • John Baez says:

      Your question will unleash a flood of opinionated comments, but let me point you to some of the information you’re asking for:

      • Intergovernmental Panel on Climate Change, Climate Change 2007: Working Group II: Impacts, Adaptation and Vulnerability. (Free online.)

      • Intergovernmental Panel on Climate Change, Climate Change 2007: Working Group III: Mitigation of Climate Change. (Free online.)

      • US National Research Council, Climate Stabilization Targets: Emissions, Concentrations, and Impacts over Decades to Millennia, 2010. (You can either register and download a free PDF or read the book online.)

      • US Global Change Research Program, Global Climate Change Impacts in the United States, 2009. (Free online.)

      • US Environmental Protection Agency, The Social Cost of Carbon, 2009. (Free online.)

      This is a lot to read, but it’s very important stuff, and there are nice executive summaries.

      • Timothy says:

        Thank you very much for these resources. This is a question that has been bugging me for quite some time. Hopefully these will provide an answer.

      • Marvin J. Greenberg says:

        @Timothy “Why is global warming assumed to be bad?”

        Excellent question. Indeed, several years ago the great physicist Freeman Dyson spoke publicly about specific positive effects of global warming, if it is not too extreme.

        I don’t have time at the moment to locate the precise references for all his statements. Here is one:

        “Dyson had proposed that whatever inflammations the climate was experiencing might be a good thing because carbon dioxide helps plants of all kinds grow.”

        Also Dyson said in a 2009 interview with Yale Environment 360 after that NY Times piece was published:

        “My objections to the global warming propaganda are not so much over the technical facts, about which I do not know much, but it’s rather against the way those people behave and the kind of intolerance to criticism that a lot of them have. I think that’s what upsets me.”

        I think the difference between me and most of the experts is that I think I have a much wider view of the whole subject. I was involved in climate studies seriously about 30 years ago. That’s how I got interested. There was an outfit called the Institute for Energy Analysis at Oak Ridge. I visited Oak Ridge many times, and worked with those people, and I thought they were excellent. And the beauty of it was that it was multi-disciplinary. There were experts not just on hydrodynamics of the atmosphere, which of course is important, but also experts on vegetation, on soil, on trees, and so it was sort of half biological and half physics. And I felt that was a very good balance.

        And there you got a very strong feeling for how uncertain the whole business is, that the five reservoirs of carbon all are in close contact — the atmosphere, the upper level of the ocean, the land vegetation, the topsoil, and the fossil fuels. They are all about equal in size. They all interact with each other strongly. So you can’t understand any of them unless you understand all of them. Essentially that was the conclusion. It’s a problem of very complicated ecology … ”

        Dyson did not mention there the effects of the sun and of cosmic rays that Svensmark theorized. But that interview of him was before the CERN experiment that confirmed part of Svensmark’s claims.

        • Marvin J. Greenberg says:

          Here is the reference for the entire Yale interview:

        • Frederik De Roo says:

          I have great respect for Freeman Dyson’s contribution to physics, and yes he is a great physicist, but that doesn’t imply he would be a great earth scientist.

          Carbon dioxide fertilization is, as far as I know, still debated within the scientific community itself (I would gladly be corrected by someone better versed in this topic). Of course, we may always pray that plants will miraculously remove all the extra carbon put in the atmosphere. If you know more about the subject of carbon dioxide fertilization, please add it to our wiki. Our wiki is aimed to be of interest to anyone who takes the scientific method seriously.

        • There’s an Azimuth project page on “CO2 fertilization“. The old glossary page explains why it would never save us on our current path, even in theory (where to put all the trees?). In reality, results are mixed, with some ecosystems taking up more CO2, and others less. Grassland seems to do better than forests.

          Problem is, CO2 alone is no fertilizer. Other nutrients are needed, above all Nitrogen to keep the C/N ratio good. Plants are intimately connected with soil (a complex system of microbes, funghi, worms, etc. etc.), which holds a much larger C pool (3200 Gtc) than plant biomass alone (650GtC).

          In David Archer’s book, The Global Carbon Cycle, there’s something about a “missing sink”, sequestering 1-2 GtC/y, possibly due to CO2 fertilization (or it’s effect on soil C).

          I’d like to know more about the role of phytoplankton: Diatoms have no calcium shell to dissolve in acidified ocean. They do C4 photosynthesis, and ocean water holds more CO2 than air. There’s lot’s of space opening in the arctic ocean for massive phytoplankton blooms…

    • What you are missing is that the predictions are based upon smoothed projections and linear extrapolations … These are used because these are what are definitively known. In fact, however, we also know that the climate system is highly nonlinear, and projections do not capture its amazing complexity and couplings. The predictions should be thought of as average results based upon what is known. In practice, regional climate will veer away from these, obtaining these estimates, it is believed on the average.

      The nonlinearities to which I refer also mean that there will be “surprises”. One is the rapid melting of Arctic ice. No climate model predicted that would happen as fast as it is. The other is “La Nada” … the quiescent state of the Pacific, neither La Nina or La Nino, that’s driving long term projections nuts.

      It is possible some “surprises” may be so-called “bifurcations”, and these could be extremely dangerous. See

      A presentation on what could happen is available at my blog, at It advertised a lecture given on 4th February by Dr Emily Shuckburgh, sketched, and has a video link to an interview with her.

      If you would like to understand this stuff better in connection with climate, there are an awesome series of blog posts by Dr John Baez beginning at which talk about climate possibly having multiple stable states.

      The basic think people forget is that while climate has been hotter or colder than it is now, transitions to those states took a long time, forced gently there by small forcings like those provided by the Milankovitch cycles. Understanding how, say, the Ice Ages started by those small forcings was a tremendous finding in 20th century geophysics. But that same insight revealed that it meant Earth’s climate system is REALLY sensitive. In comparison to natural forcings, our collective dumping of carbon dioxide is slamming the thing with a mallet, quickly. In some sense, if we keep it up, we don’t know WHERE the climate system will end up.

      This is why Dr Wally Broecker has the phrase, which I very much like, “Earth’s climate system is an angry beast, and we are hitting it with a stick.”

    • davidtweed says:

      Timothy wrote

      “the period of change is on the same level as the life time of most constructions (a few decades).”

      I’m reminded of a story (maybe apocryphal) I heard on the radio. An American tourist couple are looking the Bodleian library in Oxford and grab a busy but also rather snooty senior librarian. “Gee, that’s one really amazing building. Is it pre-war?” The librarian draws himself up to his full height, looks down his nose and says “Sir, that building is pre-America”.

      Most of the infrastructure that’s younger is mostly younger because the “use case” didn’t exist before, e.g., there’s no economic/political incentive to motorways/freeways before there’s widespread car ownership. The view that the huge pieces of infrastructure get replaced every couple of decades doesn’t seem to have been true even in an era of plentiful energy and money; what sort of replacement schedules will occur in a future when there may be less of both…

  6. Marvin J. Greenberg says:

    @Arrow “Predictions of climate apocalypse are not convincing to anyone who takes scientific method seriously enough.”


  7. John Baez says:

    Let’s talk about facts instead of each other. Some very interesting and important issues are being discussed here, but I’m starting to see remarks that focus on other commenters’ personal defects instead of the science, and I’m not going to allow that. I’m talking about things like this:

    it is difficult to get a man to admit something, when his salary depends upon his not admitting it.

    You are one of those people, sir.

    Well, Steve, then I object to your…

    I’m sorry, Mr. Greenberg, this sounds more like you…

    I suggest, sir, that you have not gotten deeply enough into the details…

    These comments are all much more polite than a typical internet discussion, and for that I’m grateful. But I think we can do a lot better by presenting clear arguments with lots of facts to back them up, and letting each others’ flaws speak for themselves.

    • Marvin J. Greenberg says:

      @ Baez “I’m starting to see remarks that focus on other commenters’ personal defects instead of the science, and I’m not going to allow that. Let’s talk about facts instead of each other.”

      I agree and wish you luck with moderating the intense heat of this debate.

      Please keep in mind that there is often intense disagreement on the interpretation of the facts and what government policy should be in response to the interpretation. Moreover, partisans often present only selected facts that support their views, ignoring other facts.that raise doubts and disagreement. New facts (and new theories) are constantly being discovered (respectively being invented).

    • Arrow says:

      For the record the first example, which is a paraphrase of Upton Sinclair quote, was meant as a commentary on the fact skeptics are underrepresented among climate scientists and not aimed at anyone here. I am pretty sure many climate scientists prefer to keep their doubts to themselves.

      • davidtweed says:

        Another statement that’s not really in anyway capable of being established: “I am pretty sure many climate scientists prefer to keep their doubts to themselves.” Due to the very careful phrasing it probably is a true proposition (it’s probably true that you are pretty sure that….) But the more interesting and relevant qustion: is it the case that many climate scientists prefer to keep their doubts to themselves? If we’re going to bring issues like this into the discussion, can we at least try to apply the scientific method to them? How would we establish this rather than just decide by fiat that we’re pretty sure of this? (If you’re going to use the scientific method, then the rhetorical tricks of the debating chamber don’t really have a place.)

    • nad says:

      John wrote:

      Let’s talk about facts instead of each other. Some very interesting and important issues are being discussed here, but I’m starting to see remarks that focus on other commenters’ personal defects instead of the science, and I’m not going to allow that. I’m talking about things like this:

      it is difficult to get a man to admit something, when his salary depends upon his not admitting it.

      Also if repeating myself – I do think this aspect is important.

      That is a certain source of funding may distort people’s opinions and it may be important in a discussion to know whether discussants may be presented with a conflict of interests, be presented with a moral conflict etc.

      • Related, here’s another hindrance: Dreams.

        This very comment thread serves at least 3 excellent examples of how a life long of dreams of space age can distort vision of the ground base: Freeman Dyson, Larry Bell, Dr. David R. Whitehouse.

      • @nad, In certain disciplines and contexts, whether or not someone is supported with funding in a certain way may be pertinent. This is true notably in legal contexts, and in political ones. Science is neither. Whether you believe it or not, most scientists and many engineers will do their professional best to pursue what’s true irrespective of whether their bosses or organizations approve of the finding or not.

        Moreover, scientific funding of its nature does not expect a certain outcome. This again may be a cynical transfer from other disciplines where people are paid to produce a report with a pre-designated outcome. Moreover, true science cannot involve proprietary information, since the result needs to be published, including the data.

        The ultimate test of a scientific finding is that its result is reproducible, even by the most critical of its audience. If the knowledge of the field is a barrier, well that cannot be helped. Mechanisms in Nature can be complicated. However, much of what is done in geophysics is approachable, given enough math training. It isn’t, for example, as opaque as quantum physics (e.g., Bell’s Theorem), at least in my opinion.

        • Todd Trimble says:

          @hypergeometric: I think the re-emphasis made by nad isn’t necessarily made to support Arrow’s point (which is presumably suggesting that scientists who support AGW are “corruptible”); instead it might be a reminder that that point cuts both ways, in particular, it also applies to scientists who collect paychecks from corporations whose perceived interests are in opposition to or in conflict with AGW.

        • @Todd Trimble,

          And I would say that just because a scientist receives a paycheck from XOM or BP or anyone else does not mean their view should be discounted. NOT AT ALL. But people need to participate and DO THE SCIENCE, not try to create legalistic arguments which are like proposing perpetual motion machines. If the argument is sound science, ANYONE should be listened to.

          “If even the devil states that 2 x 2 = 4, I am going to believe him.” — P. P. Waldenstrom, famous Swedish religious leader of the 19th century

        • Todd Trimble says:

          @hypergeometric: sure, the scientific arguments should be weighed first and foremost. I agree with you completely there. On the other hand, the caps make me wonder whether I’ve upset you. Maybe I shouldn’t have said anything; it was the way you wrote to nad (“Whether you believe it or not, most scientists and many engineers will do their professional best…”) — I believe nad is a scientist herself and sympathetic to the Azimuth Project — that made me think that maybe some clarification was in order. But I’m happy to let this be my last comment on this score.

        • No, Todd, please don’t read into the caps. I use them in place of italics at times. Old habits die hard. I’ve been doing email and discussion boards since 1974.

  8. Marvin J. Greenberg says:

    Here are some more facts and statements interpreting them:

    Did global warming [pause or] stop 16 years ago?

    The U.K.’s Met Office released new data showing that there was no rise in aggregate global temperatures from the beginning of 1997 until August 2012. That means that the gradual rise in the world’s temperatures has hit a “plateau” or “pause” that’s lasted 16 years — roughly as long as the upward climb that ran from 1980 to 1996.

    “The new data confirms the existence of a pause in global warming,” Judith Curry, chair of the School of Earth and Atmospheric Science at Georgia Tech university.

    A statement from the Met Office in response to the story says the Daily Mail chose a starting point that came in the middle of “an exceptionally strong El Nino,” which came after a “double-dip La Nina.” The unusual conditions in the Pacific Ocean led to a spike in temperatures. “Choosing a starting or end point on short-term scales can be very misleading” — start the comparison in August instead of January 1997, and you get a sharper temperature rise.”

    From the original Oct. 13, 2012 Daily Mail article referred to above (it has a nice graph showing the temperature fluctuations):

    The new data, compiled from more than 3,000 measuring points on land and sea, was issued quietly on the internet, without any media fanfare, and, until today, it has not been reported.
    This stands in sharp contrast to the release of the previous figures six months ago, which went only to the end of 2010 – a very warm year. Ending the data then means it is possible to show a slight warming trend since 1997, but 2011 and the first eight months of 2012 were much cooler, and thus this trend is erased.

    Professor Phil Jones, director of the Climatic Research Unit at the University of East Anglia, last week dismissed the significance of the plateau, saying that 15 or 16 years is too short a period from which to draw conclusions.

    Others disagreed. Professor Judith Curry, who is the head of the climate science department at America’s prestigious Georgia Tech university, told The Mail on Sunday that it was clear that the computer models used to predict future warming were ‘deeply flawed’. Even Prof Jones admitted that he and his colleagues did not understand the impact of ‘natural variability’ – factors such as long-term ocean temperature cycles and changes in the output of the sun.

    The lengthy Daily Mail article goes on to discuss the implications for government ‘green’ subsidies and how those have significantly increased everyone’s energy bills in the U.K.–chart-prove-it.html#axzz2KKtbydfy

    There is a similar ongoing discussion in Germany about the high energy bills there. Citizens with a low-income are suffering particularly. 10 to 15 percent of Germans are now struggling to pay their energy bills. 600,000 households have the electricity turned off every year.

    • Marvin J. Greenberg says:

      One more fact for now:

      “Since 1998, more than 31,000 American scientists from diverse climate-related disciplines, including more than 9,000 with Ph.D.s, have signed a public petition announcing their belief that “…there is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of the Earth’s climate.” Included are atmospheric physicists, botanists, geologists, oceanographers, and meteorologists.”

      • Frederik De Roo says:

        more than 31,000 American scientists from diverse climate-related disciplines, including more than 9,000 with Ph.D.s

        So who were those 22,000 scientists without PhDs? Students? On the Forbes website I couldn’t find a link to this public petition to see who signed it.

        Btw, that quote reminds me of this one:

        “That book was approved by sixty-five engineers at the Such-and-such Aircraft company!”

        • Todd Trimble says:

          Maybe everyone reading this knows what Frederik De Roo is alluding to with “sixty-five engineers”, but in case not, it’s a story told by Richard Feynman about reviewing school textbooks (“Judging Books by Their Covers”, from Surely You’re Joking, Mr. Feynman!, circa 270-272). Feynman was on a committee to review a number of math books and has some discouraging experiences, but thinks maybe the science books will be a little better. He winds up going virtually apoplectic over one which repeatedly explains to children how “Energy makes it go”. That book was the final straw, and he winds up resigning from the committee, but makes a last ditch effort at a public hearing to explain why the book is bad and should not be accepted. They guy who had replaced him on the committee says, “That book was approved by sixty-five engineers at the Such-and-such Aircraft Company!” Feynman goes on to comment, “I didn’t doubt that the company had some pretty good engineers, but to take sixty-five engineers is to take a pretty wide range of ability — and to necessarily include some pretty poor guys! … It would have been far better to have the company decide who their better engineers were, and to have *them* look at the book. I couldn’t claim that I was smarter than sixty-five other guys — but the *average* of sixty-five other guys, certainly!”

      • Marco says:

        The OISM list is quite infamous for its inclusion of a lot of non-scientists. They may have university degrees, but that does not make them scientists.

        Moreover, when Scientific American did a short survey of the listed PhDs, they found that:

        Of the 26 we were able to identify in various databases, 11 said they still agreed with the petition —- one was an active climate researcher, two others had relevant expertise, and eight signed based on an informal evaluation. Six said they would not sign the petition today, three did not remember any such petition, one had died, and five did not answer repeated messages.

        And if this petition makes any impact on your thinking, I guess I can make you doubt that evolution is tenable as a scientific theory:

        • Frederik De Roo says:

          And if this petition makes any impact on your thinking, I guess I can make you doubt that evolution is tenable as a scientific theory

          Oh, no worries, there is Project Steve to counter that ;-)

      • John Baez says:

        Marvin wrote:

        “Since 1998, more than 31,000 American scientists from diverse climate-related disciplines, including more than 9,000 with Ph.D.s, have signed a public petition announcing their belief that “…there is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of the Earth’s climate.”

        This is again a famous meme, worth studying in some detail. Luckily Skeptical Science has already done so:

        In early 2008, the Oregon Institute of Science and Medicine (OISM) published their Petition Project, a list of names from people who all claimed to be scientists and who rejected the science behind the theory of anthropogenic (human-caused) global warming (AGW). This was an attempt to by the OISM to claim that there were far more scientists opposing AGW theory than there are supporting it. This so-called petition took on special importance coming after the release of the Intergovernmental Panel on Climate Change’s Fourth Assessment Report, and specifically the Working Group 1 (WG1) report on the science and attribution of climate change to human civilization.

        The WG1 report was authored and reviewed by approximately 2000 scientists with varying expertise in climate and related fields, and so having a list of over 30,000 scientists that rejected the WG1’s conclusions was a powerful meme that AGW skeptics and deniers could use to cast doubt on the IPCC’s conclusions and, indirectly, on the entire theory of climate disruption. And in fact, this meme has become widespread in both legacy and new media today.

        It is also false.

        Skipping over a description of how the Oregon Institute of Science and Medicine defined a ‘scientist’—basically, anyone with a bachelors degree in any technical field!—we find:

        If we remove all the engineers, medical professionals, computer scientists, and mathematicians, then the 31,478 “scientists” turn into 13,245 actual scientists, as opposed to scientists according to the OISM’s expansive definition. Of course, not all of them are working in science, but since some medical professionals and statisticians do work in science, it’s still a reasonable quick estimate.

        However, it’s not reasonable to expect that all of those actual scientists are working in climate sciences. Certainly the 39 climatologists, but after that, it gets much murkier. Most geologists don’t work as climate scientists, although some certainly do. Most meteorologists do weather forecasting, but understanding the weather is radically different than understanding climate. So we can’t be sure beyond the 39 climatologists, although we can reasonably assume that the number is far less than the 13,245 actual scientists claimed by the OISM.

        13,245 scientists is only 0.1% of the scientists graduated in the U.S. since the 1970-71 school year.

        We can, however, compare the number of atmospheric scientists, climatologists, ocean scientists, and meteorologists who signed this petition to the number of members of the various professional organizations. For example, the American Geophysical Union (AGU) has over 55,000 members, of which over 7,200 claim that atmospheric sciences is their primary field. The OISM claims 152 atmospheric scientists. Compared to the atmospheric scientist membership in the AGU, the OISM signatories are only 2.1%, and this estimate is high given the fact that the AGU does not claim all atmospheric scientists as members.

        The AGU hydrology group has over 6,000 members who call hydrology their primary field. The OISM list has 22 names that claim to be hydrologists, or 0.4%.

        The AGU ocean sciences group claims approximately 6,800 members. The OISM has 83 names, or 1.2%. And again, given that AGU membership is not required to be a practicing ocean scientists, this number is inflated.

        The American Meteorological Society claims over 14,000 members and the OISM claims 341 meteorologists as petition signatories. That’s only 2.4%.

        It’s clear that the OISM names don’t represent a significant number of scientists when compared to either the total number of science graduates in the U.S. or to the number of practicing scientists who work in likely relevant fields. But that’s not all.

        Over recent years, various organizations have set out to estimate just how widespread the supposed “scientific consensus” on AGW actually is. Two recent efforts were conducted by the Statistical Assessment Service (STATS) at George Mason University and by the Pew Research Center for the People and the Press. The STATS survey found that 84% of climate scientists surveyed “personally believe human-induced warming is occurring” and that “[o]nly 5% believe that that human activity does not contribute to greenhouse warming.” The STATS survey involved a random sampling of “489 self-identified members of either the American Meteorological Society or the American Geophysical Union” and it has a theoretical sampling error of +/- 4%.

        The Pew survey was taken in early 2009 and asked over 2000 members of the American Association for the Advancement of Science (AAAS) their opinion on various scientific issues, including climate disruption. 84% of AAAS respondents felt that “warming is due to human activity” compared to only 10% who felt that “warming is due to natural causes.” The AAAS has over 10 million members, and the results of the survey are statistically valid for the entire population with a theoretical sampling error of +/- 2.5%.

        84% of 10 million scientist members of the AAAS is 8.4 million scientists who agree that climate disruption is human-caused. 84% of the climate scientists (conservatively just the members of the atmospheric science group of the AGU) is, conservatively, 6,000 scientists who have direct and expert knowledge of climate disruption. The 13,245 scientists and 152 possible climate scientists who signed the OISM petition represent a small minority of the totals.

        The IPCC AR4 WG1 report was written and reviewed by approximately 2000 scientists. If we assume that the 20,000 AGU members who claim to be atmospheric scientists, ocean scientists, or hydrologists represent the pool of potential experts in climate science in the U.S., then approximately 10% of all climate scientists were directly involved in creating the over 1000 page report.

        That compares to less than 1% of all OISM “scientists” who mailed a pre-printed postcard.

        A more recent survey of earth scientists asked the question “Do you think human activity is a significant contributing factor in changing mean global temperatures?”. 97.5% of climatologists who were actively publishing papers on climate change responded yes.(Doran 2009). What is most interesting about this study was that as the level of active research and specialization in climate science increases, so does agreement that humans are significantly changing global temperatures.

        There are problems with doing science by consensus… but there are much bigger problems with letting everyone with an undergraduate degree in any technical subject send in postcards opposing the scientific consensus, and then claiming it’s significant when 0.1% of these people actually do this!

    • John Baez says:

      Regarding that famous Daily Mail article, it’s worth reading this:

      • Dana Nuccitelli, Misleading Daily Mail article pre-bunked by Nuccitelli et al. (2012), 17 October 2012.

      It’s also worth watching this.

      It would be great if there were a pause in global warming, but all this, together with the rapid melting of the Arctic, this list of the 10 warmest years on record:

      2010, 2005, 1998, 2003, 2002, 2006, 2009, 2007, 2004, 2012

      and various other pieces of data make me less optimistic than some.

      • Marvin J. Greenberg says:

        @Baez “It would be great if there were a pause in global warming …”

        Consider this: James Hansen of NASA is a well-known outspoken warmist. Yet even he made this concession in a joint article dated 1/15/13:

        “The 5-year mean global temperature has been flat for a decade, which we interpret as a combination of natural variability and a slowdown in the growth rate of the net climate forcing.”

        This link is to their paper, not to a yellow journalist newspaper article:

        Click to access 20130115_Temperature2012.pdf

        And here are the bottom lines of an informed critique of their paper by Dr. David Whitehouse:

        The bottom line is that the recent global temperature standstill is a real event. It is explained in a hand-waving way as due to natural climatic variations masking the long-term trend, even if we do not understand those natural variations. Some believe the standstill might be pointing the way to a deeper revision of our understanding of climate. One thing is clear: the stuff you heard until very recently about mankind’s signal of warming being the strongest (and getting stronger) is wrong. The standstill has already taught us that.

        • Todd Trimble says:

          Regarding Dr. David Whitehouse (who serves on the advisory board of GWPF): his 1983 doctorate is in astrophysics; for some more background, see here. According to Skeptical Science, he has published no peer-reviewed articles in the area of climate science. It might be a little hard to accept, just on somebody’s say-so, that he is particularly well-informed in this area.

      • Arrow says:

        Highly ironic that starting around 1973 gives you the steepest possible warming trend of 0.27C/decade. If you start from say 1900 you will end up with only 0.09C/decade. Other years give other values of course:

        • Dan says:

          Just to clarify, when you say that “starting around 1973 gives you the steepest possible warming trend” you’re talking about in comparison to starting years prior to that, right? If one is willing to choose a starting year later than 1973, then one can find ordinary least squares (OLS) trends with slopes steeper than 0.27C/decade. For example, I downloaded the data used to create the graph Professor Baez posted (namely, the so-called BEST data from the Berkeley Earth folks) and did a little loop in R to find the slope of the OLS trend lines for each starting year in turn (using the annual average anomalies, centered on June of each year) and found several starting years with steeper warming trends (e.g., 1974 gives 0.28C/ decade, 1982 gives 0.30C/decade, 1991 gives 0.34C/decade, and 1992 gives 0.37C/decade). And for what it is worth, I get 0.26C/decade for 1973 and 0.10C/decade for 1900. Indeed, as the hockey-stick shape of the graph you linked to would suggest, I find that the OLS slopes are systematically shallower for earlier starting times (all the way back to 1753 when the data series linked to starts) and steeper for more recent starting times, up until the mid-1990s when the small sample size starts giving more variable point estimates. Again, I just wanted to clarify that because the first time I read your post I mistakenly misinterpreted it to mean that 1973 gives the steepest of all possible starting times (which I’m sure you’ll agree isn’t true) and I didn’t want anyone else to similarly confused.

        • John Baez says:

          Thanks for clarifying that, Dan and putting in some work to do so! This is the kind of comment I really like: hard data.

          If there are lots of short-term fluctuations in the Earth’s temperature—and there are—we’d expect to find bigger slopes and smaller slopes, even negative slopes, as we study the trend over shorter and shorter time intervals.

          Since some people seem to think these fluctuations are unexplained ‘hand-waving’ by climate scientists who secretly doubt the party line but aren’t brave enough to admit it, let me talk about one of the main ones: the El Niño Southern Oscillation, or ENSO. We have a pretty good introduction to this on the Azimuth Wiki. This animation produced by the Australian Bureau of Meteorology shows how it works:

          During El Niño years, trade winds in the tropical Pacific weaken, and the eastern part of this ocean warms up. During La Niña years, the trade winds get stronger again. The average temperature of the Earth is higher during El Niño years.

          Scientists keep track of this cycle using the Southern Oscillation Index, or SOI. This is based on measure sea level air pressure differences between Tahiti and Darwin, Australia:

          When the SOI is low, waters in the eastern tropical Pacific tend to be hotter. When it’s high, these waters tend to be hotter. You can see that very clearly here:

          Unfortunately this graph stops around 2000. But here’s a graph showing global mean surface temperature of the Earth along with the Niño sea surface temperature and volcano eruptions:

          I would like to learn more about precisely how much of the Earth’s temperature variability can be accounted for by the ENSO. It would be fun to read some papers and do some data analysis.

          As usual, you can click any of the pictures for more information about them.

        • Arrow says:

          @Dan: Well, yes and no. My main point was indeed about years prior to 1973 – omitting them from the graph is as misleading as restricting it to just the last 15 years, only in the opposite sense.

          However I thought 1973 gave roughly the steepest warming trend of all the years. I only eyeballed the graph though and I missed that 1992 would produce significantly steeper trend (it’s kinda hard to see on the graph), so I stand corrected on that point.

    • Marco says:

      Marvin, this is what the Met Office had to say about the misleading Daily Mail article:

      An article by David Rose appears today in the Mail on Sunday under the title: ‘Global warming stopped 16 years ago, reveals Met Office report quietly released… and here is the chart to prove it’

      It is the second article Mr Rose has written which contains some misleading information, after he wrote an article earlier this year on the same theme – <a href = "you see our response to that one here.

      To address some of the points in the article published today:

      Firstly, the Met Office has not issued a report on this issue. We can only assume the article is referring to the completion of work to update the HadCRUT4 global temperature dataset compiled by ourselves and the University of East Anglia’s Climate Research Unit.

      We announced that this work was going on in March and it was finished this week. You can see the HadCRUT4 website here.

      Secondly, Mr Rose says the Met Office made no comment about its decadal climate predictions. This is because he did not ask us to make a comment about them.

      You can see our full response to all of the questions Mr Rose did ask us below:

      Hi David,

      Here’s a response to your questions. I’ve kept them as concise as possible but the issues you raise require considerable explanation.

      Q.1 “First, please confirm that they do indeed reveal no warming trend since 1997.”

      The linear trend from August 1997 (in the middle of an exceptionally strong El Nino) to August 2012 (coming at the tail end of a double-dip La Nina) is about 0.03°C/decade, amounting to a temperature increase of 0.05°C over that period, but equally we could calculate the linear trend from 1999, during the subsequent La Nina, and show a more substantial warming.

      As we’ve stressed before, choosing a starting or end point on short-term scales can be very misleading. Climate change can only be detected from multi-decadal timescales due to the inherent variability in the climate system. If you use a longer period from HadCRUT4 the trend looks very different. For example, 1979 to 2011 shows 0.16°C/decade (or 0.15°C/decade in the NCDC dataset, 0.16°C/decade in GISS). Looking at successive decades over this period, each decade was warmer than the previous – so the 1990s were warmer than the 1980s, and the 2000s were warmer than both. Eight of the top ten warmest years have occurred in the last decade.

      Over the last 140 years global surface temperatures have risen by about 0.8ºC. However, within this record there have been several periods lasting a decade or more during which temperatures have risen very slowly or cooled. The current period of reduced warming is not unprecedented and 15 year long periods are not unusual.

      Q.2 “Second, tell me what this says about the models used by the IPCC and others which have predicted a rise of 0.2 degrees celsius per decade for the 21st century. I accept that there will always be periods when a rising gradient may be interrupted. But this flat period has now gone on for about the same time as the 1980 – 1996 warming.”

      The models exhibit large variations in the rate of warming from year to year and over a decade, owing to climate variations such as ENSO, the Atlantic Multi-Decadal Oscillation and Pacific Decadal Oscillation. So in that sense, such a period is not unexpected. It is not uncommon in the simulations for these periods to last up to 15 years, but longer periods are unlikely.

      Q.3 “Finally, do these data suggest that factors other than CO2 – such as multi-decadal oceanic cycles – may exert a greater influence on climate than previously realised?”

      We have limited observations on multi-decadal oceanic cycles but we have known for some time that they may act to slow down or accelerate the observed warming trend. In addition, we also know that changes in the surface temperature occur not just due to internal variability, but are also influenced by “external forcings”, such as changes in solar activity, volcanic eruptions or aerosol emissions. Combined, several of these factors could account for some or all of the reduced warming trend seen over the last decade – but this is an area of ongoing research.

      • Marvin J. Greenberg says:

        @Marco Re. the U.K. Met Office

        The problem involves two different sets of historical data from two respected agencies: the UK Met Office and America’s National Oceanic and Atmospheric Administration (NOAA).

        There are rules that scientists must follow in order for their work to be judged valid. The work must be done openly, transparently—there can be no secret steps or hidden incantations. This is because the work must be reproducible, not just by those who originated it but by outsiders as well. Things began going off the rails when NOAA recently reprocessed the SSU temperatures and published the full processing methodology and the resulting data in the peer-reviewed literature. This is as it should be, NOAA followed the rules. But it soon became obvious that there were grave discrepancies between the new NOAA data and the older Met Office data….

        “The methodology used to generate the original Met Office SSU data remains undocumented and so the climate community are unable to explain the large discrepancies between the original Met Office and NOAA SSU products highlighted here,” Thompson et al. summarize. And the damage doesn’t stop there.

        The data from the erroneous dataset has been used widely to help drive and define computer climate models, the same models used to prop-up alarmist claims of impending catastrophic climate change.

        Those are excerpts from this troubling 1/15/2013 report:

        which in turn is based on this report in the 29 November 2012 issue of Nature

        “The mystery of recent stratospheric temperature trends”

        Those are the facts. Continuing in the first troubling report is this commentary I have excerpted:

        The methodology used to develop the Met Office SSU product was never published in the peer-reviewed literature, and certain aspects of the original processing “remain unknown.”

        The bottom line here is that models based on this almost universally accepted data are wrong. “If the NOAA SSU data are correct, then both the CCMVal2 and CMIP5 models are presumably missing key changes in stratospheric composition,” the report plainly states. The article goes on to suggest corrective actions to prevent such a travesty being repeated in the future. Alas, the damage has already been done.

        How other climate scientists blindly accepted the Met Office’s manufactured data, even when their models could not be reconciled with nature, leads one to question the scientific integrity of many of those in the field. This is not acceptable behavior in any realm of scientific endeavor, and when the results of research are used to inflame the public and drive questionable socioeconomic programs the malfeasance could be considered criminal. This is what happens when the race for fame, government funding and political advantage collide with science—the validity of the science is destroyed.

  9. Jack says:

    As I’m reading all of the comments to this site, I suspect that the following quote rings true to even the most die-hard advocates of global warming…

    “Poor people across the developing world determine that their contribution to climate change is insignificant relative to the benefit they will receive from introducing heat and electricity into their homes. Every day millions of people around the world determine that the benefit of them filling up with gasoline and driving to work outweighs the cost of their fossil fuel consumption. Everyone … can argue that the cost-benefit analysis favors their usage of fossil fuels. People from all walks of life — including staunch environmentalists — use fossil fuels every day and justify it based on the cost-benefit to themselves.”

    That quote comes from this blog:

    So, as much as everyone is hyperventilating about these models and what they mean, I seriously doubt that anyone has taken personal responsibility to make a meaningful (and not just token) net personal reduction in fossil fuel use (especially as you drive in to work each day, or fly off to your conferences to discuss the above issues).
    I’m just say’n…..

    • Frederik De Roo says:

      There are certainly people who take personal responsibility.

      On the other hand, if all climate scientist were suddenly to live in tents on campus, feeding on potatoes locally grown on their own dung, I kind of doubt that would convince you either…

      Besides, I think the goal of staunch environmentalists is not to return to hunter-gatherer times, it’s instead to leave some benefits for the coming generations.

  10. domenico says:

    I tried to solve a challenge some time ago for Innocentive (I send it to Virgin and Bellona), a theoretical solution to capture atmospheric carbon: a reconstruction of the petroleum carbon reserve in the exhaust petroleum deposit using an organic-liquid-carbon introduction (seaweed, grass or leafs powders).
    I think that it is possible a Green Pact between Seven Sisters and politic: the oil reserve go to run out, and the technology and oil infrastructure become useless, so it is possible to use the structure in a reverse way to inject atmospheric carbon in a liquid form; with the viscosity equal to the petroleum using carbon-complex as tree powder (cultivate or not cultivate) seaweed powder, grass powder, mixed with water,
    If there is a continuous water low level adjustment (with an extraction pump), then the introduction pump must not make many work to pump in the carbon mixture, but the introduction pump and the extraction pumt must draw in the bottom of the reserve to avoid blockage (I think a perforated introduction pipeline in the reserve).
    If this system work, then you can introduce 1 m^3 of solid atmospheric carbon each minute (1m^3 seaweed=20Kg), so you can obtain 1440*365 m^3 seaweed=525.600 m^3 seaweed=20*525.600Kg=10.512.000Kg of atmospheric carbon for year (I think that a part of carbon must change in methane for bacteria digestion).
    There is a problem: the sequestration include organic nitrogen (atmospheric reduction), sulfur and phosphorus (biologic reduction); it is necessary the purification of the extracted water with algae, or bacteria
    This system can be tested with a little reserve: can it solve the Beijing problem now?Some lakes with seaweed, some pipeline, some pumps, a sealed reserve.
    There is not a leakage problem, because it is not a high pressure reserve.
    The politic can give money for carbon sequestration (with reduction of the cost each year), only with an open project (no patents) so that the injection have ever lower cost in the time (the people must not pay too for the anti-greenhouse effect criticim).
    An other – no cost – carbon sequestration can be the change of the usual reforestation, using sequoia, Montezuma cypress, Kauri, Pacific redcedar, …; the carbon mass of these forest can increase in some centuries (the problem grow in some centuries, and the solution is long centuries or millennia).



  11. domenico says:

    It is possible an optimization of the wind generators, to obtain lower cost of the energy (to substitute coal).

    The energy loss is due to turbulence for the not optimal blade form.
    It is possible a great increase of the efficiency using genetic algorithmic
    applied to the reality.

    You imagine thousand electromechanical actuators that change the geometric shape of blades in a wind tunnel (with constant wind velocity) to increase the power production (the error function): it is not necessary a numerical simulation of the wind generator, it is only necessary a power measure for each little random change of the real shape, and store the optimal shape.



  12. domenico says:

    Is it possible a global energetic optimization to reduce global pollution?
    Is it possible the optimization of the propellers for large vessels with evolution strategy?
    It is possible the optimization of the electronic control unit for cars during the evaluation testing: if the parameter of the engine operation (the intake valve times,electrical time spark, …) have a little random change during the test driving, then the minimum fuel consumption is the right parameters value; so it is possible the optimization of all the new cars (many cars, many energy reduction).
    It is possible optimize, in general, each human mechanism, so as to reduce consumption (energy,petroleum,coal,etc.); for example the hull shapes, electronic circuit (serial-parallel variable elements instead of a constant element?), water impulse turbine, steam turbine (change of the vane angles and dimension?).
    Is it possible a material optimization (with evolution strategy) using a random change of the element of the alloy?
    Is it possible to optimize solar cell composition with brickyard-robot that change contiuously the doping impurities and structure?



    • domenico says:

      I am thinking to an optimal wing, for airplane and wind turbine, so that there is a friction (and energy loss) reduction.
      I am thinking to a N-transversal section of the wing (with a thickening in the end), with N two ball joints, so that each section can change the wing shape; each region, on the Earth, have a measured wind velocity, so that it is possible to try the maximization of the power production for the local wind speeds



      • domenico says:

        I am thinking that the perfect shape of a wing can be obtained with a optimal triangulation: each side of the mesh is a electromechanical actuator.
        The wing mesh is covered with a elastic surface.
        If this work, than the wind turbine plant can replace coal extraction.



  13. Wolfgang says:

    In my opinion, as a natural scientist myself, climate science fails to be a science at all, because of one single reason: the inability to admit the complexity of the topic (every week there are new “unexpected” findings regarding important details with a major impact on all existing theories) and the ignorance of everything not fitting into the predictions. In other words…everything that is observed is interpreted as a sign for global warming…if it gets hotter, well, of course, global warming…but if it remains cooler than expected for more than a decade, well, of course, also global warming…thus, with a little change in the argument, everything is fine again. But this clearly is rather ideologic than scientific. And it is not the usual way, scientific results emerge and are discussed!

    • qcoder says:

      There is a hierarchy of effects which you are not admitting here. Sure, at smaller levels of influence, there is a lot not known about the workings of the climate system and the geophysics of it all. However, the basic science is known, and it is incredibly unlikely the major influences would be overturned without some corresponding basic change in the understanding of the physics. Basic physics cannot be subjected to a hypothesis test. Basic physics provides a powerful and fundamental prior distribution which data and likelihood functions must be really compelling to overturn.

      Indeed, the physics is so powerful, there is no need for “confirmatory evidence”. In fact, climate change HAS to happen if the physics are correct.

      The statistics and non-linearities of turbulence associated with energy distribution cannot magically overcome basic thermodynamics and the physics of blackbody radiation.

    • John Baez says:

      Wolfgang wrote:

      In my opinion, as a natural scientist myself, climate science fails to be a science at all…

      Unfortunately your comment contains very little information, since we’ve all heard people say this before, and also the opposite. It’s much more interesting to get into the actual details of climate physics, which is what Pierrehumbert’s talk did.

  14. This article was quoted in “”, but unfortunately credited to John Baez rather than Steve Easterbrook.

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