Oh Good, We Have Consensus About Climate Change

Everybody who believes science should be conducted by vote, raise their hands.
See if you agree with me: agreeing with me isn’t proof that that which we agree about is true. Doesn’t mean that that which we agree about is wrong, neither, because this agreement is about something which is true. Rather, our consensus is not of much interest, except sociologically.

Consider other consensuses (consensi?). A century ago the intelligentsia thought it was a swell idea that people should have perfection forced upon them by making a Utopian omelette created by cracking a few tens of millions of skulls. The consensus among us civilians is that the intelligentsia was bat-guano crazy. The consensus among the intelligentsia now, on the other hand, hasn’t budged: government (meaning rule by themselves) knows best—about everything.

Medieval scientists agreed to a man that Ptolemy’s theory about the movement of celestial objects was true. They were rational to do so, because the thing worked. Well, mostly worked, or worked good enough for everyday purposes. Scientists now agree that a better theory has come along. This one works, too.

Modern scientists shook hands and were adamant the continents were fixed objects. Doctors laid their thumbs upon their noses when asked their opinion about hygiene (they were against it). And on and on.

The batting average for Consensus is like that of an aging player being sent down to the minors in July. We had such hopes for it early on, but it consistently failed under pressure, though we’re still willing to give it one more try.

The leftwards press delights in telling us there is a consensus among climate scientists. Why they should be so pleased that the sky is falling is a mystery, unless it’s another symptom of the bloodlust found in progressives. The Guardian—protecting British minds from the onslaught of reality since 1821—is giddy over the statistic that 97.1% (and not just 97.0%) of academic papers agree that “climate change is anthropogenic.”

Just what is this capital-C Consensus? My pal Gav Schmidt asked me to tell you (his words; “the update” is found on the page linked):

  1. The earth is getting warmer (0.6 +/- 0.2 oC in the past century; 0.1 0.17 oC/decade over the last 30 years (see update)) [ch 2]
  2. People are causing this [ch 12] (see update)
  3. If GHG emissions continue, the warming will continue and indeed accelerate [ch 9]
  4. (This will be a problem and we ought to do something about it)

The last one is in brackets because whilst many would agree, many others (who agree with 1-3) would not, at least without qualification. It’s probably not a part of the core consensus in the way 1-3 are. Most (all?) of us here on RealClimate are physical scientists — we can talk sensibly about past, present and future changes in climate, but potential impacts on ecosystems or human society are out of our field.

Since it hasn’t been hotting up recently at the rates quoted by Gav, “People are causing this” is ambiguous, and there is substantial uncertainty in the historical observations, the Consensus can only be of minor interest. Climate scientists have to agree on something and it is a good thing they’re trying to sort out how things work, but their forecasts haven’t been of sufficient precision to encourage the rest of us to pay too close attention. Not yet, anyway.

Gav rightly emphasizes the “we ought to do something about it” isn’t a major part of the Consensus, if it’s there at all. But the Guardian, representing the perpetually “outraged” crowd, think it is; indeed, they think the Consensus is nothing but that. One prominent fellow with a mind permanently and deeply scarred by youthful “experimentation” said the Consensus is “about activism” and “is about converting people.”

Politicians and journalists who couldn’t read a thermometer, even if you threatened to withhold their kickbacks and deny their bylines, are so eager to believe climate change is man-made because that makes it “a problem and we ought to do something about it.”

This explains the mysterious glee over every heatwave headline and the perverse delight politicians display when organizing hearings on the end of the world. They believe they are the “we.” Just as with the earlier consensus, they believe paradise is just around the corner if only, if only.


Thanks to Ye Olde Statistician and the many others who asked about this topic and provided references.


  1. Re-posting my comment from Kloor’s:

    Fact: 97% of scientists agree that we’re going to die horrible weather related deaths. Those who survive will eat one another in a Mad Max style post-apocalyptic nightmare. This is a scientific FACT, 97% of scientists agree to this. Stop denying science, bumpkin.

    Fact: 97% of scientists agree that if we don’t subsidize solar panel companies you hate science and your brain is probably incapable of thinking scientifically at all (Lewandowsky 2009)

    Fact: 97% of scientists agree that the main cause of continued growth in C02 emissions is Anthony Watts and not hundreds of millions of Chinese, Indians and others who stubbornly resist returning to subsistence farming.

  2. Previous post was sarc if not obvious.

    From the main post:

    “…climate change is man-made because that makes it “a problem and we ought to do something about it.””

    I have come to realize that human need to “do something” regardless of efficacy or evidence is really quite pervasive. This is of course most obvious in a social context with politicians in examples such as gun control, environmental policy etc.

    Locally in my small hometown the city council recently passed a motion to outlaw smoking in any public parks, beaches, or on the grounds of any public properties. I certainly do not encourage smoking by any means but it is becoming apparent that “anti-smoking” legislation has become less a tool for the net improvement of public health and more of a dumb opportunity for politicians to demonstrate their moral preening. “Look! Members of my constituency! I am your caretaker and protector!”

    While this is an admittedly minor issue I believe it is a microcosm of a larger pattern. The movement away from government as simply a means to enforce the rule of law and towards the micromanagement and risk mitigation of every single element of existence is, suffice it to say, disheartening.

  3. Even in fields other than Climate Science, the consensus often breaks down in the face of new information. See this article from the field of immunology where a recent discovery has completely reset our understanding (consensus) of how cells become infected. Search for work by Leo James, William McEwan of Cambridge for more details. Also WSJ had a review article on May 24 but is paywalled.

  4. The authority of science derives only from the legacy of centuries of trial and error, not from recent publications or opinions currently held among scientists.

  5. Science works because it is largely self-correcting. Aristotle thought that velocity was proportional to force applied and that the natural state of things was to be at rest. This model worked (and still does) here on Earth in many cases. Aristotle’s error was that he failed to realize that friction is a force. He saw that, if he stopped pushing the cart, the cart slowed and stopped. Along came Newton, who realized that it’s change in momentum that is proportional to an applied net force, and that the mass was the constant of proportionality. That model works too, until relativistic speeds are approached. Newton also came up with a model for the gravitational force, i.e., F=Gm1m2/r^2 (leaving out the vector notation). It works as well, until black holes, neutron stars, or relativistic speeds are approached.

    Steven Goddard (a strident and arrogant climate sceptic blogger who, for some unknown reason, is afraid to not use a pseudonym) has a tagline on his site quoting Richard Feynman, who said that “Science is the belief in the ignorance of experts.” It’s a cute quote but I don’t think that Feynman would have followed it with “rather, science is the belief in the expertise of ignoramuses.”

    It’s certainly the case that scientific “facts” are not determined by a pole among scientists. And that, of course, is not what the paper in question did. Nevertheless, unless YOU possess the requisite background and expertise, if there’s a strong consensus among those who DO have that background and expertise, you’re rather foolish to think that you know better.

  6. The human urge to do something is respectable in itself, but it needs no science to ask a very simple question: “Will what you want to do, actually *do* something?” or to rephrase it, “Are you willing to do something that will actually *do* something?”

    For example, if the numbers provided by some ACD (anthropogenic climate-disruption) advocates are taken as read, one quickly realizes that in order to achieve a reduction that will have any effect within a reasonable timeframe, the following practices will have to be discontinued or severely curtailed:

    1) Private air travel;
    2) Private automobile travel;
    3) Industrial-scale meat farming (cows & pigs emit methane);
    4) Society-wide electrification (no more lights after dark, no more radio, TV or Internet, and *one* appliance at best in private homes — pick your stove or your refrigerator, basically; which also, incidentally, yanks women out of the workforce en masse, because daily home maintenance is no longer something that can be done in an hour or two of minimal effort);
    5) Mass-production assembly-line manufacturing, of *anything* (which guarantees increased accidents and fatalities when anything one tries to build on the assumption of assembly-line standards falls down).

    No amount of mere conservation or cap & trade will suffice. And even assuming one is willing to agree to all this and can get a majority of people in one’s own country to agree as well, you still have to be willing to enforce compliance on other countries, and willing to live with the fact that whoever enforces all the above standards will certainly not be subject to them themselves.

    When the proposed solution to a problem really doesn’t do much to address the problem, it is always worth asking if maybe the solution is really intended to achieve something else.

  7. Rob Ryan: “if there’s a strong consensus among those who DO have that background and expertise, you’re rather foolish to think that you know better.”

    Fair enough. The problem there is an oft heard cry from activist climatologists when their papers are criticized by non-climate scientists is that “well, you’re not a climatologist”. That is credentialism. Anyone with the requisite skills in mathematics, statistics can conceivably read a climate science paper and critique it. People should always be skeptical of anyone in society who is claiming special authority, especially when there are large implications for policy and even more so when criticism is demonized. Nullius In Verba.

    There are numerous problems with that paper. The major problem with the appeal to consensus argument is the bait and switch that often occurs. An activist blogger will cite an outlier paper or prediction from someone like James Hansen “SEA LEVEL RISE WILL BE 20 FEET THIS CENTURY!!!!” and then tag on that “97% of climate scientists believe global warming is real” as if the two are synonymous.

  8. Consensus, in Latin, is a noun of the fourth declension (like, say, apparatus and fetus), so the plural in Latin is consensûs.

  9. @Kuze: I guess we’ll know better in 86.6 years what the sea level will be.

    On a more serious note, it’s true that a background in mathematics, physics, and statistics constitutes a good starting point for understanding a geophysics paper in a scholarly journal, there is also a huge bed of knowledge and hard-won understanding of false starts, hidden assumptions, obscure errors, etc. that the many years of specialized study of geophysics (or solid state physics, or physical chemistry, or zoology, or you name it) will allow you to understand and either implement or avoid as may be appropriate. There’s an excellent comic by Russel Munroe at: http://xkcd.com/793/ that touches on this issue.

    That’s not to say that being embedded in the culture of a particular scientific discipline can’t sometimes make it impossible to adapt to new information or a new paradigm.

  10. To borrow a Presidential phrase “The overwhelming judgment of science” on this matter is not a good one.

  11. I’ve come to the opinion that there are three camps to this consensus:

    1) The earth worshipers

    2)The techno-utopians

    3)the bandwagoners.

    3 is the smartest choice for professional and social survivors. 1 is the group fueling the moral alarm. 2 is the most interesting because I believe this group ultimately controls, or will control any and all environmental concerns.

    2 consists of the old-time utopians who believe man is destined to reign and climate alarm is the best means available to funnel money into creating a field of climate engineering- which I believe is the goal of 2. In the end, a conviction of catastrophe doesn’t really matter to them as long as they get closer to learning how to make it rain how they want it, when they want it. Nothing will change their mind on this.

    And I’ve yet to see anything to dissuade me of these views.

  12. We should have consensus, but instead we have at least three or four broad schools of thought. It is time to realise that disagreements in science are no longer acceptable. The truth must be sought. I believe it worth re-iterating what I have said on another thread, and several climate blogs today …

    If you still believe that planetary surface temperatures are all to do with radiative forcing rather than non-radiative heat transfers, then you are implicitly agreeing with IPCC authors (and Dr Roy Spencer) that a column of air in the troposphere would have been isothermal but for the assumed greenhouse effect. You are believing this because you are still believing the 19th century simplification of the Second Law of Thermodynamics which said heat only transfers from hot to cold – a “law” which is indeed true for all radiation, but only strictly true in a horizontal plane for non-radiative heat transfer by conduction.

    The Second Law of Thermodynamics in its standard form explains a process in which thermodynamic equilibrium “spontaneously evolves” and that thermodynamic equilibrium will be the state of greatest accessible entropy.

    Thermodynamic equilibrium is not just about temperature, which is determined by the mean kinetic energy of molecules, and nothing else. Pressure, for example, does not control temperature.

    Thermodynamic equilibrium is a state in which total accessible energy (including potential energy) is homogeneous because, if it were not homogeneous, then work could be done and so entropy could still increase.

    When such a state of thermodynamic equilibrium evolves in a vertical plane in any solid, liquid or gas molecules at the top of a column will have more gravitational potential energy (PE), and so they must have less kinetic energy (KE), and so a lower temperature, than molecules at the bottom of the column. This state evolves spontaneously as molecules interchange PE and KE in free flight between collisions, and then share the adjusted KE during the next collision.

    This postulate was put forward by a brilliant physicist bythe name of Loschmidt in the 19th century, but has been swept under the carpet by those advocating that radiative forcing is necessary to explain the observed surface temperatures. Radiative forcing could never explain the mean temperature of the Venus surface, or that at the base of the troposphere of Uranus – or that at the surface of Earth.

    The gravitationally induced temperature gradient in every planetary troposphere is fully sufficient to explain all planetary surface temperatures. All the weak attempts to disprove it, such as a thought experiment with a wire outside a cylinder of gas, are flawed, simply because they neglect the temperature gradient in the wire itself, or other similar oversights.
    The gravity effect is a reality and the dispute is not an acceptable disagreement.

    The issue is easy to resolve with a straight forward, correct understanding of the implications of the spontaneous process described in statements of the Second Law of Thermodynamics.
    Hence radiative forcing is not what causes the warming, and so carbon dioxide has nothing to do with what is just natural climate change.

  13. Briggs,

    The “One prominent fellow” link (3rd paragraph from the end) is broken. Probably should remove the “www.briggs.com/blog” part at its beginning.

    Doug Cotton,
    It is time to realise that disagreements in science are no longer acceptable

    Yet you seem to be posting disagreements.

    This isn’t the proper place for this argument but I’m curious to know how you think the temperature of the lower atmosphere of Uranus was determined. Is it possible the only measurements were of the radiation from the outer portion and the temperature of the lower atmosphere was calculated? If so, what were the premises involved in the calculation? Were they faulty? If they were, how can you claim to have a better explanation for a non-measured value? It’s not possible at all that a temperature gradient in an atmosphere might exist, at least in part if not in whole, because some of its energy is lost into space?

  14. The issue of “net flows” has been stretched literally beyond belief in the climatology world. The Second Law is talking about an isolated system (See Wikipedia – “Laws of Thermodynamics”) and any physicist should be able to tell you that a system in physics has a very specific definition. (Also see Wikipedia “System.”) It can of course have a single component (often represented by a one-way heat transfer between two objects) but if it has more than one component, then the components must be interdependent.

    Now, if radiation from a cooler atmosphere were actually able to add thermal energy to a warmer target on the surface, say a rock beside a tidal lake, then that is the first “component.” The problem then to consider runs like this: if that extra energy is then stored for a while (say, until high tide) and the energy then transfers to some water on the surface by conduction, and then that same parcel of energy eventually gets back into the atmosphere with two further “components” such as evaporative cooling of the water, followed by subsequent release of latent heat, where then is the interdependence between any of these four separate components which you are in effect assuming to be all part of the one system, as defined by the Second Law? Sorry, the very first component (if it could occur) is not just a component of a larger system and it would be an outright and indisputable violation of the Second Law.

    Think of Venus. Every 4-month long day its surface warms by 5 degrees, and then it cools by five degrees as the atmosphere radiates to space during the 4-month night. The surface temperatures are in the vicinity of 730K to 735K approximately. It takes a lot of energy to warm it by 5 degrees, and it doesn’t happen in the first day of sunshine, especially when you remember that such Solar radiation reaching the surface has only about one tenth of the power of that reaching Earth’s surface. So there must be a process in which energy builds up during the 4 month day.

    Now we know that about 97.5% of incident Solar radiation is either reflected or absorbed by the atmosphere, so obviously the atmosphere will warm while the Sun is shining, but gradually over 4 months – say I.25 degree per month.

    Clearly we are not talking about a radiative process warming the surface here, because incident radiation would have to be about 16,100W/m^2 into the surface to have any effect in that temperature range. And if it were it could probably do the job in a few hours, not 4 months. Furthermore, we at PSI would insist that any such radiation having any effect on such a hot surface would have to be directly from a hotter source, namely the Sun. We just don’t believe in non-interdependent components violating the Second Law, so we rule out radiation from the colder atmosphere. In any event, with only about 10W/m^2 of incident insolation entering the surface, there’s not a lot of energy to play with for back radiation, now is there?

    Perhaps you think that the energy entering the TOA will do the trick. Well look at the figures – something like 2,600W/m^2 from memory before any is reflected away, which is much more than half of it. Perhaps we have about 1,000W/m^2 starting on its way into the atmosphere. (That’s to 1 significant figure – it doesn’t matter what the precise figure is.) How could the atmosphere somehow magnify this about 16 times before it comes out of the base of the atmosphere and into the surface, and why would it have so much more success getting through the atmosphere than did the Solar radiation? Remember – no more than 10W/m^2 could be from back radiation that was sending back energy from the surface, which was sending back energy from the Sun. By the way, Science of Doom has a totally incorrect figure of about 158W/m^2 (if I remember correctly) for the incident Solar radiation reaching the Venus surface. You’d think he would have checked the data from the Russian probes before using a figure which is at least 10 times the real one.

    So the Venus surface is not heated by any “runaway greenhouse effect.” If you’re not convinced, then think about how energy gets down into the Uranus atmosphere which is mostly hydrogen and helium. I’m happy to discuss any questions you may have about my explanation of what is happening on these planets – and on Earth, where the Sun cannot heat our surface to 288K with direct Solar radiation alone. Just use SBL to convince yourself of this obvious fact.

    Radiative forcing is not what is the primary determinant of Earth’s mean surface temperature. As on Uranus and Venus, and throughout the universe, temperatures in any atmosphere have a propensity to follow a temperature gradient which is between about 65% and 100% of the quotient of the acceleration due to gravity and the weighted mean specific heat of the gases. The level of the plot is determined by the need for radiative balance, so that Is the “starting point.” Then, at whatever temperature the plot intersects the surface, we have a pre-determined base supporting temperature which slows all radiative and non-radiative cooling at night, enabling the Sun (if applicable) to warm somewhat the next day, this being but a marginal effect, as is the slowing of cooling as the surface comes back towards the base temperature. No big changes in climate will occur without natural changes in the parameters just mentioned. That is the “New School of Thought” which we are starting to talk about at PSI. Keep watching for a new article on such within a few days.

  15. DAV: I suggest you take up your point about Uranus with Wikipedia and numerous other websites which have similar information about Uranus. To me I believe the data because I understand the physics that supports it. But if you want concrete proof, stick to Venus where Russian probes did make actual measurements on the surface. So just go through the above comment I have been posting on a few blogs today before I came here to read your question.

  16. I am not sure that the cheerleaders in the Guardian are fully in tune with the core thinking of the paper (and the British left) on the approach to (what they view as) a nasty small minority of the disaffected. They have absorbed one plank – exclusion of voices and negative images – but as any expert social worker will tell you, they are lacking positive images to bring people into the fold of the consensus. Without such images this disaffection will grow. Although a tad skeptical myself I have volunteered three areas where such positive public relations might help.
    1. Nobody can understand climate models like the climate scientists. However, their understanding will have lead to short-term predictions that have come true. So they should trumpet their successes.
    2. Skeptical voices claim they practice pseudo-science. They should show climate science works in the traditions of the great scientists and philosophies of science.
    3. Being Guardian readers, they should not want to support policies that will hurt the poorest. So they would naturally support careful checks that policy, in both drafting and implementation, has the necessary controls and monitoring to ensure objectives are achieved rather than people exploited by nasty profiteers.


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