The Consensus On Global Cooling

It is an interesting exercise to read press reports of the Consensus. The Consensus as was, not as is. The Consensus as of 1975, when the sky was literally going to fall, frozen into a giant blue cube and killing, oh, just about everything.

Reader Jim Fedako sent in the 28 April 1975 Newsweek article “Our Cooling World” by Peter Gwynne. The hyperbole then is the same as now: “serious political implications for just about every nation on earth,” “The drop in food production could begin quite soon,” “devastating outbreak of tornadoes”, “national boundaries make it impossible for starving peoples to migrate from their devastated fields,” and so forth.

Nothing but dead, dying, and soon-to-be suffering everywhere, with subtle lamentations for the (as-yet?) non-existent one-world government (“national boundaries…”). Given the similarity with news reports of today, it suggests activists have a limited palate of horrors and hobgoblins with which to terrorize, trotted out with depressing regularity. All that was missing were threats of sea-level rise. Why were there no reports then of an increase in beach property? Ocean water would have been sucked up in glaciers, see.

It was a Consensus, incidentally. “Meteorologists disagree about the cause and extent of the cooling trend…But they are almost unanimous in the view that the trend will reduce agricultural productivity for the rest of the century.” Note “almost unanimous”, which equaled ninety-seven or so percent of meteorologists—here curiously defined as people expert in weather and agriculture.

The distinctions between the old Consensus and the new one? The old Consensus was formed by meteorologists; now it’s climatologists. Though most are true believers, meteorologists are now among the prominent defectors from the current Consensus. Why? In 1975 climatology was only beginning to be a separate field, complete with their own grants (i.e. money from government), conferences in exotic locations, and journals in which to publish papers few would read.

Then, scientists were not agreed why the world was nearing a “tipping point”; that frightening term had not yet been invented, or it wasn’t in wide-spread use. They did however say that something had to be done, by which then as now meant government should increase in size and power. Makes sense: Consensus-holders depend on government for their salaries, and larger government means fatter and surer paychecks. For both, it didn’t and doesn’t matter what the government does, as long as they act in the name of the Consensus.

The older Consensus was only pretty sure that what was causing the planetary sickness was humanity. The new Consensus is morally certain of it. Both groups were convinced that whatever good happened to the planet was due to Nature, and that whatever bad happened was our fault. Scientific imagination has thus not advanced beyond paganism.

Members of the current Consensus say there is a dramatic distinction between them and the holders of the old Consensus: current scientists say that now—here and now—they know more than did the members of the old Consensus. This is true: they do know more.

But the certainty scientists in both Consensuses held in their prognosticative abilities is the same. Scientists know much more about (say) clouds now, but the folks of 1975 were convinced that what they knew was sufficient to forecast a trial by ice, just as scientists now insist it will be a gauntlet of fire.

Concentrating on the differences of knowledge is wrong, because it doesn’t answer the main question: Do they know enough? We had their word on it in 1975, just as we have sworn Congressional testimony today. Clearly, we cannot use ardency as a measure of truth. Neither is the apoplexy resulting from departures from the Consensus any guide. The very public exasperation against “deniers” is not convincing, and is not evidence, that the current forecasts are any better than the old.

A citizen is well justified to think: “Scientists were so sure before, and claim to be so again. But they were wrong before. Therefore it is rational to suppose they might be wrong again. Only a zealot would disagree. Plus, the dire threats of starvation and so forth are just the same then as now. So which is it? Is it a cooler world or a hotter one which spells death? And just what is the ideal, to-be-desired-for-all-time climate? Exactly now, please.”


  1. Luis

    … and then the wolf came and ate all the sheep.

  2. Chinahand

    Prof Briggs, you seem to have missed this bit of the article:

    “Meterologists disagree about the cause and extent of the cooling trend, as well as over its specific impact on local weather conditions.”

    I’m a bit confused how you managed to do that considering you quoted the very next sentence.

    Do you not think there might have been a bit of conditional thinking going on in the sentence you quoted – IF the trends continue and are of a certain extent, then it will effect agriculture.

    Also are you sure Mr Gwynne undertook a rigorous survey, or was the particular sentence you quote journalese?

    It’s been well documented that there were some scientific papers published in the 1970s about Global Cooling, but these were never a consensus.

    A literature review shows only 10% of relevant papers published between 1965 and 1979 predicted cooling, 62% predicted warming.

    Of course, science can be wrong, and over-confident. But even in the 1970s the bounds for doubling the amount of CO2 in the atmosphere would have been in the 2 to 5 range in something like 95% of studies.

    Prof Briggs – what do you think the range for doubling CO2 is?

    Are you willing to put your knowledge up against the consensus?

    It would seem to be a more useful pedalogical exercise than cherry picking 38 year old articles which document meteorological disagreement.

  3. Briggs


    Right. The old Consensus was not certain why we were headed for doom, the new one is sure.

    Wait. Are you claiming the Newsweek reporter lied? Or did he make up his quotations? Did he exaggerate intentionally? It has to be that if there was not old Consensus.

  4. DAV

    The Gloom and Doom crowd have persisted throughout history. The message is always the same: “We are surely Doomed unless we mend our Evil Ways”. The message itself never changes but the form of the impending doom changes with the circumstances. To paraphrase Bob Dylan: you don’t have to be a weatherman do know which way the wind blows.


    There is an IF in today’s message as well, but downplayed because it’s bad for business. Clogs the milking machine donch ya know?

  5. Briggs


    Love it!

    Chinahand, be sure to see his link. It’s a lot of fun.

  6. It’s not cooling yet in the long term – just until about 2028. Long term (500 year) natural cooling should start within 100 to 200 years.

    Nearly everyone, (including myself until a year ago) is still sucked into the line of thinking first thrust upon the world by the AGW crowd, namely that it is all to do with radiative forcing. Yes, this includes virtually all other PSI members..

    I have been thinking this through for a long time and am now firmly of the opinion that all these energy budgets are incomplete, mainly because they don’t show the missing link. On Venus and Uranus that missing link is a huge amount of energy which must flow downwards in the atmosphere. It’s quite a lot on Earth too. Over the life of these planets there has been a build up of thermal energy from the Sun which can’t escape.

    So these planets (Uranus, Venus, Earth) are not still cooling off. It’s cold out there where Uranus is because it only receives about 3W/m^2 in the very top of its atmosphere. It could easily have cooled off, but for the one thing that stops it. And that one thing is the gravitationally induced thermal gradient which forms by diffusion at the molecular level,, because molecules in free flight between collisions interchange kinetic energy and gravitational potential energy. In just two lines of calculations, you can derive the -g/Cp value by equating PE and -KE. Kinetic energy will tend towards being homogeneous during collisions, but only at each altitude. Inter-molecular radiation reduces the gradient by up to about a third, but by less than 5% on Uranus where there is just a little methane causing that.

    The Clausius (hot to cold) statement of the Second Law is not comprehensive and for conduction and diffusion it only applies in a horizontal plane. The process described in the Second Law means that thermodynamic equilibrium evolves spontaneously, and, in the process of maintaining such equilibrium there must evolve a temperature gradient. Most importantly, extra energy absorbed at higher altitudes can actually flow up this gradient because that will help restore the equilibrium.

  7. John M


    Like Chinahead sez, you got this all wrong. The “correct” way of viewing this is “it was all the media”. The same climate scientists that run with fresh press release in hand to the medial today claim that Newsweek, Time, etc. got it all wrong then.

    It is the classic “throw your ‘friends’ under the bus” strategy to save yourself.

    Speaking of Time, somewhere I have the full article, but the free synopsis is pretty indicative of the whole thing.,9171,944914,00.html

    As I recall, they also claimed an uptick in midwestern tornadoes was being caused by global cooling.

    Just the media of course…

  8. (continued from above)

    The primary determinants of atmospheric and surface temperatures are then based on the autonomous thermal gradient and the overall level of the plot of temperature against altitude. This level is set by the need for radiative balance and, in general, radiative balance cannot be disturbed by internal processes, such as back radiation.

    A planet’s surface temperature just depends on where the plot of temperature against altitude intersects the surface. On Uranus the temperature at the base of the theoretical troposphere is about 320K. This is all in line with calculations, and, if there were a surface there, then it too would be 320K – hotter than Earth’s surface, even though no direct solar radiation even reaches down there through 350Km of atmosphere that’s mostly hydrogen and helium. There is thought to be a solid core with about half the mass of Earth, but that’s roughly 20,000Km further down and it may be about 5000K.

    So, as on Venus also, where it’s about 730K at the surface, the temperature of a surface is all to do with the height of the atmosphere through which the temperature plot reaches hotter and hotter temperatures the closer it gets towards the surface. It has nothing to do with radiative forcing. It has nothing to do with any greenhouse effect. It has nothing to do with carbon dioxide.

  9. GregO

    Ah the ’70s – I feel young again! Yes, cooling was all the rage and it was kind of cold.

    But it wasn’t just global cooling or as I remember presented in the media, “the immanent ice age”; it was overpopulation (caused by you-know-what: people), and the cooling was caused by pollution (people again)and it was leading to famine. For sure.

    Search around a bit on the internet and you can find a now declassified CIA report from that time on the very topic of global cooling and yes, “Famine 1975!” is actually cited in the bibliography.

    Global cooling, overpopulation, pollution, famine – all very hip back then, very much in fashion with the smart crowd. Save the earth you know. In 1975 I was 20 years old and serving in the US Army in Europe. I was there in the 70s. I even read Paul Ehrlich’s book “The Population Bomb.” There was very much a global cooling consensus. To say otherwise is revisionist history.

    Also, there were weird fashion crazes – there was something called “the leisure suit”:

    I never owned one or even wore one; but as career military my hair was too short anyhow.

    So. Don’t be a ’70s global cooling denier; or a ’70s leisure suit denier; people really did dress like that and think like that. There was a consensus on cooling and wearing leisure suits. I was there.

  10. Chinahand

    Prof Briggs said:
    Are you claiming the Newsweek reporter lied? Or did he make up his quotations? Did he exaggerate intentionally? It has to be that if there was not old Consensus.

    Interesting. “It has to be that?” Erm are you claiming your list of options is comprehensive?

    Come on Prof Briggs, you’ve done entire posts on the fallacy you’ve just committed!

    Do you really think the journalist couldn’t have been a bit sloppy? Could have only concentrated on those making a lot of noise – with a book to sell perhaps?*

    When the journalist writes “Meteorologists disagree … But they are almost unanimous” is he really referring to ALL meteorologists, or just those he interviewed? As I’ve said I am pretty certain this was an example of lazy journalism – the flawed humanity explanation is so much more persuasive than the one which assumes your Machiavellian motives.

    A literature review of the time shows those who thought there even was climatologically relevant cooling trend was a small minority – certainly they may have received greater prominence in the press etc but such is life!

    Perception is often not reality and my understanding is that the perception of a Cooling consensus in the 1970s is inaccurate based on what was being published in the science at the time, rather than what was getting press/public attention.

    My understanding of the way science works is that it tends to get better over time, but that there can be all sorts of noise and attention seeking from its various practitioners at any particular moment.

    I am sure there are both Alarmist and Coolist scientists out there, but there is also the mainstream and most of them would say a range of something like 2 to 5 degrees for a doubling of CO2 is about what the evidence and the theory point to. Given the technology and economic profile the world is on it is likely we’ll more than double CO2 in the next 100 years.

    Is this a prudent thing to do? Or is the investment in sustainable energy a better use of resources than the cost of adapting to a likely warmer world?

    I think that political question is a better issue to be questioning than demeaning scientists – I tend to think they are well meaning and not involved in Machiavellian plots!

    *There are modern parallels – think about Mr Hansen’s sea level claims which are well beyond the mainstream, but that is where the attention goes, rather than the lower, more moderate, more scientific “consensus”!

  11. DAV

    My understanding of the way science works is that it tends to get better over time, but that there can be all sorts of noise and attention seeking from its various practitioners at any particular moment.

    Sensationalism pays more today than yesterday. More jump on the bandwagon to get a share of the grant money going to the noisy ones. One of the reasons why global warming causes everything from toenail cancer to the demise of the polar bear ( Just human nature. As more join, in the “consensus” grows. It’s one of the problems with government grant money. It can buy an opinion. Those in government are especially fond of opinions that get them more power. One of the measures of bureaucratic power is the amount of money passed out. All the sensationalist has to do is use recent trends to be believable.

    Have to hand it to Jimmy the H. He almost single-highhandedly got climatology onto the grant money radar.

    Yes, the media report the sensationalism but they don’t manufacture it. Note how the it’s-getting-cooler/hotter reports in the media have changed direction approximately every 25-30 years and almost at the extremes of each cycle.

    I predict the media reports circa 2025 will be discussing the impending doom indicated by the obvious declining temperature trend.

  12. PaddikJ

    Much as I hate to cede him anything, William Connelly made a pretty persuasive argument a few years ago (at WUWT, if memory serves), in which he claimed to have reviewed the scientific literature (as opposed to stories in Newsweek, etc.) from the 70s and found that the majority of scientists working in climate and related fields were concerned not with cooling, but with impending warming. I don’t have the time or expertise to check his research, but I would suggest that anyone wishing to refute it would have to do so.

    “Majority of scientists” did not of course include Steven Schneider. I was living in Boulder, CO at the time, when Schneider was with NCAR, and the local press had almost daily pronouncements from him concerning the impending deep freeze. The guy loved an audience.

    BTW, whether or not the OED or Websters Unabridged agrees, I think “consensuses” is an abomination. Proper usage is set by common usage, so why don’t we all agree that “consensii”, or perhaps the old Greek form “Consensae” is much nicer and use that instead. The arbiters will have to come around eventually.

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