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The global cooling mole

By John Fleck and William Connolley

To veterans of the Climate Wars, the old 1970s global cooling canard – “How can we believe climate scientists about global warming today when back in the 1970s they told us an ice age was imminent?” – must seem like a never-ending game of Whack-a-mole. One of us (WMC) has devoted years to whacking down the mole (see here, here and here, for example), while the other of us (JF) sees the mole pop up anew in his in box every time he quotes contemporary scientific views regarding climate change in his newspaper stories.

The problem is that the argument has played out in competing anecdotes, without any comprehensive and rigorous picture of what was really going on in the scientific literature at the time. But if the argument is to have any relevance beyond talking points aimed at winning a debate, such a comprehensive understanding is needed. If, indeed, climate scientists predicted a coming ice age, it is worthwhile to take the next step and understand why they thought this, and what relevance it might have to today’s science-politics-policy discussions about climate change. If, on the other hand, scientists were not really predicting a coming ice age, then the argument needs to be retired.

The two of us, along with Tom Peterson of the National Climatic Data Center, undertook a literature review to try to move beyond the anecdotes and understand what scientists were really saying at the time regarding the various forces shaping climate on time human time scales. The results are currently in press at the Bulletin of the American Meteorological Society, and Doyle Rice has written a nice summary in USA Today, and an extended version based on a presentation made by Tom at the AMS meeting in January is on line.

During the period we analyzed, climate science was very different from what you see today. There was far less integration among the various sub-disciplines that make up the enterprise. Remote sensing, integrated global data collection and modeling were all in their infancy. But our analysis nevertheless showed clear trends in the focus and conclusions the researchers were making. Between 1965 and 1979 we found (see table 1 for details):

  • 7 articles predicting cooling
  • 44 predicting warming
  • 20 that were neutral

In other words, during the 1970s, when some would have you believe scientists were predicting a coming ice age, they were doing no such thing. The dominant view, even then, was that increasing levels of greenhouse gases were likely to dominate any changes we might see in climate on human time scales.

We do not expect that this work will stop the mole from popping its head back up in the future. But we do hope that when it does, this analysis will provide a foundation for a more thoughtful discussion about what climate scientists were and were not saying back in the 1970s.

Update: Full paper available here.

243 Responses to “The global cooling mole”

  1. 51
    Red Etin says:

    It’s definitely warming here in Scotland – we never see polar bears here now. I think they may have moved up North. Here is an article about the remains of one in Scotland.

  2. 52
    David B. Benson says:

    Ike Solem (31) & several others — From Archer/Ganapolski, A moveable trigger: Fossil feul CO2 and the onset of the next glaciation, available here

    about 7th down, as well as other sources, the next attempt at a stade (massive ice sheets) will be in about 20,000 years. Even baring AGW the orbital forcing is rather weak and so this one might well be skipped. The next attempt will be about 50,000 years from now.

  3. 53
    Debra says:

    Just dis information if you ask me, people that are in a state of fear are easily controlled.

  4. 54
    SecularAnimist says:

    Lynn Vincentnathan wrote: “I think the creators of DAY AFTER TOMORROW made it clear … that they were greatly speeding up the process for dramatic effect … the real problem is how to make great movies about global warming, that captivate audiences … how to make it photogenic with the necessary ‘ticking time bomb’ so people will watch and get inspired to mitigate.”

    The problem is that a realistic portrayal of the arrival of catastrophic global warming would have to span years or decades, which presents a dramatic challenge (although a sudden world-wide mega-drought that led to a global collapse of agriculture and mass die-off from starvation within a year or two would be pretty dramatic).

    So, if I were developing a screenplay for a global warming disaster movie, I would probably finesse that problem by borrowing from the tradition of post-nuclear-holocaust dystopia movies, and set the movie after the worst effects of global warming had already occurred — say around mid-21st century. The drama would be in the struggle of the few remaining humans to survive in the harsh environment of a wrecked civilization and ruined biosphere. In other words more like Soylent Green than Godzilla.

  5. 55
    Tim McDermott says:

    Slightly OT, but here is more evidence from the natural world the things are disturbed. NPR had an item this week about the expansion of phytoplankton regions of the ocean. They are increasing 1-4% per year. That amounts to 2.5 million square miles in the last decade.

    “Scientists studying climate change have predicted this kind of change. But the sea desert has been spreading 10 times faster than climate scientists predicted.”

    One more underestimate. They do offer the caveat that they may have just caught a particularly rapid period of change, and it may slow down again.

    The abstract from GRL is here.

  6. 56
    Hank Roberts says:

    Good pointer, Tim; one important word missing, it’s low-phytoplankton or phytoplankton-desert areas that are expanding:

    “… vast areas that were once green with plankton have been turning blue, as marine life becomes scarcer …”

  7. 57
    Johan Gutermein says:

    So technology ascends as the human condition declines.

    “History shows that every technical application from its beginning presents certain unforeseen secondary effects which are more disastrous than the lack of the technique would have been. Every successive technique has appeared because the ones which preceded it rendered necessary the ones which followed.”

    Jacques Ellul, The Technological Society

  8. 58
    D Price says:

    The funny thing about the day after tommorow was that it seemed to say that global warming will lead to everwhere getting much colder. Is there any science to support this? Did the film’s makers think tropical heat is less scary?

  9. 59

    What shall we do with ” Torch “, the 1950′s Astounding Science Fiction short story about re-glaciation arisingfrom the ignition of a Siberian oilfield by a botched Soviet nuclear test?

    Is it a cautionary tale of the hazards of Zero-Dimensional climate modeling, the precursor of TTAPS and Roland Emmerich’s Crutzen-based dystopic aerosol film, Der Arkprinzep, or the great grand-daddy of Niven & Pournelle’s sci fi novel Fallen Angels,in which excess of zeal in suppressing AGW leads to a Snowball Earth?

    Then again, in 1932 The New York Times ran a ‘Fish Will Swim In Buckingham Palace’ story under the headline :
    “Next Great Deluge Forecast By Science”; CF:

    The mole is the least of our whacking worries –it’s a regular Pandora’s Menagerie.

  10. 60

    “…the old 1970s global cooling canard…” is hardly an accurate characterization. Many top scientists at that time bought into the “Ice Age Coming” hysteria, including apparently, James Hansen himself.

    Take a look at

    [Response: This is an appalling piece of reporting. Rasool and Schneider did not 'predict an ice age' in their paper, Hansen was not an author on the paper and his role (as mentioned in the acknowledgements was a piece of code that calculated Mie scattering for aerosols - equivalent to sharing code that does a fast fourier transform. How this rises to 'predicting an ice age' is impossible to say. This is just a drive-by smear, which IBD has a history of (see Deltoid for more). - gavin]

  11. 61
    Steve Bloom says:

    Re #45: That’s an early paper referring to the Pacific Decadal Oscillation (PDO), although the term isn’t used. The PDO is a multi-decadal climate cycle that is associated with changes in ENSO; in its positive phase there are more El Ninos and in its negative phase more La Ninas. The PDO has been in a postive phase since 1976 and ever since it was identified (in the ’90s) some of the less-informed denialists have been hoping that a flip to the negative phase will erase the recent warming trend. Their idea is that if one El Nino can result in a warm year then a series of them will make for an entire trend.

    What they neglect (among other things) is that what would be seen is an initial step followed by little or no further warming, and that the global trend looks nothing like that (but see below). A lot of them also seem to have the idea that ENSO cycles result in a real rather than an apparent heating or cooling, whereas what they mainly do is move heat around in the oceans (resulting in a change in ocean surface temperature that in turn affects the atmosphere).

    Slightly more informed denialists will pull out the example of the temperature trend in southern Alaska as proof of their idea. In 1976 there was indeed a large step increase in temperature in that region followed by little change since. Of course the problem is that the trend in one small region proves exactly nothing with regard to the global trend.

    The ENSO-sea ice correlation seems neither here nor there.

  12. 62
    Holly Stick says:

    In THE DAY AFTER TOMORROW, the weather special effects were great as long as you could suspend belief; but the ravening pack of wolves that conveniently showed up when the kids went outside was just lame.

  13. 63

    Here is an old video from 1958 –

    The text of the message is very similar to today’s

  14. 64
    Timothy Chase says:

    Another article from Peter Ward for Alastair, “Impact from the Deep” …

    The SciAm location:

    … is down for maintanence at the moment, so try:

  15. 65
    John Norris says:

    re #9
    Pete Best Says:
    7 March 2008 at 11:41 AM

    “Maybe a article on the 1940 to 1970 cooling may be in order and the reasons as to why?”

    I have been curious about this as well. Has RealClimate written or linked to any info on why 1940 was warm, or why 1970 was cool?

  16. 66
    Ian says:

    Just for fun, here’s another source. Back in 1982, did anyone reading this take it at face value ? A picture book showing “The Coming Ice Age” at .

  17. 67
    Mitch Golden says:

    In the caption of fig 1 of the paper, it says that in no year were there more cooling papers than warming. However, it shows 2 cooling and 1 warming in 1971. Does it mean to refer only to the cumulative number? It certainly doesn’t read that way.

  18. 68

    #45, MJ. I don’t buy that hypothesis completely. they forgot the larger picture. Melting of a large chunk of old Polar ice in 07 has caused unknown after effects, one may be observed as already documented continuing Arctic clear air, this is a predominant phenomena now, there were a preponderance of Low pressure systems passing through Bering Strait, did see a few Highs as well, but the main cause of this continental cooling was born in North American Arctic , the window was open for simple surface radiation escaping upwards. Awaiting spring time cloud and fog bursts, however if unusual low cloud extent continues, there will be a transformation in the temperature scene towards greater warming, returning to the summer of 2007 main melting conditions.

  19. 69

    Lynn, “Soylent Green” came actually close to what a realistic depiction of a worst-case aftermath would look like. It ought to be re-done in the light of the newest knowledge. (What stops you from doing this? Like George Lucas re-did Buck Rogers :-)

    (But the reality of failed nuclear states — famine decimating populations doesn’t promote good government, or friendly international relations for that matter — and an atmosphere carrying radioactivity from local nuclear war should be glossed over; we don’t want to completely scare off our audience now do we.)

  20. 70
    Lawrence Coleman says:

    Re: 51 Red Etin..haha! That means you must be 18000 years old..geez! what health sups are you taking??? But seriously…read a bit about warming scotland..and the 3000ft mountains at the border of the cairngorm plateau’s which in years past always were covered in snow now for the past decade are now snow free.

  21. 71
    Ken Rohleder says:

    Pg. 2 “By the early 1970′s…the notion of a global cooling trend was widely accepted.”

    Agreed. That’s the point — before scientists wrung their hands about GW, they were ringing them about global cooling. The article count doesn’t matter if you concede (correctly) that the notion of global cooling was widely accepted.

  22. 72
    S. Molnar says:

    In his response to #60, gavin referred to Deltoid, but neglected to give a link. One can do worse than read Deltoid in its entirety, but here is the entry in question.

  23. 73
    William Astley says:

    In reply to Ike Solem’s comment #31
    “The modern picture seems to be that ice ages tend to end abruptly, but the onset of an ice age is gradual, driven by changes in sunlight across the northern land masses and decreasing atmospheric CO2 levels. So, we might have been past the warmest period of this most recent interglacial, and beginning a slow, multi-thousand year descent into a new ice age – until we changed the atmospheric composition.”

    Ike, The data and analysis does not support your comment. Are there any papers or text books that support your statement? (I have Cronin’s “Principles of Paleoclimatology” and Bradley’s Paleoclimatology, “Reconstructing Climates of the Quaternary”. Neither of those text books supports a gradual change from interglacial to glacial or glacial to interglacial.)

    In the 1990’s analysis of the Greenland ice sheet core (which was confirmed, by analysis of ocean floor sediment), showed that there are millennium separated, abrupt (not gradual) planetary temperature changes. (The Younger Dryas is an example.) The Antarctic ice core proxy data masked the rapid climate changes due to the polar sea saw where the Antarctic ice sheet initially cools when the planet warms and visa versa. The polar see saw effect is occurring now. The Antarctic ice sheet has cooled slightly while the rest of the planet has warmed.

    See Adam’s paper for a review of the discovery of abrupt climate change.


    The other problem with the theory of insolation changes driving planetary temperature change, is that some other forcing function over rides insolation in the Southern Hemisphere, to synchronous the cooling and warming of both Hemispheres. This forcing function does not seem to be GWG, however, as the change in GWG levels lags changes in planetary temperature changes by a thousand years, based on the data and the GWG mechanisms.)

    The recent discovery of synchronization of abrupt temperature changes between hemispheres (see link below) is new and was partially unexpected. (Cronin’s textbook notes this is an important question, as to whether Northern and Southern Hemisphere cooling is sychronized, as it sets a criteria for the forcing function.)

    “We’ve been able to get quite precise ages directly on these glacial deposits,” says Singer, whose specialty is geochronology. “What we found was that the structure of the last South American ice age is indistinguishable from the last major glaciation in the Northern Hemisphere.”

    “…seem to undermine a widely held idea that global redistribution of heat through the oceans is the primary mechanism that drove major climate shifts of the past.”

    “The implications of the new work, say the authors of the study, support a different hypothesis: that rapid cooling of the Earth’s atmosphere synchronized climate change around the globe during each of the last two glacial epochs.”

    “Because the Earth is oriented in space in such a way that the hemispheres are out of phase in terms of the amount of solar radiation they receive, it is surprising to find that the climate in the Southern Hemisphere cooled off repeatedly during a period when it received its largest dose of solar radiation,” says Singer. “Moreover, this rapid synchronization of atmospheric temperature between the polar hemispheres appears to have occurred during both of the last major ice ages that gripped the Earth.”

  24. 74
    steve says:

    Thanks for the relevant information with sources. GW opponents I can only assume are mostly under 40yrs of age. Anybody that age or older knows from basic personal experience that the climate has changed radically from what it used to be.

  25. 75
    dean says:

    Has anyone watched “Assume the Position”, the documentary/comedy that Robert Wuhl did? He makes a very salient point about our society and it’s one that we need to understand. His main point is that facts don’t matter in the age of mass media. He points out several cases where fact was completely distorted by fiction and now fiction is what is commonly accepted as fact.

    He starts with a clip from “The Man who Shot Liberty Valance”:

    “When the legend becomes fact, print the legend”

    With respect to the coming ice age of the 70s, the public just doesn’t care anymore about it. They accept it as fact and no amount of scientific study otherwise will change that. Wuhl point out that most of the people think Columbus sailed west to prove the world was round and Oliver Stone showed the real conspiracy behind the JFK assasination when the overwhelming evidence shows otherwise in both cases.

    We must also realize that the press thrives on controversy. And while they don’t usually invent controversy, they do everything they can to play up even the smallest controversy. Saying that we’re about to dive into an ice age sells. Saying that 25% of the scientists surveyed think that there’s a 15% chance that the planet will fall into the ice age won’t sell anything. So it’s not likely that the press would ever pick up on it.

    A very current example was the NOAA release within the month that said that the main reason hurricane damage is up is because people have moved to the beach and NOT because of an increased number of hurricanes. The press didn’t cover it because it wasn’t controvercial. Likewise, we have record-breaking box office movies every year and yet none of these have ever approached the popularity of “Gone with the Wind” in terms of number of tickets sold. The press likes to sell the “new and improved” and they typically ignore “there is nothing new here…”

    Re #69, George Lucas didn’t redo Buck Rogers, Glen Larson did. Checking IMDB shows no connection between George Lucas and Buck Rogers.

  26. 76
    Neil B. says:

    Right, just some climate thinkers espoused the cooling view, and the warming idea was usually orthodox since the famous Arrhenius paper of 1896 (!). (But that paper was soon criticized since CO2 and water vapor have such similar absorption bands, what’s up with that?) I have a Time-Life “Weather” book from 1965 which discusses global warming from CO2 as a danger. In any case, how goes the idea that a cooling Sun will comp. for global warming?

  27. 77
    mahatmakjeeves says:

    i am reading an article about the coming ice age in 18,000 a.d. as predicted by british major general drayson in popular science monthly 1936. the article, by gaylord johnson, shows how anyone can do an experiment to show how the polar caps will extend as glaciers to new york , where they had once been the last time they made their 23 to 35 degree angle cycle ,between which we always rotate. so predictions of a new ice age go way back in the popular press.there does seem to be quite a difference in what is said amongst professionals and what gets out through the popular media.

  28. 78
    pete best says:

    Watch this, it states some of the popular press and statements at the time. It sure does seem to be reinventing the wheel with regard to the environmental message of imminent doom but how true is it ?

  29. 79

    RE#69, I actually contacted the author of the book on which it was based (the screenwriter has passed away) and asked if SOYLENT GREEN could be remade, with more of a global warming mention, and he said MGM had been considering doing a sequel, but chucked that idea. Then I wrote to MGM about them getting a professional screenwriter and doing a remake, but never heard back. I’m thinking even the original film could be slightly tweaked to mention global warming. That would be enough. Then re-released.

  30. 80
    Les Porter says:

    re: #65, Re#9 – and – #4

    1940-143 = 1800
    1970-143 = 1830

    As I mentioned to Hank Roberts, I tried to use bore hole data to reflect the curves. I think there is smear since the translation from air temp averaged over a year to sub-surface (bore hole)values might not be fine enough compared to the relationship of air temperatures and CO2 amounts, but otherwise I can’t see a relationship.

    From the bore hole stuff, there seemed to me to be a lot of normalization that could be hiding the weak correlation for the periods and the shift. I felt the bore holes should have shown a pattern, a depression that they did not show.

    Anyway, On the Runaway Green house and problems with the ice ages, I agree. I have been examining the paper, and so far it looks like Forenc Miskolczi has proven an identity. I am still examining the work in my slow way, so I could be “way off,” and I am not, the one to take it apart bit by bit by bit. Too many other things happening.

    0!= 1

    Runaway Greenhouse..?
    There is some work on the pacific warm pool, and NASA and 87F SST where a kind of “runaway” take-off starts but collapses. . . I also fault the above paper on failure to deal with Venus — because the Russians showed there was light aplenty on Venus’ surface. That is a semi-transparent planetary atmosphere with way over 1500 W/m^2 even when the sun was 500Million years old 4 Gya ===============

    Read the complete statement on the pacific warm pool and lots of water vapor here:

    Also relevant:

    Venus is a real situation and as Venus is, Earth will become.


    As for old text books. Denver Radio KOA “Weatherman Bowman” used to describe the jet streams and how they controlled the weather, moving large masses of air around — even in the late 50′s early 60′s — and was an early user of this information from aircraft, especially stratospheric Jet information on head and tail wind speeds and directions, etc. This was before we had an Air Force Academy.

    As for text books, nah. Meteorology has a long history, but the push to do real met science became possible after we sent the men to the moon. . .then the republicans and tricky Dicky flushed the space program except where the M-I complex could build cold war spy stuff.

    Weather became a priority when insurance could estimate risks and warnings of hurricanes. . .etc. But the early weather sat’s …

    I remember all these

    Also I was on a team to look for impact dust on the moon where and when we crashed our cameras. (That is a while back.) I read Fall of Moondust as published in The Saturday Evening Post and even though Clarke was one of my favorite writers, I did not think there would be any dust danger of significance by looking at the

    I remember Sputnik, and Laika, and I remember echo 1 and echo 2. I looked for them among familiar skies that now, global warming and local weather changes has destroyed. Oh yes, population is a problem we licked for a bit in the 1970′s when we were aimed at zpg.

    Met took off with NOAA and NASA investigations.

  31. 81
    Mark A. York says:

    “So, if I were developing a screenplay for a global warming disaster movie, I would probably finesse that problem by borrowing from the tradition of post-nuclear-holocaust dystopia movies, and set the movie after the worst effects of global warming had already occurred — say around mid-21st century. The drama would be in the struggle of the few remaining humans to survive in the harsh environment of a wrecked civilization and ruined biosphere. In other words more like Soylent Green than Godzilla.”

    Hmmm. I handled it differently and in current time. I was in the last version of Godzilla. “Run but don’t step where the digital foot goes!”

  32. 82

    Of interest is this particular morsel – the Ecologist’s 1972 publication “Blueprint for Survival” predicted 379ppm by 2000, and suggested a doubling of CO2 would see 2 degrees warming. The “chicken little” earth is cooling myth is exactly that – even in the early 70s warming was a serious concern for many.

    SCEP points out that the trend towards depleting the remaining stands of original forests, such as those in tropical Brazil, Indonesia and the Congo, will further reduce the capacity of the ecosphere to absorb CO2 and may release even more CO2 to the atmosphere. The CO2 content of the atmosphere is increasing at a rate of 0.2 percent per year since 1958. One can project, on the basis of these trends, an 18 percent increase by the year 2000, i.e. from 320 ppmm to 379 ppmm. SCEP considers that this might increase temperature of the earth by 0.5°C. A doubling of CO2 might increase mean annual surface temperatures by 2°C. [See Table 3]


  33. 83

    Re #69, George Lucas didn’t redo Buck Rogers, Glen Larson did. Checking IMDB shows no connection between George Lucas and Buck Rogers.

    dean, oops you’re right, I meant Flash Gordon.

  34. 84

    Ken Rohleder (#71): you quote the article as saying ““By the early 1970’s…the notion of a global cooling trend was widely accepted.” but left out the next 3 words, “albeit poorly understood”.

    I suggest if you read the paper again, you will realize you understood it poorly. The thing that was widely accepted is the temperature trend at the time, which appeared to be cooling. This is rather different from nonexistent widespread prediction of further cooling (as evidenced by the literature review), and was in fact an error which was soon after corrected.

    Further on: “A closer examination of Southern Hemisphere data showed that what appeared to be a global cooling trend was in fact dominated by Northern Hemisphere temperatures, while thermometers in the Southern Hemisphere seemed to be headed in the opposite direction”.

    #9, #65: 1940-70 cooling: I can’t find anything specific on realcimate though you would do well to read a few of the articles in the aerosols section (see sidebar). This one mentioned a while back is interesting:
    and also:

  35. 85
    Julian Flood says:

    re 55 56

    I’m always chary of short-run information about global systems: the SeaWiFS stuff is only a decade long and needs more time to become significant. At the moment it’s no more and no less relevant than a couple of year’s cooling from a La Nina.

    However, there’s one detail on which I’d like more info. What is happening to the phyto populations at the edges of the expanding areas? I am on record as suggesting that starved phytos (I predicted the spreading of the ocean’s blue deserts) would switch to C4 metabolism, increasing the pulldown of heavier C isotopes and leaving a low atomic weight carbon signal in the atmosphere. Has anyone seen any research along these lines?


  36. 86
    pete best says:

    I am now hearing, the ice has returned and a large part of the NH 2008 winter has broken records for coldness and snowfall. Apparantly AGW has stopped !

    What is realclimates answer to the ice returning and its being very cold in some of the NH this winter? La nina/ el nino cycle I have read. Would this be as good a explanation as any ?

  37. 87
    AdeV says:

    [Response: Runaway Greenhouse is a strawman. I’m sure someone will take the paper to bits properly. The obvious problem for it is to explain the ice age cycle -William]

    Interesting response… surely you shouldn’t be looking to “take the paper to bits properly”, rather, it should be viewed as possible new information & a determination made as to whether it is a) accurate, and b) if so how it can be integrated into GCMs OR if not, why not?

    Part of the reason I have a problem with this whole Global Warming malarky is the bitter sniping from both sides which does nothing to move the science forward, and everything to create a snarky atmosphere & gosh-wow headlines. I do realise that science (any field) is competitive & some snarkyness is to be expected; but honestly all this does is turn agnostics (such as me) off the the whole thing. And since – like, I suspect, most agnostics – my default position is “don’t worry, be happy”, that ends up favouring the “AGW is not the end of the world” camp.

    So come on folks (and RC does have some of the world’s pre-eminent climate scientists as contributors), stop sniping & start analysing. Maybe an article would be useful? After all, this is not some News of the World (The Inquirer is, I guess, the American equivalent) article – this is a peer-reviewed paper.


    [Response: There are far more papers published than anyone person can read. You have to be selective. A paper that speaks as that one does is off to a bad start in the shall-I-bother stakes. And I already raised one problem, which is that it would make the ice age cycle unintelligible. There are lots of genuine problems to work on in climate change; the basic radiative physics though are well known. There are two other filters people use for shall-I-read-this: is it in a major journal? - in this case, no; and has it been cited? - in this case, its doesn't look like it; even the skeptic blogs aren't endorsing it. -W]

  38. 88


    I’m pretty sure 95% of life didn’t die out 251 years ago. I assume you meant 251 million?

  39. 89

    Ken Rohleder writes:

    [[Pg. 2 “By the early 1970’s…the notion of a global cooling trend was widely accepted.”

    Agreed. That’s the point — before scientists wrung their hands about GW, they were ringing them about global cooling. The article count doesn’t matter if you concede (correctly) that the notion of global cooling was widely accepted.]]

    You have acceptance by the public or the media confused with acceptance by the scientific consensus. There was never a scientific consensus behind global cooling the way there is now behind global warming.

  40. 90

    Les Porter writes:

    [[I also fault the above paper on failure to deal with Venus — because the Russians showed there was light aplenty on Venus’ surface. That is a semi-transparent planetary atmosphere with way over 1500 W/m^2 even when the sun was 500Million years old 4 Gya =]]

    You’re confusing the Solar constant at Venus’s orbital distance with the amount absorbed by the Venus climate system and the amount that penetrates to Venus’s surface, all of which are different numbers. The Solar constant at Venus’s distance is about 2,611 watts per square meter (1500 or so early in Solar system history, as you point out). But the amount absorbed by the Venus climate system is:

    F = (S / 4) (1 – A)

    where A is the bolometric Bond albedo. The factor of 1/4 comes from the fact that Venus absorbs sunlight on its two-dimensional cross-sectional area but radiates on its spherical surface area. NASA gives the present albedo of Venus as 0.750, so we’re talking an absorbed flux of 163 watts per square meter — actually less than Earth gets (237 W m^-2). And of the 163, only 16.8 watts per square meter penetrate to the surface of Venus, the rest being absorbed by the cloud layers or the clear atmosphere. That’s enough light to read by, plus you’ve got some red glow from the rocks at 735.3 K, but it’s way less than 1500 W m^-2.

  41. 91
    MattN says:

    Mr Fleck/Connelly:

    “Between 1965 and 1979 we found:

    * 7 articles predicting cooling
    * 44 predicting warming
    * 20 that were neutral”

    What criteria did you use to select the titles? You have 71 articles over a 15 year period. Certainly there were many hundreds more over that period that you did not select.

    Basically, was this a random selection of articles?

    [Response: No, it wasn't a random selection. The linked pre-print described the methodology -W]

  42. 92
    Hank Roberts says:

    > I am on record
    Cite, please?

    > starved phytos … switch to C4
    Mechanism for this? (Is it in the source? population change? species change? individual organism change?)

  43. 93
    Rod B says:

    Steve (74): Nonsense.

  44. 94
    Richard Ricardo says:

    Hello all,

    I was curious about global warming and found this site through a Google search. I have a question, why is the warming of the earth so bad? It is hot in the tropics year round and life there seems to thrive. I read some place that the ice caps are melting, and that places like Florida adn some other coastal areas would be flooded,would not people just move further inland or adapt like the Dutch building dykes?

    Like I said I am pretty ignorant about the subject I just thought I could get some answers here.


  45. 95
    Fred says:

    Whether one believes in man-made global warming, man-made global cooling, or natural climatic cycles, the real worry that many people have is that some political body will dictate their perceived solution via punitive laws rather than allowing the free market to sort things out. Additionally, the hysteria to “do something now” ignores the immense ability for humans to adapt to wildly changing environmental conditions, and may cause the human race to take actions with unintended consequences which are more damaging to humankind than the climate change itself.

    Those who believe in man-made climate change would do well to back off from the ledge if you want the so-called “deniers” to believe you are credible. (And also, explain the lack of correlation between RISING carbon emissions and STEADY global temperatures since 1998, as well as the sharp decline in the average global temperature to pre- “global warming era” levels in the past year alone – which just happens to correlate better with the extended solar minimum!)

  46. 96

    RE #90, many hundreds? It’s really difficult to get articles published in peer-reviewed scientific journals. First you need to do years of study, then write up an article based on that, then if the manuscript is not outright rejected, you usually have to rewrite it, or even do some more study and rewrite it. The process from study to published article could take years.

    I also imagine at the time not a whole lot of climate scientists were specifically studying warming or cooling trends, or writing articles about them — not like today anyway. So I’d think 71 articles (averaging about 5 per year) sounds to me like the whole population of science articles in peer-reviewed journals dealing specifically with the topic at hand here.

  47. 97

    #87, yes, my mistake I meant to write “251 mya.”

  48. 98

    RE #86, I’m not too sure what the issue is here, but climate scientists are quite adament about not using the term “runaway warming” for the various climate scenarios in Earth’s past (& possibly to come in the future) in which initial warming causes nature to emit more GHGs (such as through carbon release from melting permafrost and ocean hydrates) & albedo decrease (from melting snow & ice), which in turn leads to greater warming, which in turn leads to greater GHG emissions/albedo reduction, and so on until it gets quite hot, but then after many millennia the process in reverse causes the earth to cool back down again. I’ve heard them use the term “hysteresis” for this process, which happened several times in Earth’s past — 251 mya & 55 mya, being 2 great warming periods connected to mass extinction.

    However, I think “runaway” is still a good term to help laypersons understand the process, as in “runaway horse” or “runaway train” — something eventually stops them, so it isn’t permanent runaway. I would then consider the situation on Venus to be a special case of “permanent runaway warming.”

    And I don’t completely share your view re “don’t worry, be happy.” I “expect the worst and hope for the best,” and keep paying my insurance premiums (tho I didn’t get onto the dental plan this year — bad mistake). However, I agree we should NOT waste time worrying; we should instead take up the challenge and reduce our GHGs as much as possible — and do it with a joy that transcends mere happiness.

  49. 99
    J.S. McIntyre says:

    re 95: “the real worry that many people have is that some political body will dictate their perceived solution via punitive laws rather than allowing the free market to sort things out.”

    I don’t think the free market can sort it out. Every free market solution to a problem is based on response after something has affected them; it the case of AGW, many of the negative effects are 10 to 30 years out, by all accounts. Also, the free market is based to a large extent on accumulation of wealth – a credible response to AGW involves a counterintuitive response, the idea that no matter how we adapt, we’re going to be forced to give up things we take for granted.

    “Additionally, the hysteria to “do something now” ignores the immense ability for humans to adapt to wildly changing environmental conditions…”

    There is a credible argument that suggests there is an upward limit to adaptation. Too much of what we take for granted in the natural world depends upon the temperatures staying more or less stable. In a warming world, particularly if we hit 3 degrees, we might not be able to adapt.

    “Those who believe in man-made climate change would do well to back off from the ledge if you want the so-called “deniers” to believe you are credible.”

    No offense, but what you are asking for is akin to demanding that the king’s subjects acknowledge he has clothes when, in fact, he’s parading around in his skivvies…

  50. 100
    Les Porter says:

    # 90

    Yeah Bart. Sorry. I should have clarified that. When the Sun ignited on main sequence 4.567 billion years ago, most solar models indicate it was only 70% as bright at it is now. (Sackmann, Boothroyd, Kraemer 1993 and subsequent).

    Since, This Real Climate blog “comments section” won’t let me post an HTML table, I’ll put the numbers here:

    Luminosity % ———–”Solar constants at top of atmosphere—–
    L sol % of now —— Venus W/m^2 —– Earth W/m^2 —- Mars W/m^2

    L 60% Sun 4.567Gya — 1568.3 ————820.6 ————-353.5

    L 70% Sun 4.567Gya——1833.7 ————959.4————–412.4

    L 100% Sun Present——2613.9————-1367.6————-589.2

    L 110% 1.1Gy future—–2875.3————-1504.4————-648.1

    L 134% 3.2Gy future—–3476.5————-1818.9————-783.6

    OK. After the Sun main-sequenced (settled down) the models provide various scenarios of burn, but generally use a slow linear fusion growth rate for the Sun around 10 billion years long. Then it grows red giant, possibly pulses and lots of 1 solar mass end-life-kinds- of-things even the AGB era and helium shell burning flashes and lots of planetary nebula forming mass ejections. Earth(as a molten blob) may escape engulfment, pending the solar wind mass ejection timing and rate. The table above carries NONE of the Solar endgame, but does show earth-life endgame beginning 1.1 billion years ahead. Venus undenied ensues for sure around 3.4 Gya from now. Earth’s runaway greenhouse, ends.

    My point was that even when the Sun ignited at 70% present luminosity, the planet Venus had to begin with more than the Earth receives from the warmer Sun 3.4 billion years from now. Further, even when the Sun warms to its 3.4 billion years from now state, Earth will be at the terminus of any oceans, nearly all the available C in rocks (even) will be in the CO2 atmosphere of Earth which will have a ~101 atmosphere pressure, at the surface and the N2 will still be here at about 4% or so component part instead of 78% proportional part.

    The 1500 W/m2 is my slack-jawed reference to the Solar Constant at Venus even if the Sun was only 60% as bright as present. My contention is that VENUS never had OCEANS, EVER.
    I know those are bad words, but they would have been in lower gravity, etc. And Life never had a chance on the surface.

    Thanks “Bart” for digging that out, and I will not post when I can’t be clear.(I hope) (Next time, (after this one) I might have my wife read it. . . to be sure.)

    Oh… the promises we make ourselves. . .

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