Arguments
What were climate scientists predicting in the 1970s?
What the science says...
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The vast majority of climate papers in the 1970s predicted warming. |
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Climate Myth...
Ice age predicted in the 70s
"If you go back to Time Magazine, they actually were proclaiming the next ice age is coming, now it's become global warming… How do you believe the same people that were predicting just a couple decades ago that the new ice age is coming?" (Sean Hannity)
At a glance
If you are aged 60 or over, you may remember this particular myth first-hand. For a brief time in the early to mid-1970s, certain sections of the popular media ran articles describing how we were heading for a renewed ice-age. Such silliness endures to the present day, just with a different gloss: as an example, for the UK tabloid the Daily Express, October just wouldn't be October without it publishing at least one made-up account of the impending 100-day snow-apocalypse.
There were even books written on the subject, such as Nigel Calder's mischievously-entitled The Weather Machine, published in 1974 by the BBC and accompanying a “documentary” of the same name, which was nothing of the sort. A shame, because the same author's previous effort, The Restless Earth, about plate tectonics, was very good indeed.
Thomas Peterson and colleagues did a very neat job of obliterating all of this nonsense. In a 2008 paper titled The myth of the 1970s global cooling scientific consensus, they dared do what the popular press dared not to. They had a look at what was actually going on. Obtaining copies of the peer-reviewed papers on climate, archived in the collections of Nature, JSTOR and the American Meteorological Society and published between 1965 and 1979, they examined and rated them. Would there be a consensus on global cooling? Alas! - no.
Results showed that despite the media claims, just ten per cent of papers predicted a cooling trend. On the other hand, 62% predicted global warming and 28% made no comment either way. The take-home from this one? It's the old media adage, “Never let the truth get in the way of a good story”
Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!
Further details
In the thirty years leading up to the 1970s, available temperature recordings, with a poor global coverage compared to today, implied at times there might be an ongoing cooling trend. At the same time, research was continuing into the building levels of carbon dioxide and their effects on future climate, but the science world of that time was somewhat disconnected, compared to the modern age of instant communication, Zoom and so on.
There were also some notably cold winters scattered through that time, such as the UK one of 1962-63. As a result of these various goings-on, some scientists suggested that the current interglacial period could rapidly draw to a close, which might result in the Earth plunging into a new ice age over the next few centuries.
We now know that the smog that climatologists call ‘aerosols’ – emitted by human activities into the atmosphere – caused localised cooling closest to the areas where most of it originated. Smogs constitute a deadly health hazard and governments acted quickly to clean up that type of pollution: highly visible (unlike CO2), it was hard to ignore. Once largely removed, its effects no longer influenced Northern Hemisphere temperatures, that have steadily climbed since around 1970.
In fact, as temperature recording has improved in coverage, it’s become clear that the cooling trend was indeed localised – it was most pronounced in northern land areas. Other places around the world revealed a different story. Furthermore, at the same time as some scientists were suggesting we might be facing another ice age, a significantly greater number - approximately six times more - published papers indicating the opposite - that we were warming. Their papers showed that the growing amount of greenhouse gases that humans were putting into the atmosphere would cause much greater warming – warming that would exert a much stronger influence on global temperature than any possible natural or human-caused cooling effects.
By 1980, with northern hemisphere smogs a distant memory, the predictions about ice ages had ceased, at least among those working on the science, due to the overwhelming evidence for warming presented in the scientific literature (Peterson et al. 2008). Unfortunately though, the small number of predictions of an ice age were far more 'sticky' than those of global warming, so it was those sensational 'Ice Age' stories in the 1970s popular press that so many people tend to remember. Sticky themes sell papers. Today of course, with 40+years more data, far better coverage and a far bigger research community, we've reached a clear scientific consensus: 97% of working climate scientists agree with the view that human beings are causing global warming.
Last updated on 8 March 2024 by John Mason. View Archives
Barry,
As Scaddenp states, your two comments conflate stratospheric ozone and tropospheric ozone. These are two different subjects and treating them as similar suggests that you do not understand atmospheric chemistry.
I will address your comment at 71 on stratospheric ozone first. According to this RealClimate post, the decrease in stratosheric ozone caused by human pollution will result in approximately -.15 w/m2 of cooling. The CFC's released by humans have caused approximately +0.34 w/m2 of heating due to their greenhouse properties. Thus the result of CFC pollution is a net warming of the surface.
The total warming caused by CO2 pollution is much larger (about 1.7 W/m2 in 2011). Larger amounts of CFC pollution would result in more warming, not cooling as you suggest. Dr. Hansen's 1989 projections, especially the high emission pathway, overestimated warming somewhat because the Montreal protocol resulted in CFC emissions being lower than he projected (more emissions mean more heating).
Your comment at 72 addresses tropospheric ozone. Everyone except you knows that ozone is a greenhouse gas. It causes warming when increases in trophospheric ozone occur. Ozone is not even on the table in my reference above. The contribution of CO2 is much greater because CO2 accumulates in the atmosphere over time while ozone is destroyed and does not accumulate.
I stand by my comment that " I have never heard of significant heat being let out." The Realclimate post I linked starts out "One of the most common mistakes that we have observed in discussions of climate and atmospheric change is confusion between the rather separate concepts of ozone depletion and global warming." When I taught High School students often confused climate change and ozone depletion. As Realclimate states, they are different problems, although they are tangentially related.
The original question from post 69 was "They told me when I was at school we were heading steadily for another ice-age and the cause was CFCs". The answer is scientists have never said that CFC's would cause an ice age to occur. The person who asked the question was either misinformed or attempting to mislead others with a false question.
michael sweet states
I have never heard of significant heat being let out. #70
"As Scaddenp states, your two comments conflate stratospheric ozone and tropospheric ozone. These are two different subjects and treating them as similar suggests that you do not understand atmospheric chemistry." #76
No it does not Again Sweet comments in #76
"According to this RealClimate post, the decrease in stratosheric ozone caused by human pollution will result in approximately -.15 w/m2 of cooling. The CFC's released by humans have caused approximately +0.34 w/m2 of heating due to their greenhouse properties. Thus the result of CFC pollution is a net warming of the surface" Sweet
Actually ozone accounts for up to 0.6 W m-2
"We all know that ozone in the stratosphere blocks harmful ultraviolet sunlight, and perhaps some people know that ozone at the Earth's surface is itself harmful, damaging people's lungs and contributing to smog.
But did you know that ozone also acts as a potent greenhouse gas? At middle altitudes between the ground and the stratosphere, ozone captures heat much as carbon dioxide does.
"In fact, pound for pound, ozone is about 3000 times stronger as a greenhouse gas than CO2. So even though there's much less ozone at middle altitudes than CO2, it still packs a considerable punch. Ozone traps up to one-third as much heat as the better known culprit in climate change. "
http://www.aoas.org/article.php?story=20080522125225466
I think that a third of that of CO2 is significant --others have it as high as 40% but sweet
#70 sweet states Grade school teachers are not really atmospheric experts. Neither are secondary teachers Those that ca do those that can't teach
[DB] Inflammatory snipped.
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"At middle altitudes between the ground and the stratosphere,"
ie the troposphere. You appear to continue to get confused about difference between O3 in stratosphere versus effect in troposphere. Again the ozone hole is about lose of stratospheric ozone around poles, especially Antarctica, and no, it still doesnt let the heat out and cool climate.
In the stratosphere, ozone causes warming of the surrounding air through its interaction with incoming UV.
"It might also help discussions if you explained why you think ozone depletion reduces stratospheric temperature (or perhaps more to point, why ozone warms the stratosphere)." scaddemp #75
S Could you please point out that I have stated it? No you cannot because it is an invention of your imagination!
"Everyone except you knows that ozone is a greenhouse gas. " sweet #76
Moderator
this is an absolute falsehood, please could you ensure that it is removed.
Sweet has no knowledge of my thoughts but he may think he does! and if everybody knows that ozone is a greenhouse gas why are there so many climate deniers?
Please could sweet supply citations for both of his postulates?
Again the ozone hole is about lose of stratospheric ozone around poles, especially Antarctica, and no, it still doesnt let the heat out and cool climate.
I never stated that.
please locate the phrase that you purport to this comes from
you cannot because it is your invention.
but I do suggest that you think about what you are posting
"S Could you please point out that I have stated it?"
It is entirely possible that we are misunderstanding each other. Michael Sweet was pointing out what was wrong with the idea that an ozone hole was going to lead to global cooling.
You replied:
Mr sweet,
This may enlighten you
Cooling of the Arctic and Antarctic Polar Stratospheres due to Ozone Depletion
Which correctly shows that loss of ozone leads to stratigraphic cooling (but not to climatic cooling). Your manner of comment suggested that you were trying to contradict Michael Sweet. If you were trying to support his argument, then indeed, we are cross-purposes. You seemed somewhat confused between tropospheric and stratospheric ozone and so I thought it might clarify matters if you explained how you thought it worked.
My understanding is this:
In the stratosphere, O3 reduces the energy reaching the surface because it traps incoming UV. (ie unlike N2, O2, and for that matter CO2, it is NOT transparent to incoming solar radiation). This warms the stratosphere but it is a cooling effect on surface climate. On the other hand, O3 is also a greenhouse gas so traps outgoing IR causing some warming. I believe the balance is towards a very small warming effect.
In the troposphere by comparison, UV is mostly absent and so the greenhouse effect is more important (but O3 levels are very low).
Reducing the O3 cools the stratosphere alright but it means there is more energy (UV) warming the surface and so no, the O3 hole is not a climate cooling mechanism.
If you are in disagreement with Sweet and articles here, it would be best if you clearly stated what your disagreement is rather than have others try to guess.
By the way... has anyone written a post debunking the Wattsupwiththat article (Nov 2018) on why there was a consensus on global cooling / imminent ice age etc? It is of course riddled with misunderstandings / errors / assumptions. I was going to have a go myself (I am not a scientist) but just in the area of logic and comprehension there are all sorts of problems.
Dave Evans @84,
The Wattsupian nonsense from Nov 2018 you ask about doesn't appear to have been de-bunked but the major slight-of-hand employed by the denialist-&-nonsense-author Angus MacFarlane has been de-bunked by SkS.
The Nov 2018 nonsense purports to itself de-bunk Peterson et al (2008) which is the main evidence base for the OP above. [The co-authors seem to have been overlooked by the OP above who call it Peterson 2008.] In directly challenging Peterson et al, the Wattsupian denier reclasifies 20% of the surveyed papers cited by Peterson et al (14 of the 66 re-assessed with 5 Peterson et al citations not assessed) and thus attempts to convert the result from 7 'cooling', 20 'neutral' and 44 'warming' into 16 'cooling', 19 'neutral' and 36 'warming'. This is not greating different and certainly does not support the contention that there was a scientific global cooling concensus during the 1970s.
To provide more fire-power, the Wattsupian denilaist adds extra citations to the survey - two which he found for himself (again not a level of evidence that would change the Peterson et al result) and an additional 117 papers gleaned from an earlier denialist attempt to debunk Peterson et al. It is only with this extra denialist fire-power from 2016 that anything like the number of citations can be obtained to overcome the Peterson et al result. This 2016 nonsense has been debunked in a two-park SkS post here & here.
The general nonsense in this 2016 denialist blather is possible best summed up by the denialistical use of the 1974 CIA document which considers the global food supply and within this considers climate as potentially a major factor. Global cooling is presented as a potential increase in risk to an adequate global food supply. There is no 'consensus' being waved that global cooling is expected. Instead they cite HH Lamb but ignore Lamb's view at that time in the mid-1970s that "On balance, the effects of increased carbon dioxide on climate is almost certainly in the direction of warming but is probably much smaller than the estimates which have commonly been accepted." As this may sound itself a little 'denialist' to modern ears, I should all that the 1977 book containing this quote had added into its 1984 preface:-
The evidence-base for the CIA document is set out in its Annex II is based on the work of one scientist, Reid Bryson who did continue to find it beyond his abilities to accept the idea of AGW as a problem that needed tackling. So even though the 1974 CIA document runs with global cooling, a worst-case scenario, there is no scientific consensus backing it up.
The other study cited by the 2016 nonsense is Stewart & Glantz (1985) which talks of an emerging AGW-warming consensus but itself analyses the conclusions of a 1978 study on climate projection to the year 2000. This 1978 study would presumably have been advised by any 'cooling' concensus had such a thing existed in the mid-1970s. So their conclusions will be of interest:-
So here the 1970s view was more towards 'warming' than 'cooling' although I note the 'warming' opinion prevailed as warming 1975-2000 was +0.5°C.
And today we see nothing but blather in that Nov 2018 Wattsupian whittering. It is ever thus there on the remote planetoid Wattsupia.
Hi MA
Thanks for the links and the post. Very interesting. The thing I find fascinating is that I started tackling the Wattsup post but came from a very different angle- though equally unimpressed by it. I think your approach and mine are complementary. Will try to post later.
My interest was just how using some basic knowledge of science and careful reading of the Wattsup article meant I could identify numerous logical fallacies and inaccuracies. It would be interesting to see what you make of my thoughts.
Apparently the media thaught Global Cooling was the problem. And apparently a lot of teh scientists thaught the same. Could that hae been because the majority of people realize cold kills and warmth gives life? Apparently the scientists at Brown University were not concerned so much about CO2 warmth but were concerned enough about the cold that kills that they sent a letter to the president.
(Was going to include a scan of the letter, but I would need my own URL with name and all and as such I cannot do that.)
[DB] Please read both the Basic and Intermediate versions of this post.
A review of the scientific literature from the 1970s shows that the broad climate science community did not predict “global cooling” or an “imminent” ice age. On the contrary, even then, discussions of human-related warming dominated scientific publications on climate and human influences.
https://climatefeedback.org/claimreview/scientists-didnt-announce-impending-environmental-catastrophes-every-decade-since-the-1970s/
https://nca2018.globalchange.gov/chapter/appendix-5#heading-3-2
The large majority of climate research in the 1970s predicted the Earth would warm as a consequence of CO2.
Rather than 1970s scientists predicting cooling, the opposite is the case.
https://journals.ametsoc.org/doi/abs/10.1175/2008BAMS2370.1
This venue uses the scientific method; thus, when you make claims here you need to support them with an appropriate level of citations to the credible scientific literature. Thus:
Available evidence shows that it is the human adaptation to weather extremes that is key in limiting mortality:
"Adaptation measures have prevented a significant increase in heat-related mortality and considerably enhanced a significant decrease in cold-related mortality. The analysis also suggests that in the absence of any adaptive processes, the human influence on climate would have been the main contributor to both increases in heat-related mortality and decreases in cold-related mortality."
and
"With regard to heat-related mortality, projected future increases in the frequency and intensity of heat waves may exert a stress beyond the adaptive limits of the population."
Causes for the recent changes in cold- and heat-related mortality in England and Wales
Nikolaos Christidis, Gavin C. Donaldson, Peter A. Stott; Climatic Change, October 2010
Related
Mitchell et al 2016 - Attributing human mortality during extreme heat waves to anthropogenic climate change
"In summer 2003, anthropogenic climate change increased the risk of heat-related mortality in Central Paris by ~70% and by ~20% in London, which experienced lower extreme heat"
Further:
"contrary to the propositions of those who like to stress the potential benefits of global warming, a net reduction in mortality is the exception rather than the rule, when comparing estimates around the world"
And
"the world would witness a dramatic increase in heat-related mortality rates in the most populous and often poorest parts of the globe"
I assume that "letter to the President from Brown University scientists" was this one from Kukla and Matthews to President Nixon. The context was questions at the time over how this current interglacial would end. As detailed by this article and the moderator, this was a minority opinion at the time, and of course, later research (Berger, A. and Loutre, M.F., Insolation values for the climate of the last 10 million years, Quat. Sci. Rev., 1991), made the question moot, never mind considerations of anthropogenic change. No one is questioning that some scientists in 1970s were worried about cooling; but it was not even a majority view, let alone a consensus.
Please note: the basic version of this rebuttal has been updated on Feb 14, 2023 and now includes an "at a glance“ section at the top. To learn more about these updates and how you can help with evaluating their effectiveness, please check out the accompanying blog post @
https://sks.to/at-a-glance
Thanks - the Skeptical Science Team.
There was an article by Naomi Oreskes regarding the cooling climate dominant view of the 1950s to 1970s.
I was finally able to locate her work after months of research, I heard rumors about it but it turns out to be real.
It might advance the discussion if this is included in the consensus debate. It needs to be tackled head-on, what does Naomi Oresekes say about her previous paper?
LINK
[RH] Shortened and activated link.
Don... Best I can tell, this looks like an early draft of an abstract for a potential paper or even a draft for a chapter of a book. I wouldn't put much credence in this piece, one way or another, since people are allowed to explore ideas and decide in the process they're wrong and choose not publish.
Don:
That is a pretty short article by Oreskes, with very few references, and carries no date. It has a ucsd.edu email address (U California at San Diego). For her current Harvard web page, you can find a link to her CV, which tells us she was at UCSD from 1998 to 2013. So it is potentially a rather old article.
In the 1970s, there was indeed speculation that the observed cooling might continue, but the "Further reading" section of this rebuttal shows more detailed analysis of how much of the scientific literature believed it was likely (not much).
Also note that the title of the paper you link to includes "The work of Gordon J.F. MacDonald". Wikipedia has a page on Gordon J.F. MacDonald, and it is likely that Oreskes is summarizing the views of MacDonald rather than presenting her own detailed analysis. After all, she is a science historian. Also note that in her first paragraph, Oreskes states (emphasis added),
MacDonald was a geophysist, and according to the Wikipedia page he also was skeptical about continental drift/plate tectonics. The contrarian community is littered with geologists that have limited understanding of climate science.
I don't see this as an expression by Oreskes that she thought the "it's cooling" crowd had a legitimate argument.
Reading further into the Wikipedia page on Gordon MacDonald, it seems that he became concerned about the effects of climate change in the 1960s (both natural and anthropogenic), and was warning about the risks of fossil fuel combustion and global warming back in the 1960s.
To Rob Honeycutt,
The article - as is - was presented at a meteorological conference in Germany.
I'm sure I can find the link to the seminar that hosted her article.
She's a professor of the history of science so I'll have to defer to her expertise
Unfortunately she seems to have suggested rather awkwardly, that contrarians exploit the about face.
To Rob Loblaw
She offered no other context so I can't dispute it, even encouraging contrarians to exploit the reversal - how was that speaking for MacDonald and not her own thoughts?
To Rob Loblaw
I couldn't find any reference to MacDonald saying the dominant view of the 1950s to 1970s was a cooling climate in your wikipedia link. Perhaps you could demonstrate that it was his thoughts not hers. I can't really bend my brain into that logic without supporting documents. What have you found?
To Rob Loblaw
Oreskes stated that it was the dominant view, not that was the only view. The alternative or flip side to that dominant view is that the minority held to the global warming view. It looks like the minority were right and the dominant view was wrong.
????
Don... I know Dr. Oreskes fairly well, and have had several one-on-one conversations with her in the past during AGU in SF.
I think perhaps you're misinterpreting what's being stated in this piece. Re-reading it myself, I wonder if you're thinking stating the dominant scientific view in the 1950's, 60's and into the 1970's was that the earth was cooling and would continue to do so. That would be an inaccurate interpretation.
Mid-century cooling was, and is, very well understood and accepted. There was some exploration at that time whether cooling or warming would dominate in the coming decades, but even then the dominant view was that it would likely be CO2 induced warming.
Famously, the renowned climate scientist Dr. Stephen Schneider, produced one paper suggesting that cooling due to global dimming from aerosol pollution was the bigger problem. Fairly soon, though, he also became convinced by the weight of evidence that the underlying warming from CO2 was the larger problem.
To Rob Honeycutt
Quoting her article isn't a misinterpretation. Maybe she regrets it now, especially egging on contrarians, but it is what it is [circa 2004]
Feel free to ask her about it, I'm not able to offer insights into her state of mind.
:)
To Rob Honeycutt
Her inclusion of some fearing the coming ice age indicates at least some thought it was going to continue. I'm not aware of surveys of that era so I can't offer insights for what the dominant view predicted for the next years, decades or centuries.