Massive Cover-up Exposed: 285 Papers From
1960s-’80s Reveal Robust Global Cooling Scientific
By Kenneth Richard on 13. September 2016
Beginning in 2003, software engineer William Connolley quietly removed the highly inconvenient references to the global cooling scare of the 1970s from Wikipedia, the world’s most influential and accessed informational source.
It had to be done. Too many skeptics were (correctly) pointing out that
the scientific “consensus” during the 1960s and 1970s was that the Earth had been cooling for decades, and that nascent theorizing regarding the potential for a CO2-induced global warming were still questionable and uncertain.
Not only did Connolley — a co-founder (along with Michael Mann and Gavin Schmidt) of the realclimate.com blog — successfully remove (or rewrite) the history of the 1970s global cooling scare from the Wikipedia
record, he also erased (or rewrote) references to the Medieval Warm Period and Little Ice Age so as to help create the impression that the paleoclimate is shaped like Mann’s hockey stick graph, with unprecedented and dangerous 20th/21st century warmth.
A 2009 investigative report from UK’s Telegraph detailed the extent of dictatorial-like powers Connolley possessed at Wikipedia, allowing him to remove
inconvenient scientific information that didn’t conform to his point of view.
“All told, Connolley created or rewrote 5,428 unique
His control over Wikipedia was greater still, however, through the role he obtained at Wikipedia as a website administrator, which allowed him to act with virtual impunity. When Connolley didn’t like the subject of a certain article, he removed it — more than 500 articles of various
descriptions disappeared at his hand. When he disapproved of the arguments that others were making, he often had them barred — over 2,000 Wikipedia contributors who ran afoul of him found themselves blocked from making further contributions.
Acolytes whose writing conformed to Connolley’s global warming views, in contrast, were rewarded with Wikipedia’s
In these ways, Connolley turned Wikipedia into the missionary
wing of the global warming movement.“
After eviscerating references to 1970s global cooling scare and the warmer-than-now Medieval Warm Period from Wikipedia, and after personally
rewriting the Wikipedia commentaries on the greenhouse effect to impute a central, dominant role for CO2, Connolley went on to team up with two other authors to publish a “consensus” manifesto
in 2008 that claimed to expose the 1970s global cooling scare as a myth, as something that never really happened.
Connolley, and Fleck (2008, hereafter PCF08) published “The Myth of the 1970s Global Cooling Scientific Consensus” in Bulletin of the American Meteorological
Society, hoping to quash once and for all the perception that there were scientists in the 1960s and 1970s who agreed the Earth was cooling (and may continue to do so), or that CO2 did not play a dominant role in climate change.
The Concoction Of ‘Consensus’ Achieved Via Exclusion
The primary theme of PCF08 can be summarized in 4 succinctly quoted sentences from the paper:
“[T]he following pervasive myth arose [among skeptics]: there was a consensus among climate scientists of the 1970s that either global cooling or a full-fledged ice age was imminent. A review of the
climate science literature from 1965 to 1979 shows this myth to be false. … During the period from 1965 through 1979, our literature survey found 7 cooling, 20 neutral, and 44 warming papers. … There was no scientific consensus
in the 1970s that the Earth was headed into an imminent ice age. Indeed, the possibility of anthropogenic warming dominated the peer-reviewed literature even then.”
William Connolley and colleagues
claimed that the determination of scientific “consensus” regarding global cooling and the influence of CO2 on climate during the 1970s could be divined by counting scientific publications that fell into arbitrarily-defined categories which allowed
them to intentionally exclude hundreds of papers that would undermine the alleged myth-slaying purpose of the paper.
The PCF08 authors decided that when “quantifying the consensus” (by counting publications),
a scientific paper could only be classified as a “cooling” paper if it projected that future temperatures would (continue to) decline, or that a “full-fledged ice age was imminent.” Papers published during the arbitrarily
chosen 1965-’79 era that affirmed the climate had already been cooling for decades, that this cooling wasn’t a positive development, and/or that the effects of CO2 on climate were questionable or superseded by other more influential climate
change mechanisms … were not considered worthy of classification as a “cooling” paper, or as a paper that disagreed with the claimed “consensus” that said the current (1960s-’70s) global cooling will someday
be replaced by CO2-induced global warming.
Of course, the global cooling scare during the 1970s was not narrowly or exclusively focused upon what the temperatures might look like in the future, or whether
or not an ice age was “imminent”. It was primarily about the ongoing cooling that had been taking place for decades, the negative impacts this cooling had already exerted (on extreme weather patterns, on food production, etc.), and
uncertainties associated with the causes of climatic changes.
By tendentiously excluding 1960s and 1970s publications that documented global cooling had been ongoing and a concern, as well as purposely excluding
papers that suggested the climate’s sensitivity to CO2 forcing is weak or questionable relative to other mechanisms, the authors could brazenly claim that there were only 7 papers published in the scientific literature between
1965 and 1979 that disagreed with the “consensus” opinion that global warming would occur at some point in the future (due to CO2 increases). According to PCF08, there were 44 papers that fell into the latter warming-is-imminent-due-to-CO2
category from 1965-’79, ostensibly entitling them to claim that dangerous anthropogenic global warming projections “dominated” the scientific literature even then.
An 83% Global Cooling/Weak
CO2 Influence Scientific ‘Consensus’ During 1960s, ’70s
As will be shown here, the claim that there were only 7 publications from that era disagreeing with the presupposed CO2-warming
“consensus” is preposterous. Because when including the papers from the 1960s and 1970s that indicated the globe had cooled (by -0.3° C between the 1940s and ’70s), that this cooling was concerning (leading to extreme weather, drought,
depressed crop yields, etc.), and/or that CO2’s climate influence was questionable to negligible, a conservative estimate for the number of scientific publications that did not agree with the alleged CO2-warming “consensus”
was 220 papers for the 1965-’79 period, not 7. If including papers published between 1960 and 1989, the “non-consensus” or “cooling” papers reaches 285.
Again, these estimates should be viewed as conservative. There are likely many dozen more scientific papers from the 1960s-’70s cooling scare era that would probably fall into the category of a “cooling” paper, but have not yet
been made available to view in full online.
But let us say that the PCF08 claim is true, and that there were indeed only 44 papers published between 1965-’79 that endorsed the position that the Earth’s
climate is predominately shaped by CO2 concentrations, and thus the Earth would someday start warming as the models had suggested. Interestingly, if we were to employ the hopelessly flawed methodology of divining the relative degree of scientific
“consensus” by counting the number of papers that agree with one position or another (just as blogger John Cook and colleagues did with their 2013 paper “Quantifying the Consensus…”
that yielded a predetermined result of 97% via categorical manipulation), the 220 “cooling” papers published between 1965-’79 could represent an 83.3% global cooling consensus for the era (220/264 papers),
versus only a 16.7% consensus for anthropogenic global warming (44/264 papers).
The 1970s Global Cooling Scare Was Not Mythological
reviewing the available scientific literature from the 1960s-’80s, it is plainly evident that there was a great deal of concern about the ongoing global cooling, which had amounted to -0.5°C in the Northern Hemisphere and -0.3°C globally between
the 1940s and 1970s.
Of course, this inconvenient global-scale cooling of -0.3°C between the 1940s and 1970s has necessarily been almost completely removed from the instrumental record by NASA (GISS) and the
MetOffice (HadCRUT). After all, the observations (of cooling) conflicted with climate modeling. Overseers of the surface temperature datasets (such as the MetOffice’s Phil Jones or NASA’s Gavin Schmidt) have recently adjusted
the -0.3°C of cooling down to just hundredths of a degree of cooling. NASA GISS, for example, has reduced (via “adjustments”) the global cooling down to about -0.01°C between the 1940s and 1970s, as shown below. It is
likely that, during the next few years of adjustments to past data, the mid-20th century global cooling period will disappear altogether and mutate into a warming period.
For those who actually experienced the non-mythological cooling scare during the 1960s and 1970s (that has since been made to disappear from graphs), the consequences of the -0.5° Northern Hemispheric cooling (especially) were frequently discussed
in scientific publications. There were geoengineering strategies proposed by scientists to melt Arctic sea ice. Droughts and floods and extreme weather anomalies/variability were blamed on the ongoing global cooling. Glaciers
were advancing, even surging at accelerated rates during this period. Sea ice growth and severe Arctic cooling meant that the oceans were much less navigable. Crop growth and food production slowed as the Earth cooled, which was of great concern
to world governments. Severe winters in the 1960s and 1970s led many climatologists to assume that the Earth was returning to an 1800s-like Little Ice Age climate. Observations of mammals migrating to warmer climates during the 1960s and 1970s
due to the colder temperatures were reported in scientific papers.
Synonyms for the 1960s-’70s climate cooling conditions commonly used in the literature were words such as deterioration, recession,
detrimental, and severe. In contrast, warming periods such as during the warmer Medieval times or the warm-up during the first half of the 20th century were referred to positively, or as optimum (i.e., the Medieval Warm
Period was referred to as the “Little Optimum”).
According to Stewart and Glantz (1985),
in the early 1970s it was the “prevailing view” among scientists that the Earth was headed into another ice age. It wasn’t until the late ’70s that scientists changed their minds and the “prevailing view” began
shifting to warming. This is in direct contradiction to the claims of PCF08, who allege warming was the prevailing view among scientists in the 1960s and early 1970s too. Furthermore, as recently as 1985, it was still acknowledged that “the
causes of global climate change remain in dispute.”
Stewart and Glantz, 1985
“The conclusions of the NDU study might have been predicted from a knowledge of the prevailing ‘spirit of the times’ (i.e., the prevailing mood in the science community) when the first part
was conducted. This was an interesting time in recent history of climate studies. One could effectively argue that in the early 1970s the prevailing view was that the earth was moving toward a new ice age. Many articles appeared in the scientific literature
as well as in the popular press speculating about the impact on agriculture of a 1-2°C cooling. By the late 1970s that prevailing view had seemingly shifted 180 degrees to the belief that the earth’s atmosphere was being warmed as a result
of an increasing CO2 loading of the atmosphere. … The causes of global climate change remain in dispute. Existing theories of climate, atmospheric models, and actuarial experience are inadequate to meet the needs of policymakers
for information about future climate.”
According to scientists reporting to the U.S. Central Intelligence Agency (1974), 22 of 27 forecasting methods predicted a cooling trend for the next 25 years,
and “meteorological experts” were thinking an 1800s climate was around the corner, with the concomitant return to monsoon failures, shorter growing seasons, and “violent weather”.
Central Intelligence Agency,1974
Potential Implications of Trends in World Population, Food Production, and Climate
“According to Dr.
Hubert Lamb–an outstanding British climatologist–22 out of 27 forecasting methods he examined predicted a cooling trend through the remainder of this century. A change of 2°-3° F. in average temperature would have an enormous
impact. … A number of meteorological experts are thinking in terms of a return to a climate like that of the 19th century. This would mean that within a relatively few years (probably less than two decades, assuming the
cooling trend began in the 1960’s) there would be brought belts of excess and deficit rainfall in the middle-latitudes; more frequent failure of the monsoons that dominate the Indian sub-continent, south China and western Africa; shorter
growing seasons for Canada, northern Russia and north China. Europe could expect to be cooler and wetter. … [I]n periods when climate change [cooling] is underway, violent weather — unseasonal frosts, warm spells, large storms, floods,
etc.–is thought to be more common.”
The Selective Emphasis On Particular Scientific ‘Facts’ To Advance An Agenda
is rather ironic that the below quote impugning the motives of “skeptics” by Connolley and his co-authors (PCF08) appeared in a paper that insisted the 1970s concerns about global cooling never really happened from a scientific standpoint, and
their “proof” that it never really happened is that they could only manage to locate 7 scientific papers (via selection bias) that supported this “contrarian” view:
“Underlying the selective quotation of the past literature is an example of what political scientist Daniel
Sarewitz calls ‘scientization’ of political debate: the selective emphasis on particular scientific ‘facts’ to advance a particular set of political values. In this case, the primary use of the
myth is in the context of attempting to undermine public belief in and support for the contemporary scientific consensus about anthropogenic climate change by appeal to a past “consensus” on a closely related topic that is alleged to have been
William Connolley may have successfully erased the Medieval Warm Period and 1970s cooling concerns from the pages of Wikipedia. He may have successfully written over 5,400 original Wikipedia
articles in an attempt to persuade the public to believe in a dominant role for humans and CO2 in causing climate changes. But the internet has a long and expansive memory, and it is unforgiving when opportunists and activists attempt to dupe the
public by concocting false narratives and employing the very same practice of “scientization” they hypocritically claim to deride.
285 Scientific Publications Affirming A Global Cooling/Weak
CO2 Influence ‘Consensus’
Again, there were at least 285 scientific publications that did not agree with the alleged CO2-warming “consensus” opinion during the 1960s to
1980s. The list is divided into several sub-sections:
Cooling Since 1940, Forecasts for Continued Cooling/Ice Age (156 papers)
Human Influence on Climate, Low CO2 Climate Sensitivity (44 papers)
Rising CO2 Leads to Cooling (7)
Uncertainties, Lack of Climate Understanding,
Climate Modeling Problems (30)
Miscellaneous Questionable Human, CO2 Influence on Climate (12)
Non-CO2 Climate Change Mechanisms (26)
Warmer past despite lower CO2 (10)
The complete list of 285 Global Cooling/Weak CO2 Influence papers from the 1960s to 1980s can be found using the below
For those who may lack the time (or interest)
to view the full list of 285, a summarized version of 35 sample papers are listed below. Keep in mind that these 35 sample publications represent less than 1/8th of the total volume of papers published during that era, affirming the position that
concerns about global cooling were quite real, widespread, and scientifically-supported.
35 Sample Global Cooling/Low CO2 Climate Influence Papers
Cimorelli and House, 1974
“Between 1880 and 1940 a net [global] warming of about 0.6°C occurred, and from 1940 to the present
our globe experienced a net cooling of 0.3°C. … [I]t has since been found that the rate of temperature increase decreases with increasing CO2 and increases with increasing particulates. Therefore, global particulate loading is of foremost concern.
… [A]n increase in man-made global particulates by a factor of 4.0 will initiate an ice-age. In order that we safeguard ourselves and future generations from a self-imposed ice-age it is necessary that we effectively monitor global concentrations of
Angell and Korshover, 1978
1976 surface temperature equated the global record for the lowest temperature set in 1964; but even so the trend in global temperature since 1965 has been small compared to the 0.5°C decrease during 1960–65.”
“The nine-banded armadillos (Dasypus novemcinctus) have been moving northward in the Great Plains
region from the late 1800s to the 1950s but now seem to be retreating from their lately acquired northern range. The armadillos have a nontypical homoiothermic blood system which makes them fairly vulnerable to cold climates.”
“The cooling from about 1950 to 1974 is ~0.3°C (Brinkmann, 1976).
Moran (1975) suggests that the recent drought of peninsular Florida is largely due to decreased frequencies of tropical storms, associated with the general atmospheric and oceanic cooling since about 1940 (Wahl and Bryson, 1975).”
Nelson et al., 1975
“Concern about climatic change and its effects on
man has been increasing. Climatic changes affect the production of food and the allocation of energy resources. … Even with the temperature corrections included, Indiana June, July and August mean temperatures showed a decrease of approximately 3°F
[-1.7°C] from 1930 to 1976.”
“According to the academy report
on climate, we may be approaching the end of a major interglacial cycle, with the approach of a full-blown 10,000-year ice age a real possibility.”
“Increased atmospheric carbon dioxide content was concluded to have had an ambiguous climatic influence and may be less important than sometimes considered. Several studies have suggested increased turbidity has produced
a recent global cooling trend.”
“[T]he author is convinced
that recent increases of atmospheric carbon dioxide have contributed much less than 5% of the recent changes of atmospheric temperature, and will contribute no more than that in the foreseeable future.”
Ellsaesser , 1974
“The 1968 AAAS Symposium on Global Effects of Environmental Pollution initiated a flood of papers supporting monotonically
if not exponentially increasing pollution. The particulate increases were usually cited as at least contributing to the post 1940 cooling and possibly capable of bringing on another ice age.”
Introduction: “In the last century it is possible to document an increase of about 0.6°C in the mean global temperature between 1880 and 1940 and a subsequent fall of temperature by about 0.3°C
since 1940. In the polar regions north of 70° latitude the decrease in temperature in the past decade alone has been about 1°C, several times larger than the global average decrease. Up till now, past climatic changes (except possibly those
of the last few decades [of cooling temperatures]) could hardly have been caused by man’s activities.”
“It is not clear how such favorable and relatively consistent conditions are related to the higher temperatures in this century or the peaking of temperatures around 1940. The reversal of this
warming trend, however, could mark the beginning of a new ice age as some climatologists have indicated. It should be noted, though, that even if we are in fact heading for another ice age, many years or decades will elapse before this will become apparent”
“Unlike some other pollutants introduced into the atmosphere by Man, carbon
dioxide is naturally occurring and non-toxic. The direct effect of increased concentrations may be beneficial notably because it will tend to increase the rate of photosynthesis in plants. On the other hand, there may be deleterious effects through its influence
on climate but this is still unproven and we cannot be certain whether, on a global scale, it will on the whole be harmful or beneficial. … The problem of determining the effect of increased carbon dioxide on climate is difficult, the more so because
there are some essential aspects of the physical basis of climate that are not well understood”
“Recent anomalous weather conditions of the 1970s have revealed the possibility that significant aberrations in global climate have and are occurring with serious consequences. The 1970s have
seen a generally overall greater variability and instability of global weather. Regions in Asia, Central America, and Africa have witnessed a higher frequency of monsoon failure which has led to a prevalence of severe drought conditions and an extension
of desert boundaries. Whereas in other parts of the globe, severe flooding has been recorded. … Records of past climates have indicated that a greater variability of climate is generally synonymous with a major cooling trend in temperatures.”
Conclusions: “The scenario of a CO2-warming globe contains many uncertainties.
The warming of the atmosphere is not an established fact, and even if it was there may be no need to invoke increased atmospheric CO2 or other ‘greenhouse’ gases as the cause when such warmings have been a part of our temperature time series historically.”
“Since about 1968/69 the glacier fronts have advanced by up to 158 m following a marked climatic recession [cooling] during
the 1960s and early 1970s.”
“A new glacial insolation
regime, expected to last 8000 years, began just recently. Mean global temperatures may eventually drop about 1oC in the next hundred years.”
“Between 1000 and 1300 average summer [Arctic] temperatures were about 1°C higher than today, with the mean annual temperature higher by perhaps 4°C in a largely ice-free Arctic. …
[B]etween 1900 and 1940, the most striking temperature gains occurring in the Arctic winter… an average rise of more than 8°C keeping her seas ice-free for seven months of the year instead of barely three months less than a century before. …
Since about 1958 the reduced heat transport via the warm air sectors of the depressions has permitted an increase in pack-ice off northern and eastern Iceland to a condition comparable with the 1880s, and Polar Bears Thalarctos maritimus have been
able to cross from Greenland for the first time for half a century (Marshall 1968). This relapse from warmth continued into the 1970s with one winter, 1962/63, as devastating over the English Midlands and south as anything experienced since 1740 (Manley n.d.,
Lamb 1966, Booth 1968). People asked, are we on the threshold of another long climatic recession?”
“Instrumental surface temperature records have been compiled for large portions of the globe for about the past 100 years (Mitchell, 1961; Budyko, 1969). They show that the Northern Hemisphere annual mean temperature
has risen about 1°C from 1880 to about 1940 and has fallen about 0.5 °C since then … Climate change may be a natural internal feature of the land-oceanic-atmosphere (climate) system. … Three runs were made testing anthropogenic
effects of CO2, aerosols and heat. … One could sum the anthropogenic effects for each region, which would show almost no effect in the NH and warming in the SH. … Because the magnitudes of the effects are small, and may cancel, it cannot be concluded
that these high correlations show that man has produced climate change.”
Karl et al., 1984
“An appreciable number of nonurban stations in the United States and Canada have been identified with statistically significant (at the 90% level) decreasing trends in the monthly mean diurnal temperature range between
“At the present the imbalance is thought to correspond
to a natural cooling of the ocean, which will lead to the next Ice Age.”
“In particular, detection of an anthropogenic influence through statistical analysis alone requires a long run of data of good quality and careful attention to measures of significance. It is most important to avoid the post hoc ergo propter
hoc fallacy that a trend of a few years’ duration or less, following some change in human activities, can be attributed to that change even when no sound physical causal relationship is evident.”
Bulatov and Zakharov, 1978
Changes in the amount of multi‐year ice in arctic seas during the current cooling trend
“[T]he southern boundary of old ice was up to 100 miles farther south to the west of the divide, and up to 100 miles farther north to the east. The significance of these changes with regard to navigation conditions is self‐evident.”
“Concern over the vulnerability of a heavily populated world to climatic fluctuations affecting harvests and world
food supply has emerged only recently. This concern has been stimulated by anomalous weather patterns beginning with the colder winters in Europe and North America in the 1960s, the Indian monsoon failures and droughts in the Soviet and Chinese grainlands
in that decade and since, and the drought which continued for many years in Africa and brought chaos to the Sahel and Ethiopia. But, despite the computer revolution in meteorology, no generally accepted theory of climatic change to inform the future
exists at this time.”
increase in carbon dioxide in the atmosphere, according to the most recent computations, would not be enough to have any measurable climatic effect.”
SPECIFIC SCHEMES FOR CLIMATE MODIFICATION
Ice Free Arctic Ocean The largest scale enterprise that has been discussed
is that of transforming the Arctic into an ice free ocean.
Bering Strait Dam The basic idea is to increase the inflow of warm Atlantic water by stopping or
oven reversing the present northward flow of colder water through Bering Strait.
Deflecting the Kuroshio Current It has been proposed that the narrow
mouth of Tatarsk Strait be blocked by a giant “water valve” to increase the warm inflow to the Sea of Okhotsk and reduce the winter ice there.
“Evidence derived from the carefully screened temperature record at Eau Claire, Mich., and from radiosonde data at [A] return to the temperature and circulation features of the early and mid-19th
century in the eastern United States may be underway. … All 3 mo[nths] show temperature declines since the height of the recent climatic optimum during the 1930s. July temperatures have decreased about 3.5°F since the decades beginning with
the early 1930s, and August temperatures have decreased about 3°F since the decades beginning with the late 1930s and early 1940s.”
and Ehrlich, 1971
Global Ecology: Readings toward a rational strategy for man [pgs. 76,77]
“A final push in the cooling direction comes from man-made
changes in the direct reflectivity of the earth’s surface (albedo) through urbanization, deforestation, and the enlargement of deserts. The effects of a new ice age on agriculture and the supportability of large human populations scarcely need
elaboration here. Even more dramatic results are possible, however; for instance, a sudden outward slumping in the Antarctic ice cap, induced by added weight, could generate a tidal wave of proportions unprecedented in recorded history.”
“The large-scale circulation of the atmosphere during the current decade has produced patterns that had never
been seen earlier in this century, but which seem to represent a recurrence of a regime that prevailed over long periods before 1895. … On this evidence, something like the climatic regime of the years since 1960 should probably be expected to
persist till the end of the century or beyond”
Newell and Dopplick, 1979
“Estimates of the atmospheric temperature changes due to a doubling of CO2 concentration have be with a standard radiative flux model. They yield temperature changes of >0.25 K. It appears that the much larger changes predicted
by other models arise from additional water vapor evaporated into the atmosphere and not from the CO2 itself. … It is important to stress…that CO2 is not the main constituent involved in infrared transfer. Water vapor plays the major role
and ozone is also of importance.”
“In the period from 1880 to 1940, the mean temperature
of the earth increased about 0.6°C; from 1940 to 1970, it decreased by 0.3-0.4°C. Locally, temperature changes as large as 3-4°C per decade have been recorded, especially in sub-polar regions. … The drop in the earth’s temperature
since 1940 has been paralleled by a substantial increase in natural volcanism. The effect of such volcanic activity is probably greater than the effect of manmade pollutants.”
“In 1970, Mitchell stated that by the late 1960s global temperatures had fallen 0.3°C from the peak in the 1940s, approximately one-half of the prior rise. … Summaries
by Schneider and Dickenson, Kalnicky, Robuck, Roberts, and Agee all report Northern Hemisphere temperatures declines by at least 0.5°C since the 1940s. In summary, Gribbin states ‘In worldwide terms, we are in a situation where the earth is cooling
more quickly than it warmed up earlier this century.’ From the above it is clear that the general consensus in the recent literature is that there has been a cooling in the Northern Hemisphere since the early 1940s.”
Kondratiev and Niilisk, 1960
On the question of carbon dioxide heat radiation in the atmosphere
“The dependence of atmospheric heat radiation on CO2 and H2O contents and also on temperature vertical distribution is investigated with the help of the radiation chart. It is shown that the heat radiation of the
atmosphere almost doesn’t depend on variations of carbon dioxide content in the atmosphere.”
“The climatic ‘improvement’ of the late 1930’s had, as was expected, given way to a colder trend in the 1950’s and 1960’s … Dunbar (1976, p. 190) writes that he
finds it “difficult to believe that either Carbon dioxide in the atmosphere, water vapour, freon, or any other substance produced by man’s efforts is going to compete seriously with Nature in changing our climate”. … Heino’s
diagrams illustrate the exceptional nature of the climatic improvement experienced in the 1930’s, but they also show clearly the slow deterioration which set in in the 1950’s. The 1960’s constituted climatically a rather unfavourable decade
from man’s point of view”
Wahl and Lawson, 1970
(1966) had already suggested that it appears likely that we have passed the height of the warming episode in the first half of this century and are now reverting to a pattern characterized by lower zonal flow and intensification of the trough/ridge systems,
essentially a reestablishment of the climatic character of the last century.”
ENVIRONMENTAL PROBLEMS OF TIMELY IMPORTANCE
WEATHER MODIFICATION BY CHANGING CO2 CONTENT OF ATMOSPHERE [p. 48]
Item: American Scientist, January-February 1970,
p. 18, “‘Though dire effects on climate of an increase in CO2 have been predicted, they are far from being established. The cycle is not really understood; carbon dioxide may well prove to be the least objectionable or the only beneficial addition
to the atmosphere from industrial sources'”