Massive Cover-up Exposed: 285 Papers From 1960s-’80s Reveal Robust Global Cooling Scientific ‘Consensus’

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.

Journal Cooling Chart

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 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 Wikipedia articles. 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 blessings. In these ways, Connolley turned Wikipedia into the missionary wing of the global warming movement.

After eviscerating references to 1970’s 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 1970’s global cooling scare as a myth, as something that never really happened.

Peterson, Connolley, and Fleck (2008, hereafter PCF08) published “The Myth of the 1970’s 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 1970’s Global Cooling Scare Was Not Mythological

In 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”.

U.S. 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

It 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 wrong.”

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)

Dubious 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 links:

Part 1
Part 2
Part 3

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.

Read rest…

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    Thanks Climatechangedispatch! This answers my question I asked in a comment two weeks ago. That question is, when was the turning point for the warmists, when man-made CO2 emissions became their single factor outstripping all others? They didn’t want to reckon it from the early 70s, when the latest warming trend started (and ended in 1998). That didn’t look good, so they attempted to erase from history the cooling trend of the mid-20th century. With that smoothed out, they could say man-made CO2 as determining factor kicked in about a hundred years ago, along with cars.
    From there, they had to smooth out the Medieval Warm Period to make today look serious, and the Hockey Stick was the Belle of the Ball. So, for Connelly, Mann, and their cohorts, the project is to erase from memory the periods of climate change that don’t fit the narrative.
    I see on Wikipedia they’ve begun work on yet another cover-up project. That is to demote the Andean-Saharan Glaciation to a “minor” ice age.


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