OPINION

Is there really a 97% consensus about global warming and its consequences?

John Kane-Berman asks three questions of the commonly cited claim

On its Climate Science Information Centre, extended in February to South Africa, Facebook states that “at least 97% of published scientists agree that global warming is real and caused by humans”.

Referring to the “claim” that global warming over the past century could be caused by the sun, Facebook says scientists have concluded that it could only have been caused by “the billions of tons of carbon pollution created by human activities” (emphasis added). It is, moreover, a “myth that scientists disagree on climate change”.    

Facebook further states that climate change is making “heatwaves, droughts, and wildfires more frequent and intense”, while damaging plant life and causing polar bear populations to decline.      

In 2014 John Kerry, then Barrack Obama’s secretary of state and now Joe Biden’s special envoy on climate change, said that “97% of the world’s scientists” tell us it is “urgent” to deal with the “crippling consequences” of climate change. Mr Obama himself stated that “97% of scientists agree [that] climate change is real, man-made, and dangerous”.

Referring to Donald Trump as a “climate arsonist”, Mr Biden said last year that if Mr Trump were to be given four more years in the White House, “why should anyone be surprised” if more of America were “ablaze” or “under water”?

It is course inherently unlikely that 97% of the world’s scientists agree about such diverse things as droughts, heatwaves, floods, hurricanes, polar bears, damage to plant and insect life, and all the other “dangerous” and “crippling” consequences we are told global warming will have, among them drowning islands, shrinking forests, disappearing species, growing food insecurity, catastrophic wildfires, and disappearing coral reefs. All these involve countless different branches of science, from agronomists through meteorologists to zoologists.              

Let us therefore ask three questions. How many scientists constitute the 97% consensus? What is it that they agree about? How much warming do humans cause?

The 97% figure dates back to an article by John Cook and others published in 2013. Their key finding – in what they claim is the “most comprehensive analysis to date” - is that “97.1% endorsed the consensus position that humans are causing global warming”. So the question is, 97% of whom?

The Cook paper is based on an analysis of 11 944 “climate abstracts from 1991-2011”. Two thirds of these abstracts expressed no position. Of the one third who did express a view, 97% endorsed the “consensus that humans are causing global warming”. The 97% is therefore actually 97% of one third of the abstracts, which means 3 781 of the abstracts analysed.

However, the paper admits, the 11 944 papers are only a “fraction of the climate literature”. A “web of science” search for “climate change” yields 43 548 papers. A search for “climate” yields 128 440 papers.

The views on climate and/or climate change expressed in all these additional papers are unknown. Not only is the sample on which the 97% claim is based extraordinarily small, but the issue on which the 97% agree is also very limited, namely that “humans are causing global warming”. There is no reference to any of the “dangerous” and “crippling” things human-induced global warming is supposed to be causing.

There’s more. David Legates and others published an analysis of the Cook claims. They said that only 41 of the 11 944 papers to which the Cook papers referred explicitly stated that humans had caused most of the warming since 1950. This shrinks the 97% to 0.3%.

One of the joint authors, Christopher Monckton, wrote that many scientists no doubt considered it possible that humans caused some warming, but that no more than 41 papers had explicitly stated that humans were responsible for most warming (which is repeatedly presented as the “consensus” position). It was, Lord Monckton wrote, “unscientific to assume that most scientists believe what they have neither said nor written”.    

The Cook paper cites a study that found that 57% of Americans either disagreed with, or were unaware of, the “overwhelming” consensus that the earth is warming because of human activity. It argues that this “consensus gap” between perception and reality is the result of campaigns designed to confuse the public which are exacerbated by the media practice of providing both sides of the story, allowing a “vocal minority to have their points amplified”.

Al Gore, author of An Inconvenient Truth, also blames public confusion on the media, which gives “equal weight” to “scientists and self-interest” groups. This, he says, gives the “false impression that there is a debate over facts when there isn’t”.

So now we have the following situation. Anyone disputing the claims made by people such as Messrs Gore, Obama, Kerry, and Biden is doing so only because the media has misled them. By labelling the idea of disagreement among scientists as a “myth”, Facebook is attempting to rectify this by consigning non-believers to oblivion.

Lord Monckton indeed warned against a “manufactured consensus” that can be used to “stifle discussion, debate, and critical thinking”.  

Yet the sample on which the 97% is based is minuscule. To the extent that there is any agreement about anything, such agreement extends only as far as the possibility that humans are causing some of the warming that may be taking place. There is no evidence, let alone proof, that 97% of even the minuscule sample of scientists think climate change and/or global warming are dangerous, contrary to what various American and other politicians keep telling us.                     

Back in August 1946 the Ladies Home Journal carried an advertisement to the effect that “more doctors smoke Camel than any other cigarette”. It was based on a coast-to-coast survey of 113 597 doctors. That at least was a larger sample than the one on which the 97% consensus about the impending climate apocalypse is based.  

*Kane-Berman is a policy fellow at the IRR, a think-tank that promotes political and economic freedom. Readers are invited to take a stand with the IRR by clicking here or sending an SMS with your name to 32823. Each SMS costs R1. Ts and Cs apply.