Contradictory Contrarian Claims, Part 3 - "There's No Consensus in Science"

You often hear contrarians repeating mantras about there being "no consensus in science" or that "science is never settled," two related claims that I take to be nearly synonymous. Many examples could be given, but I'll offer a few (with links to the source so you can check up on me):

"There is no consensus science. Consensus is group-think

and is very dangerous in science. During the Little Ice Age,

there was a consensus that witches caused bad weather,

and so climate justice resulted in witch killings." (John Shewchuk)

"There is no consensus in science …

science is about facts" (John Coleman)

"Science is never settled." (Matthew Wielicki)

"The minute you hear the science is settled,
you know something is wrong.
Science is never settled." (Richard Lindzen)

It's common enough that sometimes you see it dressed up in pretty memes, like this one with a quote from Michael Crichton.

I haven't decided yet if it's better to describe this as a contradiction or just hypocrisy. Either way, you often hear contrarians talk about how there was strong opposition widely held positions in the past, and the opposition was well-founded. Wielicki reminds us that continental drift was once widely disputed and enjoyed only a few defenders before the mid-Atlantic ridge was discovered. After this we discovered that the Earth's crust is made up of moving plates, and we arrived at our current theory of plate tectonics, which currently enjoys essentially universal agreement among geologists. So maybe for Wielicki there can be a "consensus" on "settled science" after all. So, which is it?

It strikes me that virtually everyone using this mantra applies it selectively to address consensus positions that they disagree with. They're completely fine with there being a consensus on other matters, like:

• The Earth is a globe
• There's no solid dome covering a flat earth.
• Stars exist light years away from our Sun.
• Our solar system is part of the Milky Way galaxy.
• There are other galaxies outside our own.
• CO2 is a molecule, made up of one Carbon and two Oxygen atoms.
• Newtons Laws of Moton (where v<<c)
• Plate Tectonics
• Ideal Gas Law
• Germ Theory of disease

So I could describe this selective application of a universal mantra as being somewhat hypocritical. But when I bring up these matters of scientific consensus, they sometimes concede to me that there's a consensus on at least one the points listed above, but not on other matters (usually AGW and vaccines). In this case, we have a contradiction. The moment you accept that there is at least one scientific consensus, you must reject the mantra that there is no such thing as scientific consensus. And the moment you admit that the science is settled on any one of the above points, you have to reject the mantra that science is never settled. Wielicki's admission of a scientific consensus on plate tectonics contradicts his claim that there's no consensus in science. If you accept that there is a scientific consensus on any of the above points and also say "there's no consensus in science," you're contradicting yourself.

Improving the Mantra

Now it strikes me that there may be ways to pull out a nugget of truth from these claims. Maybe we can help contrarians out a little and find a way to say things that are both truthful and defensible. Here are some valid and defensible things that I think could be said:

• Scientific consensus is the consequence of overwhelming evidence. You can't conclude with Lindzen that "something is wrong" solely on the basis the fact that there's a consensus. When the evidence for a conclusion is sufficiently compelling, scientists publishing research in the field generally agree with the conclusion.
• Scientific consensus doesn't determine what is true. Any consensus can be overturned with contrary evidence. It's logically fallacious to say that something is true simply because a consensus exists.
• Scientific consensus does not require absolute proof. The scientific method does not have a mechanism to prove theories and hypotheses true. Instead, we test theoretical predictions against experiment, and if these fail, the theory or hypothesis is revised or discarded. At no point is the theory proven true. Feynman has an excellent presentation on this. Scientific consensus emerges when evidence for it is compelling and no alternatives can compete with the consensus position.  
• Scientific consensus is not comparable to religious dogma, and religious dogma is not scientific consensus. In Shewchuk's quote above, he describes a religious conviction about witches (that wasn't even a consensus in Christian dogma) as if it's comparable to a scientific consensus. A scientific consensus can and will adapt with new evidence. For example, consider how F = ma was adapted to observations of objects near the speed of light.

In fact, the idea of consensus can be extremely valuable in science, since it allows scientists to assess the strength of the evidence that exists in other fields. But consensus is almost never quantified. The only reason I can think of to quantify a consensus is to show voters that the consensus is strong enough in policy-relevant fields to convince virtually all scientists doing research in that field. Nobody had to quantify the consensus on plate tectonics. The research just shifted from justifying the theory to building on the theory.

Consensus on AGW Exists

I think some may be using this mantra incorrectly to claim that, while consensus may exist in science, it doesn't exist on AGW. That is, some claim that there is still wide spread scientific debate on whether human activity is the dominant cause of warming above the 1850-1900 mean. And this is demonstrably false. Whether you agree or disagree on the existence of consensus, it's demonstrably true that there's no longer any significant scientific debate on AGW (where AGW is defined as the conclusion that human activity is the dominant cause of recent warming). The continuing debate is almost entirely political, and it's manufactured by policy propaganda groups like Clintel, CO2 Coalition, GWPF, IPA, Heartland Institute, and the Heritage Foundation. The loudest voices in public debates today come not from publishing climate scientists but from shills, grifters and an assortment of non-experts that have decided to become political activists in their retirement years. I think a few things can be said here that are beyond rational dispute:

• IPCC assessment reports and NCA climate reports are essentially consensus documents. They are meta-analyses that evaluate the state of climate science at the time of publication. They show a clear, unambiguous and conclusive evidence that human activity is the dominant cause or warming above the 1850-1900 mean. This evidence originates in the scientific literature that convinced the vast majority of climate scientists.
• The contrarian political tracts like the so-called NIPCC, Clintel and even DOE reports exclusively present fringe positions on climate by cherry picking low-quality studies from low to no impact journals and misrepresenting the scientific literature. These reports are almost exclusively products of political think tanks with a policy-driven agenda. The only real exception to this is the DOE report, which was probably formed illegally, leading to the dissolution of the CWG that authored the report.
• Multiple studies show that the fraction of papers taking a position on AGW that agree with AGW is consistently in the "high nineties" with the most recent analysis showing a consensus exceeding 99%. There are loud objections to the contrary, but virtually all depend on not knowing what number goes in the denominator when calculating the fraction of papers taking a position on AGW that agree with AGW. None of the people making objections can produce the papers that justify saying the consensus is below the high nineties.
• There is an unanimous consensus on AGW among US-based scientific organizations and agencies (though this may change if the Trump administration directs agencies to abandon the scientific evidence to support his own agenda). I list over two dozen of these agencies here.
• There is an unanimous consensus on AGW globally among scientific organizations and agencies taking a position on AGW. I list almost 200 such agencies here.
• The consensus on AGW is on the major conclusions of climate science, especially that humans are the dominant cause of recent warming, and sensitivity is large enough to cause harm on relevant time scales (ECS is between 2.5 C and 4 C). There is still continuing discussion and debate on more specific issues.
• Almost all the practicing climate scientists with contrarian convictions that are still alive have either retired from publishing (Curry, Lindzen) or have announced their retirements this year (Christy, Spencer). I can only think of a couple continuing to do active research on climate (Scafetta, and if I'm generous, Soon), and they are not having a significant impact on the development of climate science. Seven years ago, Spencer lamented that the average age of contrarians with credentials in climate science was between 65 and 70; that age has increased to 72 to 77 now. He also noted that there are no new contrarian "researchers coming up through the ranks." In other words, contrarian positions among credentialed climate scientists is experiencing a death by attrition.
• The continuing contrarian movement is dominated by non-experts, most of whom do not do any actual climate research. This includes physicists who have done no research in climate (Happer, Koonin, Clauser), people with qualifications in unrelated fields (Wielicki, Plimer, Pielke Jr, Lomborg, Crok, McKitrick, McIntyre, Shellenberger), fossil fuel shills (Andy May, Gregory Wrightstone, Linnea Lueken), and grifters (Ole Humlum, Patrick Moore, Tony Heller, John Shewchuk, Javier Vinós). This is not a complete list, but I think it's representative of the kinds of people that are directing the now essentially political movement that challenges AGW. This by itself should not be construed as proof that their positions are wrong. But the fact remains that none of these people are producing research or showing scientific evidence that the consensus on AGW is wrong.

If I had to guess why this mantra is so common among contrarians, I would guess it's because of a widely held belief that the perception of  consensus is somehow enforced by some combination of governmental and funding agencies. So the consensus on AGW is artificially constructed, and so the science is declared to be "settled" because contrarian scientists have been "silenced." There has never been sufficient evidence for this to warrant that conclusion, but if there was any doubt about this, the current administration has erased it. The current administration is defunding scientists doing climate research and has hired scientists to write reports (most notably the DOE report) to prop up arguments that question AGW. This was motivated by a desire to repeal the EPA's endangerment finding. And yet they have been unable to manufacture any consensus. Instead, scientists have come out of the woodwork and have donated their time to write responses to the DOE report, documenting the way the report mishandled their research. If we've learned anything from this in 2025, it's that the US lacks the ability to artificially politically enforce a scientific consensus. It's a product of convincing evidence.