A Skeptical Reply to Dr. Steven Novella’s “Skeptic vs. Denier”

Guest skeptical reply by David Middleton

Dr. Steven Novella‘s NEUROLOGICA blog posts are often featured on Real Clear Science. They are always well-written, I probably agree with him most of the time and when I disagree, I can at least see the logic in his position. I particularly like his series of posts debunking faked Moon landing conspiracy theories, like this one.

Where I usually disagree with Dr. Novella, Dr. Alex Berezow and the other regular authors at Real Clear Science, is on the subject of climate change. Dr. Novella’s latest post is a generally thoughtful effort to distinguish a “skeptic” from a “denier.” I find myself agreeing with much of what he wrote… However, he made one YUGE mistake in his post: He cited Skeptical Science as an authoritative source for the 97% consensus.

Skeptic vs Denier
Published by Steven Novella

The skeptic vs denier debate won’t go away. I fear the issue is far too nuanced for a broad popular consensus. But that should not prevent a consensus among science communicators, who should have a technical understanding of terminology.

[…]

It is not a logical fallacy (argument from authority) to defer to a strong consensus of legitimate expert opinion if you yourself lack appropriate expertise. Deference should be the default position, and your best bet is to understand what that consensus is, how strong is it, and what evidence supports it. Further, if there appears to be any controversy then – who is it, exactly, who does not accept the mainstream consensus, what is their expertise, what are their criticisms, and what is the mainstream response? More importantly – how big is the minority opinion within the expert community.

This is where a bit of judgment comes in, and there is simply no way of avoiding it. There is no simple algorithm to tell you what to believe, but there are some useful rules. Obviously, the stronger the consensus, the more it is reasonable to defer to it. There is always going to be a 1-2% minority opinion on almost any scientific conclusion, that is not sufficient reason to doubt the consensus. But you also need to find out what, exactly the consensus is, and what is just a working hypothesis. Any complex theory will have multiple parts, and it’s not all a package deal.

[…]

That the Earth is warming at a faster rate than has historically been seen is fairly solid, with about 97% of climate scientists (yes, that is the real number) agreeing that this is almost certainly true. That this forcing of the climate is largely anthropogenic is also fairly certain. But the more detailed we get, the less certain we get also. Exactly how much warming will happen in the future, with what climate sensitivity, and with what effects becomes increasingly murky as we try to extrapolate further into the future. Also, what will be the effect of specific policies to mitigate warming is also open for debate.

With this as background, let me propose an alternate definition of skeptic vs denier. Actually, I already did:

– Deniers do not fairly assess the scientific evidence, but will cherry pick the evidence that seems to support their position.

– They will make unreasonable or impossible demands for evidence, move the goalpost when evidence is presented, and refuse entire categories of legitimate scientific evidence.

– They will attempt to magnify scientific disagreements over lower level details as if they call into question higher level conclusions. (For example, biologists might disagree over the details of evolutionary history, without calling into question evolution itself.)

– They primarily focus on sowing doubt and confusion over the science they deny, rather than offering a coherent alternate theory or explanation.

– They will exploit ambiguity (and even create ambiguity) in terminology or employ shifting definitions in order to create confusion or apparent contradiction.

– They will attack scientists personally, and engage in a witch hunt in order to impugn their reputations and apparent motives.

– They will cast doubt on whether or not a scientific consensus exists, attempt to claim that the tide is turning in their favor, or claim that a secret consensus of denial exists but is suppressed. They may also cite outlier opinions as if they were mainstream.

– When all else fails they will invoke a conspiracy theory to explain why mainstream views differ from their own.

In short – being a denier is about your behavior, not your position or even necessarily your credentials. A climate scientist with impressive degrees can be a denier if they act like one, and a lay person can be a skeptic if they act like one. By contrast, how does a legitimate skeptic behave:

– A skeptic will try to understand the scientific consensus and defer, as a default, to superior expertise.

– A skeptic will deviate from the mainstream view only cautiously, reluctantly, and with very good specific reasons grounded in logic and evidence. In short, a good skeptic is humble.

– A skeptic is open to any conclusion, going wherever the evidence and logic leads. Specifically, they will follow the evidence, and not start with a conclusion and then backfill the evidence.

– A good skeptic will not rationalize away contradicting evidence or problems with internal logical consistency, but will modify their opinions accordingly.

– Above all a good skeptic is intellectually honest.

So you are a denier if you behave like a denier, and a skeptic only if you behave like a real skeptic. This is all about process, not any particular position.

This also means that if you call someone a denier you should be prepared to back up that designation with specific examples of how they are behaving like a denier. It is also fair to refer to a position or even movement with the term denier or denial. It’s fair to refer to “global warming denial” as a phenomenon, especially since there is a solid-enough consensus on the basic conclusion that the Earth is warming and humans are causing it that it does create a reasonable starting position that anyone who disagrees is engaging in denial until proven otherwise.

And a lot of this does have to do with the burden of proof. Anyone making a scientific claim carries the burden of proving that claim. However, once a claim has met that burden, to the satisfaction of a vast majority of experts, the burden of proof then shifts to those who would refute the consensus.

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NEUROLOGICA

There may be a 97 or even 99.9% consensus that carbon dioxide is a greenhouse gas, emissions from fossil fuel combustion are the cause of anywhere from 50 to 100% of the rise in atmospheric CO₂ since the mid-1800’s and that humans are responsible for at least some of the observed warming since the end of the Little Ice Age, the coldest climatic era of the Holocene.

However, there is no consensus “that the Earth is warming at a faster rate than has historically been seen.” There is quite a large disagreement on this among the climate reconstruction community.

So, what would it mean, if the reconstructions indicate a larger (Esper et al., 2002; Pollack and Smerdon, 2004; Moberge t al., 2005) or smaller (Jones et al., 1998; Mann et al., 1999) temperature amplitude? We suggest that the former situation, i.e. enhanced variability during pre-industrial times, would result in a redistribution of weight towards the role of natural factors in forcing temperature changes, thereby relatively devaluing the impact of anthropogenic emissions and affecting future predicted scenarios. If that turns out to be the case, agreements such as the Kyoto protocol that intend to reduce emissions of anthropogenic greenhouse gases, would be less effective than thought.

Esper et al., 2005

For that matter, a skeptical analysis of the Fourth National Climate Assessment would conclude the same thing.

6. Temperature Changes in the United States
KEY FINDINGS
1. Average annual temperature over the contiguous United States has increased by 1.2°F (0.7°C) for the period 1986–2016 relative to 1901–1960 and by 1.8°F (1.0°C) based on a linear regression for the period 1895–2016 (very high confidence). Surface and satellite data are consistent in their depiction of rapid warming since 1979 (high confidence). Paleo-temperature evidence shows that recent decades are the warmest of the past 1,500 years (medium confidence).

Page 267

Fourth National Climate Assessment (NCA4), Fifth-Order Draft (5OD)

“Medium confidence” is equivalent to a Scientific Wild-Ass Guess (SWAG). Which the mainstream media turned into…

Just as troubling were draft findings destined for the quadrennial National Climate Assessment. Scientists from 13 federal agencies found that a rapid rise in temperatures since the 1980s in the United States represents the warmest period in 1,500 years.

USA Today

A “medium confidence” Mannian Hockey Stick became: “Scientists from 13 federal agencies found that a rapid rise in temperatures since the 1980s in the United States represents the warmest period in 1,500 years.”

They based this assertion on one hockey-stick climate reconstruction, Mann et al., 2008.

NCA4 Figure 1.8 Mann et al., 2008. Even with this Hockey Stick, the modern warming only exceeded pre-industrial natural variability by 0.5° F (0.3° C). At least they had the decency to clearly identify where they spliced in the instrumental data.

When the uncertainty range of the proxy data is honored, it cannot be stated that the rate of recent warming is unprecedented.

Regarding Dr. Novella’s criteria for differentiating a skeptic from a denier, I only take serious issue with one criterion in each category

I disagree that this makes one a denier:

[Deniers] will attack scientists personally, and engage in a witch hunt in order to impugn their reputations and apparent motives.

When the scientists in question are attacking other scientists personally, engaging in witch hunts and impugning the reputations of other scientists, as the Climategate CRU did, it’s entirely reasonable to fight back.

CRU email #1140039406. This email, dated February 15,2006, documented exchanges between several climate scientists, including the Deputy Director of CRU, related to their contributions to chapter six ofthe IPCC AR4. In one such exchange, the Deputy Director of CRU warned his colleagues not to “let [the Co-Chair of AR4 WGl] (or [a researcher at Pennsylvania State University]) push you (us) beyond where we know is right” in terms of stating in the AR4 “conclusions beyond what we can securely justify.”

NOAA OIG Report

The CRU’s Keith Briffa was warning his colleagues to not allow NOAA’s Susan Solomon or Penn State’s Michael Mann to coerce them into going along with unsupportable conclusions. This particular e-mail exchange dealt extensively with paleoclimate reconstructions. Briffa also urged his colleagues not to “attack” Anders Moberg, who had recently published a climate reconstruction which actually honored the data and used proper signal processing methods.

Susan Solomon is the NOAA official who claimed that NOAA work related to the IPCC was not subject to FOIA.

Michael Mann was the lead author of the thoroughly debunked original Hockey Stick.

Keith Briffa was the lead author of one of the problematic reconstructions in which “Mike’s Nature Trick” was employed to “hide the decline.”

If personal attacks, witch hunts and efforts to impugn the reputations of scientists makes one a denier… What does that make Michael Mann and Susan Solomon?

I also disagree that a skeptic should “defer, as a default, to superior expertise.”

A skeptic will try to understand the scientific consensus and defer, as a default, to superior expertise.

No self-respecting scientist would ever “defer, as a default, to superior expertise.”

I also strongly disagree with his assertion that the burden of proof (null hypothesis) has been reversed:

It’s fair to refer to “global warming denial” as a phenomenon, especially since there is a solid-enough consensus on the basic conclusion that the Earth is warming and humans are causing it that it does create a reasonable starting position that anyone who disagrees is engaging in denial until proven otherwise.

And a lot of this does have to do with the burden of proof. Anyone making a scientific claim carries the burden of proving that claim. However, once a claim has met that burden, to the satisfaction of a vast majority of experts, the burden of proof then shifts to those who would refute the consensus.

However, this entirely relies on what the so-called consensus is. If the consensus is that carbon dioxide is a greenhouse gas, emissions from fossil fuel combustion are the cause of anywhere from 50 to 100% of the rise in atmospheric CO₂ since the mid-1800’s and that humans are responsible for at least some of the observed warming… Then the burden of proof has generally been met.

If the consensus is this, then the burden of proof has not been met.