On the Center and Fringes of Climate Science

It's hard sometimes to find ways to describe the range of views expressed by those participating in public discourse on climate change without sounding pejorative.  Public discourse is frequently corrupted by various forms of name calling; those who disagree with climate science are called "deniers" and those who agree with it are called "alarmists." Perhaps even more damaging to public discourse is the heavy reliance on simple bulverism: "you believe AGW is a problem because you're a socialist or communist looking to control people's lives and raise people's taxes," or, "You reject the evidence for AGW because you're a fascist shill serving fossil fuel interests." To avoid these pejoratives in this blog, I've used "proponent" to refer to those who accept the basic positions in climate science and "contrarian" to refer to those who reject those views. But if you read the scientific literature, the actual areas of debate and discussion are very different from what you find in public discourse.

If we restrict ourselves to the views expressed in the peer-reviewed literature, and in particular high impact journals (think Nature, Science, PNAS, AGU, etc.), there is no longer any meaningful debate on whether human activity is the dominant cause of recent warming (a view I'm going to abbreviate with AGW). Recent surveys of the literature show that papers questioning this view are in the neighborhood of ~1% of the papers taking a position on AGW. The IPCC assessment reports (the most recent being AR6) present what are effectively consensus positions on AGW and its expected impacts, and AR6 is unequivocal that that there are dangers associated with AGW that warrant mitigation efforts to keep us below the + 2.0 C target (2 C warming above preindustrial levels) and if possible the +1.5 C target, and we're uncomfortably close to that +1.5 C target. According to AR6, the 2010-2019 mean was about 1.1 C above preindustrial levels; we're now about 1.2 C. For sure, there are continuing areas of debate; is ECS closer to 2.5 C or closer to 4 C? Do conditions in the Arctic and Antarctic favor a rapid collapse of ice sheets that could result in a "pulse" of sea level rise? If so, we may experience a rapid increase in sea levels at much greater rates than what we're now experiencing. Questions like these continue to be discussed in the literature, but not so much whether human activity is largely responsible for current warming. Which leads to an important question - why is it that public discourse looks so different from areas of continuing scientific debate and discussion?

At least for the purposes of this discussion, I'd like to use a different set of terms to describe this range of positions in public discourse that is (I hope) completely devoid of pejoratives. I'd also like these to not be perceived as if there are only two camps, as if all those belonging to "us" agree with each other and those belonging to "them" also agree with each other. Descriptively, there are a continuum of views, including those with "centrist" positions and those with varying degrees of "fringe" positions. I think "fringe" should be an acceptable term since scientific revolutions frequently come from the fringes, and contrarians often fancy themselves Galileos rebelling against established orthodoxy. And personally I have no issues with advocating for a fringe position, so long as advocates admit that their positions are currently fringe and rigorously follow the scientific method in their argument that AGW is flawed and should be replaced by some alternative.

The scientific literature has consistently estimated ECS to be about 3 C since at least the the 1970s, with the current likely range being between 2.5 and 4 C in the AR6 report (consistent with Sherwood 2020, the most comprehensive assessment published to date). Even simple empirical calculations using the energy balance equation support this conclusion. The best estimate in the literature is also that human activity (GHGs and land use partially masked by aerosols) is responsible for ~100% of warming above the 1850-1900 mean. This is true both in AR6 and in the literature (Gillett 2021). I think also that these two metrics are highly predictive of how "centrist" or "fringe" someone may be on AGW. Calculations for ECS bunch up around 3 C, with few arriving at conclusions outside of 2.5 C and 4 C, especially among those published in high impact journals that climate scientists actually read.

Above I plot how this would look if it were a normal distribution with a mean of 3 C and a standard deviation of 0.5. Technically a mean of 3.25 C would be necessary for  2.5 C and 4 C to be equidistant from the mean, but I think it's better to keep 3 C as the mean. The vast majority of climate scientists would put their best estimate for ECS inside the green window. If this were a real analysis of views with a normally distributed population, this would represent about 82% of values (between Z= -1 and Z = 2), but I don't want this to be a formal assessment. Instead, this is just a graphical illustration that scientific positions on ECS outside the green window are relatively rare; centrist views bunch up around 3 C. And putting ECS at 3 C essentially requires that human activity is responsible for virtually all warming. So ~3 on this scale would correspond to ~100% of warming caused by human activity. Let's put some papers on this hypothetical scale. 

1. Nick Lewis published a paper "correcting" Sherwood's ECS estimate to 2.3 C; the paper wasn't really a correction, but it does arrive at a conclusion that is in the "moderate fringe" range, and correspondingly, Lewis is frequently thought of as a "contrarian." 
2. Curry (with Lewis) published a paper in 2018 estimating ECS to be ~1.7 C, and she says that it's as likely as not that humans are responsible for ~50% of current warming, putting her position nearer to a "radical" fringe. 
3. Happer and Lindzen are listed as authors of CO2 Coalition publications estimating ECS to be less than 1 C (0.84 C), which puts that position firmly in the "radical fringe" category. 
4. Happer is also an author of an unpublished paper putting a clear-sky estimate for ECS at 2.3 C. I find it interesting that his estimate for ECS is in the radical fringe range when speaking to politicians and only moderately fringe when writing a paper that is supposed to be more scientific.

Now it's hypothetically possible (there's a non-zero chance) that one of these fringe positions could win the day. A scientific revolution could at least in principle reorient climate science to a new normal, and centrist and fringe positions would then be reoriented around the new center. But while these revolutions do occur, they are rare; most fringe positions are fringe positions for a reason - the evidence doesn't back up their claims. It's statistically a bad bet that any fringe position will win over science. This is particularly the case in climate science because these fringe positions appear to be dominated by ideological biases. Those fringe positions on the low end of the scale are dominated by those with conservative political biases; they are almost exclusively held by those with libertarian politics. Likewise, those fringe positions on the high end of the scale (think Extinction Rebellion, Just Collapse, etc) tend to be dominated by those with "liberal" political biases; they are almost exclusively held by those who identify as eco-socialists (and those advocating for veganism). And both groups appeal to what can only be described as pseudoscience - politically motivated tracts or junk science papers published in low impact or predatory journals. It's difficult to find anyone among climate scientists in the radical fringe who are writing legitimate science and seeking to publish their research in credible peer-reviewed journals. All indicators currently show that the consensus on AGW has developed as a consequence of overwhelming evidence, with those scientists closer to the fringes as stragglers who have not yet (and may never) adopt the consensus that has was forged by thorough investigations of the evidence. The current consensus on AGW began to form around 1938, when Callendar identified fossil fuel emissions as the culprit for rising CO2 levels, and it culminated around 1988, when Hansen published model projections for current warming, projections that have been shown to have been largely accurate over the last 35 years. 

And yet fringe positions are over-represented in public discourse, especially in "debate" groups, where those on the fringes have been weaponized by junk science papers, political tracts, and misrepresentations of the scientific literature. Worse, many times those on the fringes present themselves as centrists fighting extremists who accept what virtually the entirety of climate research is saying. The best explanation for the discrepancy I can think of is that public discourse is more motivated by desires to sway public opinion towards ideological (and in particular political) positions, and not to understand the scientific evidence. Fringe debates rarely engage honestly in the literature and evaluate the current state of the evidence, identifying areas of continuing uncertainties that need further investigation. 

If there's a smoking gun that public discourse is dominated by ideological biases, I think the CO2 Coalition supplies it. The CO2 Coalition is a partisan organization that "publishes" position papers written by fringe scientists (a few with actual climate science credentials) and promote them to political conservatives. They also assemble "comments" (mostly boiler plate) that they submit for consideration for policy decisions. I mentioned earlier that Happer is listed as an author of these. In another post, I documented discrepancies between what Happer claims in these political tracts (ECS is 0.84 C) and what he wrote in an unpublished scientific paper (ECS is 2.3 C). It turns out that Happer was caught in a kind of sting operation that showed he had agreed to advocate for fringe positions - in particular, that increasing CO2 levels by coal and other fossil fuels are beneficial to humanity. And yet he presents himself very differently: "My activities to push back against climate extremism are a labor of love, to defend the cherished ideals of science that have been so corrupted by the climate change cult.” Happer's position is clearly an extreme fringe position, but he presented himself as if he were a centrist opposing "extremism" by some imaginary "climate change cult." 

And Happer is not alone. Willie Soon was found to have received $1 million to produce "deliverables" for corporate interests, and sometimes he did not disclose his funding when ethically bound to do so. Hilariously, Patrick Moore claimed you can drink a quart of glyphosate and it won't hurt you, but refused to do so when given the opportunity, saying he "isn't stupid." These incidences indicate that some who object to climate science (or other environmental issues) are motivated by other factors than their own convictions from the available evidence, and they may not even believe that they say. It would seem that at least some fraction of the state of public discourse is explained corporations pay paying scientists with compatible political ideologies to support conclusions favorable to corporate interests. Now some qualifications are in order:

1. The fact that scientists receive funding from corporate interests isn't bad in and of itself; but receiving funding to "deliver" products that support predetermined conclusions is hugely problematic, and the promotion of these deliverables may help explain why fringe views are over-represented in public discourse.

2. Just because some scientists promoting fringe views are paid to hold their opinions doesn't mean that all scientists with fringe views have similar funding; we shouldn't assume all contrarian scientists hold their views because they are funded by corporate interests. I try to stick to documented evidence.

3. It's fallacious to claim that a position is wrong because it is fringe. These fringe positions have been discarded by scientists because they are not backed by evidence, not because they are fringe.

But there remain a vanishingly small number of climate scientists on the fringes that honestly do believe the views they promote, but they are not producing compelling evidence that the consensus is wrong. So we're left with a choice. Either 1) the consensus is largely right and these contrarian scientists have fallen victim to their biases; they the last remnants of science that has moved on. Or 2) these scientists are right, but climate scientists are fabricating their data to invent a climate-related problems that don't actually exist, and there's a giant global conspiracy to fake the evidence and remove from view all the evidence supporting the fringe. The former explanation is much more likely than the latter.