The Multidisciplinarian

NASA reports that ninety-seven percent of climate scientists agree that human-caused climate change is happening.

As with earlier posts on popular miscarriages of science, I look at climate science through the lens of the 20^th century historians of science and philosophers of science and conclude that climate science is epistemically thin.

To elaborate a bit, most sensible folk accept that climate science addresses a potentially critical concern and that it has many earnest and talented practitioners. Despite those practitioners, it can be critiqued as bad science. We can do that without delving into the levels or claims, disputations, and counterarguments on relationships between ice cores, CO₂ concentrations and temperature. We can instead use the perspectives of prominent historians and philosophers of science of the 20^th century, including the Logical Positivists in general, positivist Carl Hempel in particular, Karl Popper, Thomas Kuhn, Imre Lakatos, and Paul Feyerabend. Each perspective offers a distinct philosophical lens that highlights shortcomings in climate science’s methodologies and practices. I’ll explain each of those perspectives, why I think they’re important, and I’ll explore the critiques they would likely advance. These critiques don’t invalidate climate science conceptually as a field of inquiry but they highlight serious logical and philosophical concerns about its methodologies, practices, and epistemic foundations.

The historians and philosophers invoked here were fundamentally concerned with the demarcation problem: how to differentiate good science, bad science, and pseudoscience using a methodological perspective. They didn’t necessarily agree with each other. In some cases, like Kuhn versus Popper, they outright despised each other. All were flawed, but they were giants who shone brightly and presented systematic visions of how science works and what good science is.

Carnap, Ayer and the Positivists: Verification

The early Logical Positivists, particularly Rudolf Carnap and A.J. Ayer, saw empirical verification as the cornerstone of scientific claims. To be meaningful, a claim must be testable through observation or experiment. Climate science, while rooted in empirical data, struggles with verifiability because of its focus on long-term, global phenomena. Predictions about future consequences like sea level change, crop yield, hurricane frequency, and average temperature are not easily verifiable within a human lifespan or with current empirical methods. That might merely suggest that climate science is hard, not that it is bad. But decades of past predictions and retrodictions have been notoriously poor. Consequently, theories have been continuously revised in light of failed predictions. The reliance on indirect evidence – proxy data and computer simulations – rather than controlled experiments (which would be impossible or unethical) would not satisfy the positivists’ demand for direct, observable confirmation. Climatologist Michael Mann (originator of the “hockey stick” graph) often refers to climate simulation results as data. It is not – not in any sense that a positivist would use the term data. Positivists would see these difficulties and predictive failures as falling short of their strict criteria for scientific legitimacy.

Carl Hempel: Absence of Appeal to Universal Laws

The philosophy of Carl Hempel centered on the deductive-nomological model (aka covering-law model), which holds that scientific explanations should be derived from universal, timeless laws of nature combined with deductive logic about specific sense observations (empirical data). For Hempel, explanation and prediction were two sides of the same coin. If you can’t predict, then you cannot explain. For Hempel to judge a scientific explanation valid, deductive logic applied to laws of nature must confer nomic expectability upon the phenomenon being explained.

Climate science rarely operates with the kinds of laws of nature Hempel considered suitably general, simple, and verifiable. Instead, it relies on statistical correlations and computer models such as linking CO₂ concentrations to temperature increases through statistical trends, rather than strict, law-like statements. These approaches contrast with Hempel’s ideal of deductive certifiability. Scientific explanations should, by Hempel’s lights, be structured as deductive arguments, where the truth of the premises (law of nature plus initial conditions plus empirical data) entails the truth of the phenomenon to be explained. Without universal laws to anchor its explanations, climate science would appear to Hempel to lack the logical rigor of good science. On Hempel’s view, climate science’s dependence on complex models having parameters that are constantly re-tuned further weakens its explanatory power.

Hempel’s deductive-nomological model was a solid effort at removing causality from scientific explanations, something the positivists, following David Hume, thought to be too metaphysical.  The deductive-nomological model ultimately proved unable to bear the load Hempel wanted it to carry. Scientific explanation doesn’t work in certain cases without appeal to the notion of causality. That failure of Hempel’s model doesn’t weaken its criticism of climate science, or criticism of any other theory, however. It merely limits the deductive-nomological model’s ability to defend a theory by validating its explanations.

Karl Popper: Falsifiability

Karl Popper’s central criterion for demarcating good science from bad science and pseudoscience is falsifiability. A scientific theory, in his view, must make risky predictions that can be tested and potentially proven false. If a theory could not in principle be falsified, it does not belong to the realm of science.

The predictive models of climate science face severe challenges under this criterion. Climate models often project long-term trends, typically, global temperature increases over decades or centuries, which are probabilistic and difficult to test. Shorter-term, climate science has made abundant falsifiable predictions that were in fact falsified. Popper would initially see this as a mark of bad science, rather than pseudoscience.

But climate scientists have frequently adjusted their models or invoked external factors like previously unknown aerosol concentrations or volcanic eruptions to explain discrepancies. This would make climate science look, to Popper, too much like scientific Marxism and psychoanalysis, both of which he condemned for accommodating all possible outcomes to a prediction. When global temperatures temporarily stabilize or decrease, climate scientists often argue that natural variability is masking a long-term trend, rather than conceding a flaw in the theory. On this point, Popper would see climate science more akin to pseudoscience, since it lacks clear, testable predictions that could definitively refute its core claims.

For Popper, climate science must vigorously court skepticism and invite attempts at disputation and refutation, especially from dissenting insiders like Tol, Curry, and Michaels (more on below). Instead, climate science brands them as traitors.

Thomas Kuhn: Paradigm Rigidity

Thomas Kuhn agreed that Popper’s notion of falsifiability was how scientists think they behave, eager to subject their theories to disconfirmation. But scientific institutions don’t behave like that. Kuhn described science as progressing through paradigms, the frameworks, shared within a scientific community, that define normal scientific practice, periodically interrupted by revolutionary shifts, with a new theory displacing an older one.

A popular criticism of climate science is that science is not based on consensus. Kuhn would disagree, arguing that all scientific paradigms are fundamentally consensus-based.

“Normal science” for Kuhn was the state of things in a paradigm where most activity is aimed at defending the paradigm, thereby rationalizing the rejection of any evidence that disconfirms its theories. In this sense, everyday lab-coat scientists are some of the least scientific of professionals.

“Even in physics,” wrote Kuhn, “there is no standard higher than the assent of the relevant community.” So for Kuhn, evidence does not completely speak for itself, since assent about what evidence exists (Is that blip on the chart a Higgs boson or isn’t it?) must exist within the community for a theory to show consistency with observation. Climate science, more than any current paradigm except possibly string theory, has built high walls around its dominant theory.

That theory is the judgement, conclusion, or belief that human activity, particularly CO₂ emissions, has driven climate change for 150 years and will do so at an accelerated pace in the future. The paradigm virtually ensures that the vast majority of climate scientists agree with the theory because the theory is the heart of the paradigm, as Kuhn would see it. Within a paradigm, Kuhn accepts the role of consensus, but he wants outsiders to be able to overthrow the paradigm.

Given the relevant community’s insularity, Kuhn would see climate scientists’ claim that the anthropogenic warming theory is consistent with all their data as a case of anomalies being rationalized to preserve the paradigm. He would point to Michael Mann’s resistance to disclose his hockey stick data and simulation code as brutal shielding of the paradigm, regardless of Mann’s being found innocent of ethics violations.

Climate science’s tendency to dismiss solar influence and alternative hypotheses would likely be interpreted by Kuhn as the marginalization of dissent and paradigm rigidity. Kuhn might not see this rigidity as a sign of dishonesty or interest – as Paul Feyerabend (below) would – but would see the prevailing framework as stifling the revolutionary thinking he believed necessary for scientific advancement. From Kuhn’s perspective, climate science’s entrenched consensus could make it deeply flawed by prioritizing conformity too heavily over innovation.

Imre Lakatos: Climate as “Research Programme”

Lakatos developed his concept of “research programmes” to evaluate scientific progress.  He blended ideas from Popper’s falsification and Kuhn’s paradigm shifts. Lakatos distinguished between progressive and degenerating research programs based on their ability to predict new facts and handle challenges effectively.

Lakatos viewed scientific progress as developing within research programs having two main components. The hard core, for Lakatos, was the set of central assumptions that define the program, which are not easily abandoned. The protective belt is a flexible layer of auxiliary hypotheses, methods, and data interpretations that can be adjusted to defend the hard core from anomalies. A research program is progressive if it predicts novel phenomena and those predictions are confirmed empirically. It is degenerating if its predictions fail and it relies on ad hoc modifications to explain away anomalies.

In climate science, the hard core would be that global climate is changing, that greenhouse gas emissions drive this change, and that climate models can reliably predict future trends. Its protective belt would be the evolving methods of collecting, revising, and interpreting weather data adjustments due to new evidence such as volcanic activity.

Lakatos would be more lenient than Popper about continual theory revision and model-tweaking on the grounds that a progressive research agenda’s revision of its protective belt is justified by the complexity of the topic. Signs of potential degeneration of the program would include the “pause” in warming from 1998–2012, explained ad hoc as natural variability, particularly since natural variability was invoked too early to know whether the pause would continue. I.e., it was called a pause with no knowledge of whether the pause would end.

I suspect Lakatos would be on the fence about climate science, seeing it as more progressive (in his terms, not political ones) than rival programs, but would be concerned about its level of dogmatism.

Paul Feyerabend: Tyranny of Methodological Monism

Kuhn, Lakatos, and Paul Feyerabend were close friends who, while drawing on each other’s work, differed greatly in viewpoint. Feyerabend advocated epistemological anarchism, defending his claim that no scientific advancement ever proceeds purely within what is taught as “the scientific method.” He argued that science should be open to diverse approaches and that imposing methodological rules suppresses necessary creativity and innovation. Feyerabend often cited Galileo’s methodology, which bears little in common with what is called the scientific method. He famously claimed that anything goes in science, emphasizing the importance of methodological pluralism.

From Feyerabend’s perspective, climate science excessively relies on a narrow set of methodologies, particularly computer modeling and statistical analysis. The field’s heavy dependence on these tools and its discounting of historical climatology is a form of methodological monism. Its emphasis on consensus, rigid practices, and public hostility to dissent (more on below) would be viewed as stifling the kind of creative, unorthodox thinking that Feyerabend believed essential for scientific breakthroughs. The pressure to conform coupled with the politicization of climate science has led to a homogenized field that lacks cognitive diversity.

Feyerabend distrusted the orthodoxy of the social practices in what Kuhn termed “normal science” – what scientific institutions do in their laboratories. Against Lakatos, Feyerabend distrusted any rule-based scientific method at all. Science in the mid 1900’s had fallen prey to the “tyranny of tightly knit, highly corroborated, and gracelessly presented theoretical systems.”

Viewing science as an institution, he said that science was a threat to democracy and that there must be “a separation of state and science just as there is a separation between state and religious institutions.” He called 20th century science “the most aggressive, and most dogmatic religious institution.” He wrote that institutional science resembled more the church of Galileo’s day than it resembled Galileo. I think he would say the same of climate science.

Feyerabend complained that university research requires “a willingness to subordinate one’s ideas to those of a team leader.” In the case of global warming, government and government-funded scientists are deciding not only what is important as a scientific program but what is important as energy policy and social agenda. Feyerabend would be utterly horrified.

Feyerabend’s biggest concern, I suspect, would be the frequent alignment of climate scientists with alternative energy initiatives. Climate scientists who advocate for solar, wind, and hydrogen step beyond their expertise in diagnosing climate change into prescribing solutions, a policy domain involving engineering and economics. Michael Mann still prioritizes “100% renewable energy,” despite all evidence of its engineering and economical infeasibility.

Further, advocacy for a specific solution over others (nuclear power is often still shunned) suggests a theoretical precommitment likely to introduce observational bias. Climate research grants from renewable energy advocates including NGOs the Department of Energy’s ARPA-E program create incentives for scientists to emphasize climate problems that those technologies could cure. Climate science has been a gravy train for bogus green tech, such as Solyndra and Abound Solar.

Why Not Naomi Oreskes?

All my science history gods are dead white men. Why not include a prominent living historian? Naomi Oreskes at Harvard is the obvious choice. We need not speculate about how she would view climate science. She has been happy to tell us. Her activism and writings suggest she functions more as an advocate for the climate political cause than a historian of science. Her role extends past documenting the past to shaping contemporary debate.

Oreskes testified before U.S. congressional committees (House Select Committee on the Climate Crisis, 2019, and the Senate Budget Committee, 2023), as a Democratic-invited witness. There she accused political figures of harassing scientists and pushed for action against fossil fuel companies. She aligns with progressive anti-nuclear leanings. An objective historian would limit herself to historical facts and the resulting predictions and explanations rather than advocating specific legislative actions. She embraces the term “climate activist,” arguing that citizen engagement is essential for democracy.

Oreskes’s scholarship, notably her 2004 “The Scientific Consensus on Climate Change” and her book Merchants of Doubt, employ the narrative of universal scientific agreement on anthropogenic climate change while portraying dissent solely as industry-driven disinformation. She wrote that 100% of 928 peer-reviewed papers supported the IPCC’s position on climate change. Conflicting peer-reviewed papers show Oreskes to have, at best, cherry-picked data to bolster a political point. Pursuing legal attacks on fossil fuel companies is activism, not analysis.

Acts of the “Relevant Community”

Countless scientists themselves engage in climate advocacy, even in the analysis of effectiveness of advocacy. Advocacy backed by science, and science applied to advocacy. A paradigmatic example – using Kuhn’s term literally – is Dr. James Lawrence Powell’s 2017 “The Consensus on Anthropogenic Global Warming Matters.” In it, Powell addresses a critic’s response to Powell’s earlier report on the degree of scientific consensus. Powell argues that 99.99% of scientists accept anthropogenic warming, rather than 97% as his critic claims. But the thrust of Powell’s paper is that the degree of consensus matters greatly, “because scholars have shown that the stronger the public believe the consensus to be, the more they support the action on global warming that human society so desperately needs.” Powell goes on for seven fine-print pages, citing Oreskes’ work, with charts and appendices on the degree of scientific consensus. He not only focuses on consensus, he seeks consensus about consensus.

Of particular interest to anyone with Kuhn’s perspective – let alone Feyerabend’s – is the way climate science treats its backsliders. Dissenters are damned from the start, but those who have left the institution (literally, in the case of The Intergovernmental Panel on Climate Change) are further vilified.

Dr. Richard Tol, lead author for the Fifth IPCC Assessment Report, later identified methodological flaws in IPCC work. Dr. Judith Curry, lead author for the Third Assessment Report, later became a prominent critic of the IPCC’s consensus-driven process. She criticized climate models and the IPCC’s dismissal of natural climate variability. She believes (in Kuhnian terms) that the IPCC’s theories are value-laden and that their observations are theory-laden, the theory being human causation. Scientific American, a once agenda-less publication, called Curry a “climate heretic.” Dr. Patrick Michaels, contributor to the Second Assessment Report later emerged as a vocal climate change skeptic, arguing that the IPCC ignores natural climate variability and uses a poor representation of climate dynamics.

These scientists represent a small minority of the relevant community. But that community has challenged the motives and credentials of Tol, Curry, and Michaels more than their science. Michael Mann accused Curry of undermining science with “confusionism and denialism” in a 2017 congressional testimony. Mann said that any past legitimate work by Curry was invalidated by her “boilerplate denial drivel.” Mann said her exit strengthened the field by removing a disruptive voice. Indeed.

Tampering with Evidence

Everything above deals with methodological and social issues in climate science. Kuhn, Feyerabend, and even the Strong Program sociologists of science, assumed that scientists were above fudging the data. Tony Heller, Harvard emeritus professor of Geophysics, has, for over a decade, assembled screenshots of NASA and NOAA temperature records that prove continual revision of historic data, making the past look colder and the present look hotter. Heller’s opponents relentlessly engage in ad hominem attacks and character-based dismissals, rather than focusing on the substance of his arguments. If I can pick substance from his opponents’ positions, it would be that Heller cherry-picks U.S.-only examples and dismisses global evidence and corroboration of climate theory by evidence beyond temperature data. Heller may be guilty of cherry-picking. I haven’t followed the debate closely for many years.

But in 2013, I wrote to Judith Curry on the topic, assuming she was close to the issue. I asked her what fraction of NASA’s adjustments were consistent with strengthening the argument for 20th-century global warming, i.e., what fraction was consistent with Heller’s argument. She said the vast majority of it was.

Curry acknowledged that adjustments like those for urban heat-island effects and differences in observation times are justified in principle, but she challenged their implementation. In a 2016 interview with The Spectator, she said, “The temperature record has been adjusted in ways that make the past look cooler and the present warmer – it’s not a conspiracy, but it’s not neutral either.” She ties the bias to institutional pressures like funding and peer expectations. Feyerabend would smirk and remark that a conspiracy is not needed when the paradigm is ideologically aligned from the start.

In a 2017 testimony before the U.S. House Committee on Science, Space, and Technology, Curry said, “Adjustments to historical temperature data have been substantial, and in many cases, these adjustments enhance the warming trend.” She cited this as evidence of bias, implying the process lacks transparency and independent validation.

Conclusion

From the historical and philosophical perspectives discussed above, climate science can be critiqued as bad science. For the Logical Positivists, its global, far-future claims are hard to verify directly, challenging their empirical basis. For Hempel, its reliance on models and statistical trends rather than universal laws undermines its deductive explanatory power. For Popper, its long-term predictions resist falsification, blurring the line between science and non-science. For Kuhn, its dominant paradigm suppresses alternative viewpoints, hindering progress. Lakatos would likely endorse its progressive program, but would challenge its dogmatism. Feyerabend would be disgusted by its narrow methodology and its institutional rigidness. He would call it a religion – a bad one. He would quip that 97% of climate scientists agree that they do not want to be defunded. Naomi Oreskes thinks climate science is vital. I think it’s crap.