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The Limits of Knowledge and the Climate Change Debate

Brian J. L. Berry, Jayshree Bihari and Euel Elliott, Cato Journal

The “debate” over climate change — which is really, in Matt Ridley’s terms, a “war” absent any real debate — has potentially done grave harm to the scientific enterprise.

The question of whether climate change is produced by anthropogenic global warming (henceforth AGW) has triggered an increasingly contentious confrontation over the conduct of science, the question of what constitutes scientific certainty, and the connection between science and policymaking. In a world in which we seek to understand complex, multifaceted phenomena such as climate (and to extract from this knowledge appropriate policy responses) the enduring epistemological question arises: What do we know? Logical inquiry might be expected to help resolve this knowledge problem (Hayek 1945) but is confounded by the assertion that the “science is settled,” by condemnation of those who disagree as “deniers,” and even by proposals that they be prosecuted as RICO offenders. There is increasing talk on the left— and even among Democratic state attorneys general and the highest levels of the Obama administration—of criminalizing the very effort to rebut the climate change orthodoxy (Gillis and Schwartz 2015, Moran 2016).

What could have been a fruitful, albeit perhaps contentious debate over decisionmaking when addressing highly complex phenomena has degenerated into a prolonged contest. While recognizing the problems attending denial of climate change, our purpose here is to elucidate the limitations of the now-dominant view. We ground this view within a Kuhnian framework and suggest the limitations of that framework in understanding the uncertainties of climate change and policies that flow from it. Kuhn (1962) points to an often-repeated process whereby scientific paradigms become locked in and resist challenges to their validity because knowledge production is socially controlled and deeply invested in the political currents of the day.

Power relationships and vested interests have frequently played a critical role in determining what acceptable science is or is not. In contemporary parlance there is historical lock-in and path dependence: once there is commitment to a particular body of knowledge that relates to a particular course of action, the costs of change increase over time and even if one wishes to move to a different path, it is difficult to do so. This is not to say that it is impossible for dissenters from the standard accepted approach to get their views expressed in the standard academic journals, but it is clearly more difficult. Moreover, consistent with the concept of path dependency (Greif and Laitin 2004, Arthur 1989), once a scientific paradigm becomes locked in, it becomes increasingly difficult to challenge the status quo in the accepted scientific outlets, at least until challenges to the orthodoxy of the day become so compelling they cannot be ignored.

To be sure, sometimes change does take place in a relatively smooth fashion, as when Lavoisier’s description of oxygen led to the abandonment of Becher’s phlogiston theory of combustion. At other times, where long-held doctrine is at stake, the conflict over new ideas becomes brutal: Galileo was tried by the Inquisition, found guilty, and spent the rest of his life under house arrest. In all cases, time is involved and supporting facts must be provided before a new paradigm gains acceptance. Both Wegener’s 1915 theory of continental drift and Milankovitch’s 1912 theory of the relationship of climate cycles to earth-sun geometry were dismissed for many decades until new evidence was provided—the Wilson-Morgan-Le Pinchon-McKenzie evidence for plate tectonics that was codified in 1965–67 and the Hays-Imbrie-Schackleton spectral analysis of ice core data that reinforced the idea of orbital forcing in 1976 (Hays, Imbrie, and Shackleton 1976). […]


As awareness of the uncertainties of global warming has trickled out, polling data suggests that the issue has fallen down the American public’s list of concerns. This has led some commentators to predict “the end of doom,’ as Bailey (2015) puts it. In light of this, it seems odd to keep hearing that “the science is settled” and that there is little, if anything, more to be decided. The global warming community still asks us to believe that all of the complex causal mechanisms that drive climate change are fully known, or at least are known well enough that we, as a society, should be willing to commit ourselves to a particular, definitive and irreversible, course of action.

The problem is that we are confronted by ideologically polarized positions that prevent an honest debate in which each side acknowledges the good faith positions of the other. Too many researchers committed to the dominant climate science position are acting precisely in the manner that Kuhnian “normal science” dictates. The argument that humanity is rushing headlong toward a despoiled, resourcedepleted world dominates the popular media and the scientific establishment, and reflects a commitment to the idea that climate change represents an existential or near-existential threat. But as Ellis (2013) says, “These claims demonstrate a profound misunderstanding of the ecology of human systems. The conditions that sustain humanity are not natural and never have been. Since prehistory, human populations have used technologies and engineered ecosystems to sustain populations well beyond the capabilities of unaltered natural ecosystems.”

The fundamental mistake that alarmists make is to assume that the natural ecosystem is at some level a closed system, and that there are therefore only fixed, finite resources to be exploited. Yet the last several millennia, and especially the last two hundred years, have been shaped by our ability—through an increased understanding of the world around us—to exploit at deeper and deeper levels the natural environment. Earth is a closed system only in a very narrow, physical sense; it is humanity’s ability to exploit that ecology to an almost infinite extent that is important and relevant. In other words, the critical variables of creativity and innovation are absent from alarmists’ consideration.

In that sense, there is a fundamental philosophical pessimism at work here—perhaps an expression of the much broader division between cultural pessimists and optimists in society as a whole. Both Deutsch (2011) and Ridley (2015b) view much of the history of civilization as being the struggle between those who view change through the optimistic lens of the ability of humanity to advance, to solve the problem that confronts it and to create a better world, and those who believe that we are at the mercy of forces beyond our control and that efforts to shape our destiny through science and technology are doomed to failure. Much of human history was under the control of the pessimists; it has only been in the last three hundred years that civilization has had an opportunity to reap the benefits of a rationally optimistic world view (see Ridley 2010).

Yet the current “debate” over climate change—which is really, in Ridley’s (2015a) terms, a “war” absent any real debate—has potentially done grave harm to this scientific enterprise. As Ridley documents, one researcher after another who has in any way challenged the climate orthodoxy has met with withering criticism of the sort that can end careers. We must now somehow return to actual scientific debate, rooted in Popperian epistemology, and in so doing try to reestablish a reasonably nonpolitical ideal for scientific investigation and discovery. Otherwise, the poisoned debate over climate change runs the risk of contaminating the entire scientific endeavor.

Full paper