Another embarrassing feature of climate models concerns the earlier of the two twentieth-century warmings from 1910 to 1940, when human influences were much smaller. On average, models give a warming rate of about half of what was actually observed. The failure of the latest models to warm fast enough in those decades suggest that it’s possible, even likely, that internal climate variability is a significant contributor to the warming of recent decades, Koonin suggests. “That the models can’t reproduce the past is a big red flag – it erodes confidence in their projections of future climates.” Neither is it reassuring that for the years after 1960, the latest generation of climate models show a larger spread and greater uncertainty than earlier ones – implying that, far from advancing, The Science has been going backwards. That is not how science is meant to work.

The second part of Koonin’s indictment concerns the distortion, misrepresentation, and mischaracterization of climate data to support a narrative of climate catastrophism based on increasing frequency of extreme weather events. As an example, Koonin takes a “shockingly misleading” claim and associated graph in the United States government’s 2017 Climate Science Special Report that the number of high-temperature records set in the past two decades far exceeds the number of low-temperature records across the 48 contiguous states. Koonin demonstrates that the sharp uptick in highs over the last two decades is an artifact of a methodology chosen to mislead. After re-running the data, record highs show a clear peak in the 1930s, but there is no significant trend over the 120 years of observations starting in 1895, or even since 1980, when human influences on the climate grew strongly. In contrast, the number of record cold temperatures has declined over more than a century, with the trend accelerating after 1985.

Notes Koonin, “temperature extremes in the contiguous U.S. have become less common and somewhat milder since the late nineteenth century.” Similarly, a key message in the 2014 National Climate Assessment of an upward trend in hurricane frequency and intensity, repeated in the 2017 assessment, is contradicted 728 pages later by a statement buried in an appendix stating that there has been no significant trend in the global number of tropical cyclones “nor has any trend been identified in the number of U.S. land-falling hurricanes.”

That might surprise many politicians.

“Over the past thirty years, the incidence of natural disasters has dramatically increased,” Treasury secretary Janet Yellen falsely asserted last month in a pitch supporting the Biden administration’s infrastructure package. “We are now in a situation where climate change is an existential risk to our future economy and way of life,” she claimed.

The sacrifice of scientific truth in the form of objective empirical data for the sake of a catastrophist climate narrative is plain to see. As Koonin summarizes the case:

“Even as human influences have increased fivefold since 1950 and the globe has warmed modestly, most severe weather phenomena remain within past variability. Projections of future climate and weather events rely on models demonstrably unfit for the purpose.”

Koonin also has sharp words for the policy side of the climate change consensus, which asserts that although climate change is an existential threat, solving it by totally decarbonizing society is straightforward and relatively painless.

“Two decades ago, when I was in the private sector,” Koonin writes, “I learned to say that the goal of stabilizing human influences on the climate was ‘a challenge,’ while in government it was talked about as ‘an opportunity.’ Now back in academia, I can forthrightly call it ‘a practical impossibility.’”

Unlike many scientists and most politicians, Koonin displays a sure grasp of the split between developed and developing nations, for whom decarbonization is a luxury good that they can’t afford. The fissure dates back to the earliest days of the U.N. climate process at the end of the 1980s. Indeed, it’s why developing nations insisted on the U.N. route as opposed to an intergovernmental one that produced the 1987 Montreal Protocol on ozone-depleting substances.

“The economic betterment of most of humanity in the coming decades will drive energy demand even more strongly than population growth,” Koonin says.

“Who will pay the developing world not to emit? I have been posing that simple question to many people for more than fifteen years and have yet to hear a convincing answer.”

The most unsettling part of “Unsettled” concerns science and the role of scientists.

“Science is one of the very few human activities – perhaps the only one – in which errors are systematically criticized and fairly often, in time, corrected,” Karl Popper wrote nearly six decades ago.

That condition does not pertain in climate science, where errors are embedded in a political narrative and criticism is suppressed. In a recent essay, the philosopher Matthew B. Crawford observes that the pride of science as a way of generating knowledge – unlike religion – is to be falsifiable. That changes when science is pressed into duty as authority in order to absolve politicians of responsibility for justifying their policy choices (“the science says,” we’re repeatedly told). “Yet what sort of authority would it be that insists its own grasp of reality is merely provisional?” asks Crawford. “For authority to be really authoritative, it must claim an epistemic monopoly of some kind, whether of priestly or scientific knowledge.”

At the outset of “Unsettled,” Feynman’s axiom of absolute intellectual honesty is contrasted with climate scientist Stephen Schneider’s “double ethical bind.” On the one hand, scientists are ethically bound by the scientific method to tell the truth. On the other, they are human beings who want to reduce the risk of potentially disastrous climate change.

“Each of us has to decide what the right balance is between being effective and being honest,” Schneider said.

“Being effective” helps explain the pressure on climate scientists to conform to The Science and the emergence of a climate science knowledge monopoly. Its function is, as Crawford puts it, the manufacture of a product – political legitimacy – which, in turn, requires that competing views be delegitimized and driven out of public discourse through enforcement of a “moratorium on the asking of questions.” This sees climate scientist gatekeepers deciding who can and cannot opine on climate science. “Please, save us from retired physicists who think they’re smarter and wiser than everyone in climate science,” tweeted Gavin Schmidt, NASA acting senior climate advisor, about Koonin and his book. “I agree with pretty much everything you wrote,” a chair of a university earth sciences department tells Koonin, “but I don’t dare say that in public.” Another scientist criticizes Koonin for giving ammunition to “the deniers,” and a third writes an op-ed urging New York University to reconsider Koonin’s position there. It goes wider than scientists. Facebook has suppressed a “Wall Street Journal” review of “Unsettled.” Likewise, “Unsettled” remains unreviewed by the “New York Times,” the “Washington Post” (though it carried an op-ed by Marc Thiessen based on an interview with Koonin) and other dailies, which would prefer to treat Koonin’s reasoned climate dissent as though it doesn’t exist.

The moratorium on the asking of questions represents the death of science as understood and described by Popper, a victim of the conflicting requirements of political utility and scientific integrity. Many scientists take this lying down. Koonin won’t. For his forensic skill and making his findings accessible to non-specialists, Koonin has written the most important book on climate science in decades.