The Starship vs. Spaceship Earth

Dyson espouses a generic disdain for climate models and climate modellers: ” Here I am opposing the holy brotherhood of climate model experts and the crowd of deluded citizens who believe the numbers predicted by the computer models.” Like most of us, he has little confidence in the modelling of clouds. But with great ignorance of the nature of the modelling enterprise, he declares: “It is much easier for a scientist to sit in an air-conditioned building and run computer models, than to put on winter clothes and measure what is really happening outside in the swamps and the clouds” Actually, those of us who go to Antarctica to drill ice cores certainly put on winter clothes, and paleoclimatologists are out in the swamps and ocean muck all the time. And there are plenty of scientists flying around in the clouds, trying to gauge their effects. The mainstream estimate that the climate sensitivity is around 3°C for a doubling of CO2 does not simply comes from computer models. Study of the Last Glacial Maximum, the Pliocene and the Paleocene-Eocene Thermal Maximum all rule out the idea that there is a strongly stabilizing cloud feedback. Ahe fact that we cannot precisely quantify cloud feedbacks also means that there is a lot of risk, that cloud feedbacks could make a doubled-CO2 world much hotter, not much cooler. Dyson’s writings conveniently ignore this two-directional implication of uncertainty, and they they also ignore the implications of the long atmospheric lifetime of CO2, which means if we wait and see how hot it gets and find we don’t like it, there’s nothing much to be done (unless, of course, we can simply go somewhere else).

Finally, there is the familiar examples of Dyson attacking the style of the debate, rather than its substance. Reporting on written debate between Richard Lindzen and Stefan Rahmstorf, in the New York Review of Books New York Times book review, Dyson juxtaposes Lindzen’s claim that “observations suggest that the sensitivity of the real climate is much less than that found in computer models” with Stefan calling this “simply ludicrous”. Dyson gives the impression that rational arguments from skeptics are met with “open contempt” by the majority. But he fails to mention that Stefan showed in detail why Lindzen’s claim is wrong: Lindzen ignored ocean thermal inertia when comparing observed warming with the equilibrium climate sensitivity. Any physicist should be able to judge that Stefan is right and Lindzen is wrong on this point. He also failed to mention that Stefan used the word “ludicrous” only in a “personal postscript” to a completely sober scientific article, referring to Lindzen’s claims that a vast conspiracy of thousands of climatologists worldwide is misleading the public for personal gain. Dyson’s account of the Lindzen-Rahmstorf exchange neither fairly covers the substance of the argument, nor is it a fair portrayal of its style – Dyson seems to have twisted it as much as he could to score a political point.

In the Heresy essay, Dyson repeatedly gives himself a way out by claiming he is only tossing out ideas that should be thought about; he at times emphasizes that he does not know the answers, only the questions that should be raised. However, that does not stop him from making confident claims that he has a broader view than others, as in this interview with Mike Lemonick, and somehow Dyson never gets around to thinking about what the consequences are if we continue inaction on CO2 emissions and he turns out to be wrong. More importantly, all of the things Dyson argues “heretically” should be looked at — e.g. land carbon sequestration or the lessons from the Altithermal period around 8000 years ago — are in fact already being intensively investigated and are not turning up any silver bullets to allay concern about climate change. When push comes to shove, Dyson is really only offering warmed-over standard contrarian talking points. Heresy, or more broadly an outsider’s viewpoint, can be a good thing when it shakes loose new ideas. But surely, we have a right to expect a more original form of heresy from the architect of Dyson spheres and nuclear starships.

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