The Atomic Age

How arguments about nuclear weapons shaped the debate over global warming.

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Beginning on the day black rain fell on Hiroshima, nuclear weapons shaped environmental science. In 1949, the U.S. Weather Bureau launched Project Gabriel, a classified meteorological study of weapons and weather. The next year, the Department of Defense, in a study titled “The Effects of Atomic Weapons,” coined the word “fallout.” Researchers considered making the quantity, spread, and duration of fallout the standard measure of the force of a nuclear explosion, but found that approach to be too dependent on the weather. (Instead, they chose blast radius.) They measured and modelled the best weather conditions for explosions and the effects of those explosions on the natural world; they invented and refined tools to detect atmospheric weapons tests conducted by the Soviets; and they investigated the possibility of using nuclear weapons to alter the weather and even the climate of adversaries. Sagan, after finishing his Ph.D. at the University of Chicago, in 1960, worked on a secret military project code-named A119, which had begun in 1958, a year after Sputnik. Sagan was charged with calculating “the expansion of an exploding gas/dust cloud rarifying into the space around the Moon.” The idea was to assess whether a mushroom cloud would be visible from Earth, and therefore able to serve as an illustration of the United States’ military might.

Government-funded environmental scientists began noticing something curious: nuclear explosions deplete the ozone layer, which protects the Earth’s atmosphere. This finding related to observations made by scientists who were not working for the military. In the wake of Rachel Carson’s “Silent Spring,” published in 1962, the U.S. government formed a number of advisory and oversight organizations, including the Environmental Pollution Panel of the President’s Science Advisory Committee. The panel’s 1965 report, “Restoring the Quality of Our Environment,” included an appendix on “Atmospheric Carbon Dioxide,” laying out, with much alarm, the consequences of “the invisible pollutant” for the planet as a whole. In 1968, S. Fred Singer, an atmospheric physicist who had worked on satellites and was now a Deputy Assistant Secretary of the Interior, organized a symposium on “Global Effects of Environmental Pollution.” Four papers were presented at a panel on “Effects of Atmospheric Pollution on Climate.”

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The nuclear-winter debate has long since been forgotten, but you can still spy it behind every cloud and confusion. It holds a lesson or two. A public understanding of science is not well served by shackling science to a national-security state. The public may not naturally have much tolerance for uncertainty, but uncertainty is the best that many scientific arguments can produce. Critics of climate-change science who ground their argument on uncertainty have either got to apply that same standard of evidence to nuclear-weapons strategy or else find a better argument. Because, as Sagan once put it, theories that involve the end of the world are not amenable to experimental verification—at least, not more than once. ♦

Read more at The Atomic Origins of Climate Science