The Wizard and the Prophet: Two Remarkable Scientists and Their Dueling Visions to Shape Tomorrow's World

by Charles C. Mann

About radiocarbon dating: Earth is constantly bathed by a rain of high-energy subatomic particles from outer space. When these “cosmic rays” slam into a nitrogen atom, the violent collision can change the nitrogen into a mildly radioactive form of carbon: carbon-14 (14C), as scientists call it. By happenstance, 14C disintegrates into a form of nitrogen at almost exactly the same rate that it is created by cosmic rays. As a result, a small, steady percentage of the carbon in the air, sea, and land consists of 14C. Plants take in 14C through photosynthesis. When animals eat plants, they take it in, too. In consequence, every living cell has a steady, small level of 14C—they are all slightly radioactive. When organisms die, they stop absorbing 14C. Because the 14C in their cells continues to disintegrate, their bodies’ 14C level falls in a predictable way that researchers can use to estimate when the creatures were alive. Suess realized that carbon dioxide from burning petroleum would have almost no 14C because the organisms that had created it had died millions of years ago. It would thus be possible to detect if fossil fuels were pumping this 14C-less carbon dioxide into the environment—the overall 14C level would be a hair lower than it would be otherwise.