There is something like a pathology of climatology. To avoid mixing fact and speculation, earth scientists are, Laughlin says, “ultraconservative,” meaning they focus on the present and the immediate future: “[They] go to extraordinary lengths to prove by means of measurement that the globe is warming now, the ocean is acidifying now, fossil fuel is being exhausted now, and so forth, even though these things are self-evident in geologic time.”

Climate change over geologic time is, Laughlin says, something the earth has done “on its own without asking anyone’s permission or explaining itself.” People can cause climate change, but major glacial episodes have occurred “at regular intervals of 100,000 years,” always “a slow, steady cooling followed by abrupt warming back to conditions similar to today’s.”