Carl Sagan, according to Lowell Ponte, gave up being a scientiest and became a politician. And that politicization of science continues:
Carl Sagan, an astrophysicist and expert on other planets, created a computer model of Earth to demonstrate “nuclear winter,” and the world media dutifully reported his claims as fact.
Dr. Stephen Schneider, then at NCAR as Deputy Head of the Climate Project and now at Stanford University, wondered why Sagan bothered to create his own computer model. “We would have been glad to let Sagan simulate nuclear war on NCAR’s Supercomputer model,” Dr. Schneider told me.
But when Schneider tried to duplicate Sagan’s results on the NCAR computers, he discovered that “the most we could replicate was a little bit of ‘nuclear autumn,’ a bit more frost in a few places.”
Upon examining the model Sagan had shown to the world press to “prove” the danger of “nuclear winter,” Schneider found it was of a barren ball of rock with no mountains and no oceans. Oceans, as both Schneider and Sagan knew, act as gigantic energy flywheels that moderate temperature, helping cool adjacent continents in summer and warm them in winter.
Sagan, in other words, knowingly committed deliberate scientific fraud. He cooked up a phony computer model to concoct the phony “nuclear winter” results he wanted for political reasons. He avoided the already-available NCAR computer climate model precisely because he knew it would not produce the “nuclear winter” he wanted to sell to gullible journalists and an ignorant public. And were he still alive, Sagan would doubtless be among the signers, like Ehrlich, of this letter accusing President Bush of politicizing science.
There's more, a lot more, in Ponte's story. Go read the whole thing.
"Nuclear autumn." I like that one.