WASHINGTON — Astronomer Carl Sagan clashed Thursday with a top Pentagon official over a new Defense Department study that acknowledges nuclear war could plunge the world's climate into a civilization-ending deep freeze but dismisses the need to re-examine nuclear strategy in light of the findings.
Sagan, co-author of a 1983 research paper that first warned of a devastating "nuclear winter," complained in testimony at a joint hearing of two House subcommittees that the Pentagon used the survey to justify Administration arms policies rather than to reappraise them.
"If this were a paper I assigned in my graduate seminar at Cornell University, I think I would give it a 'D,' or maybe a 'C minus' if I was in a good mood," Sagan said.
Richard N. Perle, assistant secretary of defense for international security policy, responded: "I didn't hear a word of science (from Sagan). I heard a shallow, demagogic policy pronouncement. I wouldn't even give it an 'F.' "
The Pentagon analysis, released earlier this month, agreed with the findings of Sagan and other scientists that fires from nuclear explosions might produce a massive cloud of smoke and dust that could block the sun and plunge temperatures worldwide to below freezing.
However, Sagan charged that the study was riddled with "grave omissions" and failed to examine such thorny questions as the impact of such a catastrophe on food production, plant and animal life and society at large.
Perle defended the study's conclusion that the findings on nuclear winter should simply reinforce the Administration's nuclear strategy, including plans to proceed with research into the so-called "Star Wars" space-based missile defense system.
"We had better ensure the effectiveness of our deterrent force," Perle insisted. "Whether we like it or not, the best assurance that this phenomenon (nuclear winter) will never take place is an effective deterrent force."
Sagan, meanwhile, dismissed the "Star Wars" proposal as a wildly expensive "Maginot Line in the sky"--a reference to the supposedly impregnable series of French fortifications that proved useless when they were bypassed by German invaders at the beginning of World War II.
"You'd have to be really loony-tunes to bet the human race on this one," he said.
He suggested that a U.S.-Soviet research team more fully assess the potential impact of a nuclear winter, but Perle rejected the notion, saying that Soviet scientists taint their findings with politics.