"The major policy implication of nuclear winter was that a full-scale nuclear attack would produce climatic effects which would so disrupt the food supply that it would be suicide for the attacking country (Robock, 1989) and would also impact non-combatant countries. The subsequent end of the arms race and reduction of superpower tensions can be traced back to the world being forced to confront both the direct and indirect consequences of the use of nuclear weapons by the public policy debate in response to nuclear winter theory. The Soviet Union did not end until five years after nuclear warhead numbers began to drop steeply, and the end of the Soviet Union did not alter the slope of the decline."I have to say that I think that this is one of the least plausible explanations for the end of the Cold War. I've certainly never heard a historian make this argument, much less a historian of the USSR. It's based on a faulty understanding of the psychology of nuclear weapons found within governments- an assumption that these things are decided by rational actors on the basis of evidence and reason. Scientists have been saying that nuclear war is a really really bad idea since the 1940s, so why was nuclear winter different? And while it's true that some Soviet scientists were early to jump on the nuclear winter bandwagon back in the 1980s, I've never seen any evidence that the idea ever influenced Soviet/Russian nuclear strategy, and any influence on US nuclear thinking certainly hasn't inspired the military to abandon nuclear weapons. Indeed, from my perspective the arms race doesn't exactly look like it ended. Slowed down? Sure. But with all the American ABMs and Russian Topol-M ICBMs sure it sure looks like we've got an arms race going on.
An aside: I'm not very impressed by the latest round of nuclear winter studies. Although worth reading and vastly improved from the 1980s originals, they make assumptions about firestorm effects resulting from nuclear bombing that I find difficult to swallow. But not nearly as hard to swallow as the belief of the authors that they single-handedly ended the arms race.