In short, the study uses a 1 dimensional model of the atmosphere, a particle of soot can go up or down, but there are no winds, no oceans, etc.  These models are said to be especially prone to failing hard when given extreme inputs, and the second part is the soot they claimed would be lofted into the air, sizes and quantities, which they did not justify, or justify well (can&#x27;t remember, it&#x27;s been decades since I read the paper).<p>Their excuse for using such a model was a lack of computing resources, and they were indeed dear back then.  But that made their running a massive propaganda campaign based on this inadequate at best &quot;science&quot; all the worse.<p>Anyway, LLNL, which had serious supercomputer resources for designing nuclear warheads and such, ran 3D simulations with more plausible inputs, and indeed found effects were possible, but they weren&#x27;t a big deal.  Certainly not on the scale of some of the bigger volcanic events.  (It&#x27;s a bit arrogant to automatically humans are so capable of changing the earth that much, especially that quickly; compare, as you do, to events like Tambora.)<p><i>The folks arguing - as you appear to be - that a nuclear war wouldn&#x27;t be that big a deal, got a lot quieter.</i><p>Not that I noticed.  Especially since we never argued that, only that it wouldn&#x27;t be &quot;the end of the world&quot;.  Maybe we just got more thoroughly ignored by the media, after all, the sainted Carl Sagan was wielding SCIENCE! and we were nobodies.  Note Sagan and Turco of the TTAPS team should have been a little more modest when the prospect of Kuwait&#x27;s oil wells getting set on fire in the first Gulf War came up, their theorizing did not match the reality to soon follow.<p>Of course, to the extent this might be an issue (and even modest effects would be less than welcome in the aftermath of a major nuclear exchange), it made SDI&#x2F;BMD all the more important, to prevent city busting in the first place....