It would take a lot of nuclear weapons to produce nuclear winter climate effects, so if we’re particularly worried about nuclear winter, we should focus on nuclear exchange scenarios that would involve large nuclear arsenals.
I don’t think this is quite right. Robock 2007 finds a severe nuclear winter effect from an exchange with just 100x 15kt bombs. AFAIK, the only country with an arsenal below that threshold today is North Korea, which would suggest that — on Robock’s modelling at least—any bilateral exchange involving nuclear powers other than NK is large enough to pose a significant risk of nuclear winter.
Thanks for raising this! You’re right — Robock 2007 does find that even a relatively small nuclear exchange would have devastating climate effects that would probably cause a famine. But my understanding (from both Robock’s paper and this report on the impact of a regional nuclear exchange on the global food supply) is that a regional nuclear war, while horrible, would not cause a severe enough nuclear winter to risk human extinction.
I’ll clarify in the post that I’m most worried about nuclear exchange scenarios that would lead to a nuclear winter severe enough as to pose an extinction risk.
Are you only worried about extinction, or existential risk more broadly? I talk about a number of ways that a catastrophe the size of a regional nuclear war could lead to long-term impact, including instability leading to full-scale nuclear war.
I’m excited to read this series!
I don’t think this is quite right. Robock 2007 finds a severe nuclear winter effect from an exchange with just 100x 15kt bombs. AFAIK, the only country with an arsenal below that threshold today is North Korea, which would suggest that — on Robock’s modelling at least—any bilateral exchange involving nuclear powers other than NK is large enough to pose a significant risk of nuclear winter.
Thanks for raising this! You’re right — Robock 2007 does find that even a relatively small nuclear exchange would have devastating climate effects that would probably cause a famine. But my understanding (from both Robock’s paper and this report on the impact of a regional nuclear exchange on the global food supply) is that a regional nuclear war, while horrible, would not cause a severe enough nuclear winter to risk human extinction.
I’ll clarify in the post that I’m most worried about nuclear exchange scenarios that would lead to a nuclear winter severe enough as to pose an extinction risk.
Are you only worried about extinction, or existential risk more broadly? I talk about a number of ways that a catastrophe the size of a regional nuclear war could lead to long-term impact, including instability leading to full-scale nuclear war.