I expect that a US first strike against Russia would involve around 1,300 nuclear weapons used exclusively on counterforce targets (90% confidence interval: 670 – 1,700), and that a Russian first strike against the US/NATO would involve around 1,100 nuclear weapons (90% confidence interval: 750 – 1,200), also exclusively used on counterforce targets.
I expect that a counterforce second strike would look pretty similar to a first strike, though it’s possible that a second strike by Russia would be somewhat smaller than its first strike […]
In effect, there’s a 90% chance that the actual change in temperature caused by a nuclear exchange between the US and Russia will be between −1.6 degrees Celsius and −4.2 degrees Celsius at its most severe. Similarly, there’s a 90% chance that the actual change in precipitation caused by a US-Russia nuclear exchange would be between −9.2% and −24% during the worst period of climate disturbances. […]
By my estimation, a nuclear exchange between the US and Russia would lead to a famine that would kill 5.5 billion people in expectation (90% confidence interval: 2.7 billion to 7.5 billion people).
Don’t buy the stuff about expecting a famine that kills billions at all? Especially since she didn’t seem to have dug into the actual criticisms of the nuclear winter theory in her post sequence, e.g. the independent components of the theory. I think very likely (>90%) there won’t be any change in temperature at all, which will be the case if any of those components fail. And as I understand it she has since updated towards being less bullish on it since those posts, and people who succeeded her at RP don’t think nuclear winter is that likely either.
What do you think about the conclusions of How bad would nuclear winter caused by a US-Russia nuclear exchange be? - EA Forum (effectivealtruism.org) ?
Don’t buy the stuff about expecting a famine that kills billions at all? Especially since she didn’t seem to have dug into the actual criticisms of the nuclear winter theory in her post sequence, e.g. the independent components of the theory. I think very likely (>90%) there won’t be any change in temperature at all, which will be the case if any of those components fail. And as I understand it she has since updated towards being less bullish on it since those posts, and people who succeeded her at RP don’t think nuclear winter is that likely either.