1. Indeed, Bayesian updating the lognormal distribution from Barrett based on no nuclear war for 72 years would cut off the high probability tail. Barrett notes that 7% per year is unlikely given the data. This is why Anders uses a beta distribution in his model. If you assume a uniform prior and 72 years of no nuclear war with a beta distribution, you get an annual probability of approximately 1.4%. He adjusted this downward to 0.7%, but as I noted this does not take into account the possibility of China conflicts. Hellman’s model indicated roughly 1% per year. So I think this is the right order of magnitude, but feel free to put your own number in. The overall conclusions are likely not to change very much. To give you some idea, the ratio of marginal 100 millionth dollar on alternate foods versus marginal now is two orders of magnitude ratio in cost effectiveness of alternate food. So even if one were two orders of magnitude less optimistic about alternate foods, it would still have ~60% confidence that funding alternate foods now is better than AI.
2. I agree that slow climate changes are much less problematic. One way of quantifying this is the agricultural loss velocity, percent loss in productivity per year. For nuclear winter, this is roughly 100% per year. For the sudden 10% agricultural losses (like regional nuclear war or volcano like the year without a summer), this is about 10% per year. For the abrupt regional climate change, this is about 10% over 10 years, or 1% per year. But if the 5°C over 100 years is a 20% agricultural effect, this is only 0.2% per year. And yet, there seems to be much more concern in the EA community (e.g. CSER) about extreme climate change, than the abrupt 10% shortfalls. And as I noted, the 80,000 Hours estimate of the long-term impact of extreme climate change was 20%. I guess one possible mechanism of why slow extreme climate change could be bad is there could be mass migration causing political tensions and potentially nuclear war. But in general, these risks seem to be significantly less serious than nuclear war directly.
3. My time horizon is only about 20 years. For the blocking of the sun, improvements in agricultural productivity are not really relevant. They would be relevant for the 10% shortfalls. Another thing that would be relevant is general economic development so the poorest of the world could handle price shocks better. Anders’ time horizon is significantly longer, but he is less concerned about the 10% shortfalls. So overall I do not think it would be too large of an adjustment.
4. For the probability of nuclear winter given full-scale nuclear war, there appear to be two camps: people that think it is near 100% and people to think it is near 0%. I did a Monte Carlo analysis on it and found if you define nuclear winter as near-complete agricultural collapse of crops where they are currently planted, this was around a 20% probability. This was so low because I considered significant probabilities of counter industrial and counterforce (trying to destroy the other side’s nuclear weapons) attacks. The usual understanding is maximum casualties, and then I would say the probability is more like half. I would also note that it is possible to have far future impacts of nuclear war even without nuclear winter (e.g. worse values ending up in AGI).
Thanks for your good questions.
1. Indeed, Bayesian updating the lognormal distribution from Barrett based on no nuclear war for 72 years would cut off the high probability tail. Barrett notes that 7% per year is unlikely given the data. This is why Anders uses a beta distribution in his model. If you assume a uniform prior and 72 years of no nuclear war with a beta distribution, you get an annual probability of approximately 1.4%. He adjusted this downward to 0.7%, but as I noted this does not take into account the possibility of China conflicts. Hellman’s model indicated roughly 1% per year. So I think this is the right order of magnitude, but feel free to put your own number in. The overall conclusions are likely not to change very much. To give you some idea, the ratio of marginal 100 millionth dollar on alternate foods versus marginal now is two orders of magnitude ratio in cost effectiveness of alternate food. So even if one were two orders of magnitude less optimistic about alternate foods, it would still have ~60% confidence that funding alternate foods now is better than AI.
2. I agree that slow climate changes are much less problematic. One way of quantifying this is the agricultural loss velocity, percent loss in productivity per year. For nuclear winter, this is roughly 100% per year. For the sudden 10% agricultural losses (like regional nuclear war or volcano like the year without a summer), this is about 10% per year. For the abrupt regional climate change, this is about 10% over 10 years, or 1% per year. But if the 5°C over 100 years is a 20% agricultural effect, this is only 0.2% per year. And yet, there seems to be much more concern in the EA community (e.g. CSER) about extreme climate change, than the abrupt 10% shortfalls. And as I noted, the 80,000 Hours estimate of the long-term impact of extreme climate change was 20%. I guess one possible mechanism of why slow extreme climate change could be bad is there could be mass migration causing political tensions and potentially nuclear war. But in general, these risks seem to be significantly less serious than nuclear war directly.
3. My time horizon is only about 20 years. For the blocking of the sun, improvements in agricultural productivity are not really relevant. They would be relevant for the 10% shortfalls. Another thing that would be relevant is general economic development so the poorest of the world could handle price shocks better. Anders’ time horizon is significantly longer, but he is less concerned about the 10% shortfalls. So overall I do not think it would be too large of an adjustment.
4. For the probability of nuclear winter given full-scale nuclear war, there appear to be two camps: people that think it is near 100% and people to think it is near 0%. I did a Monte Carlo analysis on it and found if you define nuclear winter as near-complete agricultural collapse of crops where they are currently planted, this was around a 20% probability. This was so low because I considered significant probabilities of counter industrial and counterforce (trying to destroy the other side’s nuclear weapons) attacks. The usual understanding is maximum casualties, and then I would say the probability is more like half. I would also note that it is possible to have far future impacts of nuclear war even without nuclear winter (e.g. worse values ending up in AGI).