EA - More global warming might be good to mitigate the food shocks caused by abrupt sunlight reduction scenarios by Vasco Grilo

Link to original articleWelcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: More global warming might be good to mitigate the food shocks caused by abrupt sunlight reduction scenarios, published by Vasco Grilo on April 29, 2023 on The Effective Altruism Forum.Disclaimer: this is not a project from Alliance to Feed the Earth in Disasters (ALLFED).SummaryGlobal warming increases the risk from climate change. This “has the potential to result in—and to some extent is already resulting in—increased natural disasters, increased water and food insecurity, and widespread species extinction and habitat loss”.However, I think global warming also decreases the risk from food shocks caused by abrupt sunlight reduction scenarios (ASRSs), which can be a nuclear winter, volcanic winter, or impact winter. In essence, because low temperature is a major driver for the decrease in crop yields that can lead to widespread starvation (see Xia 2022, and this post from Luisa Rodriguez).Factoring in both of the above, my best guess is that additional emissions of greenhouse gases (GHGs) are beneficial up to an optimal median global warming in 2100 relative to 1880 of 3.3 ºC, after which the increase in the risk from climate change outweighs the reduction in that from ASRSs. This suggests delaying decarbonisation is good at the margin if one trusts (on top of my assumptions!):Metaculus’ community median prediction of 2.41 ºC.Climate Action Tracker’s projections of 2.6 to 2.9 ºC for current policies and action.Nevertheless, I am not confident the above conclusion is resilient. My sensitivity analysis indicates the optimal median global warming can range from 0.1 to 4.3 ºC. So the takeaway for me is that we do not really know whether additional GHG emissions are good/bad.In any case, it looks like the effect of global warming on the risk from ASRSs is a crucial consideration, and therefore it must be investigated, especially because it is very neglected. Another potentially crucial consideration is that an energy system which relies more on renewables, and less on fossil fuels is less resilient to ASRSs.Robustly good actions would be:Improving civilisation resilience.Prioritising the risk from nuclear war over that from climate change (at the margin).Keeping options open by:Not massively decreasing/increasing GHG emissions.Researching cost-effective ways to decrease/increase GHG emissions.Learning more about the risks posed by ASRSs and climate change.IntroductionIn the sense that matters most for effective altruism, climate change refers to large-scale shifts in weather patterns that result from emissions of greenhouse gases such as carbon dioxide and methane largely from fossil fuel consumption. Climate change has the potential to result in—and to some extent is already resulting in—increased natural disasters, increased water and food insecurity, and widespread species extinction and habitat loss.In What We Owe to the Future (WWOF), William MacAskill argues “decarbonisation [decreasing GHG emissions] is a proof of concept for longtermism”, describing it as a “win-win-win-win-win”. In addition to (supposedly) improving the longterm future:“Moving to clean energy has enormous benefits in terms of present-day human health. Burning fossil fuels pollutes the air with small particles that cause lung cancer, heart disease, and respiratory infections”.“By making energy cheaper [in the long run], clean energy innovation improves living standards in poorer countries”.“By helping keep fossil fuels in the ground, it guards against the risk of unrecovered collapse”.“By furthering technological progress, it reduces the risk of longterm stagnation”.I agree decarbonisation will eventually be beneficial, but I am not sure decreasing GHG emissions is good at the margin now. As I said in my hot takes on counterproductive altruism:Mitigating global warming dec...