Ashitosh Rajesh Varne, Simon Blouin, Baxter Lorenzo McIntosh Williams , David Denkenberger

To combat global warming, energy systems are transitioning to generation from renewable sources, such as wind and solar, which are sensitive to climate conditions. While their output is expected to be little affected by global warming, wind and solar electricity generation could be affected by more drastic climatic changes, such as abrupt sunlight reduction scenarios (ASRSs) caused by nuclear war or supervolcanic eruptions. This paper assesses the impacts of an ASRS on global energy supply and security in a 100% renewable scenario. National generation mixes are determined according to roadmaps for a global transition to renewable energy, with wind and solar contributing a combined 94% of global energy supply. Wind and solar generation are determined for a baseline climate and an ASRS following a large-scale nuclear exchange. While effects vary by country, overall wind and solar generation is expected to reduce by 59% in the first year following an ASRS, requiring over a decade for full recovery. Sufficient energy for critical needs for everyone, including water, food, and building heating/cooling, would require international trade, resilient food production, and/or resilient energy sources, such as wood, geothermal, nuclear power, tidal power, and hydropower.