Expansion of cropland area during an abrupt sunlight reduction scenario

In the eventuality of a major volcanic eruption or nuclear war, particles would accumulate in the stratosphere and reduce sunlight, potentially altering climate conditions severely and decreasing crop yields. Mass starvation could be prevented with the help of resilient foods, such as transforming natural gas into protein, wood into sugar, and relocating crops. One intervention not yet analysed is expanding cropland area by converting other types of land, such as pasture and second-growth forests into land that could be cultivated. We find approximately 515 million hectares would be fit for cropland expansion during a catastrophe. Three land-clearing scenarios were explored: the global-equipment-sharing scenario, in which the area fit for expansion is cleared in 12 months, feeding 39% of the global population by the end of the first year after the catastrophe; the no-equipment-trade scenario, in which 442 million hectares of land are cleared in 7 years, feeding 20% of people by the end of the first year, and the export-poolequipment-trade scenario, where the supply of extra machinery to a few countries allows for the clearing of 511 million hectares in 7 years, feeding 27% of people by the end of the first year. This project shows the potential to mitigate starvation during catastrophes. By sparing old-growth forests, the impact on biodiversity would be limited and could mitigate desperate humans from hunting species to extinction.