Can foraging for earthworms significantly reduce global famine in a catastrophe?

Earthworms are a resilient group of species thriving in varied habitats through feeding on decaying organic matter, and are therefore predicted to survive an abrupt sunlight reduction scenario, e.g. a nuclear winter. In this study, the feasibility and cost-effectiveness of foraging earthworms to reduce global famine in such a scenario with or without global catastrophic infrastructure loss was considered. Previously reported earthworm extraction methods (digging and sorting, vermifuge application, worm grunting, and electroshocking) were analysed, along with scalability, climate-related barriers to foraging, and pre-consumption processing requirements. Estimations of the global wild earthworm resource suggest it could provide three years of the protein needs of the current world human population, at a median cost of 353 USD·kg−1 dry carbohydrate equivalent or a mean cost of 1200 (90% confidence interval: 32–8500) USD·kg−1 dry carbohydrate equivalent. At this price, foraging would cost a median of 185 USD to meet one person’s daily caloric requirement, or 32 USD if targeted to high-earthworm-biomass and low-labour-cost regions; both are more expensive than most existing resilient food solutions. While short-term targeted foraging could still be beneficial in select areas given its quick ramp-up, earthworms may bioaccumulate heavy metals, radioactive material, and other contaminants, presenting a significant health risk. Overall, earthworm foraging cannot be recommended as a scalable resilient food solution unless further research addresses uncertainties regarding cost-effectiveness and food safety.