Reducing food’s resource and climate footprints via food waste upcycling

Abstract The global food system is a major driver of most-pressing sustainability challenges such as climate change, unsustainable resource extraction, and altered biogeochemical cycles of N and P1-5. Food loss and waste is at the heart of the problem6,7. With 1/3 of food uneaten but lost/wasted, not only do resources consumed in producing the food ‘go down the drain’ but also the wasted food continues to brew health and pollution problems8,9. Here we show that food waste recovery and upcycling can effectively mitigate food’s unintended consequences. Using global primary data, we estimated that recovering and treating food waste via composting, anaerobic digestion, or feed-making technologies could reduce carbon footprints by 614–1041 Mt CO2-eq, compared to landfill baseline, potentially offsetting global food system’s climate burden by 4.5–7.6%. Up to 6.6 Mt nutrients could be re-captured for soil-crop-based upcycling. The feed-making option could generate up to 155.6 Mt novel feeds for animal-based upcycling, potentially replacing 41% and 9% of maize and soy in global livestock feeding. Feed grain replacement can bring an array of cascading benefits such as land and fertilizer spared and pollutions avoided, which are evaluated for the U.S. and China as case-study countries.