Estimated climate impact of the end of agriculture as the primary food production system

Global agriculture is the second largest contributor to anthropogenic climate change after the burning of fossil fuels. However the potential to mitigate the agricultural contribution is limited by the imperative to supply food for the global population. Advances in microbial biomass cultivation technology have recently opened a pathway to growing substantial amounts of food for humans or livestock, by fuelling microbial growth with hydrogen produced from electrolysis powered by renewable energy. This method of food production would use a small fraction of the land presently used for agriculture. Here we investigate the potential climate change impacts of the end of agriculture as the primary human food production system. We find that microbial biomass cultivation technology has both the potential to exacerbate climate change by outcompeting economic decarbonization for renewable energy and the potential to mitigate climate change if deployed following economic decarbonization. A duality which originates from the contrast between the reversibility of agricultural driven climate change and the irreversibility of fossil-fuel CO₂ driven climate change. The range of reduced warming from the replacement of agriculture ranges from -0.22 [-0.29 to -0.04]^oC for Shared Socioeconomic Pathway (SSP) 1-1.9 to -0.85 [-0.99 to -0.39]^oC for SSP4-6.0. For limited temperature target overshoot scenarios, replacement of agriculture could thus eliminate or reduce the need for active atmospheric CO₂ removal to achieve the necessary peak and decline in global warming. Given current societal barriers to switching to a microbial-based diet, deep near-term emissions reductions in CO₂ and agricultural emissions remain necessary steps to keep warming within the bounds set by the Paris Agreement.