Quantifying US metropolitan level environmental burdens & benefits from greater localization of vegetable farming

Several US urban food action plans propose increasing local and regional vegetable production for the presumed environmental and nutritional benefits. However, such efforts, if applied nationwide, can propagate environmental benefits or disbenefits to other geographies that have not been previously evaluated. Our paper quantifies the environmental benefits and disbenefits at the metropolitan scale nationwide from various localization scenarios ranging in scope (e.g., meeting 25%–100% of local vegetable dietary demand through local production). For the first time, these localization targets are modeled nationwide with consistent methodology across 378 metropolitan areas, considering three different land reutilization scenarios: (1) shifting current commodity cropland to vegetables, (2) leveraging marginal urban land, and (3) a novel strategy of repurposing parking lots and roads, anticipating the future deployment of shared autonomous vehicle fleets. These scenarios, implemented nationwide, diffusing current, concentrated vegetable production, are evaluated in the context of land availability constraints and two critical environmental burdens: groundwater overdraft and fertilizer-related PM2.5 emissions. Broadly across the conterminous US metros, scenarios find few significant land constraints and reveal net environmental benefits to both groundwater overdraft and fertilizer-related PM2.5 emissions in 11%–55% of metros (scenario-dependent). The model also reveals where relocalization of vegetable farming would exacerbate existing environmental vulnerabilities. Such spatially disaggregated nationwide urban agriculture localization models can inform environmentally friendly urban agricultural planning across US metro regions.