Optimal Allocation of Tomato Supply to Minimize Greenhouse Gas Emissions in Major U.S. Metropolitan Markets
Abstract The United States food system requires energy, water, and land in significant proportions, releases large quantities of greenhouse gases, and contributes to other environmental concerns. Meeting future demand for fresh food will be especially challenging, requiring the adoption of holistic, systems-level thinking to maximize production and supply while limiting consequences to the climate and natural resources. We have developed a cradle-to-market life-cycle environmental model to assess the greenhouse gas footprint of fresh tomatoes supplied to ten of the largest metropolitan statistical areas in the United States. A linear optimization algorithm is applied to determine the optimal tomato distribution scheme that will minimize tomato-related greenhouse gas emissions across all ten areas. Monte Carlo simulation was performed to assess the uncertainties in the data. Results indicate that the current tomato distribution scheme is suboptimal; re-allocating the fresh tomato supply across these ten areas has the potential to decrease transportation-related emissions by 34% and overall tomato-related greenhouse gas emissions by 13%—from 277,000 MTCO2e to 242,000 MTCO2e. The substantial variability of the optimized scenario raises questions about its practical implementation. Ultimately, however, production practices and geographic conditions (such as soil and climate) are more significant with respect to environmental impact than the supply allocation or the seasonality of supply. Our analysis found a roughly six-fold difference between Philadelphia tomatoes sourced from open-field Virginian production (0.38 kgCO2e/kg) compared with controlled-environment Mexican production (2.3 kgCO2e/kg).