Greenhouse gas emissions of tomato production and supply: A systematic review

Numerous life cycle assessments (LCA) have been performed on tomato production; however, results vary greatly due to different system boundaries and assumptions, tomato production methods, and geography. This study seeks to identify the major drivers of differing results and effective interventions in reducing climate impact. This study reviews 50 LCA studies on tomato production within a standardized cradle-to-gate boundary that includes agrochemicals, farm machine fuel, and heating/cooling when applicable. We find that the median emissions are 80 kg CO2-eq/mt in open fields (OF), 83 CO2-eq/mt in climate-uncontrolled protected environments (CUPE), and 1709 CO2-eq/mt in climate-controlled protected environments (CCPE). Next, we evaluate decarbonization strategies for individual farms, including low carbon energy, organic agrochemicals, cogeneration, efficient lighting, precision agriculture, irrigation methods, improved cover materials, mulching, late starting time, and increased crop density. Our review indicates organic agrochemicals and cogeneration do not guarantee emission reductions. Lastly, we review the system-wide decarbonization potential for CCPE versus imported tomatoes grown in OF and CUPE. For most scenarios, our findings indicate imported tomatoes from OF and CUPE have lower emissions than tomatoes sourced locally from CCPE, unless extremely low-carbon heating sources are used for greenhouses. Electric trucks and trains reduce the emissions of imports further.