Effect of Surface Methane Controls on Ozone Concentration and Rice Yield in Asia

Abstract

Surface methane (CH4) is a significant precursor of tropospheric ozone (O3), a greenhouse gas that detrimentally impacts crops by suppressing their physiological processes, such as photosynthesis. This relationship implies that CH4 emissions can indirectly harm crops by increasing troposphere O3 concentrations. While this topic is important, few studies have specifically examined the combined effects of CH4 and CH4-induced O3 on rice yield and production. Utilizing the GEOS-Chem model, we assessed the potential reduction in rice yield and production in Asia against a 50% reduction in anthropogenic CH4 emissions relative to the 2010 base year. Based on O3 exposure metrics, the results revealed an average relative yield loss of 9.5% and a rice production loss of 45,121 kilotons (Kt) based on AOT40. Regions such as the India-Gangetic Plain and the Yellow River basin were particularly affected. This study determined that substantial reductions in CH4 concentrations can prevent significant rice production losses. Specifically, curbing CH4 emissions in the Beijing-Tianjin-Hebei region could significantly diminish the detrimental effects of O3 on rice yields in China, Korea, and Japan. In summary, decreasing CH4 emissions is a viable strategy to mitigate O3-induced reductions in rice yield and production in Asia.