Downscaling estimates of land carbon opportunity costs for agricultural products to provincial level in China

Abstract

Agricultural land carbon opportunity cost (COC) characterizes potentials for carbon sequestration through ecosystem restoration, which is a critical component for formulating nature-based solutions to mitigate climate change. Yet existing relevant estimates still stayed at global scale, lacking estimates at national and provincial scale. Here, we integrated multi-source downscaled data to estimate the magnitude of land COC for 20 categories of crops and livestock in 30 provinces of China. Results show that beef got the highest land COC with about 29% of the national total, and COC per unit production of beef was much higher than that of other products. The high beef-induced COC was primarily caused by vast amount of grass feed consumed by beef cattle, resulting in native forest land being cleared into grazing land. Moreover, both land COC and crops yield per unit area of cropland enhanced with latitude decrease, but the increase rate of the former was much higher than that of the latter. Therefore, improving utilization efficiency of existing grazing land and raising yields per unit area of existing croplands in low-latitude provinces, rather than clearing new native forest land into grazing land and cropland, would have great functions on declining national total land COC for agricultural products. The research could also contribute to discussions of local tradeoffs between land carbon storage and agricultural production and then inform climate mitigation strategies.