Future unbalanced-trends of grain supply and demand on the Tibetan Plateau

Forecasting the relation between grain supply and demand can help prevent potential food risk and realize sustainable agriculture development on the Tibetan Plateau (TP), which is an ecological security barrier for China. However, the patterns of future grain self-sufficiency at the county scale on the TP under different scenarios have been little analyzed. Using combining forecasts, production function, and scenario analysis, we evaluated the grain self-sufficiency ratios (SSRs) (i.e., the ratio of grain production to demand) of the staple, total, and balanced dietary grains on the TP at the county scale in 2030 and 2050. Our results showed that the staple grain on the TP will be sufficient with more than 150% SSR on average, but the supply will not meet the demands of both total grain (including staple and feed grain) and balanced dietary grain. Extreme disasters will increase the proportion of non-self-sufficient counties by 11%-16% compared with the base scenario, especially in southern Tibet. The positive effects of climate change will be low, but they can slow down the decline of SSRs in some counties in Sichuan Province and southern Tibet. In the future, the counties with better self-sufficiency will be mainly distributed in agricultural areas with high grain production, such as the Yarlung Zangbo River Basin in southern Tibet. Moreover, most counties in pastoral regions in the central TP and counties with greater population growth will not be self-sufficient. Our results provide important policy implications for agricultural layout and ecological security on the TP, such as the integrated development of agriculture and animal husbandry, increased concern about food risks in urban cities and agroecology, and the establishment of agricultural monitoring networks.