Possible future movement of the Hu line based on IPCC CMIP6 scenarios

Abstract

Whether the Hu line will move into west China is a serious issue that has implications for socioeconomic development, human geography and the environment. Based on the data related to four different levels of radiative forcing detailed in CMIP6, in this study, we analyzed the trends in precipitation and NPP (net primary productivity) on both sides of the Hu line and the ‘Central Spine of Beautiful China’ and calculated how far the 400 mm iso-precipitation line and the equivalent NPP line will shift westward to explore the possibility of Hu line movement. The results show that, under all four scenarios, both the precipitation and NPP on the west side of the Hu line will increase significantly. The central spine could help to connect the eastern and western parts of the China and reduce the development imbalance between them. The 400 mm iso-precipitation line and the equivalent NPP line will move westward significantly by 2100 (Average moving distance more than 150 km for precipitation and 300 km for NPP) and lie across the Qinghai–Tibet Plateau; the increases in precipitation and NPP within the ‘Central Spine of Beautiful China’ will be greater than those in the west of China. In addition, using population data under four SSPs, we also analyzed the population distribution changes based on Hu line under the influence of futural socioeconomic developments. All these results demonstrate that there will be a possibility of the Hu line moving into west China in the future.