Detecting land cover and land use transitions and the associated temperature changes in the East Asian monsoon region

Abstract

Unprecedented land cover and land use (LCLU) changes can significantly alter the interactions between the land and atmosphere through biogeophysical processes, potentially changing the monsoon systems. Therefore, it is necessary to quantify the LCLU changes and the impacts on the climate in the East Asian monsoon (EAM) region, where significant human‐induced LCLU changes have occurred. This study quantified the LCLU transitions with fractional maps produced using the recently developed categorical LCLU maps from 1982 to 2015. In the five sub‐regions, identified as having undergone significant LCLU transitions, the relationships of the transitions with 2 m temperature were investigated using the ERA5‐Land reanalysis data. The quantified LCLU transitions revealed that, in northeastern China, the dominant trend was forests and grasslands changing into croplands. Moreover, in the marginal areas of Inner Mongolia, the transitions of grasslands to croplands and forests were evident. Croplands were mainly converted to forests in the Sichuan region. In particular, in the Sichuan region, the temperature increased by more than 0.04°C as the forests increased by 1%. In the marginal areas of Inner Mongolia, a 1% decrease in grasslands and a 1% increase in forests, respectively, were associated with a temperature rise of more than 0.03 and 0.04°C. The detected LCLU transitions affect the regional warming as demonstrated by correlation, regression and Granger‐causality analyses and the related biogeophysical processes. Thus, the identified LCLU transitions can change the regional climate and potentially affect the monsoon systems by changing the contrast in heat between land and ocean. This empirical research will not only provide insight into possible changes to climate by LCLU transitions in the EAM region, but it will also yield practical information for implementing land cover policies while considering the geographical characteristics of the region.