Relieved drought in China under a low emission pathway to 1.5°C global warming

Abstract

AbstractDrought is detrimental to both natural systems and human societies. Although definitions of drought vary among different indices, the frequency of drought is likely to enhance in a strong warming climate either because of increased temperature or decreased precipitation. However, for a low warming target such as 1.5°C, drought tendency is uncertain as it depends on the competition between evapotranspiration and precipitation, both of which may show only moderate changes. In this study, future changes of self‐calibrating Palmer Drought Severity Index (scPDSI) in China are projected for the periods of 1.5°C global warming under two different scenarios based on outputs from Coupled Model Intercomparison Project phase 5 (CMIP5). Compared to present day, national average scPDSI decreases by 0.04 ± 0.53 at a high emission scenario but increases by 0.20 ± 0.60 at a low emission scenario to the same 1.5°C global warming. Even with large uncertainties, the multi‐model ensemble scPDSI significantly increases by 0.52 ± 1.07 in the Southeast from the high to low emission scenarios. Such relieved drought is mainly attributed to the increased regional precipitation, which is likely caused by reductions in aerosols following emission regulations. Consequently, an associated control of both carbon and air pollution emissions helps retain the warming target globally and relieve drought risks regionally.