Spatial and temporal patterns of drought hazard for China under different RCP scenarios in the 21st century

Drought is one of the most common natural disasters, with significant negative impacts on socioeconomic development and the natural environment. Evaluating this hazard is essential for risk assessment and management. In this study, historical climate data for China in the period 1961 to 2010 were used to determine the appropriate timescales for applying the standardized precipitation evapotranspiration index (SPEI) to evaluate drought hazard. Simulated representative concentration pathway (RCP) 4.5 and 8.5 scenario climate data for 2011-2099 were obtained, and the Mann-Kendall (M-K) test was used to assess the significance of drought trends. The frequency of three drought grades and durations were chosen to reflect the spatial and temporal variation in drought hazard in the three time periods 2011-2040, 2041-2070, and 2071-2099. The results indicate that, in these three stages, 2071-2099 has the highest frequency (national averaged 32.54% for RCP4.5 and 32.55% for RCP8.5) and longest duration (national averaged 3.93 months for RCP4.5 and 4.12 months for RCP8.5), followed by 2041-2070 and 2011-2040. In terms of spatial distribution, drought hazards in northern China (medium temperate zone, warm temperate zone, and plateau temperate zone) will be greater than that in southern China, especially the non-monsoon region. Comparing the two scenarios, the severity of different drought hazards under RCP8.5 is higher that under RCP4.5, i.e., higher frequency, longer duration, and more significant drying trends. These results provide references for adapting to extreme climate change and preventing and reducing the risk of drought disasters.