Changes and uncertainties of surface mean temperature over China under global warming of 1.5 and 2°C

China has experienced rapid warming in recent decades and is projected to warm at similar rates throughout the remainder of this century. In this study, the projected changes and uncertainties of surface mean temperature over China and four subregions (Northern China, Northwestern China, Southern China, and Tibetan Plateau) are investigated under global warming of 1.5 and 2 degrees C above pre-industrial levels under RCP4.5 and RCP8.5 scenarios from 21 Coupled Model Intercomparison Project Phase 5 (CMIP5) model simulations and their multimodel ensemble mean (MMEM). In comparison with the observations over China, the most CMIP5 models can capture the observed warming patterns while the MMEM of surface mean temperature has a cold bias. Under global warming of 1.5/2 degrees C, the MMEM of surface mean temperature over China, Northern China, Northwestern China, Southern China, and Tibetan Plateau under RCP4.5 (RCP8.5) will increase by 1.82/2.6 degrees C (1.83/2.52 degrees C), 1.8/2.57 degrees C (1.85/2.56 degrees C), 1.99/2.76 degrees C (1.97/2.76 degrees C), 1.43/2.13 degrees C (1.43/2.04 degrees C), and 2.11/2.96 degrees C (2.1/2.85 degrees C), respectively. This study suggests that surface mean temperature over China will exceed the 1.5 and 2 degrees C target earlier than the global mean, with the earlier regions over the Tibetan Plateau. Under global warming of 1.5 and 2 degrees C, the model uncertainty is the dominant source over China and four subregions, followed by both internal variability and scenario uncertainty. Future work should improve climate model simulations and reduce the uncertainty over China before investigating warming changes and patterns under different global warming levels.