Future temperature changes over the critical Belt and Road region based on CMIP5 models

Based on data of 22 models from the Coupled Model Inter-comparison Project Phase 5 (CMIP5), the performance of climate simulation is assessed and future changes under RCP2.6, RCP4.5 and RCP8.5 are projected over critical Belt and Road region. Compared with observations, the CMIP5 models simulate the linear trend and spatial distribution of the annual mean surface air temperature (SAT) better in the north (NBR) and south (SBR) of the Belt and Road region. The trend of the 22-model ensemble mean (CMIP5 MME) is 0.70/0.50 °C per 100 years from 1901 to 2005, and the observed trend is 1.11/0.77 °C per 100 years in the NBR/SBR region. After 1971, the relative error between CMIP5 MME and observations is 22%/15% in the NBR/SBR region. Seven/nine models are selected in the NBR/SBR to project future SAT changes under three RCP scenarios. For 2081-2100, warming in the NBR/SBR is projected to be (1.16 ± 0.29)/(0.72 ± 0.32) °C, (2.41 ± 0.54)/(1.55 ± 0.44) °C, and (5.23 ± 1.02)/(3.33 ± 0.65) °C for RCP2.6, RCP4.5, and RCP8.5, respectively. Under the RCP scenarios, the NBR region shows greater warming than the SBR region. The most significant warming is expected in Kazakhstan and the northern part of the SBR. The associated uncertainty generally increases with time under the three RCP scenarios. Furthermore, increases in warming over the Belt and Road region are more remarkable under higher-emission scenarios than lower-emission ones.