Evolution of Surface Temperature during Global Warming Hiatus Based on Observations and CMIP5 Simulations

The rise in global surface temperature has significantly declined after 2000. In this study, the evolution of the surface temperature of the global land-mean and Eurasia middle-high latitudes during the global warming hiatus was analyzed based on CRU observations. Simulations and projections were also evaluated using the Coupled Model Intercomparison Project 5 (CMIP5). The results indicate that, in the global warming hiatus period, the trend of the global land-mean surface temperature is only 0.14℃ (10 a)^-1, which is half that during 1976-1999. The trend is less than that before 2000 in nine of the 13 global land regions, and four of them show a decreasing trend. The Eurasia middle-high latitude region is the most interesting among all the regions. For 1976-1999, the Eurasia middle-high latitude region shows the largest warming among all the land regions and reaches 0.50℃ (10 a)^-1. After 2000, the trend significantly declines to -0.17℃ (10 a)^-1, the greatest cooling trend over land, globally, contributing 49.13% of the remarkable change in global land surface temperatures before and after 2000. Furthermore, the surface temperature of the Eurasia middle-high latitude region shows an opposite change in autumn and winter after 2000; the temperature of the former rises by 0.86℃ (10 a)^-1, while the that of the latter decreases by 2.68℃ (10 a)^-1. In CMIP5, only the simulation and projects in BCC-CSM1.1 under the RCP2.6 scenario and MRI-ESM1 under the RCP8.5 scenario reproduce the evolution of the global land-mean and Eurasia middle-high latitude surface temperature, as well as the opposite change between autumn and winter of the Eurasia middle-high latitude region, during the global warming hiatus. The temperature projection of the BCC-CSM1.1 under the RCP2.6 scenario for the Eurasia middle-high latitude remains flat, near 1.2℃, after 2012, and jumps to 2℃ after 2020. The change in the MRI-ESM1's projected temperature under the RCP8.5 scenario is close to zero before 2030; the temperature then rises remarkably, to ℃ (10 a)^-1.