Evaluation and quantification of surface air temperature over Eurasia based on CMIP5 models

Parts of Eurasia underlain by large areas of frozen ground that are both sensitive to, and an indicator of, climate change. Previous studies have investigated the effect of climate change on frozen ground; however, those studies did not quantify the past or projected climate change effects for specific frozen ground regions. This study applied surface air temperature from the Climatic Research Unit (CRU) data set and the multi-model ensemble mean of 16 Coupled Model Intercomparison Project Phase 5 (CMIP5) models to evaluate past and projected surface air temperature changes, and quantify changes in different frozen ground regions. Results indicate that CMIP5 can simulate surface air temperature over Eurasia well, and there is slightly better performance of CMIP5 ensemble averages in the late 20th century than in the early 20th century. Over the Eurasian continent, time-series of ensemble area-averaged mean annual air temperatures (MAT) from CMIP5 increased at about 0.074°C decade⁻¹ during 1850−2005, and are projected to increase by 0.078−0.719°C decade⁻¹, depending on future emission pathways, during 2006−2100. Compared to the period 1986−2005, the temperature is predicted to be 1.68−6.41°C higher during 2081−2100. Changes of MAT demonstrate that the fastest increase will occur in continuous permafrost regions, next in discontinuous permafrost regions, followed by sporadic, isolated, and relict permafrost, and finally non-permafrost regions. Overall, these results can be used to help estimate and project cryospheric changes.