Projection of temperatures and heat and cold waves for Aragón (Spain) using a two-step statistical downscaling of CMIP5 model outputs.

Heat-and cold-wave scenarios and temperature scenarios during the 21st century were obtained for Aragon (Spain), using, for the first time, nine Earth System Models (ESM) and two Representative Concentration Pathway (RCP) scenarios - RCP4.5 and RCP8.5 - belonging to the 5th Coupled Model Intercomparison Project (CMIP5). Local climate heat-wave scenarios show an increase of its mean intensity close to 2 degrees C (reaching temperatures of up to 38.8 degrees C) and an average increase of the maximum intensity of 3.6 degrees C (temperature of up to 41.5 degrees C) with respect to a historic period (1971-2000) for the RCP8.5 scenario at the end of the century. The duration of heat waves will increase by 7 days at the end of the century (total average duration of 12 days). The future intensity and duration of cold-wave episodes will remain stable. Local climate change scenarios for daily maximum temperatures show a gradual increase throughout the 21st century. The greatest increases will occur during the summer at the end of the century, reaching values of up to 7 degrees C for the RCP 8.5 scenario. The minimum temperature increases show similar behaviours to the maximum temperatures, but with less marked increases (3 degrees C and 5.6 degrees C for the RCP4.5 and RCP8.5 scenarios respectively in summer at the end of the century). The highest temperatures and the intensity of the heat waves will be especially intense in the Ebro Valley, the most populated area. In addition, the Pyrenees will suffer the longest heat waves, especially at the end of the century, and the greatest increases in maximum temperatures. The downscaling of the CMIP5 models, offers accurate scenarios-both spatially and temporally-of extreme temperatures and heat and cold waves, useful for decision-making for local adaptation to climate change but also as a reference for other European regions. (C) 2018 Elsevier B.V. All rights reserved.