Köppen’s climate classification projections for the Iberian Peninsula

Abstract

Projections of Köppen-Geiger climate classifications under future climate change for the Iberian Peninsula are investigated using a 7-ensemble mean of regional climate models obtained from EURO-CORDEX. Maps with predicted future scenarios for temperature, precipitation and Köppen-Geiger classification are analyzed for RCP4.5 and RCP8.5 in Iberia. Widespread statistically significant shifts in temperature, precipitation and climate regimes are projected in the 2041-2070 period, with greater shifts occurring under RCP8.5. An overall increase in temperature and a decrease in precipitation in the south-southeast is predicted. Of the two climate types, dry (B) and temperate (C), the dominant one was C in 86% of Iberia for 1961-1990, predicted to decrease by 8.0% by 2041-2070 under RCP4.5 (9.5% under RCP8.5). The hot-summer Mediterranean climate (CSa) will progressively replace CSb (warm-summer climate) in the northwestern half of Iberia until 2070. This shift, depicted by the SSIM index, is particularly noticeable in Portugal, with the projected establishment of the CSa climate by 2041-2070. The predicted retreat of humid subtropical (Cfa) and temperate oceanic (Cfb) areas in the northeast towards the Pyrenees region is noteworthy, as is the increase of desert (BW) and semi-desert (BS) climates (7.8 and 9%) in the southeast (between Granada and Valencia). Climate types BSh and BWh (hot semi-desert and hot desert, respectively), non-existent in the 1961-1990 period, are projected to represent 2.8% of the territory in 2041-2070 under RCP4.5 (5% under RCP8.5). The statistically significant projected changes hint at the disappearance of some vegetation species in certain regions of Iberia, with an expected increase in steppe, bush, grassland and wasteland vegetation cover, typical of dry climates in the southeast.