Climate change and snow cover trends in Iceland

Abstract. We studied the trends in climate change and snow cover in Iceland. Climate was classified based on the Köppen-Geiger (KG) classification system for 1950–2100 using the ensemble average of + NASA-NEX downscaled CMIP5 projections for RCP 4.5. Snow Cover Frequency (SCF) was calculated based on in MODIS10A1 snow product in days/year and SCF trends were calculated for 2001–2016. Trends in climate and snow cover changes were evaluated in 4 different elevation bands: Coastline (0–100 m.a.s.l.), Lowland (100–500 m.a.s.l.), Highland (500–1000 m.a.s.l.) and Mountains/Glaciers (1000+ m.a.s.l.). The results showed that in all elevations zones warmer climate classes have been replacing colder climates and polar tundra since 1950’s, based on climate projections we expect these trends to continue throughout the present century. We observed that in large areas of the country a significant increase in SCF had occurred during the period 2001–2016. These changes were most pronounced in the highlands where SCF had increased by 3.5 days/year on average. The only locations where we observed increasing SCF was around the termini of the country’s outlet glaciers. The results suggest that by the end of the present century polar tundra climate (ET) will have decreased from 20 % to 5 % coverage and cold climate with warm summers (Dfb), will extend around the island and spread into the highlands.