Climate change, impacts and vulnerability in Europe ... - MemoFin.fr

Changes in the climate systemMap 2.8Projected changes in 20-year maximum precipitation in summer and winterSummerWinterProjected changes in 20-year maximum precipitation in summer and winter(%)– 40 – 20 0 20 40Note: Projected changes in 20-year maximum daily precipitation in summer (left) and winter (right) from 1961–1990 to 2071–2100based on the ensemble mean using a regional climate model (RCM) nested in 6 general circulation model (GCMs). Changesthat approximately lie outside of ± 10 % for the ensemble average are significant at the 10 % significance level.Source: Nikulin et al., 2011.2.2.6 StormsRelevanceStorms are atmospheric disturbances that aredefined by strong sustained wind. In many cases,they are accompanied by heavy precipitation (rain,hail or snow) and lightning. In Europe, storms canrange from relatively small and localised eventsto large features covering a substantial part of thecontinent. They typically develop from extra-tropicalcyclones which are low-pressure weather systemsthat occur between 30 and 80 °N and capture theirenergy from the temperature contrast between thesub-tropical and polar air masses that meet in theAtlantic Ocean. These extra-tropical cyclones areKey messages: 2.2.6 Storms• Storm location, frequency and intensity have shown considerable variability across Europe over the pastcentury, making it difficult to identify clear trends. A recent reanalysis suggests that storminess hasincreased over the past century in northern and north-western Europe but this finding is not yet robust.• Climate change projections for storms in the North Atlantic and Europe region show no clear consensusin either the direction of movement or the intensity of storm activity. However, a recent study involving20 climate models projects enhanced extreme wind speeds over northern parts of central and westernEurope, and a decrease in extreme wind speeds in southern Europe.70 Climate change, impacts and vulnerability in Europe 2012