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

Climate impacts on environmental systemsMap 3.10Projected change in minimum river flow with return period of 20 years-30° a) 2020s -10° 0° 10° 20° 30° 40° 50° -30° b) 2050s -10° 0° 10° 20° 30° 40° 50° -30° c) 2080s -10°0°10°20°30°40°50°60° 60°60° 60°60° 60°50° 50°50° 50°50° 50°40° 40°40° 40°40° 40°0°10°20°0°10°20°0°10°20°Relative change in minimum river flow with return period of 20 years between future period and 1961–1990 (SRES A1B)(%)– 60 – 40 – 20 – 10 – 5 5 10 20 40 60© 2012 JRC, European CommissionNote:Relative change in minimum river flow for a) 2020s, b) 2050s and c) 2080s compared to 1961–1990 for SRES A1B scenario.Source: Rojas et al., 2012.3.3.5 Water temperatureRelevanceWater temperature is one of the parameters thatdetermine the overall health of aquatic ecosystems.Most aquatic organisms have a specific range oftemperatures they can tolerate, which determinestheir spatial distribution. Changes in temperaturealso determine ice cover periods, thermalstratification of lakes, nutrient availability and theduration of growing seasons that in turn affectspecies composition and food web structures.Past trendsThe surface water temperatures of major riversin Europe have increased by 1–3 °C over the lastcentury (Figure 3.10). For example, the averagetemperature in the Rhine near Basel has risen bymore than 2 °C in the last 50 years (FOEN, 2011). Thetemperature of the downstream part of the Rhineincreased by 3 °C between 1910 and 2010. Two thirdsof the increase at the downstream Rhine is attributedto the increased use of cooling water and onethird to the increase in air temperature as a resultof climate change (Bresser et al., 2006). A similarKey messages: 3.3.5 Water temperature• Water temperatures in major European rivers have increased by 1–3 °C over the last century. Severaltime series show increasing lake and river temperatures all over Europe over the last 60 to 90 years.• Lake and river surface water temperatures are projected to increase with further projected increases inair temperature.• Increased temperature can result in marked changes in species composition and functioning of aquaticecosystems.122 Climate change, impacts and vulnerability in Europe 2012