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

Vulnerability to climate changeThe availability of comparable urban data at citylevel is limited. Main sources are the Urban Auditdatabase (Eurostat), the Urban Atlas and the soilsealing layer (EEA). Data describe the current state.Past trends or future projections comparable acrossEurope are not available. We reflect therefore onoverall European trends (e.g. population dynamics)or highlight potential risks in the form of 'what if thecurrent development continues…?'A more extended assessment of urban vulnerabilitiescan be found in (EEA, 2012).5.4.2 Past trendsarea in 2002 was only slightly bigger than in 1890and smaller than in 1845, the flooded builtup areahad increased dramatically.High soil sealing of urban areas restricts directdrainage of water into the ground. This is also amain factor for the development of a particularurban phenomenon — urban drainage floods. Thelow drainage into the soil leads to a high run-off ofwater into the sewage system and can deplete itscapacity. Excess water travels down roads and otherpaths of least resistance and floods low-lying areasas described for the urban flood 2011 in Copenhagen(Box 5.1).The past climatic trends described in Chapter 2 arerelevant for cities as well as the overall trends ofclimate impacts on systems and sectors (Chapters 3and 4), but the latter could have been altered in citiesdue to cities' composition, management and urbandesign.Figure 5.1Flooded area in Dresden(Germany) during different floodeventsFlooded area in haFlood riskOngoing urban land take has increased the areaof impervious surfaces and buildings in Europe(EEA, 2010c). It has limited the areas for naturaldrainage, water retention, production of fresh airand fixation of CO 2in and around cities and thusoften increased the effects of heat waves, floodsor water scarcity. This has already in the past ledto higher vulnerabilities to climate impacts. Anexample is provided in Figure 5.1, which comparesthree major flood events of the river Elbe in Dresdenin 1845, 1890 and 2002. Although the total flooded3 5003 0002 5002 0001 5001 000500031.03.1845 06.09.1890 17.08.2002Total area flooded Settlement area floodedSource: Schumacher, 2005.Box 5.1 The cloudburst in Copenhagen on 2 July 2011After a substantially hot period Copenhagen was hit by a huge thunderstorm on 2 July 2011. During the afternoonclouds and thunder had been building up over the southern part of Sweden. During a 2-hour period over 150 mmof rain fell in the city centre. This constituted the biggest single rainfall in Copenhagen since measurements beganin the mid-1800s.The city's sewers were unable to handle all of the water and as a result many streets were flooded and sewersoverflowed into houses, basements and onto streets thereby flooding the city. The consequences were quitedrastic as emergency services had to close roads and attend to people trapped in their cars. The emergencyservices were within minutes of having to evacuate the city's two biggest hospitals because of flooding and powercuts. Insurance damages alone were estimated at EUR 650–700 million. Damage to municipal infrastructure notcovered by insurance, such as roads, amounted to EUR 65 million.Source: Lykke Leonardsen, city of Copenhagen, 2011 (personal communication); EEA, 2012.Climate change, impacts and vulnerability in Europe 2012223