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

Climate impacts on environmental systemsData quality and data needsDetailed data on water quantity is often difficult toassess, and homogeneous time series are generallyshorter than those for meteorological data. It may,therefore, require substantially more time beforestatistically significant changes in hydrologicalvariables can be observed than for meteorologicalvariables, especially with respect to extreme events(floods and droughts). Quantitative projections ofchanges in precipitation and river flows at the basinscale remain highly uncertain due to the limitations ofclimate models and to scaling issues between climateand hydrological models.The main data sources for European-wide studies ofextreme hydrological events and their changes areglobal databases for natural disasters. These includegeneral impact-oriented disaster databases such asEM-DAT ( 45 ) maintained by the Centre for Researchon the Epidemiology of Disasters (CRED) and theNatCatService ( 46 ) maintained by Munich RE, as wellas specific mostly event-oriented databases, suchas the Dartmouth Flood Observatory ( 47 ). Some ofthe limitations of these databases included the useof thresholds for inclusion of an event, which mayexclude smaller events with a significant regionalimpact, changes over time in the comprehensivenessof the coverage (see below), and privacy issuesrelated to detailed data collected by the insuranceindustry. Improvements of these datasets are plannedin coming years. The available data is currentlyevaluated, for example in the ongoing emBRACEproject ( 48 ). A more detailed and comprehensiveevent-oriented database that also includes eventswithout any (major) damages would be neededto separate the effect of climate change fromsocio‐economic changes.The reporting of flood and drought events hasgenerally improved during the past few decades as aresult of improvements in data collection and flows ofinformation. As a result, it is often difficult to identifywhether an increase in reported flood events (or theirimpacts) over time is due mostly to improvements indata collection or to actual changes in these events.Furthermore, river flood records are usually sourcedfrom different institutions and often collected usinga wide range of different assessment methods andrationales, which may have changed over time. Thismultitude of sources limits the comparability of keyattributes associated with such events (e.g. economiclosses, human casualties) across space and time. Fora more detailed description of the EM-DAT data, seeSection 4.4 on Human Health.As part of the preliminary flood risk assessmentfor the European Directive on the assessmentand management of flood risks (2007/60/EC) ( 49 ),EU Member States will give an overview ofsignificant past floods. In addition, a Europeanflood impact database could bring together publiclyavailable inventories of flood events. At thenational/regional level, such an inventory wouldbe particularly useful to provide accurate data andassessments which would serve as a basis for disasterprevention. At the European level, these inventoriescould assist in tracking the trends in flood-disasterlosses, and in mitigation programmes monitoring andobtaining a clearer picture of the linkages betweenclimate change and floods and flood losses.Reliable information on the extent and impacts ofwater scarcity and droughts (WSD) is indispensablefor decision-making at all levels. The EuropeanCommission has strengthened its activitiesthrough the 2007 Communication on WSD andseveral studies. The EEA reports 'Water resourcesacross Europe — confronting water scarcity anddrought' (EEA, 2009a), 'Regional climate changeand adaptation – The Alps facing the challengeof changing water resources' (EEA, 2009b), and'Towards efficient use of water resources inEurope' (EEA, 2012) include an overview of wateravailability, water abstraction and water scarcity inEurope or more specific for the Alpine region anddiscuss management options. The water exploitationindex is currently being revised to be calculated onthe level of river basins instead of the administrativeboundaries of countries. The Joint Research Centre(JRC) of the European Commission has developeda European Drought Observatory (EDO ( 50 )) fordrought forecasting, assessment and monitoring.However, despite several activities, there is nosystematic, comprehensive record of WSD eventsin Europe describing their duration, impact andseverity, other than meteorological time series forprecipitation.More detailed information is available for some riversas a result of targeted research projects (Görgen andBeersma, 2010; ICPR, 2011; Wechsung, 2011).( 45 ) See http://www.emdat.be.( 46 ) See http://www.munichre.com/geo.( 47 ) See http://floodobservatory.colorado.edu.( 48 ) See http://embrace-eu.org.( 49 ) See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2007:288:0027:0034:EN:PDF.( 50 ) See http://edo.jrc.ec.europa.eu/edov2/php/index.php?id=1000.Climate change, impacts and vulnerability in Europe 2012113