IPCC_Managing Risks of Extreme Events.pdf - Climate Access

Changes in Impacts of Climate Extremes: Human Systems and EcosystemsChapter 44.4.5.6. FloodingFlooding is the most frequent natural disaster in Europe (EEA, 2008).Economic losses from flood hazards in Europe have increased considerablyover previous decades (Lugeri et al., 2010), and increasing exposure ofpeople and economic assets is probably the major cause of the longtermchanges in economic disaster losses (Barredo, 2009). Exposure isinfluenced by socioeconomic development, urbanization, and infrastructureconstruction on flood-prone areas. Large flood impacts have been causedby a few individual flood events (e.g., the 1997 floods in Poland andCzech Republic, the 2002 floods in much of Europe, and the 2007 summerfloods in the United Kingdom). The projected increase in frequency andintensity of heavy precipitation over large parts of Europe (Table 3-3) mayincrease the probability of flash floods, which pose the highest risk offatality (EEA, 2004). Particularly vulnerable are new urban developmentsand tourist facilities, such as camping and recreation areas (e.g., a largeflash flood in 1996 in the Spanish Pyrenees, conveying a large amountof water and debris to a camping site, resulted in 86 fatalities; Benito etal., 1998). Apart from new developed urban areas, linear infrastructure,such as roads, railroads, and underground rails with inadequate drainage,will probably suffer flood damage (DEFRA, 2004; Arkell and Darch, 2006).Increased runoff volumes may increase risk of dam failure (small waterreservoirs and tailings dams) with high environmental and socioeconomicdamages as evidenced by historical records (Rico et al., 2008).In glaciated areas of Europe, glacial lake outburst floods, althoughinfrequent, have the potential to produce immense socioeconomic andenvironmental impacts. Glacial lakes dammed by young, unstable, andunconsolidated moraines, and lakes in contact with the active ice bodyof a glacier, increase the potential of triggering an event (e.g., Huggel etal., 2004). Intense lake level and dam stability monitoring on most glaciallakes in Europe helps prevent major breach catastrophes. In case offlooding, major impacts are expected on infrastructure and settlementseven at long distances downstream from the hazard source area(Haeberli et al., 2001; Huggel et al., 2004).4.4.5.7. LandslidesThere is a general lack of information on trends in landslide activity, andfor regions with reasonably well-established databases (e.g., Switzerland),significant trends have not been found in the number of events andimpacts (Hilker et al., 2009). Reactivation of large movements usuallyoccurs in areas with groundwater flow and river erosion. In southernEurope the risk is reduced through revegetation on scree slopes, whichenhances cohesion and slope stability coupled with improved hazardmitigation (Corominas, 2005; Clarke and Rendell, 2006).4.4.5.8. SnowSnow avalanches are an ever-present hazard with the potential for lossof life, property damage, and disruption of transportation. Due to anincreased use of mountainous areas for recreation and tourism, there isincreased exposure for the population leading to an increased rate ofmortality due to snow avalanches. During the period 1983 to 2003,avalanche fatalities have averaged about 25 per year in Switzerland(McClung and Schaerer, 2006). In economic terms, direct losses related toavalanches are small (Voigt et al., 2010), although short-term reactions bytourists may result in a reduction in overnight stays one year after adisaster (Nöthiger and Elsasser, 2004). Increased winter precipitationmay result in higher than average snow depth or duration of snowcover, which could contribute to avalanche formation (Schneebeli et al.,1997). Climate change impacts on snow cover also include decreases inits duration, depth, and extent and a possible altitudinal shift of thesnow/rain limit (Beniston et al., 2003), with adverse consequences towinter tourism. Increased avalanche occurrence would have a negativeimpact on humans (loss of life and infrastructure) but could have apositive result in mountain forests due to higher biodiversity within theaffected areas (Bebi et al., 2009).4.4.6. North America4.4.6.1. IntroductionNorth America (Canada, Mexico, and the United States) is relatively welldeveloped, although differentiation in living standards exists across andwithin countries. This differentiation in adaptive capacity, combinedwith a decentralized and essentially reactive response capability,underlies the region’s vulnerability (Field et al., 2007). Furthermore,population trends within the region have increased vulnerability byheightening exposure of people and property in areas that are affectedby extreme events. For example, population in coastline regions of theGulf of Mexico region in the United States increased by 150% from1960 to 2008, while total US population increased by 70% (U.S. CensusBureau, 2010).4.4.6.2. Heat WavesFor North America, there is medium confidence in observations (Table 3-2)and high confidence in projections (Table 3-3) of increasing trends inheat wave frequency and duration.Heat waves have impacts on many sectors, most notably on human health,agriculture, forestry and natural ecosystems, and energy infrastructure.One of the most significant concerns is human health, in particularmortality and morbidity. In 2006 in California, at least 140 deaths andmore than 1,000 hospitalizations were recorded during a severe heatwave (CDHS, 2007; Knowlton et al., 2008). In 1995 in Chicago, morethan 700 people died during a severe heat wave. Following that 1995event, the city developed a series of response measures through anextreme heat program. In 1999, the city experienced another extremeheat event but far fewer lives were lost. While conditions in the 1999event were somewhat less severe, the city’s response measures were258