IPCC Report.pdf - Adam Curry

Changes in Impacts of Climate Extremes: Human Systems and EcosystemsChapter 4tropical cyclones, but during Cyclone Heta that struck Niue in 2004, thecliffs were unable to provide protection.Drought is a hazard of considerable importance in SIS. In particular,atolls have very limited water resources, being dependent on theirfreshwater lens, whose thickness decreases with sea level rise (e.g.,Kundzewicz et al., 2007), floating above sea water in the pervious coral,and is replenished by convectional rainfall. During drought events,water shortages in SIS become acute on atolls in particular, resulting inrationing in some cases (Campbell, 2006).The main impacts from climatic extremes in PICs are damage tostructures, infrastructure, and crops during tropical cyclones and cropdamage and water supply shortages during drought events. On atolls,salinization of the freshwater lens and garden areas is a serious problemfollowing storm surges, high wave events, and ‘king’ tides (Campbell,2006).4.5. Costs of Climate Extremes and DisastersThe following section focuses on the economic costs imposed by climateextremes and disasters on humans, societies, and ecosystems and the costsof adapting to the impacts. Cost estimates are composed of observedand projected economic impacts, including economic losses, futuretrends in extreme events and disasters in key regions, and the costs ofadaptation. The section stands at the interface between chapters, usingthe conceptual framework of Chapters 1 and 2 and the scientificfoundation of Chapter 3 and earlier subsections in this chapter, andleading into the following Chapters 5 through 9.4.5.1. Framing the Costs of Extremes and DisastersThe economic costs associated with climate extremes and disasters can besubdivided into impact or damage costs (or simply losses) and adaptationcosts. Costs arise due to economic, social, and environmental impacts ofa climate extreme or disaster and adaptation to those impacts in keysectors. Residual damage costs are the impact and damage costs afterall desirable and practical adaptation actions have been implemented.Conceptually, comparing costs of adaptation with damages beforeadaptation and residual damages can help in assessing the economicefficiency of adaptation (Parry et al., 2009).The impact of climate extremes and disasters on economies, societies,and ecosystems can be measured as the damage costs and losses ofeconomic assets or stocks, as well as consequential indirect effects oneconomic flows, such as on GDP or consumption. In line with generaldefinitions in Chapters 1 and 2, economic disaster risk may be definedas a probability distribution indicating potential economic damage costsand associated return periods. The cost categories of direct, indirect, andintangible are rarely fully exclusive, and items or activities can haveelements in all categories.Direct damage costs or losses are often defined as those that are adirect consequence of the weather or climate event (e.g., floods,windstorms, or droughts). They refer to the costing of the physicalimpacts of climate extremes and disasters – on the lives and health ofdirectly affected persons; on all types of tangible assets, includingprivate dwellings, and agricultural, commercial, and industrial stocks andfacilities; on infrastructure (e.g., transport facilities such as roads, bridges,and ports, energy and water supply lines, and telecommunications); onpublic facilities (e.g., hospitals, schools); and on natural resources(ECLAC, 2003; World Bank, 2010).Indirect impact costs generally arise due to the disruption of the flowsof goods and services (and therefore economic activity) because of adisaster, and are sometimes termed consequential or secondary impactsas the losses typically flow from the direct impact of a climate event(ECLAC, 2003; World Bank, 2010). Indirect damages may be caused bythe direct damages to physical infrastructure or sources of livelihoods,or because reconstruction pulls resources away from production.Indirect damages include additional costs incurred from the need to usealternative and potentially inferior means of production and/or distributionof normal goods and services (Cavallo and Noy, 2010). For example,electricity transmission lines may be destroyed by wind, a direct impact,causing a key source of employment to cease operation, putting manypeople out of work, and in turn creating other problems that can beclassified as indirect impacts. These impacts can emerge later in theaffected location, as well as outside the directly affected location (Pellinget al., 2002; ECLAC, 2003; Cavallo and Noy, 2010). Indirect impactsinclude both negative and positive factors – for example, transportdisruption, mental illness or bereavement resulting from disaster shock,rehabilitation, health costs, and reconstruction and disaster-proofinvestment, which can include changes in employment in a disaster-hitarea (due to reconstruction and other recovery activity) or additionaldemand for goods produced outside of a disaster-affected area (ECLAC,2003; World Bank, 2010). As another example, long-running droughtscan induce indirect losses such as local economic decline, out-migration,famine, the partial collapse of irrigation areas, or loss of livelihoodsdependent on hydroelectricity or rain-fed agriculture. It is important tonote that impacts on the informal or undocumented economy may bevery important in some areas and sectors, but are generally not countedin reported estimates of losses.Many impacts, such as loss of human lives, cultural heritage, andecosystem services, are difficult to measure as they are not normallygiven monetary values or bought and sold, and thus they are also poorlyreflected in estimates of losses. These items are often referred to asintangibles in contrast to tangibles such as tradable assets, structures,and infrastructure (Handmer et al., 2002; Pelling et al., 2002; Benson andClay, 2003; ECLAC, 2003; Cavallo and Noy, 2010; World Bank, 2010).Adaptation costs are those associated with adaptation and facilitationin terms of planning (e.g., developing appropriate processes includingkey stakeholders), actual adaptation (e.g., risk prevention, preparedness,and risk financing), reactive adaptation (e.g., emergency disaster responses,264