Water for people.pdf - WHO Thailand Digital Repository

M I T I G A T I N G R I S K A N D C O P I N G W I T H U N C E R T A I N T Y / 2 7 9Box 11.2: Methodology and terminology adopted by the ISDRDisaster: A serious disruption to the normal functioningof a community or a society, which causes widespreadhuman, material, economic or environmental losses thatexceed the ability of the affected community/society tocope using its own resources. Disasters are often classifiedaccording to their speed of onset (sudden or slow), oraccording to their cause (natural or human-induced).Hazard: A potentially damaging physical event orphenomenon that can harm people and their welfare.Hazards can be latent conditions that may representfuture threats, as well as being natural or induced byhuman processes.Risk: The probability of harmful consequences or theexpected loss (of lives, people injured, property orenvironmental damage, and livelihoods or economicactivity disrupted) resulting from interactions betweennatural or human hazards and vulnerable conditions.Conventionally, risk is expressed by the equation:Risk = Hazard x VulnerabilityThe resulting risk is sometimes corrected and divided byfactors reflecting actual managerial and operationalcapability to reduce the extent of the hazard or thedegree of vulnerability.For the purpose of economic assessments, risk isquantifiable and perceived in monetary terms. Taken from aneconomic perspective, risk is specified as the annual cost tothe society from sudden accidental events and slowenvironmental degradation, determined from the product ofthe probability or frequency of occurrence and thevulnerability as social and economic losses in monetary terms:Risk (economic cost per year) = Probability (once inn years) x Vulnerability (economic cost/event)Risk assessment: Investigates the potential damage thatcould be caused by a specific natural or human-inducedhazard to people, the environment and infrastructure. Theassessment includes hazard or multi-hazard analysis,probability and scenario; the vulnerability analysis(physical, functional and socio-economic); and the analysisof coping capacities and mechanisms. Risk assessmentforms the necessary basis for the development of disastermitigation and preparedness measures.Risk management: The systematic application ofmanagement policies, procedures and practices that seek tominimize disaster risks at all levels and locations in a givensociety. Risk management is normally based on acomprehensive strategy for increased awareness,assessment, analysis/evaluation, reduction and managementmeasures. The risk management frameworks need toinclude legal provisions defining the responsibilities fordisaster damage and longer-term social impacts and losses.Uncertainty: Different from quantifiable risks,uncertainty is defined as unidentified and unexpectedthreats and catastrophic accidents. Uncertainty oftenmanifests as large unexpected ‘surprise’ threats andcatastrophes and requires management approachesdifferent from traditional risk management. Recentuncertainties are exemplified by the major floods inEurope and the United States in the 1990s, but also bythe chemical pollution of the Sandoz Blaze in 1986 in theRhine (Europe) and the non-water-related industrialincident in Bhopal (India) in 1984 which resulted in morethan 10,000 deaths and 200,000 people injured. The mainmanagement issues of uncertainty concern the society’sincapacity to identify and react on weak signals; and asone consequence, the reluctance of decision-makers toassume related social responsibilities.Vulnerability: A function of human actions and behaviourthat describes the degree to which a socio-economicsystem is susceptible to the impact of hazards. Vulnerabilityrelates to the physical characteristics of a community,structure or geographical area, which render it likely to beaffected by, or protected from, the impact of a particularhazard on account of its nature, construction and proximityto hazardous terrain or a disaster-prone area. It alsodesignates the combination of social and economic factorsthat determine the degree to which someone’s life andlivelihood are exposed to loss or damage by a specificidentifiable threat or event in nature or society.