Chapter 1: Fluctuating Deaths, Rising Damages—the Numbers
Box 1.2 Understanding the terms in the report The terms in this report are used differently across disciplines. Hazard is a natural process or phenomenon (floods, storms, droughts, earthquakes) with adverse effects on life, limb, or property. Hazards differ in severity, scale, and frequency and are often classified by cause (such as hydro-meteorological or geological). Exposure is the people and property subject to the hazard. Vulnerability is a characteristic that influences damage: some communities absorb and recover more readily than others because of physical assets (building design and strength), social capital (community structure, trust, and family networks), and political access (ability to get government help and affect policies and decisions). Measures to reduce vulnerability include mitigation (which reduces the hazard’s likelihood, as in reforesting the slopes to prevent rapid runoff and floods or reducing greenhouse gas emissions to reduce the frequency and intensity of extreme weather events), prevention (measures to reduce damage, as with higher plinths for floods), preparedness (evacuation plans), and relief (help after a disaster). Disaster is the hazard’s effect on society as a result of the combination of exposure and vulnerability. So strictly, disasters, not hazards, cause deaths and damage. Disaster risk is often calculated as a multiplicative function of hazard, exposure, and vulnerability. It is multiplicative because for disaster risk to exist, all three—hazard, exposure, and vulnerability—have to be present. Deaths are readily counted, but injuries require some judgment about their seriousness. Those with broken limbs are included, but what about those with mere scratches—or major mental depression—that go untreated? Differences in criteria, and how data are gathered in practice, make comparisons across countries (and time) difficult. The numbers of affected persons (injured, homeless, and in need of immediate assistance) often measure the scale of the disaster; but adding the homeless to those whose farmland was temporarily flooded implicitly accords each equal importance. Note: For formal definitions, please see http://www.unisdr.org/eng/terminology/terminology-2009-eng.html. Source: World Bank staff.
substitute for the collective (a house on stilts instead of flood embankments) and others are complements (cholera may increase during floods, but installing a septic tank is pointless if others do not). What people do affects others: those behind an embankment, for example, are protected from floods, but the redirected waters could increase damage elsewhere. And even those behind the embankment would incur greater damage if there were a breach; so embankments lower the risk of modest damage and increase the (low) risk of severe damage. These complexities are examined in later chapters. This chapter simply presents the related data and patterns (box 1.1). Some reports on disasters have noted a rising toll that has set off alarms with calls for action. While some actions may be appropriate, it is important to know how the numbers are collected and analyzed and what they may imply. (Box 1.2 explains the terminology and box 1.3 discusses the various data this report uses.)
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