The making of a riskier future: How our decisions are shaping future disaster risk Making a riskier future: How our decisions are shaping future disaster risk / xiii Executive Summary Key messages from this report: ■■ Most disaster risk assessment today is static, focusing only on understanding current risks. A paradigm shift is needed toward dynamic risk assessments, which reveal the drivers of risk and the effectiveness of policies focused on reducing risk. ■■ Global disaster risk is changing extremely fast, due to combined dynamics of hazard, exposure, and vulnerability. ■■ The drivers of disaster risk are in the control of policy makers, society, and individuals—but accurate assessment and continuous reevaluation of risk are required to enable effective risk reduction and prevent drastic increases in future losses. NEPAL Partially collapsed house after the 7.8 earthquake hit Nepal on 25 April 2015. Photo credit: © Thomas Dutour | Dreamstime.com xiv / Executive Summary There is variability in annual losses and deaths from disasters, but annual total damage (averaged over a 10-year period) has increased tenfold between 1976–1985 and 2005–2014, from US$14 billion to more than US$140 billion. Disaster risks are rapidly increasing natural hazard (vulnerability). influence on flood hazard than around the world: many regions All three of these components sea-level rise; the former occurs are experiencing greater damage are dynamic, and change over at a rate of up to 100 mm/year, in and higher losses than in the past. time under natural and human comparison with up to 10 mm/year There is variability in annual losses influences (figure ES.1). But most for the latter (Erkens et al., case and deaths from disasters, but risk assessments do not account study C). annual total damage (averaged over for these changes, so they provide a 10-year period) has increased Exposure increases as population a static view of risk. As a result, tenfold between 1976–1985 and grows in hazardous areas, and as risk management policy decisions 2005–2014, from US$14 billion improved socioeconomic conditions based on such assessments do not to more than US$140 billion. raise the value of assets. Between take into account the continuous Average population affected each 2010 and 2050, estimated global and sometimes rapid changes year has risen from around 60 population exposed to river and in the drivers of risk and so may million people (1976–1985) to coastal flood is expected to increase underestimate risk. over 170 million (2005–2014).1 from 992 million to 1.3 billion Disaster risk is influenced by Changes in hazard are driven by (Jongman, Ward, and Aerts 2012). the occurrence of potentially climate change, which raises sea Average annual GDP at risk of dangerous naturally occurring levels, changes the intensity of the earthquakes in Turkey is expected to events, such as earthquakes or strongest storms and the frequency increase by five times between 2010 tropical cyclones (hazard); the with which they occur, increases and 2080 due to socioeconomic population and economic assets extreme temperatures, and alters growth (Murnane et al., case study located in hazard-prone areas patterns of precipitation. Global G). Urbanization—encompassing (exposure); and the susceptibility sea-level rise of up to 0.6 m this both the movement of people from of the exposed elements to the century will increase disaster rural to urban areas and population risk significantly in coastal areas. growth within cities—results in D. Guha-Sapir, R. Below, and 1 In addition, subsidence (sinking larger concentrations of exposure. Ph. Hoyois, EM-DAT: International Disaster Database, www.emdat.be, land) will increase the likelihood In Indonesia, river flood risk may Université Catholique de Louvain, of flooding locally. In some coastal increase 166 percent over the next Brussels, Belgium, accessed July 2015. megacities subsidence has a greater 30 years due to rapid expansion + + + = Climate change Making a riskier future: How our decisions are shaping future disaster risk / xv of urban areas, and coastal flood (Lallemant et al., case study D). increase risk, we can positively risk may increase 445 percent over Social vulnerability also changes influence the risk environment of that same period (Muis et al. 2015). over time, influenced by the the future. The drivers of future Population is expected to increase occurrence of disasters, which risk are within the control of by at least 40 percent in 14 of the disrupt lives and livelihoods, and decision makers today: there is a 20 most populated cities in the by the effects of climate change, huge opportunity today to manage world between 2015 and 2030, with which could push over 100 million the risks of tomorrow. Climate some cities growing by 10 million additional people back into poverty change mitigation by reduction people in that period. Many of the by 2030 (Hallegatte et al. 2015). of greenhouse gases remains key largest cities are located in deltas to preventing strong increases in Increased exposure and changes and are highly prone to floods and climate-related hazard. In addition, in vulnerability have already other hazards (Hallegatte et al. a robust hazard protection strategy, affected disaster risk. A large 2013), and as these cities grow, an one that includes ecosystem-based proportion of recent increases in ever greater number of people and measures, can help to limit the harm disaster losses are attributed to more assets are at risk of disaster. caused by changes in frequency development occurring in hazardous Another feature of urban expansion, and intensity of hazard. Increases areas (Bouwer et al. 2007). the increase in impermeable in exposure can be addressed Concentrations of greenhouse surfaces, also directly affects flood by implementing and enforcing gas in the atmosphere have risen hazard. effective land-use policies that in recent decades due to human prevent urban expansion in hazard- Vulnerability too changes with activity, and recent years have prone areas. Finally, increases in urban and socioeconomic seen extreme temperatures, and vulnerability can be addressed development. Some people extremely damaging floods and by strengthening construction become less vulnerable because cyclones. However, the changes practices and improving disaster of improved construction and observed so far are difficult to preparedness. All these policy a more prosperous economic separate from natural variations in measures rely on data and risk situation. But in many areas, climate, and the greatest changes modeling: enhancements in data structural vulnerability continues in climate extremes are projected collection and risk assessment to increase because of unregulated to occur in the coming decades, are therefore a crucial part of the building practices and unplanned meaning it may be several decades policy-strengthening process. development. For example, before the full effects of climate earthquake risk in Kathmandu change are felt. Decisions being Disaster risk assessment—vital (measured as the proportion taken today are influencing future for understanding risk in terms of of buildings that collapse in an disaster risk—either reducing risk expected population affected or earthquake) is expected to double or increasing it. By promoting losses incurred—underpins disaster to 50 percent by 2045 due to policies that reduce risk and risk management activities. In informal building expansion alone avoiding maladaptive actions that order to make policy and planning Hazard Exposure Vulnerability Natural phenomena Population and assets Structural and social xvi / Executive Summary decisions that reduce future risk, is possible to adjust estimates of future climate conditions. With present and future risk must be structural vulnerability to reflect improvements in data collection, quantified. Thus risk assessments projected changes in construction, we can obtain higher-resolution that inform disaster risk but the many interdependent factors topographic and exposure management must account for the that determine social vulnerability data and can simulate trends dynamic nature of hazard, exposure, make it difficult to determine how in population movement and and vulnerability. By quantifying social vulnerability will evolve into urbanization. At this stage, it is future risk with and without the the future. important both to review the range effect of disaster risk management of efforts to quantify future risk, Despite the ability to quantify future policies and comparing the results, and to consider how to best apply risk (albeit with uncertainty), risk risk management specialists can this information in managing assessments typically fail to account demonstrate how policy actions risk. This publication provides for changing climate, population, taken now and in the near future an introduction to the problem urbanization, and environmental could affect the risk environment in of evolving risk (chapter 1), a conditions. They thus reduce the the medium to long term. further background to disaster risk opportunity to highlight long-term, (chapter 2), and an overview of Evolving hazard can be captured in cost-effective options for risk the factors driving the evolution disaster risk assessment through the reduction. This is not due to an of risk (chapters 3 to 5). Chapter implementation of climate change absence of appropriate methods; 6 discusses some of the issues scenarios in global and regional many risk assessment tools and that complicate efforts to quantify climate models. This approach makes methods exist, with differing evolving risk, and chapter 7 it possible to incorporate changes in complexity, and can be used to discusses a number of policy intensity and frequency of extreme represent the evolution of risk areas that can strongly affect wind, temperature, and precipitation, if adequate data are available. future disaster risk. This chapter along with sea-level rise, to project Risk assessments most often fail highlights steps that can be taken future flood, drought, cyclone, heat, to account for evolution of risk to mitigate the ongoing increase and storm surge risk. Simulating the because they use information that in risk and—like the publication as expansion of urban areas, projecting represents risk factors at a single a whole—seeks to raise awareness future population distribution, and time point in the past, and do not among decision makers of the implementing Shared Socioeconomic include projections of those data impacts planning and development Pathways (SSPs) as scenarios of into the future. decisions have on disaster risk. future socioeconomic conditions Advances in the risk management The report concludes with a can be carried out to demonstrate sector and relevant technologies series of studies that highlight, the influence of changing exposure mean that risk specialists are in more depth, some of the issues on disaster risk. Projection of future now better able than in the past and approaches described in the vulnerability has not been addressed to focus on assessing risk under earlier chapters. extensively in risk assessments. It Risk assessments need to account for... Changing Population Rapid Future environmental climate increase urbanization conditions Making a riskier future: How our decisions are shaping future disaster risk / xvii Figure ES.1. The result of our choices Factors affecting the three components of disaster risk can increase future risk (top) or reduce (or mitigate increase in) future risk (bottom). A RISKIER FUTURE ■■ Warmer climate ■■ Larger population ■■ Sinking coastal land ■■ More developed hazardous areas ■■ Environmental degradation ■■ More impermeable surfaces Exp ard o Haz sur e Present Risk Future Risk Vulnerability ■■ Informal ■■ Less social support ■■ More compounding construction shocks/impacts AN EQUALLY/LESS RISKY FUTURE ■■ Climate change ■■ Land-use planning mitigation ■■ Managed urban ■■ Urban design expansion ■■ Resource planning Exp rd a osu Haz re Vulnerability ■■ Urban planning/ ■■ Social safety nets ■■ Greater resilience construction xviii / Making a riskier future: How our decisions are shaping future disaster risk