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The Research Basis for Disaster Resilience

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Winter 2015   


        Federal Disaster Policy: Toward a More Resilient Future
        The Research Basis for Disaster Resilience
        Preparing for the Next Disaster: Three Models of Building Resilient Communities

The Research Basis for Disaster Resilience


      • Many data sources indicate that natural disasters in the United States are becoming more frequent and costly.
      • In the disaster context, resilience research often focuses on the ability of systems and places to mitigate the risk of, withstand, and quickly recover from extreme events.
      • The strength of social bonds within communities is a critical component of disaster resilience.

Evidence to support increasing focus and resources on disaster resilience rests on many factors, ranging from detailed analyses of local circumstances and cases to broad datasets examining the causes and consequences of disasters. This article examines both ends of this spectrum, beginning with research on trends in the frequency and costs of natural disasters, followed by an exploration of how resilience is conceptualized and promoted through best practices.

Data on Disaster Frequency and Costs

A bar chart showing number of federal disaster declarations by type for every year from 1955 to 2014.
Source: U.S. Federal Emergency Management Agency. "Disaster Declarations by Year" ( Accessed 6 February 2015.
Detailed data on natural disasters in the United States are more accessible than ever, with many government and private websites devoted to examining the frequency and costs of all kinds of domestic and international disasters. In many cases, however, precise (and therefore comparable) data on the number and scale of U.S. disasters is available only from the 1980s onward, complicating efforts to understand long-term trends. Nevertheless, various sources indicate that natural disasters have become more frequent and severe over the past few decades, and this trend is projected to continue.

The number of federal disaster declarations (combining Major Disaster Declarations, Emergency Declarations, and Fire Management Assistance Declarations) has increased precipitously in recent decades. Between the 1950s and the mid-1990s, the annual number of declarations almost never exceeded 60, but the mean from 1995 to 2004 and from 2005 to 2014 was 106 and 133, respectively (fig. 1).1 This growth does not precisely represent an increasing frequency of natural disasters, both because federal disaster declarations include a small number of non-natural disasters and because changing political and social forces may influence how willing the government may be to declare a disaster. This fact does illustrate, however, that the frequency of disaster situations for which the government has made federal funds available has risen substantially.

Data from the Insurance Information Institute, an industry-supported organization that works to improve public understanding of insurance, confirm that the number of natural disasters is increasing, with almost every year from 2006 to 2013 exceeding the highest number of disasters recorded between 1980 and 2005.2 Annual financial losses related to natural disasters, both insured and overall, have also risen. Annual insured losses related to thunderstorms (including tornadoes) have increased sevenfold since the early 1980s, and winter storm losses have almost doubled. Annual insured property losses related to hurricanes are dominated by Hurricane Katrina — the $95 billion in insured hurricane losses in 2005 is nearly triple that of any other year since 1980.3 The year 2005 also marked the highest amount of loss dollars paid through the Federal Emergency Management Agency’s (FEMA’s) National Flood Insurance Program, the primary source for flood insurance in the United States, and between 2005 and 2008, Congress appropriated $19.7 billion in supplemental Community Development Block Grant program funds for disaster recovery for states affected by Hurricanes Katrina, Rita, and Wilson. Since 1978, the five highest years of loss dollars paid through the National Flood Insurance Program have all occurred after 2004.

The number of very severe, high-loss disasters also appears to be growing. The National Oceanic and Atmospheric Administration’s (NOAA’s) National Climatic Data Center maintains data on disaster events whose costs exceeded $1 billion (adjusted for inflation using the Consumer Price Index). Although NOAA cautions against interpreting trends because of various factors, including the uncertainty of loss estimates and the variability of inflation over time, the data show that only 1 year between 1980 and 2000 saw more than six disaster events exceeding $1 billion in damages, whereas 6 years since 2000 have exceeded that number (fig. 2).4 In all, severe storms have been responsible for the highest number of billion-dollar disasters since 1980, followed distantly by hurricanes and tropical depressions, drought, and flooding.5 Data from the Insurance Information Institute again parallel NOAA’s data, finding that 8 of the 10 catastrophes with the highest estimated insured property losses (excluding flood damage insured by NFIP) happened since 2000. Except for the terrorist attacks of September 11, 2001, these are all weather-related events — primarily hurricanes.

National Weather Service data indicate that the number of fatalities attributable to extreme weather reached an average of 640 in the 10 years from 2004 to 2013 compared with 594 fatalities for the 25-year average dating back to 1989, with Hurricane Katrina in 2005 and tornado deaths in 2011 (including Alabama and Joplin, Missouri) accounting for most of the increase. However, it is notable that extreme temperatures caused several of the most deadly natural disasters reported since 1980, and these events were more frequent in the 1980s and 1990s, when assistance systems for heat waves were less well developed.6 PreventionWeb, a project of the United Nations Office for Disaster Risk Reduction, finds that 6 of the 10 events affecting the most U.S. residents between 1980 and 2010 occurred in the 2000s, led by floods in 2008 (11 million) and storms in 2004 (5 million).7

A bar chart showing number of billion dollar disaster events by type from 1980 to 2014.
Recreated with permission from the National Climatic Data Center.
Source: National Climatic Data Center. "Billion-Dollar Weather and Climate Disasters: Time Series" ( Accessed 6 February 2015.
One important contributor to the growing impact of damage caused by disasters is rapid population growth in U.S. coastal regions, which has substantially outpaced that of inland areas; as of 2010, 39 percent of Americans lived in coastal shoreline counties, which had an average population density (excluding Alaskan counties) of 446 persons per square mile, more than 4 times that of the nation as a whole.8 NOAA projects that this trend will continue, with population densities in coastal shoreline counties growing at triple the rate for the United States as a whole from 2010 to 2020.9 Even as natural disasters become more frequent, more Americans are living in places that put them at higher risk.

Although this article focuses primarily on natural disasters in the United States, global statistics also show increasing losses from disasters. EM-DAT, a worldwide database on disasters funded by the U.S. Agency for International Development and maintained by the Centre for Research on the Epidemiology of Disasters at the Université catholique de Louvain, shows a substantial increase in the number of disasters worldwide reported annually between 1990 and 2013.10 Researchers from the Centre note that "[o]ver the last decade, China, the United States, Indonesia, The Philippines, and India constitute the top 5 countries that are most frequently hit by natural disasters."11 And just as low-income individuals in the United States are at greater risk of being affected by disaster and have fewer resources to recover, those in developing countries are especially vulnerable. The World Bank states, "By 2030, there could be 325 million people trapped in poverty and vulnerable to weather-related events in sub-Saharan Africa and South Asia. Large coastal cities, many of them in growing, middle-income nations, could face combined annual losses of US$1 trillion from such events by mid-century."12

Disaster Resilience and Mitigation

Even as projections of climate change and disaster frequency continue to evolve, many kinds of practitioners at the local, regional, and state levels — from planners and developers to emergency managers and insurers, among many others — are tasked with adapting to these changing environmental conditions and increasingly extreme weather events in an effort to prevent disasters when possible, mitigate the damage caused when disasters are unavoidable, and help communities and regions bounce back from disasters more quickly. One important concept increasingly used to capture this process is resilience (see "Federal Disaster Policy: Toward a More Resilient Future"). Resilience has gained prominence as a framework for measuring the capacity of systems, including cities and regions, to bounce back from shocks of many kinds, from long-term economic events such as deindustrialization or the foreclosure crisis to immediate shocks such as natural disasters.

In the context of disasters, the concept of resilience overlaps other concepts such as hazard mitigation and disaster resistance. Tierney and Bruneau, researchers who each direct university centers related to natural hazards, state that disaster resistance "emphasizes the importance of predisaster mitigation measures that enhance the performance of structures, infrastructure elements, and institutions in reducing losses from a disaster," whereas resilience "reflects a concern for improving the capacity of physical and human systems to respond to and recover from extreme events."13 Although the authors associate mitigation with disaster resistance in this definition, mitigation also plays a crucial role in resilience. Tierney and Bruneau are members of a national research team affiliated with the Multidisciplinary Center for Earthquake Engineering Research (MCEER) at the University of Buffalo that is tasked with defining and developing metrics for assessing disaster resilience, which they defined as "the ability of social units (e.g., organizations, communities) to mitigate hazards, contain the effects of disasters when they occur, and carry out recovery activities in ways that minimize social disruption and mitigate the effects of future disasters."14

The MCEER team developed the R4 resilience framework, which posits that resilience is determined by four attributes:

  • Robustness, "the ability…to withstand disaster forces without significant degradation or loss of performance";
  • Redundancy, "the extent to which systems…are substitutable, that is, capable of satisfying functional requirements, if significant degradation or loss of functionality occurs";
  • Resourcefulness, "the ability to diagnose and prioritize problems and to initiate solutions by identifying and mobilizing…resources"; and
  • Rapidity, "the capacity to restore functionality in a timely way, containing losses and avoiding disruptions."15
  • As defined by Tierney and Bruneau, resilience can be exhibited both inherently, in a system’s ability to function well under normal circumstances, and adaptively, in how it shows flexibility in and following disaster conditions. The researchers contend that policymakers need to invest in bolstering these four components of resilience, which would require a combination of mitigation strategies and better developed organizational, community, and coping capacities.16

    The R4 resilience framework and other similar efforts to categorize disaster resilience are the focus of many academics and practitioners, particularly planners, who are developing best practice guidelines for hazard mitigation strategies that improve resilience. For example, David Godschalk, professor emeritus at the University of North Carolina’s Department of City and Regional Planning, examines the tools available to local planners and other local officials to create a vision for safe growth that takes hazards into consideration. Godschalk’s Safe Growth Audit asks questions pertaining to elements of a community’s comprehensive plan, including land use, transportation, environmental management, and public safety. The audit also considers the role of zoning ordinances, subdivision regulations, capital improvement program and infrastructure policies as well as alignment with other local codes and strategies.17 Many of these questions touch on the robustness, redundancy, resourcefulness, and rapidity of local systems. The ultimate goal of the audit is to give policymakers the information they need to limit the development of areas known to be at high risk of hazards, minimize the degree to which hazards affect already developed areas, and make existing structures more hazard resistant.18

    Godschalk’s work is featured in Hazard Mitigation: Integrating Best Practices into Planning, a FEMA-funded guide edited and primarily written by mitigation expert James C. Schwab, manager of the American Planning Association’s Hazard Planning Research Center. The guide looks at the central role of planners in visioning and goal setting to ensure safe, resilient development while also noting the need to partner with other local officials such as city managers, planning commissioners, emergency managers, fire and police officials, and transportation planners and engineers throughout the planning process.19 Schwab and Kenneth Topping, lecturer in the City and Regional Planning Department at California Polytechnic State University and president of Topping Associates International, argue that local mitigation plans, which have been institutionalized by the Disaster Mitigation Act of 2000, need to be better integrated with both local comprehensive plans and state-level mitigation plans; they also state that hazard mitigation elements should be included in area plans, functional plans, and operational plans.20 Throughout the guide, Schwab and his coauthors advocate that policymakers should engage in consistent, proactive outreach to a range of stakeholders, including community members.

    Some research has shown that mitigation activities and other efforts at developing disaster- and climate-resilient infrastructure yield long-term economic savings in addition to benefits such as increased public safety and community well-being, but they do typically require higher upfront costs. For example, according to the World Bank, building structures "back better" during postdisaster reconstruction often costs between 10 and 50 percent more than simply replacing the structures as originally built — and when populations need to be relocated from locations that cannot be made sufficiently resilient, the social and economic costs can be much higher.21 Nevertheless, the World Bank argues that, given the high worldwide risk posed by increasingly frequent and costly disasters, "it is important to ultimately strengthen all aspects of climate and disaster resilient development, including coordinating institutions, risk identification and reduction, preparedness, financial and social protection, and resilient reconstruction."22 The World Bank also discusses the financing mechanisms it uses to help fund resilient development programs while also keeping in mind the importance of strong communities: "We know that communities with strong social bonds are more resilient when disaster strikes as neighbors are the first responders and can help each other in the process of reconstruction."23

    Cultural Capital and Resilience

    The strength of social bonds within communities is a critical component of disaster resilience that is sometimes overlooked in resilience frameworks because it can be difficult to measure. Cultural capital — the social bonds that build and sustain community trust, improve communication, and bolster local responses to shocks — is related to other sociological concepts such as neighborhood effects and collective efficacy. Research has found that "loose" ties that bring community members together outside the more intensive confines of such organizations as churches, clubs, boards, or industry groups promote greater resilience by generating bridging relationships between larger and more diverse segments of the community.24

    A sad case study that illustrates how communities that lack cultural capital exhibit less resilience in the face of disaster is the July 1995 heat wave that killed more than 700 Chicago residents over the course of a week. As New York University sociologist Eric Klinenberg writes in Heatwave, "[P]ublic health scholars have established that the proportional death toll from the heat wave in Chicago has no equal in the record of U.S. heat disasters."25 Other meteorologists and epidemiologists confirmed through historical research and data models that the extremity of the heat wave could only partly explain the high mortality rate; additional social factors played a key role.26 After extensive fieldwork, Klinenberg concludes that increased social isolation (especially among older residents), exacerbated by ineffective governmental services and extreme economic inequality that created some neighborhoods where residents were wary of assisting neighbors, was a primary reason why the heat wave was so disastrous.27 Subsequent Chicago heat waves of similar intensity were far less deadly, likely because city services and nonprofit organizations were better able to actively aid vulnerable residents and community members better understood the necessity of checking up on their neighbors.28 The continuing development of technical solutions — ranging from building-scale solutions that reduce internal temperatures to neighborhood- or city-scale programs such as smart grid technologies that reduce the risk of blackouts — has also helped reduce fatalities in heat waves nationwide.

    Just as limited cultural capital can hinder resiliency to disasters, communities exhibiting stronger community capital often bounce back more quickly and make lasting changes that reduce future risk. A number of communities have empowered their residents to contribute their perspectives to disaster mitigation and recovery plans and bolstered their resilience in the process (see "Preparing for the Next Disaster: Three Models of Building Resilient Communities"). Cultural capital, like many other components of the research underpinning disaster resilience, is itself a complex topic. But when considered alongside other physical and social elements of resiliency, such as infrastructure and economic indicators, cultural capital provides a more complete picture of the factors that make some communities more resilient than others.


    Given the concept’s interdisciplinary nature and relative newness, the frameworks and definitions for resilience will continue to evolve. Natural disaster data, however, clearly illustrate the need to emphasize disaster-resilient development, and the ongoing work of planning experts is ensuring that best practices for resilience are shared widely and tailored to local conditions. Only by merging large-scale research into the scale and frequency of natural disasters with local practice that is mindful of community needs and social connections can U.S. communities best prepare themselves for future weather- and climate-related challenges.

    — Keith Fudge, HUD Staff

    1. Federal Emergency Management Agency. “Disaster Declarations by Year” ( Accessed 12 February 2015.
    2. Insurance Information Institute. “Catastrophes: U.S. Natural Catastrophes” ( Accessed 12 February 2015.
    3. Insurance Information Institute.
    4. National Climatic Data Center. “Billion-Dollar Weather and Climate Disasters: Time Series” ( Accessed 12 February 2015.
    5. National Climatic Data Center. “Billion-Dollar Weather and Climate Disasters: Summary Stats” ( Accessed 12 February 2015.
    6. “United States of America — Disaster Statistics: Natural Disasters from 1980–2010,” PreventionWeb website ( Accessed 12 February 2015.
    7. Ibid.
    8. National Oceanic and Atmospheric Administration. “State of the Coast: Communities — The U.S. Population Living at the Coast” (website content has changed and this webpage is no longer available). Accessed 12 February 2015.
    9. National Oceanic and Atmospheric Administration.
    10. Debarati Guha-Sapir, Philippe Hoyois, and Regina Below. 2014. “Annual Disaster Statistical Review 2013: The numbers and trends,” CRED, 4.
    11. Ibid., 1.
    12. World Bank. 2013. “Building Resilience: Integrating Climate and Disaster Risk into Development,” Lessons from World Bank Group experience, v.
    13. Kathleen Tierney and Michael Bruneau. 2007. “Conceptualizing and Measuring Disaster Resilience: A Key to Disaster Loss Reduction,” TR News 250 (May–June), 14.
    14. Ibid., 15.
    15. Ibid.
    16. Ibid., 17.
    17. David R. Godschalk. 2010. “Integrating Hazards into the Implementation Tools of Planning,” in Hazard Mitigation: Integrating Best Practices into Planning, James C. Schwab, ed., American Planning Association Planning Advisory Service Report Number 560, 57.
    18. Ibid., 48.
    19. James C. Schwab and Kenneth C. Topping. 2010. “Hazard Mitigation: An Essential Role for Planners,” in James C. Schwab 2010, 6–10.
    20. James C. Schwab and Kenneth C. Topping. 2010. “Hazard Mitigation and the Disaster Mitigation Act,” in James C. Schwab 2010, 21; James C. Schwab. 2010. “Integrating Hazard Mitigation into Other Local Plans,” in James C. Schwab 2010, 41.
    21. World Bank, 11.
    22. Ibid., 8.
    23. Ibid., v.
    24. U.S. Department of Housing and Urban Development, Office of Policy Development and Research. 2012. “Growing Toward the Future: Building Capacity for Local Economic Development,” Evidence Matters (Winter), 7–8.
    25. Eric Klinenberg. 2003. Heat Wave: A Social Autopsy of Disaster in Chicago, Chicago: University of Chicago Press, 10.
    26. Ibid.
    27. Ibid., 230–2.
    28. Ibid., 227.


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    The contents of this article are the views of the author(s) and do not necessarily reflect the views or policies of the U.S. Department of Housing and Urban Development or the U.S. Government.