Overview
During 2020–2021, two global phenomena—the COVID-19 pandemic and climate change—shaped disaster risks worldwide, with particularly acute consequences in the Gulf of Mexico (GOM) region. The emergence and spread of COVID-19 transformed the public health risk of all other disaster events by amplifying health-compromising exposures and underlying vulnerabilities in the region. The pandemic also modified preparedness, response, and recovery procedures for the unrelenting weather–climate events that followed in the form of seven major hurricanes and a severe winter storm (Uri). The combined result was a complex and unprecedented public health and socioeconomic crisis—and an exemplar of compounding disasters.
When society experiences a disaster, the impacts are typically attributed to an individual event, and damages stemming from disasters are quantified in terms of economic losses and direct fatalities. The National Oceanic and Atmospheric Administration’s (NOAA) application of this conventional approach designated each of the seven major hurricanes and winter storm in the GOM in 2020 and 2021 as a “billion dollar disaster,” and the
COVID-19 pandemic has been characterized by some as a “trillion dollar disaster.” These monikers, however accurate, do not reflect the human toll and disparate effects caused by multiple events that increase underlying physical and social vulnerabilities, strain adaptive capacities, and ultimately make communities more sensitive and likely to
experience future disruptive events as disasters. Such is the case for many GOM
communities that were still in varying states of recovery from previous
disasters when they were impacted by the compounding disasters of 2020–2021.
In 2022, the Gulf Research Program (GRP) of the National Academies of Sciences, Engineering, and Medicine tasked a seven-member ad hoc committee with examining the unique characteristics and effects of the 2020–2021 compounding disasters in the GOM region, and examining how to manage and minimize the effects of these disasters on those who live and work in the region. Members of this committee were invited to serve because of their extensive academic and professional expertise in community resilience; disaster management; public health; and behavioral, social, and atmospheric sciences.
Features of COmpounding Disasters
Among the features of compounding disasters, four stand out as especially salient to GOM communities and the purpose of this study: (1) the disproportionate risk faced by vulnerable communities; (2) outcomes that result when that risk becomes realized impact; (3) effects on the interdependent systems and functions that serve both the routine and acute needs of a community; and (4) overlapping, interrupted, and prolonged disaster recovery.
Particular risk to vulnerable communities
Disasters manifest when a community’s capacity to prepare for, respond to, and recover from the occurrence of a disruptive event is inadequate and overwhelmed. When compounding effects originating from multiple disruptive events occurring over time, communities may bear the hardship of disaster without ever reaching traditional thresholds for a formal disaster declaration. It is the sensitivity of those who experience the brunt of the disruptive event that dictates whether the experience crosses the threshold to become a disaster. Heightened socioeconomic vulnerabilities and disaster-weakened systems and functions make many GOM communities particularly sensitive to future disruptive events and their compounding effects, regardless of the events’ intensity. Many frontline communities (those who are highly exposed to climate risks due to the places they live and the projected changes expected to occur in those places) have fewer resources, lower adaptive capacity, weak social or economic safety nets, and/or are underrepresented in policy, governance, and recovery planning to be able to reduce sensitivity.
The committee explored the evidence-based disaster risk profile of GOM communities, including first-hand accounts of information-gathering session participants about the pandemic and extreme weather-climate events’ impacts in 2020–2021. The events discussed were not restricted to federally declared or “billion dollar disasters”, but included “smaller” disruptive events (e.g., heavy precipitation events, isolated tornados) that can compound in their effects and produce large-scale impacts. [JS1] Risk profiles include components of physical, health, and social vulnerability, and exposure to extreme weather-climate events and hazards familiar to the region.
The years 2020 and 2021 broke existing billion dollar disaster records, with 22 and 20 such disasters occurring nationwide, respectively, together resulting in approximately 950 direct or indirect fatalities (NOAA, 2022b). Within this same 2-year span, Gulf of Mexico states endured 13 billion dollar disasters—six hurricanes in 2020 (Hurricanes Delta, Eta, Hanna, Laura, Sally, and Zeta) and in 2021, two tropical storms (Elsa and Fred), two hurricanes (Ida and Nicholas), a major flood event, a hailstorm, and a severe winter storm (Uri7).
Disasters Hidden Beneath the Billion-Dollar Disaster Threshold
The federal disaster declarations and billion-dollar designations for the major storms of 2020–2021 do not account for the less well-known or unnamed storms or disruptive events that occurred during those 2 years. Such events contribute to accumulated losses and damage to communities lacking infrastructure and proper mitigative measures—features that often align with vulnerability factors such as income, race, and rurality (Hendricks and Van Zandt, 2021).
Geographically limited and lower-magnitude events such as tornadoes, flooding, and even tropical systems impacting the GOM region are often seen as either distractions, stressors, or setbacks to recovery efforts. They do not meet the threshold of a billion dollars, nor do they receive the attention as major disasters tagged with such superlatives as “deadliest,” “largest,” and “earliest.” In parts of Lake Charles, Louisiana, for example, a heavy rain event in May 2021 produced 12.49 inches of rainfall in 24 hours, 6 inches of which fell in a 2-hour period (Di Liberto, 2021), while many residents were still reeling from 2020’s Hurricanes Laura and Delta. This was the third-highest amount of rain at one time on record in Lake Charles (Benedict, 2022), and it caused significant flooding, creating obstacles for a region already suffering from a series of compounding disasters.
The baseline for GOM states—one of extreme risk driven by vulnerability, upon which growing hazard exposure is overlaid—exacerbates the potential for future compounding disaster events. Actions taken to redress these inequities are critical to reducing the impacts of such events.
Conclusion 2: Increased compounding disaster risk requires greater adaptive capacity within communities to better understand and prepare for the potential co-occurrence of multiple hazards that combine with societal exposure and vulnerabilities to amplify overall disaster impact.
Drawing on existing frameworks derived from disaster scholarship, the committee began its inquiry by examining the conventional model that contemplates disaster risk as the product of intersecting hazards, exposure, and vulnerability, as illustrated by Figure S-1.
For the purposes of this report, the committee adopted the use of the following definitions:
- Hazards are understood to be processes, phenomena, or activities with the potential to cause loss of life, injury or other health impacts, property damage, social and economic disruption, or environmental degradation. Hazards may be natural or human-made and can occur individually or simultaneously.
- Exposure describes the presence of people, infrastructure, housing, production capacities, and other tangible human assets in hazard-prone geographies or situations.
- Vulnerability encompasses social and economic sensitivities of individuals and groups, along with deficiencies in the structures and systems on which they rely, that reduce their capacity to withstand hazards. Vulnerable communities are those least able to anticipate, cope with, and recover from these disruptive events.
- Disaster risk is expressed and defined as the likelihood of loss of life, injury or destruction, and damage from a disruptive event in a given period of time. Disaster risk is widely recognized as the potential consequence of the interaction between one or more hazards and the characteristics that make people and places vulnerable and exposed. Accordingly, realized disaster impacts depend not only on the severity or intensity of the hazard itself, but also on the sensitivity of the community to suffering loss and damage.
Through its deliberations, the committee found the classic Venn Diagram and its various iterations (depicting hazard, exposure, vulnerability, and risk) inadequate in its representation of the dynamics of compounding disasters. The definitions of hazard, exposure, vulnerability, and risk continue to ring true, yet the ways that risk compounds and grows requires a more integrative visualization, as depicted in Figure S-2
There is nothing linear about the movement of hazard, exposure, vulnerability, and risk. The growth and agitation within hazards, exposure, vulnerability, and risk are more algorithmic. Hazards that stack up exacerbate vulnerability and exposure. As hazards compound, they pull the interconnected mesh that extends across the exposure and vulnerability hyperplanes upward – upward into growing and more intense risk. Exposure and vulnerability increase (and decrease) by a range of choices made affecting a community.
With the onset of each new disruptive event during ongoing recovery from prior events, exposure is increased, vulnerabilities are heightened, and the sensitivity that makes a community vulnerable to experiencing a future disruptive event as a disaster is amplified. Accordingly, the committee defines compounding disasters as
The result of successive disruptive events that affect the societal, governmental, and/or environmental functions of a community or region and diminish the community’s capacity to recover and resume essential activities. The weakening of these interrelated functions inhibits and prolongs the disaster recovery period, making communities more likely to experience amplified negative effects of future disruptive events. Some communities are at disproportionate risk of suffering the effects of compounding disasters as a result of the interplay of persistent physical and social vulnerability factors and increased exposure to climatic and non-climatic hazards.
Increased “adaptive capacity” may be the most effective way to push down the exposure and vulnerability. Sensitivities are the social factors that lessen the ability of a person, family, or community to cope with a disruptive event, and can determine the degree to which they are affected by such an event. Adaptive capacity can mitigate the potential for harm by reducing sensitivity to a disruptive event. It is defined as the abilities of people (and systems, institutions, and other entities) to adjust to potential damage, take advantage of opportunities, or respond to consequences (USGCRP, 2023). Adaptive capacity enables a human community to adjust to environmental conditions and effectively offset vulnerabilities (Smit and Wandel, 2006).
Conclusion 3: When a community increases its capacity to absorb the effects of hazards and minimizes its recovery needs, disaster effects are less likely to compound.
Targeted, community-guided investments to increase the resilience of essential services and vital infrastructure are important to achieve this objective. While preferable to invest before a disaster occurs, the influx of recovery funding after a disaster can provide an opportunity to mitigate future losses and the potential for compounding disasters. These investments should not be limited to building physical capacity to withstand hazards, but also the strengthening of adaptive capacity, including formal and informal relationships among community stakeholders that underpin disaster resilience.
Conclusion 4: Perception and understanding of risk are commonly grounded in past experience, leading to complacency in preparation and mitigation.
The erosion of social memory may hamper risk communication, mitigation, and planning for disruptive events that go beyond what has been experienced or is perceived to be the benchmark extreme. These biases are similarly reflected in emergency management protocols, land-use planning and plans, zoning regulations, public utility design, and building codes, which are often grounded in historical precedent or probabilistic hazard descriptions derived from historical data. Given a changing climate, this hindcasted vantage is unlikely to be representative of future hazard risks. Overcoming these biases requires new strategies.
When people confront the threat of an impending disruptive event or disaster, their decision making can be impaired by the tendency to overemphasize recent events or personal experiences when estimating the impact of the future event (recency bias) and by the tendency to underestimate the likelihood of the occurrence or impact of the event (normalcy bias). Historical events often serve as benchmarks for how people perceive and plan for future hazards. This tendency can be dangerous. Recent examples of “benchmark” storms include Hurricanes Andrew (in 1992), Ivan (in 2004), Rita and Katrina (in 2005), and Gustav and Ike (in 2008) and the 2011 winter freeze. However, the problem with referring to storms as “benchmark” is that the bar is always shifting, and the potential for future events to surpass historical events is increasing. Hurricanes Harvey (in 2017) and Ida (in 2021) are examples of storms that render benchmark events obsolete. Accordingly, cognitive biases that inform how people interpret and respond to new threats, can result in significant underestimation of risk, leading to inadequate planning and preparation, and ultimately to more severe impacts. The effects of cognitive bias are not limited to the decision making of individuals; indeed they may be reflected in regulations, codes and policies.
According to traditional risk assessment, planners are advised to identify and prioritize risks with the highest probability of occurring locally. This approach can lead to the neglect of atypical and rarer events and leave communities susceptible to an unanticipated, but not unimaginable, event such as winter storm Uri. Responses to atypical events such as extreme cold can be outside the purview of organizations accustomed to response and recovery for hurricanes, tornadoes, and flooding, further complicating relief efforts. Those responding have steep learning curves in anticipating and responding to the needs, damages, and other impacts of such an atypical hazard. Compounding hazard events further complicate the traditional risk assessment methodology.
For example, the rainfall intensities experienced now and going forward are not like those of the rainstorms of past centuries or even decades. The literature shows that the top 1–2 percent of rainfall-intensity events have increased in recent decades (Easterling et al., 2017). In just the last 15 years, the percentage of the Southern United States experiencing extreme 1-day rainfall events in any individual spring has increased significantly (USGCRP, 2023; Di Liberto, 2021). Relatedly, jurisdictional infrastructure (e.g., roads, bridges) was designed and engineered under an assumption of “stationarity”— that is, assuming that hazards such as rainfall would have future intensities similar to those of rainstorms of decades past. A significant portion of U.S. infrastructure was designed and built in the 20th century. Not only is it aging and often in a state of deferred maintenance, but it now exists in the changing climate of the 21st century.
Conclusion 5: Effective disaster recovery requires an “epoch” rather than “event” view that more fully captures the prolonged effects of compounding disasters and reflects the experienced reality of the community.
An event-based perspective on disaster management is inherently narrow, reactive, and artificially time-constraining. The event-driven view focuses on the symptoms rather than the root causes of disaster losses. Shifting to an epoch view better frames the breadth of lived experiences with disasters and accounts for the potential for compounding losses, driving the broad disaster response and recovery enterprise to more comprehensive and effective pathways forward.
The compounding disasters within the timeframe of this study cannot be isolated from prior disasters. Each subject community was in some state of recovery from the physical and socioeconomic impacts of previous disasters, such as Hurricanes Katrina and Rita (in 2005), the Deepwater Horizon disaster (in 2010), and Hurricanes Gustav and Ike (in 2008).
Despite their widespread and devastating impacts, these prior events provided policy and decision makers with opportunities to learn from experience and make improvements to reduce future disaster risk. The committee examined how positive and negative experiences from previous disasters influenced communities’ experience within the study timeframe, in addition to identifying some barriers that may inhibit the uptake of lessons-learned. Panelists in each of the information-gathering sessions spoke about the need to act on lessons-learned with emphasis on the following broad themes: governmental functional abilities, inter-agency and community-based coordination; streamlined funding procedures for immediate and long-term disaster recovery; and social issues such as risk communication and awareness, socio-economic vulnerabilities, housing equity, mental health, and disaster fatigue among professionals and community members.
Barriers to implementing lessons-learned include isolating findings within functional organizational units; lack of information sharing with community-based organizations; prioritizing learning based on what went wrong and not validating what went right; and lack of integration of learnings into formal training curriculum.
Conclusion 6: Risk communication about extreme weather-climate and multiple/sequential events is inadequate for contemporary experiences and preparation for future conditions.
The severity of many of the disaster impacts in 2020–2021 exceeded expectations. To better accommodate the unanticipated requires more expansive risk assessment procedures. Imagine the unimaginable. Communicating around today’s events already falters. With a changing climate, the potential for rare events only increases. Preparing for the inevitable requires improved public warnings and exercises. This must be predicated on a growing level of community trust that can only be gained through enhanced transparency, inclusiveness, and multiple levels of participatory information sharing.
Public reliance on both traditional media (newspapers and television/radio news) has declined, and disinformation and misinformation are more pervasive and influential today than ever before (Pew Charitable Trust, 2023). Public officials and community leaders observed that misinformation made their jobs more difficult and contributed to frustration and erosion among trust of those in need of assistance. While social media played a vital role in disseminating information about impending weather-climate events and response efforts, these outlets also provided a medium for the distribution of misleading and inaccurate information. The erosion of trust among public health and disaster professionals and the communities they serve was evident in the case of information about COVID-19, which in turn led to skepticism toward authorities in the wake of other weather-climate events. Absent the COVID-19 pandemic, this situation might not have occurred. Panelists recommended the development and implementation of processes for contending with misinformation and disinformation such as trust building and participatory planning.
Conclusion 7: Health care and public health systems will require increased adaptive capacity to respond to diverse challenges posed by compounding disasters.
The nature of the hazards encountered influences the impacts on population health, health systems, and public health services. Even as extreme weather-climate events damage facilities and disrupt access to health care, emerging disease outbreaks require physically intact facilities so that services can be rapidly shifted to communicable disease care, and local public health capacity can be maintained.