Climate change-related mass migration requires health system resilience

For populations moving in response to a changing climate, health-related research suggests that climate-related mass migration is a stress, but a stress like no other disaster. This is because good health is place-based and context-specific: an outcome of a household's access to critical health system services and broader environmental, social, and other protective factors shaping mental and physical health (Macintyre et al 2002, Bernard et al 2007, Norris et al 2008, Lawrance et al 2022). Migrants may not be able to maintain access to those place-based resources as they move. This, in turn, can intersect with other issues detrimental to health and cascade to produce poor health outcomes for climate change-related mass migrants.

Exposure to climate disaster is almost always detrimental to mental and physical health (Sandifer et al 2017, Schwerdtle et al 2018). Exposure includes direct effects—the flood, hurricane, wildfire, or other climate change-related hazard—as well as indirect effects—the systems compromised by a climate-related hazard.

Indirect effects are not well understood but might be substantial. They include disruptions to water, housing, electricity, and other infrastructure critical to sustaining health (Clark‐Ginsberg et al 2021) and secondary hazards triggered by the initial crisis: cholera outbreaks that can occur after floods and drought (Rieckmann et al 2018), landslides that may follow wildfires (Rengers et al 2020), and petrochemical releases triggered by hurricanes (Flores et al 2021). They also include the stress of recovery; engaging with emergency management institutions seemingly hostile to survivors, resolving insurance claims, making significant decisions under tight time constraints, and securing what can be scarce and expensive reconstruction resources (Dulin 2008, Olshansky et al 2012, Wilkinson 2019, Reinke and Eldridge 2020). Finally, indirect effects also include disruptions to family- and community-level social processes that people rely on, which can have severe health consequences (Kario et al 2003, Torres and Casey 2017, Chandra et al 2018). Children, for instance, depend on their parents for a protective 'buffer' that can be disrupted during crises (Helldén et al 2021, Vos et al 2021). Likewise, families can suffer if community institutions are compromised (Chandra et al 2018, Slack et al 2020).

The impact of Hurricane Maria on the US territory of Puerto Rico illustrates the potentially substantial indirect effects that climate disasters pose to health. After hitting Puerto Rico as Category 4 hurricane in December 2017, Maria left in its immediate wake billions in damages and an official death toll of 68. However, over the months that followed that official death toll was adjusted upward, dramatically, to 4645 (Kishore et al 2018). One particular indirect effect, interruptions to medical care, was identified as a substantial contributor to that increase (Kishore et al 2018). Indirect effects such as the challenging recovery processes, high levels of uncertainty, and problems accessing critical resources also contributed to a sustained mental health load that contributed to anxiety, depression, feelings of hopelessness, and posttraumatic stress disorder (Scaramutti et al 2019, Clark-Ginsberg et al 2023b).

The health of migrants can also be impacted when relocating to a new destination. Travelling to a new destination can be precarious: migrants may be exposed to danger and may not be able access to health resources and broader systems facilitating health (McMichael et al 2010, Dannenberg et al 2019, Vos et al 2021). Time is a significant predictor of precarity, with longer journeys often more perilous. Precarity may be greatest for people whose relocation process is indefinite; those living indeterminately in 'temporary' camps, or 'trapped' in their home locations without the means to move (Logan et al 2016, Nawrotzki and DeWaard 2018, Ayeb-Karlsson et al 2020, Harasym et al 2022). Koslov et al (2021) captures the precarity of indeterminateness in their study of household-level rebuilding efforts in the greater New York City metropolitan region following 2012 hurricane Sandy. Comparing those who used federal buyout options rebuild elsewhere to those rebuilding in their previous locations, the authors find greater stress for those rebuilding in place. They suggest several factors including 'loss of control' and 're-experiencing the damage of one's home and neighborhood on an everyday basis' (Koslov et al 2021, 58) contributing to greater stress.

The process of resettlement, or 'making a home' in a new location, is another point where migrants' health can be impacted. Resettling can positively contribute to migrants' mental and physical health if it improves their access health-related resources or reduces exposure to harms (McLeman and Smit 2006, Eriksen and Lind 2009, Black et al 2011, Hynie 2018, McNamara et al 2018). However, resettling also requires making difficult adjustments over months, years, or even decades, including gaining access to mental and physical health resources. During this period, migrants can be disconnected from their friends, families, and other support structures back home, in some cases in an environment hostile to them (da Silva Rebelo et al 2018).

Migrants may experience feelings from the loss of place identity during this adjustment period—one of the most impactful contributors to poor mental health (Burley et al 2007, Agyeman et al 2009, Fresque‐Baxter and Armitage 2012, Bornstein 2017, Adger et al 2018, Vos et al 2021). In the United States feelings of loss of place and of longing for home has been documented in New Orleanians displaced by hurricane Katrina in 2005 (Fothergill and Peek 2006, Browne 2015), Puerto Ricans displaced by 2017 Hurricane Maria (Clark-Ginsberg et al 2023b), and residents of Paradise, California, whose town was near completely destroyed by the 2018 Camp fire (Garcia Junqueira 2020).

Climate change-related mass migration can affect health systems in terms of consumer volume, issues complexity, and systems capacity, which can have positive and negative effects.

The sheer volume of needs of absorbing a new population can overload health systems, which may be accustomed to servicing a certain population of a certain size. Given the potential for widespread trauma and mental health challenges, the volume of consumers needing mental health services might be particularly pronounced. Against the backdrop of already dire mental health provider shortages, both inside and outside of the United States, this stress is particularly challenging (Wainberg et al 2017, Kaiser Family Foundation 2021). With the level of chronic disease management in the U.S. as well as recovery from disease strains such as COVID-19, climate migration could potentially put new stresses on the core of health systems needed to serve new populations (e.g., the staff, stuff, space (Fiest and Krewulak 2021)).

Another impact emerges from the complexity of the issues associated with climate change-related mass migration. For new migrants, rapidly establishing a new home, dealing with traumas, and navigating new health systems can be an incredibly complex task, and one that is potentially challenging for the health system to support. Migrants might lack the ability to effectively engage with a new and unfamiliar health system, so the health system will need to support migrants in understanding the system and accessing administrative information (Sabasteanski 2020). On the positive side, when migrants enter a new location, they bring with them cultural and material resources beneficial for their own and their new communities' health and well-being (Abubakar et al 2018, Lawrance et al 2022). For instance, some health providers describe the ongoing relocation from the Isle De Jean Charles, an island off the coast of Louisiana, to Louisiana's mainland, as providing benefit to local mainland health systems in the form of new business (Clark-Ginsberg et al 2023a).

The movement type and migrant vulnerability and capacity influence how climate migration affects health system capacity. Climate migration can occur quickly and over a short time period, such as after an acute shock like a flood or wildfire, or can occur more slowly over a longer period of time, driven by drought, erosion, sea level rise and other ongoing stressors. Long-term and ongoing stressors might offer some advanced planning for migrants, and result in a slower and possibly more manageable 'trickle' of migrants. The current movement from Isle de Jean Charles previously mentioned is an example of this trickle, and has been described by health system providers as manageable (Clark-Ginsberg et al 2023a). However, in the United States current models of disaster management are typically designed for shorter term, acute events, and might need modification to work for these distended time horizons (Buck et al 2006, Jensen and Thompson 2016).

The ability to shift rapidly and adapt describes putting in place strategies for harnessing existing resources and accessing new ones to provide health services to climate migrants and their host communities. Shifting rapidly and adapting is necessary because as noted earlier, climate-related population influxes can be sudden and the resulting health needs difficult to identify in advance.

Large infrastructures can be both slow to change, but can also shift and adapt rapidly under the right conditions. Schulman and Roe (2016) identify the people whom they label 'reliability engineers' that play a crucial role in facilitating rapid shifting and adapting. For the electric grid, water, and transportation systems, it is often control room operators that play this role: empowered by technology that helps them monitor infrastructure, they are able to engage in what Weick et al (2005) label 'sensemaking', identifying emerging issues and placing them in appropriate organizational and institutional contexts to react accordingly. Others include the 'maintainers' (Russell and Vinsel 2016), who keep systems running normally and reestablish them when failures occur—the line workers responsible for servicing and repairing the electric grid's power lines, for instance.

Crucial is the ability of these stakeholders to act in response to new information and environmental changes. Simplifications, patterns, and rules facilitate fast reaction, but given uncertainties, flexibility in decision making as opposed to rigid, hierarchical rules-based governance is necessary to enable rapid shifts (Bigley and Roberts 2001, Sutcliffe and Weick 2006). Ideally, slack should also be introduced in the system to shift resources and scale up and down as needed and reduce reliance on rapid reaction (Perrow 1984, Roberts 1990). An example of slack for water and energy infrastructure is standby generation facilities and reservoirs of water.

Like these other large infrastructures, it can be extremely difficult to change health systems. Policy modifications can be politically contentious, particularly given the public–private structure of health care, the complexities in oversight and governance, and the costs of constructing new health infrastructure (Haeder 2012).

However, health systems also have the equivalent of 'reliability engineers' that support rapid adaptation: health incident managers. They are responsible for managing public health incidents by engaging in activities like maintaining situational awareness and sharing information, scaling up and down resources, and coordinating response (Clark-Ginsberg et al 2022). In the United States they are governed by a series of policy frameworks and guidance documents such as Incident Command System and the National Incident Management System (ICS NIMS), which ascribes a modular and consistent structure for incident management (FEMA 2017); the Emergency Support Function #8, which covers federal coordination of public health and medical services (FEMA 2008); and Center for Disease Control and Prevention's Public Health Emergency Preparedness and Response (PHEPER) capabilities, 15 standards for local and state preparedness planning and response (CDC 2019). Such frameworks can be modified for climate migration to varying degrees, by for instance revising ICS NIMS to improve its currently limited effectiveness for longer-term duration events, or by modifying PHEPER capabilities focused on communities (Capability 1, Community Preparedness, Capability 2, Community Recovery) to account for potentially new populations of migrants.

Slack can also be introduced in the system—but for climate migration, instead of physical infrastructure this is mostly people and resources. When crises hit, healthcare workers can and often do change their functions and respond, sometimes scale up work for short periods of time or come from other states and regions in response to needs. In order for the latter to occur in the United States, policy efforts such as cross-state practice standards or expanded licensure for nurse practitioners must be considered given the fractionated nature of US healthcare (Cebul et al 2008). Slack in the form of additional doctors, nurses, counselors, community health workers and other healthcare staff can also be introduced in these systems to account for dynamic changes in population—an additional benefit for other acute health events.

During COVID-19 for instance, US hospitals and critical care systems contended with unprecedented stress. Abir et al (2020) describes processes for addressing two levels of critical care capacity: contingency capacity strategy focused on adapting medical care spaces and approaches to address immediate staffing and supply shortages given the crisis; and crisis capacity strategies, meaning ensuring supports to address the impacts on routine health care delivery. As part of these efforts, existing climate change health system resilience guidance documents can be updated to account for mass migration related to a changing climate. An example is U.S. Department of Health and Human Services' framework for healthcare resilience (Guenther and Balbus 2014), which provides a series of practical checklists on improving healthcare resilience to extreme weather events, but does not include climate migration as a potential outcome of those events or provide guidance on how to modify processes to enhance resilience.

Multi-stakeholder collaboration is a necessary part of health system resilience to climate change-related mass migration because of the array of service provers and supporting organizations necessary to meet the broad sets of health needs that migrants have.

Infrastructure is an act of collaboration, requiring standardization and transboundary resource pooling for interoperability (Carse and Lewis 2017). Standardization allows for interchangeability across firms and boundaries. The energy system consists of an interconnected grid of shared generation, transmission, and distribution assets. Dependent on each other, energy companies in the United States have common standards for ensuring safety, reliability, resilience, and interoperability across the system as well as mutual aid systems to pool certain crucial resources (Berkeley et al 2010, Keogh and Thomas 2015). Water systems, communication networks, roads, and other infrastructures in the United States are also patterned similarly (Morley and Riordan 2006).

Despite infrastructures being built on collaboration, collaboration failures abound. Cyber systems used by infrastructure owners and operators are often be boutique to a specific firm, making information sharing difficult (Lee et al 2006). Differences in values and viewpoints can inhibit standardization and lead to conflict (Hughes 1983, Slayton 2013). Divergent goals between the many stakeholders involved in an infrastructure, such as between reliability and security, security and cost effectiveness, and environmental friendliness and profit, can challenge collaboration, as can differences in norms, cultures, and operations between these players (Slayton 2013, Slayton and Clark‐Ginsberg 2018, Mondschein et al 2021). Even if stakeholders can agree on goals, aligning disparate systems may require significant changes that come with heavy costs.

Collaboration is necessary for health systems to function given the multitude of players that make up a health system. However, it can be challenging for climate migration, since it requires working at both the location of the shock or stresses and the new area, and must involve migrants and host communities themselves given the resources and capacity that they have (Wisner et al 1977, Drabek and McEntire 2003, Jerolleman 2019, Barker et al 2020, Maat et al 2021). This is collaboration that is place-based but connected to broader processes (translocal), and involving a multitude of governmental, private sector, civil society, and individual and community members not traditionally found in health (lateral) (Semenza 2021, Translocal Health 2022).

Lateral and translocal collaboration with critical community institutions appears feasible, as evidenced by community organizations in the United States operating together across geographic boundaries on health disaster issues, from COVID-19 (Translocal Health 2022) to wildfire (Fire Safe Marin 2019) and hurricanes (ERD 2019). Further, there are regional compacts across health systems, used in examples like health in all policies and strategies (NACCHO 2023) or the federal Hospital Preparedness Program (ASPR 2023), which should be leveraged also to plan for and address climate migration needs. The features that support effective collaborations in these models (such as shared objectives, clarity of governance and decision making, and aligned roles and incentives (Alderwick et al 2021)) are likely transferable to climate migration.

To leverage the resources that climate migrants have and avoid harmful maladaptations, transformation, the ability to shift to something fundamentally new (Béné et al 2012) needs to be central to resilient health systems.

Work on the evolution of other infrastructures and systems shows the challenges in transforming during or following crisis. Although disasters are sometimes viewed as 'windows of opportunity' for positive change, empirical research suggests that transformation beneficial to vulnerable and marginalized populations rarely occurs (Birkland 2009, Birkmann et al 2010, Cheek and Chmutina 2021). Instead, the transformation that does happen tends to favor those well off, possibly because transformation beneficial to marginalized populations requires overcoming the very power structures that are often used in crisis situations where decisions must be made quickly (Olshansky et al 2012, Topp 2020, Cheek and Chmutina 2021). Furthermore, the extreme path dependency of large sociotechnical systems makes any changes—positive or negative—an incredibly costly endeavor (Hughes 2000, Eisner 2017).

Evidence on how transformation in the context of health system resilience occurs following crisis remains limited (Biddle et al 2020, Topp 2020, Saulnier et al 2021, Behrens et al 2022). Calls have been made to use the COVID-19 pandemic as a window of opportunity for transformation (Haldane et al 2021, Haldane and Morgan 2021, Kish et al 2021, van Schalkwyk et al 2021, Sagan et al 2021b) but pandemic-related changes appear to be at best incremental (Burke et al 2021, Haldane et al 2021) and at worst maladaptive. Examples of an incremental changes in response to COVID include the quickening of ongoing healthcare reforms in Ireland (Burke et al 2021) and experimentation with new forms of incident management in the United States (Dzigbede et al 2020). Maladaptations include the breakdowns in trust and subsequent failures to implement positive health seeking behaviors that have occurred across the United States (Devine et al 2021).

Developing concrete plans for transformation ahead of crises might be a way to capitalize potential windows of opportunity crises can provide while also progressing in incrementally in the meantime. Given the unique capacities and needs of migrants and host communities, plans should people-centered (Martineau 2016, Paschoalotto et al 2023) and involve migrants and host communities themselves. As a complex system with many players, coalition building with diverse health system stewards, leaders, and who can influence the health system will be required (Milstein et al 2020, Gates and Fils‐Aime 2021). Since the decision to move is an outcome of many factors and thus remains difficult to predict (Adger et al 2018, McLeman 2018) plans will need to be flexible to allow inclusion of migrants as migration occurs.