Climate change, migration and health systems resilience: Need for interdisciplinary research

Introduction

“Four thousand migrants arrive in Dhaka, the capital of Bangladesh due to various ‘push’ factors including frequent natural disasters”¹. Environmental changes due to climate change are projected to cause substantial increases in population movement, within and between countries, in the coming decades. Haiti faces a similar situation according to a 2008 report it is estimated that 100,000 people have moved for climate change reasons from rural areas to the capital Port-au-Prince². Environmental changes (e.g. drought, soil erosion, extreme weather events, etc.) lead to substantial impacts on health, economic and political dimensions at the population level, including influencing migration patterns and may result in adverse health outcomes, both for displaced and for host populations^3–5. The World Health Organization (WHO) consistently identifies climate change as a defining challenge of the 21^st century; and considers it an emerging priority for the public health community to ensure protection against its health impact^6,7. In 2015, The Rockefeller Foundation and The Lancet published the report of the Commission on Planetary Health⁸ and the UN Sustainable Development Goal 13 calls for “urgent action to combat climate change and its impacts".

For this article, we conducted a heuristic non-systematic literature review on climate change, migration and health systems. As a result of a peer-reviewed article search in the PUBMED database using climate change, health systems, and migrants as keywords, only 10 results published between 1994 and 2017 were identified. Of these, six (60%) were written in the past decade and included: two opinion papers, two study reviews, one qualitative study, and one protocol for a review that will be completed in 2018.

In this article, we describe and discuss the fundamental role that health care systems resilience can play in this regard and we identify interdisciplinary research as key to better understanding the existing linkages between climate change, migration and health systems and how to build more resilient health systems. We also propose some questions and axes to orient future research proposals.

Climate migrants and health challenges

Climate change can be translated to many forms of environmental degradations, including hurricanes⁹, rising sea levels, and/or reduced rainfall in drylands and water scarcity¹⁰. Populations confronted by climate change consequences such as exposure to hazards, loss in land productivity, absence of habitability, and/or shortage of food/energy/water security may have difficulties to subsist in a given area¹¹. Climate change consequences compounded by socio-economic pressures and/or political instability, increase propensity to migrate. Although evidence is still missing to prove this association, environmental factors are increasingly influencing a complex pattern of human mobility. A recent paper suggests “a statistically significant relationship between fluctuations in asylum applications and weather anomalies”¹². Climate migrants may be forced to leave their homes due to rapid-onset disasters, such as flooding and hurricanes (as in Haiti and Bangladesh for example)^1,2,13,14.

Nowadays, there is no conceptual consensus on the notions of environmental refugee or climate change migrants yet, or the more rarely used terms ecomigrants or environmentally displaced persons^15,16. Since 2007, the International Organization for Migration (IOM) has defined environmental migrants as “persons or groups of persons who, for compelling reasons of sudden or progressive change in the environment that adversely affects their lives or living conditions, are obliged to leave their habitual homes, or choose to do so, either temporarily or permanently, and who move either within their country or abroad”¹⁷. Others suggest restricting the definition to victims of extreme weather, drought/water scarcity, and sea-level rise and excluding the effects of the spread of tropical diseases¹⁶. The simple fact is that the implications climate change are unknown will bear on the distribution of the world population¹⁸. Current estimates range between 25 million and 1 billion people by 2050. and according to the 2017 Lancet Countdown report “the total number of people vulnerable to migration might increase to 1 billion by the end of the century without significant further action on climate change”⁵.

Climate-related migrants may or may not perceive how climate change influences and has an impact on their health needs and social patterns. For example, in Burkina Faso, the close relationship between climate change and flooding is not always fully perceived by the Burkina population suffering from it, as documented by the authors of this manuscript in previous studies. (Box 1) However, climate-related migrants experience difficulties or face challenges similar to those of refugees fleeing war and/or political persecution: overcrowded settlements, unsanitary conditions, poor nutritional status, unsafety, inequity and limited access to health services^1,2,19,20. Although these migrants may experience similar situations with regard to their health and access to healthcare research has focused almost exclusively on the latter rather than on the former. In addition, environmental change migrant population are usually the most vulnerable because migration is often expensive and climate change factors can easily be in addition to other strong socio-economic factors. For example, Haiti and Bangladesh were respectively ranked 3^rd and 6^th globally in the Long-Term Climate Risk Index (CRI) from 1995 to 2014²¹, while their health systems’ performance were ranked by the WHO in 2000 as 138^th and 88^th, respectively, out of 191 countries²². The very recent Global Climate Risk Index 2018 confirms Haiti and Bangladesh as high risk countries but also shows that several African countries (Mozambique, Malawi, Ghana, Madagascar) are highly affected and have little research on climate migrants²³.

In parallel, some individuals might be escaping slow-onset disasters, such as rising sea levels and declining agricultural yields; their migration patterns may be more similar to those of rural–urban migrants, and they might experience many similar obstacles and barriers to their health as well²⁸. It can be observed from the literature that some health related challenges may be identical between these migrant groups: First, the re-emergence of infectious diseases and geographical migration of diseases²⁹. Migrants spatially re-distribute infections from endemic areas to new populations; they are also exposed to new diseases due to unsanitary living conditions. Second, reduced access to healthcare services: mass migration applies population pressure which can exceed the capacity of the local health and social services. Perceptions of long wait times, confusing administrative procedures, or discrimination also impede health system access for migrants³⁰. Third, disrupted social support networks contribute to adverse mental health outcomes³¹, higher risk of violence, and spread of STIs, including HIV infection. Migrants are often perceived as potential security challenges for countries^18,32. Niger is one example that has conducted research to understand the phenomenon of infectious diseases and migration, and how the health system can best adapt (Box 2).

However, the lack of consensus on what constitutes a climate change migrant suggests that the same concept is defined differently across a wide range of non-integrated disciplines, leading to poor documentation of the health needs and health seeking behavioral patterns of climate change migrants.

Climate change and health systems

With its inclusion in Goal 3 of The Sustainable Development Agenda, the concept of Universal Health Coverage (UHC) has obtained consensus from the international community³⁶. UHC, regarded as the third global health transition³⁷, or, according to former WHO director Margaret Chan, “the most effective concept that public health can offer”, aims at ensure access to good quality care and limit the impoverishment of people as a result of their illness³⁸. In September 2015, the Director of WHO/PAHO for the Americas, Carissa F. Etienne, stated that “we must all cooperate to reduce those factors that are contributing to climate change and to mitigate its health effects.” Health systems are one of the major mediators in this relationship between climate change and population health. Consecutively, in September 2017, the new WHO Director-General has set UHC as his greatest challenge and highlighted at the UN General Assembly on Migration Health in New York City that “health systems must be sensitive to the needs of migrants.” The direct and indirect effects of climate change on population health and disease development are now well discussed^5,39, but there is still little literature on the health effects of migration (within and between countries) influenced by natural disasters and droughts exacerbated by climate change⁵. In addition, the role of the health care system as a social determinant of health⁴⁰ and its capacity to protect populations affected by climate change was recently identified by WHO⁶ and the Canadian Public Health Association (CPHA)⁴¹. Following the famous Canadian approach to health promotion and the social determinants of health, CPHA emphasizes, for example, the principles and practices of environmentally responsible health care.

Health systems (and health professionals) suffer the shocks provoked by climate change and migration^42,43. These shocks can be the direct consequence of climate change (floods, heat waves, hurricanes, etc) or indirect effects, i.e. the influx of patients suffering from diseases whose emergence or abnormally high frequency is due to climate change⁴⁴. Therefore, health care systems need to adapt to population migration (in and across countries) due to climate changes by considering the effects of both phenomena: 1), the diseases epidemiology evolution⁴⁵ (e.g. dengue vs malaria) and its impact for the population behavior and important skills for health professionals and 2) the identification and response to specific social (e.g. social acceptability of migrants)⁴⁶ and health problems of patients and professionals (e.g. mental health) in this context. In this sense, there is a very close link between UHC and emergency preparedness, as the WHO has just pointed out calling for “a mutual reinforcement of emergency preparedness and health systems strengthening strategies”. Health security must also be achieved through good health systems preparedness for disasters caused by climate change⁴⁷. The capacity of health systems and their actors to prepare for and adapt to these climate-related shocks is known as resilience.

Current research practice largely overlooks the interconnection between climate change, migration, and health system, so the three areas of work are largely treated in isolation from one another. However, to better understand how health systems may be resilient to climate change shocks, the collaboration and integration of different areas of work is needed.

Health systems resilience in the climate change context: still unclear concepts

According to the Sendai Framework (2015–2030) adopted at the Third United Nations World Conference on Disaster Risk Reduction in March 2015, it is essential “to enhance the resilience of national health systems”⁴⁸. Still, very little attention has been paid to the role of the health system resilience in responding to climate change^42,43,49. One of the major global health journals (Health Policy and Planning) released in November 2017 the first, to our knowledge, supplement issue about “Resilient and Responsive Health Systems”⁵⁰. None of the 11 articles, however, addressed climate change. Similarly, in 2015, WHO proposed an operational framework to build climate resilient health systems within the context of climate change⁴², but the scientific and empirical basis for its production is unclear, and the issue of population migration is not mentioned.

Thus, the question of health system resilience regarding climate migration is still in its infancy regarding the concept itself and its indicators.

Resilience is a longstanding concept in the disciplines of life sciences, psychology (Box 3) and climate change⁵¹, but it is relative new to the study of health systems^43,52,53. Health system are compounded of both hardware (structure, organization, technology, resourcing) and software (values, norms, actors, relationships) components, and their resilience requires that they be understood and measured accordingly⁵⁴.

Recently, an article has developed a non-normative index for assessing the resilience of health systems, but its validation has not yet been completed⁵⁹. The Lancet Countdown paper series has adopted an iterative and open approach to the development of indicators to identify the links between climate change and public health. The 2018 Lancet Countdown report suggests some indicators in its section 2 to point out how the health sector should be at the forefront of adaptation efforts, ensuring health systems, hospitals, and clinics remain anchors of community resilience. Among those, indicators 2.1, 2.4, 2.6; 2.7, 2.8,) (Box 4), can be useful to understand the link between climate change and health system resilience. Although the concept of health system resilience adoption is still limited and “does not capture the quality or effectiveness of efforts”, as it was described for the 2017 report^5,60 neither the resilience of health staff nor community is taken into account. The authors of this manuscript consider the selected indicators as a good example to highlight the still reductionist and uni-disicipline approach of how resilience is interpreted.

Health systems’ resilience cannot be evaluated only in terms of infrastructures. In contrast, from a more holistic and fundamental research perspective, several recent articles propose conceptual frameworks^52,53,59 that suggest analysing the five main dimensions of a resilient system: awareness, diversity, self-regulation, integration, and adaptiveness⁵³.

For interdisciplinary research

As described above with reference to existing literature, current research practice largely overlooks interconnections between climate change, migration, and health system. Typically, these 3 areas of work are treated by different groups of scholars, and the various dimensions of the links between migration and health are understood in isolation⁴⁵. In the same way, migration, climate, population’s health and resilience of health systems are typically analysed as separate components through disciplines and approaches in silos. Research on the intersection between all these components is very scarce. Consequently, there are gaps and a predominant compartmented analysis on the existing links between all of them. In contrast, interdisciplinary indicates a certain level of integration of knowledge, methods and/or ideas to construct and analyse the issue of study^61,62. Hence, interdisciplinary research can lead to a better understanding of the links between migration and health. By applying mixed methods⁶³, and the collaboration of environmental, health and social sciences, strategies can be informed and interventions to protect population health. “By learning from other researchers one increases the possibilities of creative solutions”⁶⁴.

Climate change is one of the main challenges of our century, having the potential to trigger important changes in population health which includes forcing migration. The role of health systems in the context of targeting universal health coverage may be central to address these challenges. Moreover, in the contexts of vulnerable populations and victims of climate change, health systems certainly have a very important role to play in preventing and alleviating health problems. However, vulnerable populations must be prepared to address these challenges and their resilience to climate change and potential subsequent population movements (climate migrants) is essential. This is why, for example, countries in the Americas Region adopted their health systems resilience policy in 2016 in favor of the UHC⁶⁵.

As revealed in this manuscript, the research on the intersection between climate change, health systems, and migrants is still very scarce. Because of its complexity, we need to move from a multidisciplinary (collaboration of different disciplines not necessarily from the beginning and towards a same issue) to an interdisciplinary approach (integration of different disciplines usually through a common design for a integration and holistic understanding of the same issue)⁶⁴ to understand the multiple pathways that link migration driven by climate change and population’s health.

Climate change, and in particular the issue of climate migration, is an extremely complex issue at the crossroads of multiple and fragmented research sectors (migration, population, health system, climate). The guide for interaction of the SDGs is a perfect illustration of the importance of this intersectorality⁶⁶. Thus, in the face of this complexity, it becomes impossible to mobilize fragmented disciplinary approaches in silos (earth science, demography, political science, economics, anthropology, clinical science, etc.) because they alone will not make it possible to understand the holistic nature of the phenomenon of the relationship between climate migration and health systems. This interdisciplinary approach, “which requires, rather than avoids, disciplinary specialization”⁶⁴ is also essential to understand the concept of health system resilience because knowledge about it is still too fragmented. A recent scoping review of the literature shows that the conceptual of health system resilience has not yet been sufficiently studied from an interdisciplinary perspective⁶⁷. As Bhaskar et al. (2017) described “by learning from other researchers one increases the possibilities of creatives solutions”⁶⁴ (4) and we definitely need solutions to improve the resilience of health systems for vulnerable population. As a very recent comprehensive review argues, further investments in interdisciplinarity collaborations should be made to unravel the link between climate change, migration, and health system resilience⁶⁸. It is therefore necessary to move beyond sectoral and disciplinary approaches to engage in intersectoral, systemic and interdisciplinary research programs.

We propose a series of interdisciplinary research questions to provide initial guidance in this direction (Box 5). In Table 1 and Figure 1, we suggest a first summarization attempt of the challenges triggered by climate change for the resilience of health systems.

Figure 1. Health systems resilience in the climate change context.

Figure 1 illustrates the different possible pathways, the details of which are presented in Table 1. We present them as exploratory to show how many hypotheses there are to test and how many research questions are open. It also shows how only an interdisciplinary approach can certainly help us to respond to them.

The first column of Table 1 proposes four different pathways involving the four elements that concern us here: climate, health system, space, and population. These pathways are more or less direct or complex as shown in Figure 1. The second column presents the possible scenarios in the context of each of these pathways and the last two columns present the challenges they pose to the resilience of health systems. For the first pathway (1), we believe that heat waves and extreme cold pose challenges to health systems (e.g. engineering). The second pathway (2) explains, for example, that climate change can cause floods or hurricanes, which impacts space (territory) and poses new challenges to the resilience of health systems (e.g. training health personnel in disaster preparedness). The third pathway (3) postulates that climate change will have direct effects on local populations, such as the presence of dengue fever in areas where malaria was endemic, which in turn will require the health system and its actors (e.g. power and trust issues) to adapt to these epidemic or pathological changes. Finally, the last pathway (4) we propose is at the heart of our discussion. We propose that it is essential to develop interdisciplinary research to better understand the effects of climate change causing spatial change events (e. g. floods) and thus forcing populations to migrate (within or between countries), which can have major effects on the resilience of health systems (in home or host countries).

Table 1 is proposed for illustrative purposes, but it shows the complexity of the phenomenon and the multitude of pathways that interdisciplinary research could explore.

Data availability

No data are associated with this article.