Abstract
Introduction
The scale of the interconnected climate–migration–health security challenge is immense and challenging to quantify. An individual's or community's decision to move is multifactorial and can range from voluntary migration for economic opportunities to forced displacement to escape life-threatening situations. Climate change and human migration each have consequences for health system performance and outcomes and are important considerations in planning and programming for global health security challenges. The ability of an individual or family to migrate is an important variable—some drivers of migration, like climate change, can suppress the mobility of “trapped” populations, whose precarity precludes their ability to seek opportunities elsewhere. 1
The recent experience of migrants enduring the twin stressors of COVID-19 and climate change further underscores the complexity of intersecting crises. Migrants have faced heightened risk of infection during the pandemic, as many have been unable to adhere to preventive measures like social distancing or to access health systems, which have not been available or tailored to serve their unique needs. 2
Climate change and human migration have direct and indirect consequences for individual health and overall health system performance and outcomes. They are important considerations in planning and programming for global health security—the field concerned with public health challenges that negatively impact health and economic conditions across borders and regions. 3
In this commentary, we explore the relationships between climate change, migration, and health security and define the health risks that migrants face while on the move and upon arrival to destinations. In the context of these challenges, we explore the concept of health system resilience, defined as the ability of a health system to prevent, prepare for, respond to, and recover from public health emergencies. 4 We then conclude with strategic considerations for policy and program design along 3 potential workstreams: adaptation in place, facilitation of safe migration, and programs for migrants at points of destination.
Climate Change and Migration
Climate change impacts on food and water security, sea level rise, extreme temperatures, air quality, and extreme weather events affect livelihoods and reduce livability. 5 Climate shocks and pressures are an additional stress on households and communities already facing limited economic opportunities, social or political marginalization, and poor governance. A range of responses include adapting in place, migrating as an adaptation strategy, distress migration, and forced displacement in the face of life-threatening risks. Migration and displacement may be temporary, seasonal, circular, or permanent.
Climate impacts affect people's health, safety, and livelihoods, and can accelerate or suppress migration in various contexts. Weather-related disasters, for example, currently internally displace around 26.3 million people annually, with additional people migrating away from areas of climate stress. 6 Others, however, are at risk of becoming “trapped” in situations of increasing climate risk without the ability or resources to move. Low rainfall shocks, for example, can suppress migration in certain contexts, particularly in low-income countries. 7 Inherently contextual household-level factors such as livelihood source, savings, gender, age, health, and income further influence adaptive capacity and migration decisions.
As climate change increases the frequency and severity of climate-related impacts, people are increasingly being pushed toward distress migration, subjecting them to crises related to health, housing, education, poverty, and gender inequality.
Climate-Related Migration and Health
Climate change, migration, and health are closely linked. First, climate change directly impacts both migration (as described earlier) and health, although specific mechanisms are heterogenous and context specific.5,8 Climate change negatively affects lifelong physical and mental health, mortality, food security, and access to essential services, such as healthcare; water, sanitation, and hygiene; and education. Climate-driven food insecurity, water scarcity, and diminished water quality lead to poor nutrition, waterborne diseases, and poor hygiene. Extreme climate events cause injuries and damage to primary health infrastructure. Voluntary migrants and those displaced by climate shocks alike require access to healthcare, clean sanitation facilities, hygiene, and safe drinking water to prevent the spread of diseases like cholera, which can cause serious illness and death.
Second, migration has substantial consequences for migrants and health systems at large. These consequences manifest while migrants are on the move and at temporary or long-term destinations. Migrants face heightened risk of gender-based violence, human trafficking, and mental health disorders throughout the migrant journey.9,10 En route, migrants often lack access to adequate shelter and face increased exposure to climate risks such as intensifying heat and storms. Limited access to health services while in transit or at destination points contributes to delayed or forgone care for acute conditions and exacerbation of preexisting chronic diseases.
Characteristics of destination points further influence the health security implications of migration. These sites can include temporary locations like refugee or internally displaced person camps, or more long-term settings like informal settlements in urban and peri-urban areas. Since 2008, a majority of the world's population now lives in urban areas, and this proportion continues to grow. 11 Much of this urban growth is fueled by migration, particularly in secondary cities. Globally, an estimated two-thirds of internally displaced persons reside in urban and peri-urban areas. 12 These densely populated urban districts often have limited access to municipal services like clean water, sanitation, waste removal, and health services. Some may even be located in blighted districts like flood zones. 13 Migrants in these settings are thus exposed to infectious diseases (both water and vector borne), heat-related illnesses, and heightened disaster risk.
Integration of internal or international migrants into overburdened municipal service delivery systems and government-supported social safety net programs is often limited. Lack of social protection and financial inclusion, especially in employment security, disability protection, affordable dependent care, and healthcare access, limit the economic prospects of migrants. Additionally, migrants often settle in areas with high exposure to climate risks such as flood and urban heat. 14 The resulting experience is one of the interrelated risks of poverty, poor living conditions, reduced decisionmaking power due to social norms, and heightened exposure to existing and emerging diseases. As a result of these social determinants of health, migrants suffer higher burdens of disease, lower access to health services, and higher levels of financial hardship from health expenditures. 15 While conflict linked to climate-related migration is an additional concern, research examining the climate–migration–conflict nexus has not produced consistent evidence for a causal connection linking migration to subsequent conflict.
As with the broader impacts of climate change, marginalized and vulnerable populations experience the most severe extremes of this hardship.
Strategic Opportunities for Climate Migration and Health
While the health impacts of climate change add another layer of instability to the migration journey, there are numerous opportunities to support migrant health before migrating, during migration, and at destinations.
Strategies to Adapt in Place
With climate change increasingly impacting livelihoods, water quality and availability, infectious and chronic disease, and food security, there is an acute need for targeted adaptation and systems strengthening for climate resilience. Households, local and national governments, civil society, the private sector, and donors can implement a robust range of adaptation options to address the climate drivers of migration and support community health security. Specific examples include strengthening and expanding climate information services and capacity for risk-informed decisionmaking, disaster early warning systems, climate-resilient livelihoods and markets, local governance adaptation capacity, resilience of key infrastructure, sustainable natural resource management, and nature-based solutions for adaptation. Health service capacity, especially in high out-migration areas, should be strengthened to address health impacts from climate change through prevention and treatment, including surveillance and early warning of climate-sensitive diseases; heat-health action plans; air-quality management; behavioral, clinical, and public health interventions; and mental health services. A strong health system, including the capacity to meet ongoing and changing needs, is an important factor in overall community resilience. Improved health capacity includes strong national and subnational health system governance related to forecasting, planning, budgeting, human resources, and supply chain management. Electronic health record systems and telemedicine services can extend the reach of the health system to those in need of services. 16 Countries' national adaptation plans can address climate impacts to health by including health sector vulnerability and adaptation assessments, institutional arrangements for coordination and collaboration among climate adaptation and health entities, and planning for adequate health sector resourcing, both human and financial, to increase climate resilience. 17
For some people and communities, migration to areas with more hospitable or economically advantageous environmental conditions (eg, healthy air quality or arable land) is an adaptation strategy to mitigate the health impacts on their families; however, this option may not be possible due to a myriad of factors. Recognizing that mobility has long been a key adaptation strategy around the world, governments can consider how to better support people who wish to migrate as part of their household or community adaptation approach.
Facilitate Safe Migration
As climate migration becomes increasingly common, identifying hotspots and common climate migration pathways will help partners develop and deploy appropriate services such as skill building, rights awareness, and integration and helpline services. 18 More also needs to be done to help address the protection gap and ensure the health of migrants in transit. Promoting and facilitating safe and regular migration includes improved access to justice; rescue and return services; individualized health, including mental health assessment; portability of benefits; and referral to appropriate services, especially for children. Enabling the portability of healthcare access, insurance, certifications, vaccination records, and other materials across regional and national borders will help reduce barriers to migrants accessing services in different locations. For individuals who are migrating through irregular channels or do not have health insurance or records, support should be provided to reduce gaps in care provision regardless of their migration status or phase in the journey. India's Ayushman Bharat Pradhan Mantri Jan Arogya Yojana (AB-PMJAY) universal health coverage program, for example, enables beneficiaries to access any empaneled facility across the country regardless of the state-based system in which they registered. 19
People who are displaced or voluntarily migrating may be particularly vulnerable to extreme weather and climate risks en route. Heat, flooding, and storms, coupled with difficult journeys and inadequate access to nutritious food and clean water, can lead to poor health or exacerbate existing health conditions. To address exposure to climate risks, proper care and management of health prior to migrating, linked with portable benefits and referrals at destinations, will improve disease prevention, continuity of care, and overall health.
Further contributing to unsafe passage is the underreporting of incidents of discrimination or victimization due to fears of deportation or detention. Collecting better data on migrants in transit, their motivations, their status, and their treatment en route will lend to more supportive policies and programs. In particular, data regarding children are needed to identify and respond to their unique needs. 20
The COVID-19 pandemic has revealed the importance of investing in the resilience of national and global health systems. High rates of employment in temporary, informal, or unprotected work can make migrants especially vulnerable during an emergency situation like a pandemic. Given challenges with work permits and visas, and housing situations that may be overcrowded, migrants may face limited access to healthcare services, personal protective equipment, and health insurance or other sick leave benefits. Furthermore, lack of access to clean, reliable, and affordable water remains one of the largest areas of concern among communities of likely migrants.
Work With Migrants at Destinations
Many of the opportunities to facilitate safe migration also apply to various destination areas, as a migrant's journey may include multiple destinations over a prolonged period of time. Systems need to be flexible and adaptable to respond to changing population size and demands, and sustainably financed to provide high-quality services. Everyone has the right to high-quality healthcare. 21 Specific policies can be put into place to easily enroll migrants for health services once they arrive at a destination. Local governments can then use these data to make evidence-based public policy decisions.
Additional anticipatory planning measures can be put into place for cities and other areas that are likely to draw migrants (ie, proximity to regions of high climate vulnerability, or cities with the lure of diverse economic opportunities). This includes using data analysis to track trends of where migrants and displaced populations are likely to go; where water, sanitation, and food supply chains need to be strengthened and flexible to meet growing population needs; and how health systems can be prepared to meet the needs of diverse communities, especially those who may have health needs that have gone without monitoring or treatment for a prolonged period. These data can also guide place-based, context-specific approaches to disaster risk reduction and mitigation.
Any health programming should consider digital health innovations to improve efficiency and impact and ensure that data are collected and reported in a disaggregated fashion (eg, by migrant status and occupation) to better understand the challenges facing migrant populations.
Local governments can plan for and encourage newly arrived community members to use social services such as health, education, remittance assistance, and job training. Governments should explore partnerships with formal and informal sector employers that predominantly hire migrants to improve access to and affordability of high-quality services, including healthcare, education, and childcare. Intentional linkages can also be created between the healthcare system; resettlement agencies; and education, faith-based, transportation, and housing organizations that serve migrants to better reach and care for them. Social service providers should be trained to serve the unique needs of migrants, including how to identify and assist individuals with mental health needs and individuals who have experienced gender-based violence. 9 Training community health workers on different language or cultural needs, how to build trust among migrant communities, and how to recognize migrant-specific health challenges will also increase demand for services. Migrants can also be reached by creating health promotion audio and visual materials that are tailored to these populations and their varying language or literacy levels. This media can be disseminated through multiple channels including messaging apps, local radio stations, and social media platforms. Programs in receiving communities in high in-migration regions can work to diversify the job market, ensure economic stability, and reduce xenophobia and racism.
Global Public Health Action
As a component of climate change adaptation action, the global public health community must prepare to meet the humanitarian and long-term needs of a growing population of forcibly displaced and migrant communities for whom returning home is not an option. Migrant and displaced populations often settle in marginal areas vulnerable to climate impacts such as flooding and extreme heat. Especially in cases of displacement, people often do not have a choice in where they settle (temporarily or more permanently). Efforts to improve the livability of high in-migration areas, such as peri-urban spaces, through health system policy reforms and infrastructure improvements will reduce climate-related health impacts and encourage future resilience.
Charting the Way Forward
As outlined in this commentary, there are numerous opportunities to ensure the health of people who move, forcibly or voluntarily, due to climate change. Adaptation-in-place strategies can increase community resilience in the face of a changing environment. For others, support along their migration or displacement journey can focus on continuity of care, health promotion, and data gathering for context-specific programmatic interventions. Additional consideration is needed for so-called “trapped populations” who are unable to migrate despite difficult local conditions. This support could take a variety of forms, with an emphasis on making migration safer and more accessible, and increasing the benefits of migration among both sending and receiving communities. Further, there is a critical need to accelerate climate change mitigation efforts to reduce and sequester greenhouse gas emissions and avoid the more severe climate change impacts on health and migration. This includes action in the health sector, which contributes an estimated 4.4% of greenhouse gas emissions globally.22,23
Climate migration and health security projections are challenging and at times controversial given the complex and interrelated factors driving them. Nevertheless, it is clear that climate change will cause humans to move in unprecedented numbers over the coming decades. This movement is inextricably linked to both global health security and broader progress toward the Sustainable Development Goals. Further research is needed to better understand how climate reacts with the other interrelated drivers of migration and the health impacts of these phenomena. Health security for migrants means health security for all.