World Migration Report 2024: Chapter 7
From climate change to food insecurity: Compounding and direct drivers of human mobility
The impacts of climate change on food insecurity and human mobility are nuanced and complex, as highlighted in Figure 1. Extreme processes associated with climate change, including sudden- and slow-onset events and environmental degradation,16 have the potential to affect food systems at every level of the supply chain. In parallel, global food insecurity has dramatically increased during the last 10 years, partially as a result of changes in the climate, but also due to an increase in conflict (both frequency and intensity) and economic slowdowns, compounded by the effects of the COVID-19 pandemic.17 Direct impacts of climate-related events on food security are most visible with sudden-onset disasters (such as hurricanes or floods), which tend to destroy community infrastructure or damage agricultural landscapes.
Slow-onset climate events usually associated with anthropogenic climate change (such as drought, rising sea levels, or land degradation), although less visible, also contribute to food insecurity by altering livelihoods and reducing population well-being, usually over a long period of time.18 The direct and indirect impacts resulting from suddenand slow-onset climate events are often compounded by social vulnerabilities, as in the case of food insecurity. Extreme and subtle climate events associated with climate change can be both direct and indirect drivers of migration and can, therefore, affect human mobility in a non-linear way.19
When it comes to identifying both the impacts of climate change on human mobility, and the causes of changes in climate, a key challenge is current, natural climate variability. Climate variability – including variability that operates at interannual and decadal scales – can mask or enhance the current effects of human-induced changes in the climate system. Additionally, while some of the impacts of climate change have been associated with both food insecurity and human mobility, it remains difficult to isolate climate factors from other dynamics (such as non‑climatic environmental processes, or social, economic and political factors).
The IPCC framework defines climate risk as the interaction between climatic hazards, climatic exposure and climatic vulnerability. Following this definition means that when assessing exposed food systems, climate risk analysis must consider the vulnerabilities of the exposed populations (including their sensitivity to the hazard and their adaptive capacity). These vulnerability factors include income level, access to land and land tenure security, the fragility of food production systems, access to water for irrigation, access to information, and loss and damage from sudden-or slow-onset climate events.20 Food systems exposed to climate hazards in vulnerable contexts are therefore at risk of experiencing several climate stressors, “with the largest effects being decreased crop yields and livestock productivity, as well as declines in fisheries and agroforestry in areas already vulnerable to food insecurity.”21
While studies in various countries suggest a link between rainfall variability and food insecurity, creating conditions for increased migration in vulnerable areas,22 research in African regions note that the intertwined impacts of global heating and social, economic and political factors on human mobility is not automatic but remains diverse.23 The range of impacts of climate hazards on human mobility is further explored in the next sections, where case studies of conditions of heightened vulnerability suggest multiple scenarios of climate-driven mobility. Within these scenarios, the IPCC recognizes the following potential outcomes: adaptive migration (as a relative choice at the individual and household level); involuntary migration and displacement, planned relocation and immobility.24
Sudden-onset climate hazards
Sudden-onset disasters impact people’s lives profoundly, often without warning, making the most basic of needs difficult or impossible to meet for entire communities. There are many different examples of how climate-related floods, hurricanes, wildfires and other sudden disasters have resulted in food insecurity. Floods affected food security, for example, in several locations in Africa between 2009 and 2020.25 In some countries of South Asia (such as Bangladesh, India and Pakistan), extreme floods are becoming more frequent and are expected to increase in magnitude as well, causing heavy damage to rice plantations, affecting mostly vulnerable minorities of the population.26
In 2022, Pakistan suffered what the Prime Minister called the worst floods in its history, destroying thousands of hectares of farmland, significantly impacting food production in the country and driving almost a quarter of that year’s global disaster displacements.27 In Nigeria, a study revealed that floods increased the number of food insecure households by 92.8 per cent, turning communities into food insecure sites, further delaying developmental goals.28 In Afghanistan, a study found similar results, suggesting that increased exposure to flooding decreased calorie and micronutrient consumption, with other associated impacts on household income even after the flooding event.29
Migrant voices
“We are now struggling. Many years ago, things were better. We knew when the rains would start and end, but now nobody knows…. Rainfall was very favourable in the last 10–20 years compared to today. One could cultivate small parcels of land and harvest a lot. Today, the rainfall is very unpredictable; we would rather farm larger land sizes and harvest little…. Because of a severe drought, my family and I moved permanently to the river some distance away. But this was difficult because of fighting going on in that area and eventually we moved because of it” (Woman from the Sudan, Fugnido Camp, Ethiopia).
Source: Tamer et al., 2012.
Hurricanes have also been associated with a rise in food insecurity in Haiti, with severe impacts being correlated with moderate to severe household hunger.30 In the United States, hurricane Harvey had a impact on food insecurity, with different groups affected differently; in particular, it had a stronger impact on displaced persons.31 Surveys in Ghana have also highlighted the impact of wildfires on food insecurity, both in terms of transitory food insecurity in the lean season following a crop-destroying wildfire, and in the long term, through negative effects on soil productivity.32 In Sahelian countries such as Mali, Senegal and Burkina Faso, rainfall variability and the early cessation of rainfall are linked to food security threats and food deficits.33
Slow-onset climate hazards
Just as is the case with the effects of sudden-onset hazards, the effects of slow-onset hazards like drought or rising sea levels (usually associated with the long-term influence of global temperature increases) can only be properly understood if we take an integrated approach to understanding their cross-scale interactions with food security and human mobility.34 Growing evidence points to drought as the main cause of shortage in world grain production,35 and drought remains an important driver of human mobility in sub-Saharan Africa, South Asia and South America.36 The vulnerability associated with drought in these locations will be different according to the social, geographical and temporal contexts of those affected. An assessment in the Middle East revealed that drought events impact agricultural production and food security, but that food security in this region is also affected by livestock health, population growth and the availability of agricultural products.37 Slow-onset climatic processes have been associated with both international and (especially) internal mobility, with case studies identifying populations leaving areas affected by various slow-onset hazards.38 For instance, in the Americas:
rural to urban migration in Northern Brazil, or international migration from Guatemala, Honduras and El Salvador to North America, are partly a consequence of prolonged droughts, which have increased the stress of food availability in these highly impoverished regions.39
Identifying the impacts of climate change on drought frequency and food insecurity requires acknowledging that rural and urban areas may experience hazards differently and may have different coping mechanisms.40 In detangling the complex relationships between food security, drought and migration, it is important to acknowledge the anticipated increased frequency of extreme heat events in urban areas that threaten habitability in tropical and semi-arid regions of the world.41
Migrant voices
“It’s really sad to see it. We are facing droughts and it makes it so difficult for us to grow our traditional foods like breadfruit. You can see from the distance that the sea is covering the land and pretty soon we will not be able to grow there. I am a strong believer of ‘if there’s a will, there’s a way’ because we don’t want to lose our land, we want to protect it by any means available to us.” (Nika, mayor of the remote outer atoll of Likiep in the Marshall Islands).
Source: IOM, 2022.
Aside from drought, rising sea levels and related effects have the potential to heavily impact food production and food security in coastal areas, such as in Bangladesh, where dedicated adaptation efforts are required to limit disasters.42 In coastal Cameroon, rising sea levels affect crop productivity and output through coastal erosion, flooding of coastal lowlands and saltwater introduction.43 Small island developing States are particularly exposed to sea-level rise; analysis in Kiribati, for instance, has highlighted that “rising sea levels, salinisation of aquifers, coastal erosion, changing biodiversity, increasingly frequent ‘king tides’ and drought” are increasing, affecting the well-being and food security of local populations.44
Although food insecurity partially derived from disasters remains a global challenge, its intensity is felt differently, as it intersects with multiple other variables.45 Food insecurity particularly threatens smallholder farmers in developing countries around the world, due to their limited adaptative capacity and dependence on subsistence agricultural outputs for consumption.46 In these cases, food insecurity is embedded in larger vulnerability dynamics that incorporate differentiated climate-related risks. The vulnerability of people encountering food insecurity is not evenly distributed: factors such as gender and age shape people’s experiences. Children are more likely to suffer from malnutrition, for instance, and, as a result of traditional gender disparities, women and girls are likelier to have poorer capacities to cope with climate change.47 Human mobility outcomes further depend on the different impacts of various hazards. Climate-vulnerable households can be affected by both sudden-onset hazards like floods and by slow-onset hazards like rising sea levels, further complicating risk assumptions.48
Multicausality of human mobility
The multicausality of climate change, food insecurity and human mobility, as well as the relationships between them, are very complex. Available evidence suggests that different levels of food security are related, at least partially, with the decision to migrate, and that they remain heavily shaped by gender and income levels.49 In some cases, food insecurity directly links climate disasters with the decision to migrate. However, food insecurity itself may be impacted by other factors, including social inequalities among affected communities, which shape individuals’ vulnerability and climate sensitivity levels.50 In the central dry zone of Myanmar, for instance, food insecurity and flood risks are a function of income, food production systems, transportation and access to water for irrigation, in addition to loss and damage from floods and droughts.51 In Chile, studies in the semi-arid region of Monte Patria highlighted that “uneven resource access, limited political bargaining power and the perceived impossibility to earn a sufficient income in the agricultural economy are locally considered as more important reasons for engaging in mobilities than considerations about climate change”; in particular, households and workers use preexisting labour migration channels to take themselves out of the municipality and towards the construction sector, to achieve higher education or to work in the mining industry.52
The intersection of climate impacts, displacement and conflict dynamics in the Lake Chad Basin has been well documented. There, reduced access to resources, compounded by the impacts of climate change, have strong impacts on livelihoods and food security, creating conditions for conflict and driving mobility.53 But climate change– migration–conflict dynamics are highly contextual: in Ghana, for instance, non-climatic and ecological conditions reinforce potential climate-induced conflicts, triggering migration and farmer–herder conflicts.54 And in Colombia, Myanmar and the United Republic of Tanzania, migration appears to be driven by structural vulnerabilities in areas with low resilience, and food security emerges “as a product of environmental changes (droughts and floods), [and] as a mediating factor detonating violent conflict and migration in vulnerable populations”.55
Migrant voices
“We come from the Izabal Department of Guatemala. We come from a rural community. I work in agriculture, sowing corn. There was also an okra plantation at some point. We mostly work on our land. We live on basic grains, crops, and from selling our products to buy the sustenance of our children, living day to day. When a disaster strikes, we are vulnerable. With these storms that came, these hurricanes [Eta and Iota in November 2020] we were hugely hit, which left us more vulnerable than we were. We are in a situation where we don’t know where to go”.
Source: IOM, n.d.
In Guatemala’s Dry Corridor area, coffee cultivation, dependence on low-skilled labour and poverty levels are associated with food insecurity. In addition, the impact of consecutive drought, ill health and lack of income to buy medicine further exacerbate vulnerability.56 In Guatemala, the majority of very poor and poor households in the Dry Corridor area acquire their food by purchasing it with income derived from working at coffee farms or in the sugar cane industry (more than 80%), while some grow it (less than 5%) and some collect it from wild sources (1–10%),57 showing the intricacies and non-linearities of the climate–food security–migration nexus, and entry points for adaptation to avoid food insecurity outcomes (see the figure in Appendix B).58 However, a recent study in Guatemala suggests that climate (for example, exposure to drought) is not the main variable directly associated with the decision to migrate.59 Similarly, in Honduras modest prices are paid to small-scale coffee farmers, which are then used to buy food. Hondurans in those areas are affected when coffee prices decrease, such as when international coffee prices hit historic lows in September 2018, with an impact on international migration to the United States.60 The impact of climate change on food security through a reduced availability of wild plant food sources has been assessed in southern Africa as a cause for concern under high emission scenarios.61
Estimating future impacts
Estimating future patterns of climate change-induced migration remains challenging, in part because suddenand slow-onset climate events have not been considered in many of the models of climate migration, except for the Groundswell Report, which addresses water scarcity, declining crop productivity and rising sea levels as drivers of migration.a A useful summary is provided in the IOM paper prepared for the Twenty-eighth Conference of the Parties to the United Nations Framework Convention on Climate Change (COP28).b With increased global mean temperatures as a consequence of greenhouse gases produced by industrialized countries, tipping points triggering mobility among low-income households may emerge.c Some of the current models projecting migration changes do not necessarily capture these “tipping points” of climate phenomena that influence climatic conditions, like El Niño Southern Oscillation (ENSO), that account for a great portion of climate variability in several regions of the world. Future migration models tend to focus on the potential impact of long-term trends of water availability for crops and crop yields, mostly considering temperature and precipitation variables. These models have limited applications for predicting rapid-onset disasters potentially related to food security outcomes and human mobility, as in the recent case of Eta and Iota in Central America.d
Immobility and poverty traps
While climate change is clearly linked to food insecurity and increased mobility, as the previous section has shown, climate hazards and food insecurity do not inevitably lead to the increased mobility of affected populations. In different scenarios, climate hazards can result instead in increased immobility, with distinct socioeconomic implications. In a region of Guatemala, for instance, a study found “no correlation between migration to the US and severe food insecurity in households, but the correlation became significant if the level of food insecurity was moderate, suggesting that families in extreme hardship did not have the resources to migrate.”62 In many settings, immobility is driven by multiple factors, including the availability of resources, gender dynamics and place attachment, in a continuum ranging from “people who are financially or physically unable to move away from hazards (i.e. involuntary immobility) to people who choose not to move (i.e. voluntary immobility) because of strong attachments to place, culture, and people”.63
Looking at international movements, future projections suggest that climate change can induce “decreases in emigration of lowest-income levels by over 10% in 2100 and by up to 35% for more pessimistic scenarios including catastrophic damages”.64 In Zambia, vulnerability to climate change acts for some groups as a barrier to migrate, as “poor districts are characterized by climate-related immobility”.65 Persistent poverty means that some families cannot bear the financial cost of migration, and therefore remain trapped in climate-vulnerable areas. In Bangladesh, residents of climate-vulnerable villages who would like to relocate from their current residence are sometimes unable to do so because of financial barriers, lack of access to information, lack of social networks and unavailability of working-age household members.66 In these circumstances, well-planned and supported climate mobility, including relocation, may enable increases in well-being and positive outcomes.
Migrant voices
“Extreme weather from the North took my house, washed it away. I was left living in sand, right now my house is made of sand and sheet metal that I had made, but we have nowhere to go. We are poor, we are poor people” (Ricarda Flores, in Tabasco, México).
Source: Ortuño, 2022.
The complexities of mobility discussed above are important because they nuance a simplistic view of human mobility as a natural consequence of climate change impacts and food insecurity. As summarized by the IPCC, “specific climate events and conditions may cause migration to increase, decrease or flow in new directions”.67 Similarly, it would be inadequate to surmise that food security adaptation efforts in a particular region or in response to a particular event will automatically lead to reduced mobility. Climate adaptation and food security policies can offer alternatives and resources to members of exposed households, who may opt to engage in safer and more regular forms of migration. In northern Thailand, research has shown that, given local circumstances and migration trajectories, successful climate adaptation interventions do not prevent migration.68 Furthermore, the most food-insecure populations are not likely to have the capacities and resources to migrate. Evidence suggests that migration is “mostly driven by structural vulnerabilities and unsustainable development pathways”.69 As a result, and as discussed in later sections, the objective of policy approaches should not be to prevent migration, but to address adverse drivers and enable migration as a possible choice that allows for achieving global development goals, rather than treating migration as a necessity undertaken to avoid calamities.