Climate change and rural livelihoods: How extreme heat drives international migration from El Salvador

Editor’s note: For a broader synthesis of themes covered in this article, check out our VoxDevLit on Climate Adaptation. The authors have made slides available to accompany this research here.

Extreme heat waves are becoming more frequent and severe – a trend expected to accelerate in the coming decades (IPCC 2021, Kala et al. 2023). Extreme heat erodes crop yields, cutting agricultural productivity and rural incomes, particularly in rain-fed regions where small producers have few tools to manage risk (Deschênes and Greenstone 2007, Jessoe et al. 2016). If these trends persist, the rising cost of climate change could hurt hundreds of millions of people and hamper global efforts to reduce rural poverty (Lowder et al. 2016).

Policymakers now face a pressing question: should adaptation efforts focus on financial instruments, insurance, and technology, or should migration be recognised as an important coping strategy? When insurance and credit are scarce, rural households often respond to income loss by selling assets, adjusting farm practices, relying more on family labour, or migrating (Rosenzweig and Wolpin 1993, Jayachandran 2006, Carter and Lybbert 2012).

Our recent research contributes to this policy discussion by estimating the impact of exposure to extreme heat on agricultural production in El Salvador and examining how corn producers respond to extreme temperatures – especially in a context where support from established migrant networks lowers the costs of international migration (Ibañez et al. forthcoming).

Extreme weather and international migration in El Salvador

El Salvador is a case in point. The country lies within Central America’s ‘Dry Corridor’, a region marked by recurrent droughts, heavy rainfall, and rising temperatures. In the past decade alone, El Salvador has experienced three major droughts, the most severe being in 2015. Agriculture remains central to livelihoods: roughly 87% of Salvadoran farmers are smallholders managing plots of around 1.2 hectares that are almost entirely rain-fed. These producers have limited access to irrigation, credit, or insurance, leaving them highly exposed to extreme weather fluctuations.

In this context, when agricultural yields decline, households have few mechanisms to protect against income losses. They can, for example, sell assets, reduce consumption, or rely more on family labour. Others turn to migration – an option made more feasible by strong networks abroad.

Migration from El Salvador to the US has deep historical roots. Large-scale outflows began during the civil war in the 1980s and have continued through decades of economic and social instability. By 2017, around 30% of working-age Salvadorans lived in the US. These long-standing ties reduce both the financial and psychological costs of moving, enabling international migration – even temporary migration – as a coping strategy when heat exposure disrupts rural livelihoods.

Connecting extreme temperatures, labour markets, and migration

Using nationally representative data on households and agricultural producers from 2009–2018, we examine how extreme heat affects local economies in El Salvador. This allows us to estimate the causal impact of heat exposure on crop production, labour allocation, and international migration.

Our results reveal a clear sequence of effects. Intense heat significantly reduces corn yields and forces farmers to adjust labour and input use. With little irrigation or insurance, most smallholders have limited room to adapt, cutting back on hired labour and relying more on family members – a coping strategy that can increase unpaid or child labour.

Declines in corn production affect agricultural labour markets, as producers lower their demand for hired workers. While some households move into non-agricultural activities, our findings do not provide evidence of full absorption or partial reallocation outside agriculture. We also find suggestive evidence of a decline in average wages among workers employed in corn production. However, we do not have robust evidence to assess the extent to which the non-agricultural sector can absorb these displaced workers.

The role of migrant networks

With limited access to risk-coping mechanisms, international migration – when financially feasible – becomes a viable response to income loss caused by extreme temperatures. Strong migrant networks lower the costs of moving abroad, while limited local job opportunities make migration one of the few remaining options.

Remittances and migrant networks play a central role in this process. In El Salvador, remittances account for nearly 24% of GDP (World Bank 2023), providing support for households that remain behind. These same remittance networks also finance and facilitate new migration. Municipalities with stronger migrant networks show a higher probability of international migration following exposure to extreme weather, underscoring how established corridors amplify the link between extreme temperatures and migration.

Not all migration is distress migration

Climate-related migration takes different forms. Following Kleemans (2023), we distinguish between two channels:

• Distress migration: Immediate responses to income loss, as households send a member abroad to stabilise consumption.
• Investment migration: Moves undertaken after good harvests, when households use accumulated resources to finance migration as a strategic investment in higher earnings abroad.

We find evidence of both. Short-term heat shocks trigger distress migration, but repeated bad shocks can trap households in poverty, making migration unaffordable. Conversely, after good years, some households invest their gains in planned migration. Migration is therefore not always a ‘failure to adapt’ – it can also be a pathway to opportunity when households have agency and resources.

Policy implications: Climate change and migration

Although our research focuses on El Salvador, the mechanisms are applicable across many low-income regions where migration and remittances play central roles in rural livelihoods. Globally, around 30 million farms in similar contexts face rising climate risk. Two lessons emerge:

1. Without insurance, migration is a risk-coping mechanism to tap into: when extreme weather destroys crops and jobs, households turn to migration as their fallback strategy.
2. Migrant networks can help mitigate these shocks. Agricultural workers who lose their jobs may move to the non-agricultural sector or migrate to offset income losses. In places where migration costs are lower – particularly due to established migrant networks – migration becomes a more viable coping strategy. 

Reduce distress migration. Expanding crop insurance, credit, and climate adaptation tools – such as drought-resistant seeds and irrigation – would help households absorb shocks without resorting to migration. Strengthening humanitarian assistance after extreme weather events is also critical.

Facilitate mobility and adaptation. Where farming becomes unviable, migration can serve as an adaptation strategy. Supporting households’ ability to relocate – whether to nearby urban centres or across regions – can help accelerate structural transformation and reduce the long-term costs of extreme weather. Policies that lower remittance costs and protect migrant households can further enhance these adaptive benefits.

Recognise heterogeneity. Not all households can migrate, and repeated shocks may trap the poorest in place. Policies must combine local resilience-building with measures that support safe and viable forms of mobility.

When extreme heat reduces corn yields, producers cut back on hired labour, leading to income losses that prompt some households to seek alternatives beyond farming. In this context, strong migrant networks lower the costs of moving and help households use migration as one of several strategies to cope with and adapt to changing conditions.

Yet migration is not always a sign of crisis. While many leave in response to decreasing incomes, others migrate after experiencing positive income shocks, treating migration as an investment to improve long-term prospects. These contrasting patterns underscore that migration can serve both as a coping mechanism and strategy for upward mobility.

Policies should reflect this duality. Strengthening insurance, credit, and technical assistance can help rural households withstand weather shocks without being forced to leave. At the same time, facilitating mobility where agriculture becomes unviable – by improving access to credit, reducing remittance costs, and supporting safe channels for financial transfers – can turn migration into an engine of adaptation and structural change.

References

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