It's not just coastal cities bracing for sea-level rise or farmers battling erratic weather patterns—millions of people are being driven by changing climates to relocate, not across borders, but within their own countries. A study by Marco Percoco (Director of the GREEN Research Center at Bocconi), Roman Hoffmann (International Institute for Applied Systems Analysis, Austria), Guy Abel (Department of Sociology, The University of Hong Kong), Maurizio Malpede (University of Pavia, Italy), Raya Muttarak (University of Bologna, Italy) and published in Nature Climate Change investigates the dynamics behind this internal migration. Analyzing over 107,000 migration flows within 72 countries between 1960 and 2016, the research reveals that as droughts intensify and regions become more arid, the movement of people accelerates. The results show a clear pattern: "When faced with environmental pressures like prolonged dryness, many people see migration as their least bad option," says Marco Percoco.
Drought's role in shaping migration
Drought has the power to uproot lives, especially in regions such as Southern Europe, South Asia, Africa, and the Middle East. A 1-standard-deviation increase in aridity was found to raise out-migration rates by as much as 9.3%, highlighting just how significant environmental factors have become in influencing mobility. As the authors put it, "In many areas, people are not just choosing to move—they're being pushed by environmental conditions that make staying increasingly untenable."
But the relationship between climate and migration isn't uniform. In wealthier nations, overall migration rates are higher, possibly due to more affordable movement options. Yet, within these countries, it is often the poorest regions that see the highest rates of out-migration. This suggests a complex interplay where economic constraints can both enable and limit migration. As Marco Percoco notes, "While wealthier areas might offer more opportunities to move, it's often those from the least advantaged areas who feel the most pressure to leave."
Climate change hits rural communities
Rural areas, particularly those dependent on agriculture, are hit hardest by climate changes. The paper points out that these communities are most likely to experience the effects of worsening droughts. In regions where farming is the main source of income, drying soils and dwindling water supplies translate directly into lost livelihoods. This often leads to migrating towards urban areas, where opportunities may be scarce but are perceived as more stable. "The move to cities is a coping strategy, a way for rural families to adapt to conditions that no longer support their way of life," the authors explain.
Urban areas themselves are less likely to lose residents due to arid conditions. Instead, they become magnets for those fleeing drought-stricken rural areas, intensifying the flow of people into cities. This trend is reshaping urban landscapes, as new migrants bring their needs and challenges, adding further pressure to an infrastructure already under stress.
A complex interaction of different factors
The effects of climate change are felt differently depending on age, education, and regional context. Younger adults and those with secondary education are often the first to move from poorer regions, driven by the hope of finding better opportunities elsewhere. In wealthier countries, older populations show a surprising tendency to move in response to environmental changes, perhaps due to retirement migration or a desire to relocate to more hospitable climates.
Implications for a warming world
As drought becomes a more common driver of migration, the need for proactive strategies becomes urgent. The authors call for improved support systems in urban areas that often become destinations for climate migrants. "We need to think ahead and ensure that cities can accommodate this influx, providing housing, jobs, and services for those displaced by environmental stress," Percoco advises.
Moreover, the study emphasizes the importance of policies that help rural communities adapt in place, reducing the need for migration in the first place. Better water management, agricultural innovation, and social safety nets could help stabilize populations and allow people to continue their lives without being forced to move. This holistic approach, according to Percoco and his co-authors, is crucial to addressing the root causes of climate-induced migration.
Marco Percoco and his colleagues challenge traditional views of migration as a primarily economic or conflict-driven phenomenon, showing that in many regions, environmental factors are becoming equally significant.
