A major
new study sheds light on how climate change and extreme weather are reshaping global migration — not just in terms of how many people move, but which groups are most affected. The findings reveal that age, education, and baseline climate conditions are decisive in determining whether people flee or remain trapped in place.
Events like the 2022 monsoon floods in Pakistan, which displaced 33 million people, and the rising outflow of rural Central Americans toward the United States, have highlighted how climate extremes amplify migration. Yet until now, the scientific evidence on this link remained contradictory.
The new research, based on an unprecedented dataset covering 71 countries for internal migration and 168 for cross-border flows (1988–2019), shows that extreme heat and water stress have sharply different impacts depending on people’s age, education, and socioeconomic conditions.
Who can move, who remains behind
The study confirms that environmental stress pushes some people to leave vulnerable areas, while for others it creates a kind of immobility trap, as depleted resources prevent them from migrating.
For instance, extreme heat and drought increase migration among older adults with little education, who may rely heavily on agriculture and feel the strongest push to move. By contrast, the youngest and least-educated populations — often the most vulnerable — migrate less, because they lack the means to leave.
Education emerges as a major factor. Within countries, in tropical zones, heatwaves boost migration among highly educated groups, but have almost no effect on those with lower education levels. Conversely, drought and floods tend to push less-educated populations to relocate, as seen in Kenya during the 2008–2010 drought, when rural outmigration to Nairobi surged sixfold.
Predictive power: demographics matter
The research shows that models accounting for demographic differences have five to twelve times better predictive power than traditional approaches assuming uniform migration responses. Overall, weather shocks explain a modest share of cross-border movements (about 0.4% of variation), but a much higher share of within-country migration (around 1%).
Geographic and cultural proximity remain stronger drivers of migration, but the study stresses that climate shocks are a non-negligible force — and they do not affect everyone equally.
Implications for the century ahead
Looking forward, the projections are stark. Under a mid-range climate change scenario (SSP2-4.5), migration rates between 2015–2035 and 2080–2100 are expected to shift by –31% to +26%, depending on demographics. Older adults with lower education will move significantly more, while younger and less-educated populations are expected to migrate less — not because they are safer, but because they may be too constrained to move.
The findings suggest that global debates about “climate migration” need to shift focus:
“It’s not only about how many people will move under climate stress,” the researchers conclude, “but about who will move — and who will be left behind.”
Comment