What it is
Analysing global subnational net-migration data, the authors show that the association between climate extremes and migration is not uniform but varies by hazard type, timing, consecutive events, income level, and pre-existing migration context. Floods are associated with decreased net migration across contexts, with effects lasting several years and stronger in lower-income areas, whereas droughts are associated with migration mainly in higher-income settings and over shorter terms. Tropical cyclones correspond to decreased net migration primarily in lower-income areas with multi-year effects, and for compound (repeated) exposure droughts show the clearest pattern, with prolonged exposure linked to reduced inflows into population-attracting areas.
Why it matters
Most analysis of climate and migration is short-term and coarse, leaving the longer-term and compounding effects, especially at the subnational scale, understudied. By separating hazard types and conditioning on income level, timing, and pre-existing migration context, this study shows the climate-migration relationship is heterogeneous rather than a single effect: sign, duration, and income-dependence differ across floods, droughts, and tropical cyclones. That context-specificity is what makes the associations usable for anticipating where mobility responds and how.
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Filed underClimate Change, Adaptation, Migration, Climate change impacts on agriculture, Climate variability and models