The influence of climate change on migration, both current and future, has attracted significant attention from the public and policymakers over the past decade. A new study led by IIASA has provided the first comprehensive analysis of how climate factors (specifically drought and aridity) affect internal migration.
While public discourses often focus on international migration, existing scientific evidence indicates that when climate factors drive migration, it often results in short-distance movements within national borders. However, scientific studies examining climate-induced internal migration in different countries are lacking. The new study, published in Nature Climate Changeused census microdata from 72 countries spanning the period 1960 to 2016 to provide the first global assessment of how environmental stress affects migration within national borders.
“Our analysis shows that internal migration, which we define as movement between subnational regions within a country, increases in regions affected by drought and aridification, especially in arid and hyper-arid regions. The effects are more pronounced in rural areas and agriculture-dependent areas, where livelihoods are highly vulnerable to changing climate conditions. Many climate-induced migrants move to urban areas, contributing to the accelerated urbanization trends observed in numerous countries,” he explains. lead author Roman Hoffmann, who heads the Migration and Sustainable Development Research Group at. IIASA.
The analysis revealed regional differences in impacts. For example, the effects of drought and aridification were found to be strongest in parts of Africa, the Middle East, South America, South Asia and Southern Europe, where agricultural livelihoods and climate already prevail. It’s dry. In these regions, the combination of economic difficulties and environmental challenges creates strong incentives for migration.
Globally, the findings indicate greater mobility overall in wealthier areas where restrictions on migration may be lower. Within countries, it is often the poorer regions that tend to have higher rates of emigration to wealthier areas when affected by climate stress. In addition to regional differences, the study also documents important heterogeneities in migration patterns between population groups. In less developed countries, younger adults of working age (aged 15-45) with average levels of education are more likely to migrate in response to drought and increasing aridity. In richer countries, older populations at all educational levels show stronger migration patterns.
“As climate change continues to increase the frequency and severity of droughts and water scarcity around the world, more populations will face pressures to seek better living conditions. Our work underscores the need for policies that address both the drivers of migration and the consequences for destination regions. Adequate infrastructure, health services and social support systems are critical in urban areas that are increasingly absorbing climate-induced migrants,” says co-author Guy Abel, a researcher at the IIASA Research Group on Migration and Sustainable Development.
Additionally, research highlights the importance of supporting vulnerable populations, including those who cannot migrate due to resource limitations. Policies that promote livelihood diversification, social safety nets, and building resilience in affected communities can help mitigate forced migration and displacement, while protecting those who remain.
Although the study represents a major step forward in understanding the links between climate change and internal migration, the authors also recognize the challenges posed by limited and non-comparable migration data. The data set used in the study, drawn from census microdata, provides a robust longitudinal view of internal migration for a large number of countries. At the same time, it does not capture other forms of movement, including temporary or short-distance mobility, which are also highly relevant in the context of climate change.
“As climate change continues to reshape migration trends, more comprehensive data and continued research will be essential to develop targeted interventions and policy solutions to address the complex relationship between environmental factors and human mobility. Our work highlights the urgent need to a holistic approach to development policies that takes into account spatial and social differences, recognizing the complex and context-dependent nature of migration dynamics,” concludes co-author Raya Muttarak, researcher at the IIASA Research Group on Migration and Sustainable Development and Professor of Demography and the Department of Statistical Sciences at the University of Bologna, Italy.