A recent study published in Nature Communications finds that age and education are key factors influencing who migrates due to extreme weather events such as heat waves, droughts, floods, and cold spells. The research challenges the common perception of mass migration caused by climate change, showing instead that while some groups are pushed to move, others become trapped and unable to leave.
“Weather extremes can both incentivize people to move away and increase the number of people who don’t have the ability to migrate,” said Hélène Benveniste, assistant professor at the Stanford Doerr School of Sustainability. “Our research shows that migration in response to weather, just like migration decisions in general, is highly dependent upon demographic characteristics.”
The study was conducted by Benveniste along with Peter Huybers from Harvard University and Jonathan Proctor from the University of British Columbia. They analyzed more than 125,000 cross-border migration cases from 168 countries and over 480,000 within-country moves across 71 nations. Each case was categorized by age, education level, sex, origin location, and destination. This information was then linked with daily temperature and soil moisture data.
Their findings indicate that models accounting for demographic differences predict migration patterns significantly better than those assuming uniform responses to weather shocks. Despite this improvement in prediction accuracy—up to 12 times better for international flows—the researchers found that weather accounts for only about 1% of historical changes in international migration. Other factors such as conflict or job opportunities play a larger role.
Following periods of high heat, children under 15 are less likely to migrate internationally while adults with little education—especially those over 45—are more likely to move. Adults with education beyond high school showed little change in cross-border movement due to weather.
“Our results indicate that many among those most likely to suffer from climate change impacts will not be able to get out of harm’s way,” the authors write. This leads to what they call a “double penalty,” where people least able to adapt locally also lose access to migration as an adaptation strategy.
Within countries, baseline climate conditions have a greater influence on mobility decisions. For example, adults with higher education living in tropical areas are more likely to relocate domestically when temperatures rise above certain thresholds; however, this effect is not seen among those with less education.
Projections suggest that if global temperatures rise beyond 2.1 degrees Celsius above pre-industrial levels by 2100, migration rates could increase by about a quarter among older adults with less education but decrease by up to a third among younger and least educated individuals—a much larger swing than seen when looking at population averages alone.
To isolate the impact of climate on migration patterns, the study assumed other drivers remain constant. “This approach is designed to show ‘how climate stress will change who is able to move and who is left behind,’ not to predict the number of people that will move in future decades,” Benveniste explained.
She added: “We hope that policymakers use these results as a basis to more squarely address the needs of different demographic groups. We need to answer the needs not just of the people who move, but also those who are moving less.”
Benveniste’s work received support from several institutions including Harvard University’s Center for the Environment and Salata Institute for Climate and Sustainability’s Research Cluster on climate adaptation in South Asia.
This article was originally published by Stanford Doerr School of Sustainability.
