If all other migration drivers remain constant, rising global temperatures may increase migration rates by about a quarter among older, less educated adults and decrease them by up to a third for the youngest and least educated groups.

When severe heat waves, droughts, and other weather-related disasters strike, age and education shape who migrates and who stays put, according to a Sept. 3 study in Nature Communications.

The study describes how extreme weather can push some groups to move across borders and trap many others in place. These results contrast with mass migration scenarios often invoked in public debates about climate change.

"Weather extremes can both incentivize people to move away and increase the number of people who don't have the ability to migrate," said study author Hélène Benveniste, an assistant professor of environmental social sciences 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 new analysis helps to resolve contradictory findings from past research. Some earlier studies, for example, have found mixed signals of whether men or women, or people with more or less education, are more likely to migrate following extreme heat.

Together with co-authors Peter Huybers of Harvard University and Jonathan Proctor of the University of British Columbia, Benveniste found that these conflicting outcomes often reflect global patterns shaped by local climate and the demographics of potential migrants.