Press Release by IFPRI.

Temperature fluctuations spurred more migration among women than men. Cold weather drove nearly three times as much migration as warm weather.
Drawing from over 21 million Census records, the study allows for interpretations at the national level and over broader periods of time

South Americans are migrating to urban areas due to climate change, according to the findings of a new study. Of those who migrated, more than four times as many people migrated to urban destinations than to rural destinations.

Researchers at Pennsylvania State University, the University of North Carolina-Chapel Hill, and the International Food Policy Research Institute drew on over 21 million Census record observations of people aged 15 to 40 across eight South American countries over multiple decades for the study. By comparing this data with rainfall and temperature data, the researchers were able to draw conclusions over time and at the national level.

“Migration is incredibly varied, complex, and difficult to track, but this study highlights overarching trends in the movement of South Americans in the face of a changing climate—and those movements are often across provinces to urban centers,” said Valerie Mueller, IFPRI senior research fellow, and an author of the study. “Overall, we found that changes in temperature had greater effects on migration than changes in rainfall.”

Overall, colder temperatures caused more migration than hotter temperatures. Each month of higher than normal temperatures led to a 3.6% increase in migration to urban areas, whereas each month of lower than normal temperatures led to a nearly-threefold increase of 9.9%.

Specific groups, however, responded differently to changes in their climate. The researchers estimated the effects of climate change on migration by sex, age, and educational attainment, as well as other factors.

According to the study, men and women respond differently to temperature variations. Higher-than-average temperatures had a significant effect on migration among women, but not men. The
researchers suggest women are more likely to migrate because they may be in more flexible occupations that aren’t tied to a specific plot of land or location.

Education level—which can be interpreted as a rough representation of socioeconomic status—also played a role. The study found that those with less education are generally “more likely to be displaced by gradual climatic changes than those who completed primary school, with exposure to anomalous temperatures driving these moves.” The study also found that climate change increased the likelihood of migration, challenging the assumption that climate variations trap vulnerable people in place.

“Our finding that much of the observed climate-induced migration is directed toward urban areas suggests the need to explore the consequences of such migration for the receiving communities and migrants themselves,” the authors wrote. “In cases where affected migrants are moving from rural areas, then transitions to urban areas may represent a unique set of challenges. The use of migration to urban centers as a means of adapting to climate change will require many subsequent adaptations in livelihood for these rural populations, as well as the communities they settle in.”

Photo: Lars Plougmann  CC BY-SA 2.0