(AP) – Extreme weather is contributing to undocumented migration and return of people between Mexico and the United States, suggesting more migrants could risk their lives crossing the border as climate change fuels droughts, storms and other hardships, according to a new study.
People from agricultural areas in Mexico are more likely to cross the border illegally after droughts and less likely to return to their original communities when extreme weather continued, according to research this week in the journal Proceedings of the National Academy of Sciences.
Around the world, climate change, caused by the burning of fossil fuels such as coal and natural gas, is exacerbating extreme weather. Droughts are longer and drier, the heat is more deadly, and storms are rapidly intensifying and dumping record rainfall.
In Mexico, a country of nearly 130 million people, drought has dried up reservoirs, created severe water shortages and drastically reduced corn production, threatening livelihoods.
The researchers said Mexico is a notable country to study the links between migration, return and climate stressors. Its average annual temperature is projected to rise by up to 3 degrees Celsius (5.4 degrees Fahrenheit) by 2060, and the extreme weather is likely to economically devastate rural communities dependent on rainfed agriculture. The United States and Mexico also have the largest international migration flow in the world.
Scientists predict that migration will grow as the planet warms. Over the next 30 years, 143 million people around the world are likely to be displaced by rising sea levels, droughts, scorching temperatures and other climate catastrophes, according to a report from the U.N. Intergovernmental Panel on Climate Change. .
The new immigration investigation comes as Republican Donald Trump was re-elected to the United States presidency this week. Trump has called climate change a “hoax” and promised mass deportations of an estimated 11 million people in the U.S. illegally.
The researchers said their findings highlight how extreme weather drives migration.
Filiz Garip, a researcher on the study and a professor of sociology and international affairs at Princeton University, said advanced nations have contributed much more to climate change than developing countries that are bearing the brunt.
Migration “is not a decision that people make lightly…and yet they are forced to do it more, and they are forced to stay longer in the United States” as a result of climate extremes, Garip said.
The researchers analyzed daily weather data along with survey responses from 48,313 people between 1992 and 2018, focusing on about 3,700 people who crossed the border without documents for the first time.
They examined 84 farming communities in Mexico where corn cultivation depended on the climate. They correlated a person’s decision to migrate and then return with abnormal changes in temperature and rainfall in their home communities during the corn growing season from May to August.
The study found that communities experiencing drought had higher migration rates compared to communities with normal rainfall. And people were less likely to return to Mexico from the U.S. when their communities were unusually dry or wet. That was true both for newcomers to the US and for people who had been there longer.
People who were better off financially were also more likely to migrate. So were people from communities with established migration histories where friends, neighbors or family members who had previously migrated could offer information and help.
These social and economic factors that influence migration are well understood, but Garip said the study’s findings underscore the inequities of climate adaptation. With extreme weather events, not everyone is affected or responds in the same way, he said, “and typical social and economic advantages or disadvantages also shape how people experience these events.”
For Kerilyn Schewel, co-director of the Climate, Resilience and Mobility Program at Duke University, economic factors highlight that some of the most vulnerable people are not those displaced by climate extremes, but rather those who are “trapped in place or lack the resources to move.”
Schewel, who was not involved in the study, said analyzing regions with migration histories could help predict where migrants will come from and who is most likely to migrate due to climate shocks. In “places where people are already leaving, where there is a high degree of prevalence of migration, … is where we can expect more people to leave in the future,” he said.
The survey data used from the Mexican Migration Project makes this study unique, according to Hélène Benveniste, a professor in the Environmental Social Sciences department at Stanford University. Migration data on his scale that is community-specific is “rarely available,” he said in an email. So is information about a person’s entire migration journey, including their return.
The finding that migratory return decisions were delayed due to climate stress in communities of origin is “important and novel,” said Benveniste, who studies climate-related human migration and was not involved in the study. “Few data sets allow an analysis of this question.”
However, increased surveillance and law enforcement along the U.S.-Mexico border makes returning home — and moving back and forth — more difficult, said Michael Mendez, a professor assistant in environmental policy and planning at the University of California, Irvine. And once undocumented migrants are in the U.S., they often live in deteriorating housing, lack health care or work in industries like construction or agriculture that make them vulnerable to other climate impacts, he said. Méndez did not participate in the study.
As climate change threatens social, political and economic stability around the world, experts said the study highlights the need for global collaboration around migration and climate resilience.
“A lot of our focus has been, in some ways, on the border and securing the border,” Duke’s Schewel said. “But we need much more attention not only to the reasons why people leave, but also to the demand for immigrant workers within the US.”
