Extreme Weather, Drought Linked to Increased Migration From Mexico to the U.S.

People seeking to migrate to the U.S. from Mexico are detained by U.S. Customs and Border Protection at the border in Jacumba Hot Springs, California on Dec. 14, 2023. Nick Ut / Getty Images

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Extreme weather is causing an increase in undocumented migration between the United States and Mexico, suggesting more migrants could put their lives at risk crossing the border as the climate crisis causes droughts, severe storms and other adversities, a new study has found.

The researchers discovered that people from Mexico’s agricultural regions were more likely to travel across the U.S.-Mexico border illegally in the wake of droughts. And when extreme weather conditions continued, they were not as likely to return to their original communities.

“As the world’s climate continues to change, human populations are exposed to increasingly severe and extreme weather conditions that can promote migration,” the study’s authors wrote. “The findings… suggest that extreme weather conditions, which are likely to increase with climate change, promote clandestine mobility across borders and, thus, expose migrants to risks associated with crossing dangerous terrain.”

All over the world, human-caused climate change from the burning of fossil fuels like natural gas and coal is exacerbating extreme weather. Droughts are becoming drier and longer, high temperatures are becoming more deadly and storms are intensifying rapidly while unleashing record amounts of rain.

In Mexico, drought has dried up reservoirs, creating severe water shortages and greatly reduced corn production, which threatens livelihoods, reported Phys.org.

The researchers said Mexico — a country of more than 128 million people — has an average annual temperature that is predicted to rise as much as three degrees Celsius by 2060. Rural communities that depend on rain-fed agriculture are likely to be economically devastated by global heating.

Mexico and the U.S. have the largest flow of international migration on Earth, and scientists predict it will expand as the planet warms. In the coming three decades, 143 million people around the world are likely to be forced to relocate due to soaring temperatures, drought, sea-level rise and other climate disasters, a report by the United Nations Intergovernmental Panel on Climate Change said.

Migration “is not a decision that people take up lightly… and yet they’re being forced to make it more, and they’re being forced to stay longer in the United States” due to climate extremes, said co-author of the study Filiz Garip, a sociology and international affairs professor at Princeton University, as Phys.org reported.

Garip said advanced countries have contributed much more to the climate crisis than the developing nations that bear the brunt.

The research team looked at daily weather data and responses from 48,313 individuals surveyed from 1992 to 2018, focusing on approximately 3,700 people who crossed the border undocumented for the first time.

The team analyzed 84 Mexican agricultural communities where corn farming was weather-dependent. They linked an individual’s decision to migrate and return with abnormal temperature and rainfall changes in their communities of origin during the corn growing season, which runs from May to August.

The researchers discovered that drought-affected communities had higher rates of migration in comparison with communities with normal rainfall. People were also less likely to go back to Mexico after having migrated to the U.S. when their communities of origin were abnormally wet or dry. The same was true whether the migrants had recently arrived in the U.S. or had been there longer.

The finding that decisions to return to communities of origin had been delayed by extreme weather conditions is “important and novel,” according to Hélène Benveniste, a Stanford University professor in the department of environmental social sciences, as reported by Phys.org.

“Few datasets enable an analysis of this question,” Benveniste said.

Increased enforcement and surveillance along the border between Mexico and the U.S. makes returning, as well as traveling back and forth, harder, said Michael Méndez, an environmental policy and planning professor at University of California, Irvine, who was not involved with the study.

Once undocumented migrants cross the border into the U.S., they frequently lack healthcare, live in dilapidated housing or work in industries like agriculture and construction that expose them to additional climate impacts, Méndez said.

As the climate crisis threatens the world’s social, economic and political stability, experts said the study underscores a global need for collaboration concerning migration and climate resilience.

“So much of our focus has been, in a way, on the border and securing the border,” said Kerilyn Schewel, co-director of the Program on Climate, Resilience and Mobility at Duke University, as Phys.org reported. “But we need much more attention to not only the reasons why people are leaving, but also the demand for immigrant workers within the U.S.”

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