Did climate change spark the border crisis?

The majority of immigrants crossing the southwestern US border in recent months have come from the Northern Triangle of Central America: El Salvador, Guatemala, and Honduras. In the popular narrative, they are fleeing gang violence, drug wars, and a lack of economic opportunities. An alternative narrative, however, suggests that another factor sparked the border crisis: protracted drought.

Applications for asylum in the United States have surged in the past four years, with more than a third of all applicants coming from the Northern Triangle. The increased migration coincides with an agricultural crisis there that began in 2014 and depleted food stocks. In a June 2016 situation report, the UN Food and Agricultural Organization warned that the Northern Triangle was experiencing repeated crop losses caused by severe drought—the result of a strong El Niño weather pattern. After a strong El Niño, the weather pendulum can swing in the opposite direction the following year, with heavier-than-normal rainfall that can also cause crop losses.

Some climate models predict that global warming, which increases sea surface temperatures, will make extreme El Niño events more frequent. But despite considerable progress in understanding the connection between global warming and El Niño, it is not yet possible to say with certainty that global warming made the Northern Triangle drought worse.

There is little doubt that the Northern Triangle countries are among the most dangerous in the world, but violence doesn’t tell the whole story of the border crisis. About 80 percent of the people fleeing Guatemala are coming from areas where the homicide rate is comparable to the United States but food is scarce.

A 2017 report by a coalition of international aid organizations confirmed that hunger is linked to multiple factors driving migration—including poverty, violence, and climate variability. Even if the current border crisis can’t be pinned primarily on climate conditions, future warming is likely to have a growing impact on human migration.