Unless you’ve been asleep under a tree for the past 20 years, you know there’s been a surge in families and unaccompanied children making the journey north to seek asylum in the United States. You probably also know that most of them come from Guatemala, Honduras and El Salvador in Central America’s Northern Triangle, a region notorious for drug trafficking and gang violence.

What you probably don’t know, however, is that violence cannot explain the large numbers fleeing rural areas in Guatemala, a country in which crime is largely confined to the capital and a few border provinces. These Guatemalans are being driven north by growing food insecurity linked to climate change.

The Deadly Cycle

Guatemala is located in Central America’s so-called dry corridor, which extends through Honduras and El Salvador into Nicaragua. The countries of the dry corridor share similar ecology and, by no coincidence, staple crops. They also share vulnerability to drought and extreme weather events.

Take, for example, changes in the El Niño-Southern Oscillation (ENSO), the intermittent patterns of warming and cooling in the tropical Pacific that can dramatically affect rainfall patterns thousands of miles away. ENSO events used to occur every 10 years or so. But as climate change accelerates, they are becoming more frequent, with six in the past two decades. In 2014, El Niño ushered in the worst drought to hit Central America in 35 years, and with ocean temperatures continuing to rise, conditions are only likely to get worse.

When the rains do come, the season, which formerly began in May and ended in late September, now starts later and finishes earlier. The shorter growing season means that many traditional crops fail. At the same time, storm intensity has increased, adding to rural misery with flooding and landslides. While long-run climate models suggest that Central America will eventually see a decrease in intense tropical storms, this will be accompanied by rising temperatures and drought. Guatemala’s rainfall is predicted to drop by 13 percent by 2050 and 27 percent by 2100.

Given that a third of all employment in Central America is agricultural, disruptions have devastating human consequences. In recent years, the mostly small farmers of the dry corridor have lost 50-90 percent of their crops to drought. The UN Food and Agriculture Organization (FAO) estimates that at least 1 Central American in 11 is in need of humanitarian assistance.

The Vise Tightens

Traditionally, subsistence farmers in Guatemala migrated internally in search of work when the rains failed, but with 150,000-170,000 people entering the workforce each year, the labor market is saturated. Between rising violence and few opportunities for low-skilled rural workers, moving to the capital (Guatemala City) is no longer a viable option.

Meanwhile, commercial coffee and sugar cane plantations, which have also served as a safety valve for rural workers in hard times, have been equally hard hit by climate change. In 2010-4, losses to the coffee crop were estimated at around $500 million. Part of the decline in yield is due to coffee rust, a fungus that thrives in warmer weather. With rising temperatures, the rust has moved to higher elevations, leaving farmers who have neither bank credit nor access to up-slope land out of luck. Changing rainfall patterns have also played a role, as early rains that traditionally washed away the fungus have diminished.

The Butcher’s Bill

In 2014, the first year of extreme drought, the UN Economic Commission for Latin America and the Caribbean estimated that the overall cost of climate change to Central America at between 1.5 percent and 5 percent of the region’s GDP. The cost has undoubtedly risen since, and, if it hasn’t done so already, it’s just a matter of time before the economic toll of climate change surpasses that of violence. Conservative forecasts see the cost of Central American climate change rising to an astonishing 54 percent of 2008 GDP by 2100.

Costs, too, are mounting for the United States. The number of Guatemalans seeking asylum jumped from an estimated 5,000 in 2008 to 97,000 in 2018 and continues to climb. And while the U.S. does not consider climate change a qualifying condition for refugee status, there is significant expense associated with even asylum seekers whose claims are eventually denied. The cost for processing a single deportee exceeds $10,000.

In recent years, U.S. officials have emphasized the “pull” factors — the chance of a job and a higher living standard — that attract Central Americans to explain the growing numbers arriving at the southern border. When the “push” factors that forced the migrants to leave their countries were mentioned, only drugs and crime made the list.

Then, after a fact-finding trip to Central America in October 2018, U.S. Customs and Border Protection Commissioner Kevin McAleenan announced that hunger, not violence, was behind the surge in Guatemalan migration. Almost simultaneously, President Trump threatened to precipitously cut Central American aid, which in Guatemala’s case included $16 million in food and $17 million in agricultural assistance as of 2017. Increasing aid in these areas would make a lot more sense, particularly in light of a World Bank estimate that climate-driven migration could be reduced by up to 80 percent with sufficient economic support.

USAID is already providing Guatemala’s commercial farmers with rust-resistant coffee seed. Expanding this program to include drought-resistant seed for food crops, rainwater harvesting projects and crop insurance for subsistence farmers could go a long way toward stemming the flow of rural migrants. Getting the job done wouldn’t be cheap. But it would be pennies on the dollar compared to building a border wall.