Perhaps even more than the threat of gang violence, fear of starvation is motivating the current wave of migration to the U.S. southern border. The surge is coming largely from rural parts of Central America, especially Guatemala, where drought has killed the corn and beans people grow to eat. Their coffee bean harvest brought them the lowest prices in 12 years.

It’s critical to understand the specific root cause of this latest exodus from Central America. When we do, we can see how counterproductive the proposal is to cut off all foreign aid to the region. Without this relatively small bit of assistance, even more poor rural families will succumb to desperation, and will migrate north. They will do whatever it takes to survive. Hunger does that.

This past autumn, I visited with farmers in the dry corridor of Central America, so-called because prolonged droughts and subsequent flooding increasingly plague the region. In Guatemala, where lack of rain is at crisis levels, farmers showed me their maize and bean crops which had grown to four or five inches, then simply wilted and died. Most farms in this region went more than 40 days without rain during the last growing season.

The poor of the region depend on these crops for food. The organization I head, Catholic Relief Services (CRS), surveyed families in Guatemala in December and found they lost 61 percent to 82 percent of these staple crops in both the 2018 harvests.

Families told us they could hold out until January at the latest. With severe drought expected to continue at least through this summer, they are now completely desperate, depending on fruit trees and off-farm labor and other foraging.

The last straw for many families who decided to push north to Mexico and Texas was rock-bottom coffee prices. Coffee is the main cash crop in Central America. With their pantries empty, families can sometimes survive till the next harvest with profits from coffee. Not this year. Farmers are getting $1 per pound or less for their beans, while their annual costs are at least $1.40 to $1.70. The recent coffee harvest reaped only more debt. This has become a common feature of coffee production at the farm level, despite the rising cost of a cup of coffee.

Even many specialty coffee farmers are struggling to endure during these hard times, despite the extra work to produce an organic, Fair Trade or Rainforest certified coffee. In return, they receive higher prices for their beans. Nonetheless, these prices are also only slightly above the cost of production.

To our credit, America steps in with some foreign aid to help these subsistence farmers. It’s a minuscule amount compared to the U.S. budget, but it makes a real difference. These programs help Latin American farmers become more resilient to drought by teaching them water and soil conservation measures, and to improve the sale price of their coffee with business skills and links to markets. Many farmers substantially increased their crop yields and incomes using these simple strategies. This work is partially funded by U.S. foreign aid. It’s woefully inadequate to the need but it helps. Without the generosity of the American people, the numbers of migrants would be far higher.

For years, both Republicans and Democrats in Congress have understood foreign aid is a cost-effective and wise investment. In fact, Congress cast bipartisan votes twice to ensure assistance continues at a level that protects and saves lives, and reduces migration pressures. I urge Congress to stand fast again.

We are one humanity struggling with hostile forces both natural and financial. Let us extend our hearts and our aid to our neighbors in the Americas.

Callahan is president and CEO of Catholic Relief Services.