Two months ago, the Biden administration announced an initiative to share satellite data with Central American countries including Guatemala, Honduras and El Salvador to help them prepare for severe storms.

The goal was twofold. In a region vulnerable to hurricanes and other calamities made worse by a warming climate, reducing the damage would help ease suffering. It would also relieve the pressure to migrate to the United States. And at $6.6 million, the project, run by the U.S. Agency for International Development and NASA, cost a tiny fraction of what the federal government spends on border security.

That program, along with a suite of other development projects designed to reduce the flow of people from Central America to the U.S. border, now seems to be over. The day he took office, Mr. Trump signed an order freezing U.S.A.I.D. spending; on Friday, he proposed closing the agency entirely. The State Department has assumed responsibility for the agency, which is set to lose 97 percent of its staff.

“The United States foreign aid industry and bureaucracy are not aligned with American interests,” Mr. Trump’s Jan. 20 order began. But the agency’s resilience programs show that in an age of worsening climate threats, distinguishing humanitarian programs overseas from American interests is not as clear-cut as it might seem. Cutting those programs could increase migration from Central America, the opposite of what Mr. Trump has said he wants to achieve.

“U.S.A.I.D. built a vast array of programs to help families foresee and adjust to climate shocks without migrating,” said Michael A. Clemens, a professor at George Mason University who was a senior adviser at the agency during the Biden administration. Ending those programs “leaves migration as the only viable way for many families in the Western Hemisphere region to cope.”

Noam Unger served at the State Department and U.S.A.I.D. during the George W. Bush administration and was acting chief strategy officer at U.S.A.I.D. for a period early in the first Trump administration.

Worsening weather has been particularly hard on developing countries, adding to pressure to migrate and threatening America’s national security interests, said Mr. Unger, who is director of the Sustainable Development and Resilience Initiative at the Center for Strategic and International Studies.

The State Department did not respond to questions about whether it planned to continue the climate adaptation programs in Central America — and if not, whether it had alternative plans for reducing migration pressure from the region.

After Hurricane Mitch hit Honduras in 1998, the number of Hondurans who left for the United States jumped; the same thing happened in 2020, after two Category 4 hurricanes struck Central America.

It’s not just storms that push people to move. In a paper published in 2023, researchers from the University of Utah and the University of Texas looked at weather patterns in Central America between 2012 and 2018. They found that unusually dry growing seasons in El Salvador, Honduras and Guatemala led to 71 percent more emigration to the United States, even after controlling for other factors.

Researchers from the Inter-American Development Bank came to a similar conclusion in a 2022 study, which found that extreme temperature events in El Salvador between 2009 and 2018 were strongly correlated with increased migration among people whose livelihoods rely on crops like corn.

The researchers found something else: When crops suffered, in parts of the country that had poor access to credit, people in agricultural households were more than three times as likely to migrate as those in regions with better access to credit.

In other words: Climate shocks wouldn’t compel so many people to leave the country if they could better protect themselves financially against extreme events.

“Our results suggest that despite the current anti-immigrant political climate, there should be a global responsibility relative to the consequences of climate change,” the authors wrote.

As the link between climate change and migration in Central America was becoming clearer, the Biden administration began helping to make those countries more resilient to extreme weather.

Programs included crop insurance for small farmers, making it easier for coffee producers in Honduras to get drought-resistant seeds, improving access to water for irrigation and early warning systems for flash floods.

Small farmers “are facing increased food insecurity for their entire families, linked to increased drought and changing rain patterns,” said Sarah Blodgett Bermeo, a professor of political science at Duke University who wrote a book about foreign aid. “Cutting aid will decrease funding for the people in precarious situations who so far have chosen not to migrate.”

U.S. development programs aimed at increasing climate resilience were not in place long enough to show evidence of success, said Gillian Caldwell, the chief climate officer at U.S.A.I.D. during the Biden administration, but “it stands to reason that these make incredible contributions to reducing out-migration.”

Perhaps the best way to find out whether those programs were working is to stop doing them, she said.

“You want the line 15 miles long at the border?” Ms. Caldwell said. “Go ahead — shut down the development programming, and we’ll see.”