The Trump administration scorns climate science: it has rolled back environmental regulations while promoting fossil fuels, and removed and downplayed mentions of climate change on government websites, among other moves that could weaken efforts to address global warming. It should come as no surprise, then, that the White House also seems to be ignoring—even potentially challenging—research and expert opinions on the connections between climate change and national security.

The administration has not articulated a clear-cut view on climate and security. But in 2017 President Donald Trump dropped the Obama administration’s previous inclusion of climate change as a chief threat in his first National Security Strategy (a congressionally mandated document stating what the White House sees as the U.S.’s biggest security concerns and how it intends to address them). Earlier this year The Washington Post reported the administration was working to create a panel that would likely attempt to undercut expert findings on the dangers climate change poses to national security.

A country’s security can encompass a range of elements, from cybersecurity to food production, but conflict is among the most basic. “The classic definition [of state security] has been around conflict—threats to human life from armed aggression—which includes intrastate components such as dissident groups and civil war, and then, of course, when states go to war with each other,” says David Victor, a professor of international relations at the University of California, San Diego. In the past decade scientists have looked at what climate change might mean for conflict and security, finding some significant connections—and denying them, they say, is a grave mistake.

Internal Conflict and Security

Scientists who study the issue say one of the clearest findings so far on climate change and state security is the former’s role in increasing the risk of domestic conflict. “There’s a lot of evidence that internal stability of societies is strongly coupled to the climate,” says Solomon Hsiang, a professor of public policy and director of the Global Policy Laboratory at the University of California, Berkeley. He and other researchers have been looking at historical events to see if climate factors have increased the risk of conflict, and used their findings to extrapolate what might happen as global warming intensifies. One of Hsiang’s studies found, for instance, that the risk of civil conflict in African countries has risen 11 percent since 1980 because of the warming climate. “That’s a pretty substantial number,” he notes. “It’s large enough that we shouldn’t dismiss it out of hand.” Hsiang also points to recent research by other scientists showing that coups are more likely after extremely hot years.

A new study in Nature, which evaluated expert opinions, found that those surveyed think changes in climate have played at least a small role in previous organized armed conflicts within countries—and that global warming would likely heighten the risk of such violence in the future. One of the study authors, Marshall Burke, an assistant professor of earth system science at Stanford University, says changes in climate may play a direct role in influencing internal conflicts (such as hotter temperatures potentially aggravating psychological factors that increase the risk of people committing violent acts). These changes could also affect events indirectly through other factors, including economic development. “Changes in economic outcomes locally can change incentives for people to join or start civil conflict. So all you need is for climate to change economic outcomes on the ground,” Burke explains. “We think low economic development is going to be a strong function of climate in the future.” Victor says climate-influenced economic failures would be particularly likely “to happen in places that are already living on the edge,” such as increasingly inundated coastal zones in Bangladesh.

Climate’s possible role in internal conflicts anywhere should matter to the U.S., analysts say. “We play the peacekeeping role around the world, we end up involved in some of these civil conflicts, and we know that they can open up territory or give breathing room to groups like terrorist organizations,” Burke says. “So even internal conflicts [in other countries] have important implications for the U.S.’s own security.”

International Conflicts and Migration

How climate might influence international conflicts is not as clear. “There is dramatically less evidence that countries actually engage in violence with one another in a way that connects to the climate,” Hsiang says. Part of the reason for this, Burke explains, is that the world has seen much less international conflict since World War II, and this makes it harder for researchers to pick out any potential climate connections. “Also, if [international conflict] is not happening that much, then it has to be the case that climate is not causing a large change,” Burke says. Hsiang notes, however, that researchers also cannot determine that climate change will definitely not affect international conflict in the future.

One possible international flashpoint is cross-border migration. Though this in itself is not conflict, some scientists see the issue—a major source of tension in the U.S. and Europe right now—as a critical part of the climate-conflict picture. Climate change could increase migration directly through extreme weather events, and indirectly via mounting internal conflicts. “What people are concerned about [with migration and climate change] are the levels of involuntary migration across international borders, which is really a major public policy issue” and is “very, very sensitive to climate,” says Neil Adger, a professor of human geography at the University of Exeter and another author of the recent Nature study.

Burke and Hsiang both point to a study showing the number of asylum seekers migrating into Europe so far this century rose in years that were warmer than average. “These people are not claiming to be climate refugees, but refugees seeking political asylum—but that seems to be related to whether or not the place they’re coming from is having extreme periods of heat that cause crops to fail,” Hsiang says. “That’s the way in which local economic downturns might transform into local conflicts, which then produce people trying to get out of those regions.”

Trump, Climate, and Security

Although the White House appears to be downplaying possible connections between climate and state security, researchers say they see other parts of the U.S. government recognizing the threat. The Pentagon recently released a report stating that “the effects of a changing climate are a national security issue with potential impacts to Department of Defense missions, operational plans, and installations.” DoD spokeswoman Heather Babb told Scientific American in a statement that the “DoD must be able to adapt current and future operations to address the impacts of a wide variety of threats and conditions, to include those from weather, climate and natural events.” Burke says he was recently contacted by members of the security and intelligence establishment for more information to improve their planning. “They’re taking it seriously and trying to figure out what they should do about it,” he says. The White House did not respond to a request for comment.

Experts note there are various tools the U.S. and other powerful nations could use to help break the link between climate and conflict, such as established international aid efforts. “These are interventions like social safety nets or insurance programs that help buffer people’s incomes and livelihoods against changes in climate,” Burke says.

Given the scientific research and the conclusions of the U.S. military, Burke and other experts say the Trump administration’s position on climate change is worrying. The U.S. government has a long history of stalling on climate action, but those who monitor the issue say the Trump administration is worsening the problem. “Even a few years’ delay on meaningful action here could have a huge influence on where we are,” Burke says. “We’re in a much, much worse place with regard to these outcomes—conflict and otherwise—than we would have been if we had done something about it.”