With warming temperature playing a role in everything from mass migrations (see Central America and the U.S. southern border) to civil war (see Syria), climate change has been a factor in national security for decades. This week the U.S. finally got with the program. Among the many climate-related executive orders President Joe Biden signed on Wednesday was one directing the federal government to make climate change an integral part of its foreign and national security policy.

What does that mean, exactly? Among other things, the order called for the preparation of a National Intelligence Estimate on the threat climate change poses to U.S. security. NIEs are formal, classified assessments of major security questions, incorporating intelligence from 18 agencies including the Central Intelligence Agency and the year-old Space Force. These are compiled several times a year to answer such questions as how much to worry about transnational organized crime and whether Iraq has weapons of mass destruction.

There’s been at least one climate-related NIE done before, ordered by Congress. “This is not something novel, except at the high level it is being requested,” said Rod Schoonover, former director of environment and natural resources at the National Intelligence Council, the government body that produces the NIE. “Quite honestly,” he added, “it is well past time we got beyond a couple sentences in the worldwide threat assessment done every year for Congress.”

The power of the NIE is in how it’s used, said John Morton, a former senior director for energy and climate change on President Obama’s National Security Council. “When climate change is seen purely through an environmental lens you get one audience,” he said. “When you add a national security lens that draws in a further group of policymakers who may not care at all about the environmental imperative but clearly see the long-term national security implications to act.”

It also has legs. “Once that assessment gets done, it is the basis for policy-making for a good chunk of time,” Morton said. Smaller climate assessments done for the Department of Defense are already playing a role in deciding whether to fortify naval bases at risk from rising seas and informing policing strategy in the Arctic now that warming has made it more attractive to U.S. adversaries including China and Russia.

If the NIE concludes that climate change presents a grave security risk, vast agency resources could be mobilized—national security-related budget items can be huge. It’s this awesome power that troubles some climate activists, who worry that nationalizing a global problem would leave poorer countries once again with the short end of the stick.

“In the U.S., national security is most often defined as what threatens U.S. homeland, U.S. economic partners, U.S. allies, but most of all U.S. military, economic, or geopolitical power,” said Nick Buxton, author of The Secure and the Dispossessed, a book about the security state’s contributions to climate change. Vulnerable populations and communities may find their concerns deprioritized against, say, the needs of military and security installations.

“National security bodies talk in foreboding terms of waves of migration that could overwhelm nation states saying that the military will need to be prepared,” Buxton added. “In this way the most vulnerable in the world are not only victims of climate change, but now threats too.”