The Communist regime in North Korea has threatened the small island of Guam with the launch of ballistic missiles, but some scientists say the U.S. territory is already feeling the effects of another “serious” enemy.

“Some Guam residents told reporters that they worried what might happen if North Korea’s leader, Kim Jong-un, were actually to follow through,” the New York Times reported on Friday.

“Scientists in Guam, however, say they have at least one other major threat in mind: climate change.”

“We know that it’s serious,” Austin J. Shelton III, a marine biologist and the executive director of the Center for Island Sustainability at the University of Guam said in the Times article. “Some of the impacts are here, and a lot more are coming.”

One concern is reef damage, which could hurt the $1.4 billion tourism sector that, according to the Guam Visitors Bureau, accounts for 60 percent of Guam’s yearly business revenue and nearly one third of its nonfederal employment.

The Times cited a 2007 study by the University of Guam Marine Laboratory that estimated the economic value of Guam’s coral reefs to be $2 million per square kilometer, or 0.4 square mile, and nearly $15 million per square kilometer at a 2,153-foot area “known for its diving and snorkeling sites.”

“Do these tourists want to return if they don’t see a live reef?” Peter Houk, a coral reef specialist, said in the Times article. “I don’t know the answer to that.”

“A 2012 study by the American Security Project, a research group in Washington, said that Guam’s military installations were among the five most vulnerable American ones worldwide to coastal erosion, extreme weather, rising sea levels and other projected climate change impacts,” the Times reported.

“Obviously you can’t run a war from a base that’s without power and water” after a major storm, Andrew Holland, the group’s director of studies, said, citing a 2002 typhoon that hit the island and left it without electrical power for “weeks.”

The Times reported that in June the House Armed Services Committee passed an amendment to the 2018 National Defense Authorization Act that would require the secretary of defense to report on how climate change could affect American military installations over the next 20 years.