The U.S. Defense Department has issued a dire report on how climate change could affect the nation’s armed forces and security, warning that rising seas could inundate coastal bases and drought-fueled wildfires could endanger those that are inland.

The 22-page assessment delivered to Congress on Thursday says about two-thirds of 79 mission-essential military installations in the U.S. that were reviewed are vulnerable now or in the future to flooding and more than half are at risk from drought. About half also are at risk from wildfires, including the threat of mudslides and erosion from rains after the blazes.

“The effects of a changing climate are a national security issue with potential impacts to DOD missions, operational plans and installations,” Defense Department spokeswoman Heather Babb said today in an email.

The report contradicts the view of President Donald Trump, who has rejected the scientific consensus that climate change is real and man-made. The report’s premise echoes the findings of the National Climate Assessment, written by 13 federal agencies and released in November. It concluded that the effects of global warming are accelerating and will cause widespread disruption.

Trump rejected those findings. “I don’t believe it,” he said at the time.

The new Defense Department report, which was mandated by Congress, describes widespread impacts, dispersed across the U.S., with more coastal flooding along the East coast and Hawaii.

U.S. military facilities are already encountering some of the effects, the Pentagon says, noting that Joint Base Langley-Eustis in Virginia has experienced 14 inches of sea-level rise since 1930. And Navy Base Coronado in California already is subject to flooding during tropical storms.

In the Washington area, several Defense Department sites — including Joint Base Andrews, home of Air Force One — are experiencing drought conditions that have been severe in the past 16 years, the report says. Those conditions can lead to ruptured utility lines and cracked roads, the Pentagon warns, as moisture disappears from soil.

The Defense Department stresses in its report that it is working with nations around the world “to understand and plan for future potential mission impacts” from climate change, describing it as “a global issue.”

Pentagon History

The Pentagon has long expressed concern over the phenomenon and its military implications worldwide.

Defense Secretary Jim Mattis, who resigned last month, had been at odds with Trump over climate change, telling the Senate Armed Services Committee during his confirmation process that “the Department of Defense must pay attention to potential adverse impacts generated by this phenomenon.”

“Climate change is impacting stability in areas of the world where our troops are operating today,” Mattis wrote in written responses to questions from the committee. “It is appropriate for the Combatant Commands to incorporate drivers of instability that impact the security environment in their areas into their planning.”

In 2013, Republican Senator Jim Inhofe of Oklahoma, who now is chairman of the Senate Armed Services Committee, pressed Admiral Samuel Locklear, who was head of U.S. Pacific Command, to say that his concerns about climate change were being misrepresented by “environmental extremists.”

Obama Administration

Instead, Locklear said about 280,000 people died in natural disasters in the Pacific region from 2008 to 2012. “Now, they weren’t all climate-change or weather-related, but a lot of them were,” the admiral said.

Under the Obama administration, responding to the effects of climate on the nation’s military was a top initiative, but the Trump administration has taken a different tack. Climate change was omitted in 2017 as a threat from the National Security Strategy, a list of the top dangers facing the nation.

“Given future global energy demand, much of the developing world will require fossil fuels, as well as other forms of energy, to power their economies and lift their people out of poverty,” the 2017 strategy said. “U.S. leadership is indispensable to countering an anti-growth energy agenda.”

Shortly after taking office, Trump revoked a memorandum that Obama signed in 2016, directing the Defense Department to account for climate change in its decisions about where to build new facilities and how it prepares for future threats.

Senator Dick Durbin, the ranking Democrat on the Defense Appropriations Subcommittee, responded by calling Trump’s decision to rescind the memorandum “a security disaster.”