The 22-page document looked at 79 "priority" facilities around the US and found many vulnerable to flooding and wildfires, as well as the impacts of desertification, drought and melting permafrost.

"The effects of a changing climate are a national security issue with potential impacts to Department of Defense missions, operational plans and installations," the document states.

The military "must be able to adapt current and future operations to address the impacts of a variety of threats and conditions, including those from weather and natural events."

The report found about two-thirds of the 79 installations are or will be vulnerable to recurrent flooding, and more than half are vulnerable to current or future drought.

At Fort Greely, an Alaskan facility that is a key component of America's missile-defense system, melting permafrost will impact cold weather testing and training.

But critics blasted the report for skimping on detail, noting it did not mention several recent hurricanes that destroyed or damaged US military facilities.

Hurricane Michael, for instance, last year wrecked Tyndall Air Force Base in Florida. It will cost more than $5 billion to rebuild.

President Donald Trump has openly dismissed claims -- backed by the vast majority of important scientific bodies -- that greenhouse gases caused by human activity are responsible for a rapidly warming planet, triggering ever more extreme weather.

He once claimed climate change is a Chinese hoax, and has rolled back American environmental regulations aimed at curbing the problem.

"Under current leadership, the (Defense) Department is treating climate change as a back burner issue," said Senator Jack Reed, the top Democrat on the Armed Services Committee.

The Pentagon under Barack Obama repeatedly warned that climate change posed an immediate risk to national security, and former defense secretary Jim Mattis warned it impacted political stability in areas of the world where US troops operate.

The climate report was delivered to Congress on Thursday, but the Pentagon only published it online Friday after reporters asked about it.

The Center for Climate and Security said the report did not provide all the details required by Congress.