Nonprofit group the Union of Concerned Scientists analyzed 18 military installations that represent more than 120 coastal bases nationwide to weigh the impact of climate change on their operations.
Faster rates of sea level rises in the second half of this century could mean that tidal flooding will become a daily occurrence for some installations, pushing useable land needed for military training and testing into tidal zones, said the report titled "The U.S. Military on the Front Lines of Rising Seas."
By 2050, most of these sites will be hit by more than 10 times the number of floods than at present, the report said, and at least half of them will experience daily floods.
Four of those - including the Naval Air Station in Key West, Florida, and the Marine Corps recruit depot in South Carolina - could lose between 75 and 95 percent of their land in this century.
The report said the Pentagon already recognizes the threat of climate change on its military installations but warned that more resources and monitoring systems are needed to boost preparedness.
But last month, the U.S. House appropriations committee passed an amendment that blocked funding for the Pentagon's climate adaptation strategy.
"Our defense leadership has a special responsibility to protect the sites that hundreds of thousands of Americans depend on for their livelihoods and millions depend on for national security," the report said.
