The US Navy naturally has sea ports, where all its ships are docked when not out at sea. The sea level is rising. The US biggest, most important naval base in Norfolk, VA is spending billions to protect the base, but that is temporary as the surrounding area is flooding now and will eventually isolate Norfolk. It is predicted by 2100, about 128 bases will be flooded and shut down. This is also a threat conservatives are also taking seriously, even if they do not believe the cause it man made. Bottom line, one by one Naval bases will be forced to close. And building a new one will cost TRILLIONS of $. Simply because land at higher elevations is privately owned, will need to purchased, cleared, channels made, buildings made, and the old location cleaned up. And this can start as soon as 10 years from now to the most vulnerable bases. Of course we cannot know how fast it will happen, but it is not hard to calculate the impact of each foot of sea level rise, and then factor in frequent storms that make the effects more acute.