The Marine Corps’ iconic Parris Island boot camp is threatened by rising seas, Gen. Glenn Walters, the service’s assistant commandant, said Wednesday.

Walters told the Senate Armed Services Committee that the base on the South Carolina coast faces the “most critical vulnerability” among Marine installations when it comes to sea rise, and a seawall may be needed to protect it.

“I’ve come to the conclusion in my own mind that it’s not today, we don’t have to build a seawall today, but we have to consider one and we’re monitoring it every day,” Walters testified.

The Navy also testified to the Senate committee Wednesday that it faces stark threats from sea rise to many of its bases over the next 30 years unless some action is taken.

Rising sea levels are widely attributed to climate change, which the Trump administration has cut from its new national security strategy. Meanwhile, Congress has called climate change a direct threat to national security and ordered the military to take a closer look at its facilities over the coming year.

Walters said the Corps has already done “extensive work and studies” on the dangers to Parris Island in order to come up with best- and worst-case scenarios as surrounding waters rise. He said he has been personally briefed twice over the past eight months.

“Obviously there is some big variance in there but what I do know is that we’ll eventually have to bolster that [facility],” he said.

Adm. Bill Moran, the vice chief of naval operations, said he was recently given a Naval Academy briefing looking at sea level projections over the next three decades.

“It was a pretty stark demonstration of what could happen if we don’t take some action in the next 30 years to address that rise in water level,” Moran said. “If the ocean is going to rise, we are going to be impacted everywhere, so it does demand a kind of comprehensive look at all of our bases.”

Congress ordered a report from the Pentagon on the 10 bases most in danger from climate change and the costs for shoring them up.

Sen. Tim Kaine, D-Va., the ranking Democrat on the Senate Armed Services subcommittee that heard the testimony Wednesday, said rising sea levels will likely threaten many military installations and the cost of needed improvements to protect them could be exorbitant.

“I don’t know how many don’t get done because of absence of budget resources,” Kaine said. “You start to add in significant resilience investments in things like seawalls, etc., you are really going to have a traffic jam of projects looking for scarce dollars.”

The Air Force spent the past year dealing with wildfires, flooding, and hurricanes, and is already considering the effects of climate change in construction projects, said Gen. Stephen Wilson, the service’s vice chief of staff.

“Everything we look at in terms of infrastructure we have to look at through the lens of how would I build and design infrastructure that would support changes in climate,” Wilson said.