Vice Adm. Walter E. "Ted" Carter Jr. saw the effects of extreme weather up close in 2012, when he commanded the aircraft carrier USS Enterprise on a voyage across the Atlantic.
He watched as waves kicked up by Hurricane Sandy crashed onto the carrier's flight deck, 60 feet above the surface of the ocean.
"I saw firsthand what it's like to deal with a storm of that magnitude," Carter said.
Earlier in the mission, he had sent the giant vessel back and forth through the Strait of Hormuz, where the water temperature had crept close to 100 degrees. In those kind of extreme environments, Carter said, it's difficult to carry out military operations.
The Pentagon views climate change as a global threat to national security. Carter, now the superintendent at the Naval Academy, told a group of congressmen Friday not only about the challenges he faced on that deployment with the Enterprise strike group, but also how he is dealing with the prospect of rising sea levels and floods as the leader of the elite school for future Navy and Marine Corps officers.
"Annapolis is really on the front lines," said Rep. John Sarbanes, a Democrat whose district includes the city. "There's no question this is the challenge of our generation."
Carter joined Annapolis Mayor Mike Pantiledes, a Republican, and two environmentalists to talk about the local impact of rising sea levels. The state capital, perched on the Chesapeake Bay, is especially vulnerable to flooding, recent studies show.
Waters around the city have risen 12 inches in the past century — more than the global average — and could rise another 17 inches in the next 30 years, according to Brenda Ekwurzel, a researcher with the Union of Concerned Scientists. The greatest rise could bring dozens of floods to the City Dock area annually.
"We've only barely tasted what's in store," she told the congressmen.
Ekwurzel said the rate at which the water rises could be slowed if the country finds a way to cut down on the emission of greenhouse gases, but Carter and Pantiledes are already planning for a future in which Annapolis floods more regularly.
Carter, who studied oceanography at the academy in the 1970s and '80s, said he has convened a task force to examine vulnerabilities on campus — which has water on three sides — and to come up with fixes.
The academy already has taken some steps. Damage caused by Tropical Storm Isabel in 2003 cost more than $100 million to repair, Carter said, but it also gave the academy's leaders an opportunity to redesign facilities to better cope with floods.
Heating and ventilation equipment has been moved to rooftops where possible, and giant underground reservoirs have been built to capture stormwater. A planned building in which midshipmen will be taught about cybersecurity will also serve as a flood barrier for other parts of the campus, and other new buildings are being constructed at higher elevations.
Annapolis city officials are also trying to determine ways to soften the impact of floods and preserve the 18th-century buildings clustered along the waterfront.
The city has budgeted $175,000 for the effort so far and is getting help from the Army Corps of Engineers. Pantiledes told the lawmakers that just developing a plan could cost $1 million.
"There is still more to do, which means critical dollars are needed," he said.
Efforts in Congress to pass laws that might cut back on carbon emissions have faced fierce opposition from Republicans. The Democrats who came to Annapolis —Sarbanes, Chris Van Hollen of Montgomery County, Frank Pallone of New Jersey and Paul Tonko of New York — held the event to try to show bipartisan consensus on the issue at the local level, and to publicize steps being taken by the military.
Van Hollen praised the Department of Defense for its approach.
"The U.S. military has really been a forerunner of trying to explain this challenge and threat," the Montgomery County Democrat said.
While Carter is considering the local effects of climate change, the academy is training future officers to take the challenges it poses into account in their military careers. The school offers an oceanography course that looks at the science of climate change and a political science course on how shifting weather patterns affect global security.
Senior midshipmen have done final projects involving environmental research.
"They're doing cutting-edge research and development as part of their curriculum," Carter said.
Last year, the Pentagon called climate change a "threat multiplier" — a condition that makes almost every security problem more difficult to address.
As resources in some parts of the world become more scarce, officials expect to see more frequent outbreaks of disease and greater political instability. In battle, they say, rising sea levels could affect amphibious attacks, and extreme weather might make gathering intelligence more difficult.
Closer to home, the National Guard could be required to deal with more frequent floods and snowstorms.