In the late 1700s, when America was just an idea, some of Boston’s most prominent leaders gathered in a red brick building called Faneuil Hall to discuss rebellion from England. Today, the building is one of the city’s most popular tourist attractions. Boston’s leaders hope it can serve as the symbol of a new revolution: a movement to accept that climate change is poised to have a major impact on coastal cities, and that those urban centers must take drastic steps to adapt and survive.

“We’re now as a city beginning to put together all the concerns — sea level rise, climate change, why these iconic historic buildings are threatened, and what we need to do to try to protect them,” said Boston Environment Commissioner Nancy Girard.

Like many, Girard said in 2012 Boston learned a harsh lesson when Superstorm Sandy happened to turn away from the city, and instead spread destruction along large swaths of New York. The wake-up call worked- Boston officials and area organizations began sketching out possible solutions, culminating in late May with a conference where experts and stakeholders debated options.  

Girard said they quickly realized many historic structures would be among the first buildings threatened by flooding and that steps had to be taken quickly to protect those sites from permanent damage that the next big storm could inflict. 

“When you start thinking about where the ocean is going to come in and how big the ocean is, and you start thinking about how the water will flow, you realize that these beautiful old buildings are right at the forefront of this issue,” Girard said.

Last year, a study in the science journal Nature Climate Change ranked the metropolitan areas facing flooding, naming Boston eighth with $237 million in possible damage.

The Cambridge-based Union of Concerned Scientists lists Boston's historic districts among the nation's most endangered sites. As part of a larger report published in May, the organization said Boston is seeing an increasing number of abnormally high tides: Since record-keeping began in 1921, the city has experienced waves 3.5 feet taller than normal a total of 20 times, and half of those instances occurred within the last decade.

“We’re dealing with unpredictable events. We know they’re going to happen, we’re not sure when they’re going to happen, and we don’t know how bad they’re going to be,” said Adam Markham, executive director of the Union of Concerned Scientists.

“As we get more into this world of a changing climate, officials need to be well prepared and the public will want them to be accountable to make sure that they were protected and the resources they care about were protected.”

Faneuil Hall and the nearby Blackstone Block of colonial streets are within the city’s 100-year tidal flood zone. Those streets could have been flooded at least three times since Sandy if storms that hit Boston had arrived during high tide instead of low, said Boston Harbor Association executive director Julie Wormser.

“There’s a short answer to, 'Are we doing enough now?' and the short answer is ‘No,’” she said. “The longer answer is, 'I’ve never seen public policy move so quickly, ever.'”

The association is preparing to release a report suggesting the city should consider making room for the encroaching water with canals or lagoons.

“There’s two big gnarly questions: One is – ‘What parts of the city are going to be allowed to flood, and what parts are we going to invest in to prevent flooding?'” Wormser said. “The other question is, ‘How do we pay for it?’”

Boston may not be able to protect everything it wants, she said.

“It’s really only a question of prioritizing,” Wormser said. “If we could save everything, we would.”

Girard said stakeholders gathered at the May summit were willing to consider sacrifices once they accepted that something had to be done.

“People who owned these beautiful buildings in Back Bay started to look at their public alleys and said, ‘What if we alternated every other public alley and used it to flow water through?’” she said. “At the end of a four-hour planning session there were people there who had said, ‘We could live with this if in fact we did this and it maintained our buildings.’ Because people don’t want to give those buildings up.”

Girard said final decisions on what to do may be a long way off because of the many stakeholders involved, and the lack of public funding.

“We need to get private industry to step up and say this is our problem too,” she said. “Because government has no level of resources compared to the private sector.”

While Girard hopes to garner support by focusing on the threat to places like Faneuil Hall, Boston’s city archeologist Joe Bagely, worries about what’s under that building. The Faneuil Hall area was once a wharf that merchants and residents filled in with trash and covered with dirt to create land. To Bagley, that trash is now archeological gold that could provide precious information about the day-to-day life in the 1700s.

“It’s an access issue for me,” he said. “Why should we wait for the archeological site to become an underwater archeological site before we start caring about it? It just makes it twice as hard to dig and 10 times more expensive.”

The artifacts under Faneuil Hall may be saved as the city eventually takes steps to protect the historic building. But not all of Boston's buried treasures happen to be under well-known tourist attractions, Bagley said. There are about 100 other sites across the city at risk of being washed away, he said, including some on the Boston Harbor islands that contain rare Native American artifacts.

“Most of these islands are covered in native sites that have just been sitting there,” Bagley said.

Storm surge is already eroding the islands. Little has been excavated there and at other obscure sites because archeology in Boston has been driven by development, Bagley said. In other words, digs were only done when buildings were going up. Now there’s too much to do before the next storm surge arrives, and too little resources — Bagley said there's no budget for excavations and the only professional staff he has to deploy is himself.

“Do we have to start picking and choosing which sites we’re just going to let go?” he asked. “And how do you do that? How do you choose which site is important enough? Especially when we don’t really know what’s there — only that documents say something is there.”

Bagley said he tries to keep the urgency of those questions in perspective.

“The resources we could use financially to excavate these sites are probably best served helping people that are going to be losing their houses, or working towards fortifying our infrastructure in the city of Boston, because that’s fundamentally the most important thing,” he said.

So for now, Bagley’s working as fast as he can to catalog and find a way to prioritize Boston’s historic sites. But, like building owners in Back Bay, he’s beginning to accept that some of the city’s buried treasures might have to be sacrificed, along with the knowledge of American history they could reveal.

Boston Harbor Association Executive Director Julie Wormser and Boston Environment Department Commissioner Nancy Girard discussed the city's rising tides on Greater Boston: