Protecting Boston from rising seas could cost billions of dollars over the coming decades. On that, residents, business owners, and developers all agree. But there’s a big question no one has yet answered: Who’s going to pay for it?
This week’s close shave with Tropical Storm Henri and this month’s United Nations report showing the planet warming faster than expected highlight the urgency of finding a solution, advocates say, especially for low-lying areas of the city’s shoreline, such as the Seaport’s Raymond L. Flynn Marine Park.
That’s where city officials are experimenting with a new approach to funding climate improvements, asking developers eager to build in the park to help finance a sea wall and other defenses that will protect not just their glimmering new towers of lab space but also the remnants of maritime industry that still operate there.
Advertisement
Over time, the Boston Planning & Development Agency believes it will cost up to $124 million to construct the most urgently needed protections for a 191-acre area that in its current state could be prone to flooding as soon as the 2030s and could be largely under water at high tide by the end of the century.
“The marine park, like many other parts of Boston, is vulnerable to the sea level rise from climate change,” said Devin Quirk, real estate director at the BPDA, which this year is launching an effort to lean on private sector developers to help pay for defenses.
The Climate Resiliency Fund uses an approach not unlike how the city’s requires commercial developers to contribute a set amount to affordable housing funds, or often to pay for park space or infrastructure upgrades near their projects. And it shows both the promise and the limitations of trying to tackle climate defenses through private development.
Advertisement
Boston has unique leverage in the marine park, where it owns most of the land and parcels it out to tenants and developers under long-term leases. That allows the city to set the rules, especially given the massive interest in redevelopment there.
It also allows the city to begin construction of the defenses relatively quickly, as the threat of sea level rise bears down with both economic and environmental implications.

There’s not much time left to figure out what kind of public investment it will take to defend against rising sea levels, said Bud Ris, a longtime climate scientist and senior adviser to the Boston Green Ribbon Commission, which works with the city on its climate plans.
“I just wish there was more clarity about that up front,” Ris said. “Then we’d all have a better idea of what the city’s going to have to spend, what the private sector’s going to spend, and what kind of mechanisms are going to be needed to generate that kind of money.”
He said the efforts at the marine park are among a handful in Boston that could help answer that question.
Some new developments in the Seaport District have been required to erect defenses such as flood barriers on their own properties, while the massive Suffolk Downs project in a low-lying section of East Boston is being landscaped to manage flood waters. Along Fort Point Channel, the BPDA is working with a handful of developers to plan a larger, climate-resilient park, and similar efforts are being discussed to reinforce Moakley Park in South Boston.
Advertisement
At the marine park, Boston expects developers to eventually cover about $40 million of the cost of improvements. The first new project that’ll pay into the fund — Marcus Partners’ conversion of the former Au Bon Pain headquarters on Fid Kennedy Avenue into a lab building — won BPDA board approval last week.

Marcus executives say their building, which will house space for Ginkgo Bioworks, will benefit from the certainty of neighborhoodwide protection. It will be designed with climate change in mind — critical electrical equipment will be on upper floors, for instance, and the first floor will be elevated above ground level. But a sea wall would offer protection from broader problems such as utility outages and flooded roads.

“You can attack the problem at the source, at the critical failure point,” said Levi Reilly, principal at Marcus Partners. “Also you get the cost efficiency of scale. You’re building everything at one time rather than everyone trying to do something on their own.”
The company has agreed to pay up to $250,000 per year toward climate defense in the neighborhood as part of the project. The BPDA plans to finance improvements, such as a 3- to 5-foot sea wall and elevated harbor walk, then use the money from developers to pay down debt.
The company won’t have to pay until tenants amounting to 50 percent of the city-controlled land sign onto similar agreements, but the BPDA expects that to happen relatively quickly as new developers take over parcels formerly used by seafood companies and other industries. The agency says it has completed or expects to complete deals with tenant on 10 parcels, including sites controlled by Marcus, Beacon Capital, Cronin Development, and Massport.
Advertisement
But it may take time before the city is able to recover payments from everyone. Leases at the marine park typically run for decades, and there has been a wave of new, large-scale development in recent years — everything from lab buildings to hotels — before the resiliency fund took effect. The BPDA said it will seek to renegotiate leases with existing projects, but it has not yet begun discussions with some major properties — such as Related Beal’s Innovation Square, future home of Vertex Pharmaceuticals.
And Quirk said the city doesn’t have immediate plans to ask the owners of many smaller maritime businesses to pay for climate improvements — though it may ask them to chip in smaller amounts eventually. But they will get the benefit of the protections that are constructed.
It’s too early to say whether the city might look to create similar districts elsewhere. Richard McGuinness, deputy director for waterfront planning at the BPDA, said there are precedents that could be followed.
Business improvement districts around the state, such as the one covering Downtown Boston, use assessments on property owners to pay for marketing, street cleaning, and other services. Something similar could be designed to pool resources to guard against flooding.
Advertisement
Alice Brown, chief of planning and policy at the nonprofit Boston Harbor Now, said programs like the resiliency fund may be well suited to areas where there’s a high demand for real estate and new developers who are willing to pay up. But she said the city will need many other tools to pay for protections in older, built-out, areas, especially lower-income residential neighborhoods. And it will likely require a lot of money, from a variety of sources, over decades.
“It will be important, I think, to create different kinds of funding,” Brown said. “That is going to be the challenge for the current mayor, the next mayor, and the mayor in 2050.”
This story has been updated to include more detailed information about the status of the Innovation Square project.
Andy Rosen can be reached at andrew.rosen@globe.com. Follow him on Twitter @andyrosen.