Four hundred years ago, the land that is now Boston was part of the ocean. In fact, some of Boston University’s campus was underwater at one point in time.
“Boston University used to be a salt marsh and there used to be a channel … but we filled it in the 19th century when sea level was lower so actually Back Bay is very low,” Sergio Fagherazzi, a professor in the College of Arts and Sciences’ Earth and Environment Department, said in an interview.
Boston is vulnerable to sea-level rise and coastal flooding — two phenomena resulting from climate change, Fagherazzi said. In addition to sea-level rise, climate change has also led to higher temperatures and tides, causing more destructive storm surges, hurricanes and nor’easters.
On Earth Day, WBUR hosted the panel “Climate Resilient Cities: An Earth Day Discussion of Sea-Level Rise” with experts from San Francisco, New Orleans and Boston to discuss each city’s climate action plan to combat potential sea-level rise.
At the event, Rachel Cleetus, policy director on the climate and energy program at the Union of Concerned Scientists — a nonprofit organization in Boston working to create innovative solutions to climate change problems — commented on Boston’s risk of sea-level rise at the event.
“When we look at maps of where the risks are and where the threats are, what’s striking is you almost see the city within the next few decades retreating back to the original skeleton of what it was,” Cleetus said. “It’s like nature taking back from what it was before and the fact is we’re already seeing the leading edge of these changes.”
Cleetus discussed the limitations of gray infrastructure — seawalls and dams, for instance — and Boston’s aging infrastructure.
“The fact that we have so much impermeable area doesn’t allow the water to go anywhere and be absorbed,” she said. “Over time, our development patterns have also eroded what used to be the things that would protect us, you know, the marshes, the wetlands that would blunt some of this.”
Sea-level rise results from melting land-based ice and thermal expansion in the ocean — the expansion of water as it heats up — due to excessive heat that the oceans absorb, Fagherazzi said in an interview. However, it is not only human-caused.
“It depends on cycles of cooling and warming of the earth, so it has been rising actually even before humans,” he said. “But now, because of global warming, we have an escalation of sea-level rise.”
However, Cleetus said at the event sea-level rise is much more complicated than many think because of its strong correlation to environmental justice.
“A lot of those places … have a number of neighborhoods that are low-income neighborhoods with communities of color,” Cleetus said. “The reality is that because of our country’s history of structural racism, a lot of times where people are living has a lot to do with where they were able to live.”
At the event, Cleetus pointed to east Boston as an example of a predominantly low-income, minority community that has not received much outside investment, and is thus more susceptible to flooding. Dorchester is also particularly vulnerable to sea-level rise, Cleetus said.
Fagherazzi said sea level differs at local and regional levels. Regionally, ocean circulation, tectonics and land masses are important to consider when discussing rising sea levels. In Boston, the landscape is not very flat but has many glacial slopes and more, which he said means sea level causes different threats to different areas.
“Sea-level rise problems in Boston are very localized,” Fagherazzi said. “You can just move half a mile and get much higher.”
Hadassah Flagg, a sophomore in the College of Engineering and member of the professional environmental fraternity Epsilon Eta Pi, said she chose to study mechanical engineering because of her desire to work in renewable energy.
In researching how green spaces can help combat sea-level rise, she said she found City plans for harborside parks as flooding protection. The Resilient Boston Harbor plan involves creating infrastructure to protect the city from major floods and increase resilience, such as improving Langone Park and Puopolo Playground.
“They have a lot of different plans to work on green spaces along the coast,” Flagg said, “so if there is flooding, then that will kind of act as a barrier.”
She added that it is important to recognize the severity of climate change, despite the fact that sea-level rise can feel far away.
“You have these terms like ‘100 year flood’ and ‘500 year flood’ and you think ‘well that won’t happen in like 100 years,’” she said. “Some people feel safe when they see those numbers they’re like ‘oh it’s fine, it won’t happen.’ Well it still can, we had the snow in Texas. The climate is doing unexpected things.”