How are coastal cities adapting to climate change? A dispatch from Boston.

Like many coastal cities, Boston faces threats from sea level rise and extreme storms. And like many, its progress in adapting to change has been mixed.

Tony Dutzik | TPIN
"Sunny day" tidal flooding events are becoming more common in Boston. Adding storms to the mix will put the city at risk.
isabella Acosta-Jimenez
Isabella Acosta-Jimenez

Frontier Group Intern

In October 2012, Hurricane Sandy tore through the Caribbean and the northeastern United States, causing an estimated $75 billion in economic damage, and claiming more than 200 human lives. 

While Sandy left a trail of devastation along the East Coast, for Boston, it was a narrow escape. If Sandy had struck just 5.5 hours earlier at high tide, an estimated 6.6% of the city would have been underwater, with floodwaters potentially reaching City Hall. 

However, the storm served as a stark reminder of the city’s vulnerability to rising sea level and stronger storms. Twelve years after Sandy, Boston is also a good example of how cities are – and aren’t – preparing for the future of a changed climate. 

Boston’s coastal vulnerabilities

Almost 40 percent of the U.S. population resides in coastal counties, which generate economic output that would rank as the world’s third-largest economy behind the entirety of the United States and China. Coastal cities are particularly vulnerable to the combination of rising seas and more extreme coastal storms.

Boston is no exception. In fact, the city’s historical reliance on land-making magnifies its climate vulnerability. Since the late 1700s, tidal lands and salt marshes surrounding the Shawmut peninsula (where Boston was founded in the 17th century) have been filled to expand the city’s footprint. Today, one-sixth of Boston sits on this made land, built to the level of the 19th century’s high tide lines and increasingly exposed to flooding and storm surge. 

As climate change accelerates and sea level rises, water may return to the paths it once used, despite now being occupied by many people atop “made land.” Low-lying sections of neighborhoods such as Charlestown, Downtown, East Boston, South Boston and Dorchester are particularly at risk. Critical infrastructure – including the MBTA subway system, Logan International Airport, major roads, power stations, government offices, and hospitals – is already frequently affected by severe storms. According to a study by the First Street Foundation, nearly half of the critical infrastructure of Suffolk County (home to Boston) is at risk of becoming inoperable in instances of severe flooding.

The Seaport District, branded as the “Innovation District,” marks the pinnacle of tensions between economic development and climate realities. Developers and the city pursued building on the waterfront prior to a complete understanding of future sea level rise and its implications. Critics dub the neighborhood the “Inundation District,” questioning whether investing billions in waterfront development is a worthwhile risk as the world warms and sea level rises. Citywide, high-tide flooding was predicted to occur on 12-19 days in the 2024- 2025 meteorological year. By 2050, high-tide flooding could become a routine event in Boston, with conservative estimates ranging from 50 to 70 days of inundation each year

Wetland protection and nature-based solutions

Boston’s vulnerabilities may be unique, but the city is also beginning to consider – and in some cases, adopt – nature-based solutions that reduce that vulnerability. 

Nature often outperforms human-made systems in mitigating flooding. Wetlands, for example, can absorb and store millions of gallons of water during storms – enough to shield neighborhoods from catastrophic damage. Coastal marshes can diminish wave energy by over 50 percent

Restoring Boston’s lost wetlands, and protecting those that remain, is crucial for the city’s climate adaptation efforts. Programs like the Boston Wetlands Protection Ordinance are steps in the right direction, strengthening the city’s natural defenses while creating co-benefits such as improved water quality, soil water retention, and carbon sequestration. 

Wetlands restoration and expansion fall within a broader category of “nature-based solutions (NBS),” which leverage natural processes to address environmental challenges. Centered around planning with nature, these solutions often prove more sustainable and cost-effective than traditional engineering methods. Studies indicate that every dollar invested in wetland or reef restoration yields over $7 in direct flood-reduction benefits

Boston has embraced nature-based solutions through initiatives funded under programs such as the Municipal Vulnerability Preparedness Grant Program and longstanding projects such as the Boston Urban Wilds Initiative (UWI). Established in 1977, the Urban Wilds Initiative identifies and protects undeveloped open spaces critical to Boston’s resilience. These spaces are managed by the city, with support from partnerships, to remain undeveloped and accessible to the public. Urban wilds serve as ecological buffers, mitigating the impacts of climate change by absorbing stormwater, reducing the heat island effect, and preserving biodiversity. They also foster community engagement through recreation and environmental education, highlighting the intersection of conservation and public benefit. 

Innovative projects within urban wilds further demonstrate Boston’s commitment to leveraging nature for resilience. North America’s first “Living Seawall” was installed at the Condor Street Urban Wild in East Boston in 2024. While the idea started in Sydney, Australia, this is a pilot project developed by the Stone Living Lab at the University of Massachusetts Boston. By combining ecological concepts and engineering, the design seeks to promote marine biodiversity along coastal “grey infrastructure,” improve water quality, and potentially even soften wave impacts. This initiative challenges the conventional notion that sea walls explicitly harm coastal ecosystems; instead, it demonstrates how protective infrastructure can coexist with and even support natural environments, serving as both a line of defense and a platform for coastal restoration.  

Similarly, the “Emerald Tutu”– a proposed system of floating vegetated mats named to evoke comparisons to Boston’s famed “Emerald Necklace” network of parks – exemplifies innovative resilience design. This innovative system, while still conceptual, mimics marsh environments, and could provide essential protection against rising seas, absorb wave energy, and foster biodiversity.

Investing in resilience 

Leaders in Boston and other coastal cities face a difficult question: How much longer can they afford to gamble with their future? As sea levels rise and storms intensify, the question is not if another major storm will strike Boston, but when. Hurricane Sandy was a wake-up call, and Boston has made strides in climate planning since 2012. However, the city’s luck will not hold indefinitely.

The 2016 Climate Ready Boston plan marked an exciting step forward, identifying the city’s vulnerabilities and proposing comprehensive resilience and adaptation measures. Yet, nearly a decade later, implementation remains a significant barrier. Much of the funding for these initiatives has relied on private development, meaning that areas of the city that have attracted new investment have also received resilience upgrades while other neighborhoods, including some of the most vulnerable neighborhoods, miss out. Many projects slated for competition by 2030 have also been delayed, leaving critical infrastructure and vulnerable communities at continued risk. 

The path forward for Boston and other coastal cities requires substantial investment in climate resilience. However, this investment is not merely a cost – it’s also an opportunity. Global case studies demonstrate that proactive adaptation measures yield significant returns. For example, New York City’s post-Sandy investments in green infrastructure have reduced flood risk and stormwater runoff while enhancing public spaces. 

To truly safeguard its future, Boston and other coastal cities must move beyond planning and prioritize action. By investing in innovative nature-based solutions like wetland restoration, living shorelines, and community-centered strategies, cities can transform their vulnerabilities into strengths. The time to act is now – before our luck runs out. 

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Isabella Acosta-Jimenez

Frontier Group Intern