<meta http-equiv="refresh" content="0; url=https://r.sealevelrise.org/https://sealevelrise.org/states/massachusetts/"/> Massachusetts' Sea Level Rise - Sea Level Rise

Overview

Massachusetts’ Sea Level Has Risen 8” Since 1950

And It’s Costing Over $1 Billion

The sea level off Massachusetts’ coast is 8 inches higher than it was in 1950.1 This increase is mostly due to due to changes in ocean circulation2 and ice melt.3 Solutions can be complicated because although Massachusetts has coastal wetlands and beaches that protect communities and wildlife from flooding, these natural barriers are themselves at risk from sea level rise.4 The state is planning over $1 billion in sea level rise solutions, which include restoration projects, flood prevention, and the preservation of coastal wetlands.

Sea level rise is speeding up

Although the sea has only risen by 8 inches since 1950, its speed of rise has accelerated over the last ten years and it’s now rising by about 1 inch every 8 years.1 We know this because the sea level is measured every 6 minutes.6 Scientists use different equipment like satellites, floating buoys off the coast, and tidal gauges to accurately measure the local sea level as it accelerates and changes.

Created with Highcharts 6.2.0

Sea level measurement from Boston area tide gauge since 1950

Causes & Complications

Why Are Sea Levels Rising?

While there are four main causes of sea level rise in Massachusetts, changes in ocean circulation2 and ice melt3 are the largest contributors. Because the rate of ice melt has been increasing significantly since 1992, and changes in ocean circulation are causing coastal storms such as Nor’easters to increase in frequency and intensity, Massachusetts is particularly vulnerable to sea level rise.7 Click here to learn more about sea level rise causes.

Gulf Stream
How Ocean Circulation Increases Sea Level Rise
Ice Melt
How Ice Melt Increases Sea Level Rise

Most flooding happens in the winter

The highest tides in Massachusetts occur during nor’easters, wintertime storms that push more water to the coast, raising high tides even higher. Combined with an increased gravitational pull from the moon, these tides are typically nearly two feet than normal high tides.1 Add that to the 8 inches of sea level rise since 1950 and you end up with flooding even on sunny days.

Solutions aren’t simple

Solving for sea level rise can be complicated in Massachusetts because one third of New England’s coastal wetlands have already been lost due to human activity, which makes preserving the remaining wetlands urgent.8 Wetlands protect cities and towns, as well as wildlife that depend on coastal habitats. Efforts to mitigate sea level rise and flooding will need to provide solutions that work around existing communities and developed areas, while also preserving these wetlands and habitats.

Forecast

What's the Future of Sea Level Rise?

In the last decade, the speed at which Massachusetts’ sea level is rising has increased, and is now rising by about 1 inch every 8 years. Around Boston, it took 36 years for the sea level to rise around 6 inches.1 Scientists now forecast that in the next 15 years, the sea will rise by another 6 inches.6

Scientists are not certain how fast the ocean will warm and ice will melt. They expect water levels to continue to rise faster, but are not sure just how fast. Therefore scientists from the National Oceanic and Atmospheric Administration (NOAA) and the US Army Corps of Engineers (USACE) have made predictions based on ranges from low to high.

Below you can see the range of the NOAA and USACE high and intermediate forecasts for various locations around Massachusetts.10 We are currently closest to the USACE high forecast, which is the darkest red line.

SLR speeding up - Massachussets English
SLR speeding up - Massachussets English
Boston
Created with Highcharts 6.2.0Boston Sea Level Rise Forecasts

Flooding

Why Are Floods More Frequent?

When the ocean rises high enough, high tides cause flooding even on sunny days. Even though the sea level has only risen by around 3 and a half inches, tidal flooding has increased by 267% in Massachusetts since 2000.11

Flooding
How sea level rise affects Massachusetts

Flooding even when there’s no rain

Drainage systems are designed to channel excess rainwater from the streets and drain it into the sea. But with the pressure from rising sea levels and higher tides, seawater can get pushed into these pipes and spill out into the streets. This causes flooding even on days without rain.

Drain A
Drainage Under Normal Tidal Conditions
Drainage With King Tide / Sea Level Rise

Increased storm surge flooding

Unfortunately, slightly higher sea levels make hurricanes even more damaging. Just a few more inches of sea level rise allow a hurricane to push more water onto the land, even if the hurricane itself doesn’t make landfall.

MA-hurricane-bob

Hurricane Bob, 1991

Higher sea levels create a higher launching point for storm surge. These small changes in sea level rise are enough to turn what were 100-year storm surges into much more frequent events. In fact, in a third of 55 coastal sites studied throughout the US, 100-year storm surges will be 10-year or more frequent events by 2050.12

This means that in many coastal cities, if you bought a house with a 30-year mortgage today, by the time you paid off your mortgage you could be experiencing extreme 100-year storm surges ten times more frequently due to sea level rise alone. This does not include the added risk of more intense storms resulting from warmer water and a warmer atmosphere, which could further increase storm surge damage.

In 1991, Hurricane Bob hit Massachusetts, bringing powerful storm surge that destroyed homes and eroded large sections of the coastline, including 50 feet of Martha’s Vineyard and Nantucket’s shoreline.13 Without sea level rise, Hurricane Bob’s 15-foot storm surge would have been lower.

MA-hurricane-bob

Hurricane Bob, 1991

Costs

What's at Risk in Massachusetts?

There’s a lot at risk from sea level rise and flooding in Massachusetts. Sea level rise can push water further inland and into tidal estuaries, causing saltwater to intrude into the coastal ecosystem and the porous rock that freshwater travels through underground.4 Not only can this affect drinking water, but saltwater intrusion can ruin the habitats of many bird and fish species for which Massachusetts coastal wetlands provide sanctuary. Sea level rise also puts beaches and dunes at risk, which provide important nesting grounds for migratory birds and protect communities from dangerous storm surge.4

Coastal Wetlands
Coastal Wetlands

Sea level rise can disrupt coastal wetlands, which puts important ecosystems in danger, threatens habitats, and leaves communities exposed to dangerous storm surge.

Beaches
Beaches

Rising seas increase the speed of beach erosion, pulling more sand from the beach into sea. Replacing the sand is possible, but expensive.

Drinking Water
Drinking Water

The ocean is salty, and as it rises higher, that salty water sometimes will mix with drinking water, ruining water wells.

Massachusetts is spending over $1 billion on solutions

Some cities have sufficient resources to deal with this problem while others do not. Massachusetts will need solutions at the individual, local, state, and federal levels to protect its coastal communities.

Boston
Boston

Boston will address rising sea levels and flooding with Resilient Boston Harbor, a plan that will protect 47 miles of harbor and cost the city $1.2 billion.14

Massachusetts
Massachusetts

Massachusetts has authorized $290 million to fund improvements and repairs to dams and seawalls, and to implement diverse coastal resiliency strategies across the state.15

Quincy
Quincy

Quincy has passed a $27 million parks plan that will address tide gauge updates and minimize flooding, while preserving salt marsh ecosystems.16

What can you do?

Individuals, mayors, legislators, governors, and Congress can work together to build protections before flooding, to build back stronger after flooding, and to create plans that future-proof our communities. Click here to see what solutions can help protect your home or what your community can do.