Surging Seas mapping tool shows impact of climate change on New England

Coastal casualties have almost become routine: Beloved Plum Island homes devoured by rising seas; Nantucket and Martha’s Vineyard mansions picked up and moved inland; Scituate homes continually rebuilt after being hit again and again by the Atlantic.

Now, a new sea-level rise and coastal flood mapping tool for New England illustrates in stark detail the economic risks facing the region as sea levels swell, in large part from human-caused climate change. More than $32 billion in property in the region’s five coastal states is at risk of extreme coastal flooding -- and that is after accounting for protections from dams and other flood control structures, according to the analysis by Climate Central, a climate research organization.

“Sea level rise is the impact that gives climate change an address,” said Ben Strauss, the scientist who led development of the Surging Seas interactive map. “We want to give citizens, businesses, planners and leaders the clearest possible map of risk. ... We’ve put a very high proportion of our homes, our infrastructure, and our economy in low-lying areas near the coast.”


The group recently added New England to its mapping tool to illustrate how much sea levels are expected to rise in states, counties, and neighborhoods, including the number of residents and homes that are at risk. An explanation of how they arrived at their projections is here.

Get Today's Headlines in your inbox:
The day's top stories delivered every morning.
Thank you for signing up! Sign up for more newsletters here

The rate of sea level rise in New England and globally is accelerating, and scientists predict the oceans will rise roughly two to seven feet more this century. Storm surges layer on top of those higher seas, pushing water further inland and damaging properties.

Strauss says his team was surprised “how concentrated the region’s total sea level rise and coastal flooding risk is in the Greater Boston area. We were also surprised by how important a handful of dams appear to be for protecting property at lower flood levels.”

Here are some findings:

-- In Massachusetts, 47,888 people live on land that is exposed to four-foot floods. Of this total, 17,662 are considered highly vulnerable, based on social and economic criteria. There is a 67 percent chance of a four-foot-high flood in Boston by 2030.


-- In Rhode Island, more than $4.3 billion worth of property lies on land less than five feet above the high tide line. There is a 1 in 3 chance of a flood that high in Newport by 2040.

-- In New Hampshire, $1.08 billion worth of state property lies on land less than four feet above the high tide line. There is a 40 percent chance of a flood that high by 2040.

-- In Maine, 58,379 acres of land are situated four feet above the high tide line. There is a 40 percent chance of a flood that high in Portland by 2040.

-- In Connecticut, $14.9 billion in property and 53,406 people are situated on land that is less than six feet above the high tide line. There is a 1 in 3 chance of a flood that high in Bridgeport by 2040.

Follow Beth Daley on Twitter at @BethBDaley.