For more than a decade, the impact of sea level rise and tidal flooding has been making waves on the real estate market of coastal New England, costing homeowners more than $400 million in lost value.
That’s according to a report from First Street Foundation, a Brooklyn-based nonprofit that studies the impact of sea level rise and flooding.
“It’s probably going to become even worse over time if adaptation and other approaches aren’t taken to further stop it,” said Jeremy Porter, a professor at Columbia University and a statistical consultant for First Street. “We would expect to see more [losses] on the lots that are already experiencing it, but then we’d also see if adjacent lots start to also experience tidal flooding.”
Porter said his team looked at existing models for determining home values and added a variable for lost appreciation relative to comparable homes. The methodology has been implemented in several other areas but now in coastal New England, homeowners — and maybe more importantly, prospective homeowners — can look at how properties are being affected by climate change.
The Flood IQ database allows users to look up properties and get an estimate of how much greater the value would be if not for the environmental changes.
One extreme case: a triple-decker on Marginal Street in East Boston, now valued at $374,000. First Street’s model estimated it would be worth nearly $800,000 were it not for flooding and sea level rise.
Similar information was already available to institutions — and used by banks and insurance companies — but now it’s available to everyone for free, said First Street Executive Director Matthew Eby.
Eby hopes the tool is also useful to policymakers. Municipalities “can look at [the impact on property values] as an economic input of: ‘What is the actual loss to the tax base? What solutions can we put in place to keep that from happening in the future?’ ”
The report looks at 2.5 million coastal properties in Massachusetts, Maine, New Hampshire and Rhode Island, concluding “sea level rise has eroded $403.1 million in relative home values between 2005 and 2017.” The majority of those losses are in Massachusetts.
Apart from the direct impact of flooding on specific properties, the study also concludes that flooding in neighboring areas also has an impact on home values — such as, if a street in a certain neighborhood is prone to flooding, that could hurt the values of all every home on the street, even if a particular home doesn’t experience flooding.
Jesse Keenan, a climate resiliency expert at Harvard’s Graduate School of Design, said connecting the value of homes with the well being of urban infrastructure is an important contribution to the field.
“Your property doesn’t necessarily have to be immediately inundated with floodwater to feel the impact from climate change — from flooding and sea level rise,” Keenan said. “Just because you’re on high ground, you may not necessarily be safe.”