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Here are the 5 Massachusetts towns most at risk from rising seas, according to a new report

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A flooded neighborhood near Rexhamme beach in Marshfield after a Nor'easter pummeled coastal areas in Massachusetts. Barry Chin / The Boston Globe

We already knew that climate change is expected to have costly effects on coastal communities. Thanks to a new study, we now have more precise estimates on the risk posed to Massachusetts towns by rising sea levels.

According to a report this week from the Union of Concerned Scientists, as many as 7,000 of the state’s residential homes will be at risk of “chronic inundation” by ocean flooding in 2045.

By 2100, that number jumps to 89,000 residences — home to about 178,000 people — and amounts to roughly $63 billion in property value, which the Cambridge-based organization says ranks Massachusetts fifth nationally for the most to lose due to flooding by the end of the century.

Several local towns are projected to be particularly exposed. According to the report, five Massachusetts communities have 600 or more at-risk homes by 2045, two of which are projected to experience chronic flooding in more than one-in-10 of all residential properties.

5. Salisbury

Homes at risk in 2045: 601
Percent of total homes: 16 percent
Estimated number of people currently living in those homes: 1,088
Collective property value: $189,197,800
Total property tax revenue: $2,255,234

4. Hull

Homes at risk in 2045: 629
Percent of total homes: 13 percent
Estimated number of people currently living in those homes: 1,120
Collective property value: $197,913,400
Total property tax revenue: $2,715,468

3. Quincy

Homes at risk in 2045: 659
Percent of total homes: 3 percent
Estimated number of people currently living in those homes: 1,404
Collective property value: $327,032,500
Total property tax revenue: $4,634,052

2. Marshfield

Homes at risk in 2045: 699
Percent of total homes: 7 percent
Estimated number of people currently living in those homes: 1,601
Collective property value: $198,491,400
Total property tax revenue: $2,723,300

1. Revere

Homes at risk in 2045: 1,105
Percent of total homes: 9 percent
Estimated number of people currently living in those homes: 2,575
Collective property value: $375,072,900
Total property tax revenue: $5,410,524

Projecting out to 2100, all of those communities are surpassed by another city that is projected to have much more to lose: Boston.

With a 6.5-foot relative sea level rise in the city by 2100, which past studies have said is probable if greenhouse gas emissions are not significantly reduced, 32,640 — or 25 percent — of Boston’s homes would be at-risk of being “chronically inundated.” According to their figures, that includes 78 percent of homes in the Back Bay-Beacon Hill area (02116 zip code) and the South End (02118) and 71 percent of homes in Fenway (02115) and Faneuil Hall (02109) areas.

Surrounding towns like Cambridge, Somerville, Medford, and Arlington would also see thousands of homes at risk.

Even in the scenario that the world does make major reductions in emissions by the middle of the century, Boston is still projected to see a 4-foot increase in sea levels. According to the Union of Concerned Scientists’ report, 24,580, or 15 percent, of Boston’s home would still be at experience chronic flooding.

City officials have been considering the feasibility of constructing a sea barrier to protect Boston from increasing threat of flooding. However, a city-commissioned report by UMass Boston concluded last month that the massive project might not be worth the financial costs compared with other smaller, shore-based approaches to dealing with the local effects of climate change.

Check out the full report this week from the Union of Concerned Scientists here as well as their interactive map of the coastal towns most threatened by flooding.