Here’s what rising sea levels mean for Boston

A woman watched as waves crash into Fan Pier along the Seaport district in Boston during a powerful nor’easter.Keith Bedford/Globe Staff File

Last week, the United States got a wake-up call about sea level rise in the form of a major new federal report.

An interagency study, led by the National Oceanic and Atmospheric Administration, forecasts that by 2050, sea levels along US coastlines will be about a foot higher than they were in 2000. That increase will be even sharper in Boston and elsewhere in the Northeast: The region is likely to see 16 inches of sea level rise compared with 2000 levels.

Without urgent action to curb planet-warming pollution, sea levels in the Northeast could rise almost 2 feet by 2050. That’s significant as sea levels in the region have risen by less than 1 foot in the last century.

The report, which provides the most concrete national sea level projections to date, forecasts three to six days of moderate high tide flooding a year by 2050 in the Northeast, whereas the national average will be four days. Boston already experiences some of the worst high-tide flooding in the nation.

In the later part of the century, things will get even more dire. By 2100, under a worst-case scenario where emissions keep increasing, researchers estimate that sea levels around Boston could rise by 6.4 feet. Even with major climate policies in place, the region could see sea levels pushed up by more than 2 feet by the end of the century.

What would that mean for the city of Boston? Well, it means some regions will be swallowed up by the seas. The maps below shows which parts of Suffolk County would be inundated as the seas ascend.

Higher sea levels would also increase the frequency of dangerous high-tide flooding, create extreme levels of storm surge, erode shorelines, and threaten the safety of communities and infrastructure.

According to Rob DeConto, a climate scientist at the University of Massachusetts Amherst, these threats would make adaptation an insufficient response.

“Some areas of Boston and the Massachusetts coastline would have to be abandoned,” he told the Globe.

Sea level rise is already causing more frequent coastal flooding in low-lying areas along Massachusetts’ shorelines and has put hundreds of thousands of homes at risk. Reports show these risks disproportionately affect already marginalized communities.

The time to do something about this, the NOAA report suggests, is immediately.

Preparing for the deluge — and ending fossil fuel usage to limit it as much as possible — won’t be easy, but it’s our only option.

David Abel of the Globe staff contributed to this report.