BOSTON (CBS) – Boston has a target on its back. Over the last two decades, sea level rise has become more than a concern for the city. Now, it’s an imminent threat.

“We are in a bullseye for accelerated sea level rise,” said UMass Professor Dr. Rob DeConto. “The coastline is going to become a dangerous place to live.”

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A contributing factor to that, as DeConto explains, is a shift in the Atlantic Ocean topography.

“The water in the ocean responds to the topography at the ocean surface,” DeConto said. “It wants to flow down the hill.”

That hill isn’t a figure of speech. Bermuda is at the top of this “oceanic hill.” The U.S. and Europe are at the bottom. As water circulates, a current known as AMOC, ensures low laying areas don’t pile up. In recent years, that circulation has slowed.

“If the AMOC slows down and that hill relaxes, the ocean around Bermuda will actually drop and the ocean levels around the east coast will actually rise,” DeConto told WBZ-TV.

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These effects take years, decades, and even centuries to feel.

“We don’t have these dramatic impacts. It’s going to be more of a chronic problem,” said DeConto.

In Boston, the result is what’s called sunny day flooding. According to the National Oceanic and Atmospheric Administration, the city saw 22 days of fair-weather floods in 2017. DeConto says that is just the beginning.

“Imagine that was happening twice a day. Every time there is a high tide. That’s going to be incredibly disruptive,” he told WBZ.

But we can control this disruption. Not by blocking the water entirely, but by building a cityscape that interacts with the rising tides.

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“We would elevate not with monolithic, concrete flood walls. We would elevate with parks and playgrounds and harbor walls. The elevation would provide the protection. It would also provide really important social, economic co-benefits,” said DeConto. “It’s really a chance to redo a lot of the wrongs that we did in the last century or so.”

Zack Green