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Global sea levels could rise 8 feet by 2100, more in NJ, Rutgers study says

Back bay flooding

South Jersey’s barrier islands would pretty much disappear at high tide, according to a Rutgers review of flooding studies projecting out to 2100.

By the dawn of the next century, South Jersey’s barrier islands will pretty much disappear at high tide, based on data in a Rutgers University review of scientific literature.

Global sea levels could rise by almost 8 feet by 2100 and 50 feet by 2300, if emissions remain high and the physics of ice sheets work against us, according to the review.

“And that rise would be 10 feet in New Jersey (by 2100),” said lead author Robert Kopp, director of Rutgers’ Institute of Earth, Ocean and Atmospheric Sciences.

At 10 feet of rise, “about 7 percent of the current New Jersey population and $190 billion (of real estate) would be permanently flooded, and more would be exposed to more frequent flooding,” Kopp said.

Even with just 6 feet of sea-level rise, the highest that can be visualized on Rutgers’, parts of New and Shore roads on the mainland in Atlantic County would be underwater, as well as many properties within blocks of the bay. The trend is the same for other coastal counties as well.

The paper is a review of 20 studies published between 2012 and 2018, said Kopp. It is published in this month’s Annual Review of Environment and Resources.

Stewart Farrell of Stockton University’s Coastal Research Center said data from the National Oceanic and Atmospheric Administration estimate low, intermediate low, intermediate high, high and extreme sea-level rise predictions for 2100.

“The folks at FEMA have asked, when we do Community Rating Service reviews for coastal towns, that we use the intermediate high,” said Farrell. “For New Jersey, that is rounded off to about 5 feet (of rise by 2100).”

At that level, beach-block properties are relatively OK, he said.

“It’s the back bay that’s either abandoned or eventually has to be accessed a la Venice, Italy, by boat,” said Farrell. “It puts low tide in the streets every day.”

Since 2000, global average sea level has risen by about 2.4 inches, and about 4 inches in New Jersey, said Kopp.

And scientists are confident further sea-level rise will only amount to 6 to 10 inches globally by 2050, to a worst-case scenario of about 18 inches.

Rutgers scientists have estimated a likely sea-level rise in New Jersey of 1 foot to 2 feet by 2050. At just 2 feet, serious flooding develops on barrier islands and along bayfronts, according to njfloodmapper.

“At some level it’s simply about the ocean response to warming, and the ice response,” said Kopp. “Those are really big systems that tend to respond sluggishly.”

Much of what will happen in the next 30 years is already in the pipeline, he said.

But after 2050, uncertainty and a broader range of possibilities kick in, Kopp said.

Possibilities can also favor a better outcome. Sharp cuts in emissions, he said, can greatly reduce the most dire scenarios.

A factor that creates a great deal of uncertainty is the Antarctic ice sheet response.

“Collapsing ice cliffs, as well as a variety of other modes of instability such as uncertainty in emissions, are much more important on a longer time scale,” said Kopp.

Worst-case numbers are “the numbers you get if we are unlucky in terms of having physics that tends to favor ice sheet collapse in a high-emissions scenario,” he said.

Even under moderate emissions, mid-level estimates of global average sea level from different analyses range from 1.4 to 2.8 more feet by 2100, 2.8 to 5.4 more feet by 2150 and 6 to 14 feet by 2300, according to the study.

Eleven percent of the world’s 7.6 billion people live in areas less than 33 feet above sea level, so higher sea-level rise would pose a major risk to coastal populations, economies, infrastructure and ecosystems around the world, the review found.

Scientists also used case studies from Atlantic City and Singapore to discuss how current methods for reconstructing past sea-level change can constrain future projections.

Kopp led the review with Benjamin P. Horton, a former Rutgers professor now at Nanyang Technological University in Singapore. Co-authors include Andra J. Garner, an assistant research professor in Rutgers’ Department of Earth and Planetary Sciences, and other scientists at Boston College and Nanyang Technological University.

Contact: 609-272-7219 Twitter @MichelleBPost

In my first job after college got paid to read the New York Times and summarize articles for an early online data base. First reporting job was with The Daily Record in Parsippany. I have also worked in nonprofits, and have been with The Press since 1990.

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