Study finds sea levels rising fast; concerns grow about Shore

After Hurricane Sandy in 2012, scientists decided to help local officials plan for such scenarios by advancing recent research. Strong waves precede Sandy in Longport.
After Hurricane Sandy in 2012, scientists decided to help local officials plan for such scenarios by advancing recent research. Strong waves precede Sandy in Longport. (MICHAEL S. WIRTZ / Staff Photographer)
Posted: January 08, 2014

As the planet warms, one of the biggest questions is how fast sea level will rise.

A team of Rutgers University researchers has attempted to answer that question and localize it by studying past sea-level rise along the East Coast, as well as other factors that could influence what happens along the New Jersey Shore.

In recently published studies, they conclude that sea level at the Shore - already rising faster than at any time in the last 4,300 years - could go up by 11 to 15 inches more than the global average by 2100.

While levels worldwide will generally increase less than a foot by 2050, those at the Shore will likely rise 1.5 feet, according to a mid-range scenario. By 2100, local levels could climb 3.5 feet, bringing unprecedented flooding.

The research "clearly indicates that New Jersey is one of the regions of highest concern in the United States, as far as risk from sea-level rise is concerned," said Ben Strauss, an expert at the independent research organization Climate Central in Princeton. "This is really about how soon - not whether - sea level will rise that much."

Strauss was not involved in the Rutgers research. However, pairing it with his own analysis, he noted that Atlantic City alone has $23 billion worth of real estate sitting below a five-foot flood level. That magnitude could have a two-in-three chance of being seen in any given year by midcentury, according to the scientists' estimates.

The research was led by what Richard Lutz, director of Rutgers' Institute of Marine and Coastal Sciences, called a "sea-level rise dream team."

They include Kenneth Miller, a professor of earth and planetary sciences specializing in sea-level rise in past millennia, and Robert Kopp, a geomathematician who is assistant professor of earth and planetary sciences.

Then there's Benjamin Horton, who has focused on more recent sea-level rise - the past 10,000 years or so - along the coast. Former director of the University of Pennsylvania's Sea Level Research Laboratory, he switched to Rutgers this year, drawn by the opportunity to work at an institute specializing in marine and coastal "processes."

Suddenly, "New Jersey has one of the biggest concentrations of sea-level rise experts in the world, I think," Strauss said.

One factor that boosts sea-level rise along New Jersey: The land is sinking.

During the last glacial age, the huge ice mass that stopped just shy of North Jersey both compressed the land under it, and caused the ice-free land to the south to bulge up, like a mattress when someone sits on it.

That land is still subsiding, all these eons later.

Another reason New Jersey is sinking is that its coastal plain is geologically new - "a few tens of million years old," said Kopp - and made of mud and sediment that's still compressing. In comparison, New York and Philadelphia sit atop bedrock, and are more stable.

Plus, the more drinking water we pump out of it, the more it contracts.

Yet another reason for New Jersey's increasing vulnerability: Researchers expect the melting ice sheets to slow the Gulf Stream and cause its waters to, in effect, pile up along the coast from Long Island to North Carolina.

So now, Horton said, researchers know what the "players" are along the coast. What they're trying to do is reduce the uncertainties and better project what will happen.

One thing that wowed them was that sea level is rising faster than at any time in 4,300 years.

When those rates last occurred, the large remnant ice sheets from the last Ice Age were melting. "The rates were so fast that there weren't any barrier islands in New Jersey, or anywhere else in the world," Horton said. "There were hardly any coastal wetlands."

Only after sea-level rise slowed did those barriers form, becoming nurseries for fish and habitat for birds and other wildlife.

People often think of sea-level rise as having major effects only far in the future. After Hurricane Sandy, however, the scientists felt compelled to advance recent research to help local officials plan.

To Miller, it was almost personal.

"Let's take 2050," he said. If his son buys a Shore house in the next 10 years, "he'll have a mortgage in the year 2050."

Even so, the insistent creep of sea level is not what will inundate the house. The real threat is the higher baseline that the rising sea will give to flooding in a storm. A five-foot flood today will actually be 6.5 feet by 2050, assuming a 11/2-foot rise in sea level.

"This illustrates the power of sea-level rise," Horton said. "The debate about how intense hurricanes are going to be in the 21st century, or how many there are going to be, or what track they're going to have, or what their diameter is going to be is still very much debated.

"But the one thing we do know is that sea level is going to rise. And it's going to rise faster than in the 20th century."


sbauers@phillynews.com

215-854-5147 @sbauers

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