New Online Tool Gauges Local, Statewide Threats from Rise in Sea Level

Jon Hurdle | April 24, 2014 | Energy & Environment, Sandy
Sea-level rise has broad implications for highly vulnerable communities and those that think they're out of harm's way

Sandy flood
A new online tool to help assess New Jersey’s vulnerability to sea-level rise was released on Thursday, one that delivers both a micro and a macro level of information to homeowners, planners, local and state officials, first responders, and a host of others.

On the micro level, the Surging Seas Risk Finder from Climate Central, a Princeton-based researcher into the effects of climate change, quantifies the threat to the state’s homes, roads, power plants, schools, hospitals, and a host of other locations under varying water levels above the local high-tide line.

On the macro level, the tool’s overarching message is that all areas will be affected by sea-level rise even if they are not in coastal flood zones, according to Ben Strauss, Climate Central’s vice president for climate impacts,

“The highest-level message is that everything is in the coastal zone,” he said. “Sea-level rise is going to affect everything about our economies, our home lives, our nation.

“People who don’t live in flood-risk zones still benefit from trade that moves through our ports and over vulnerable roads,” he said. “There’s all kinds of infrastructure that’s affected.”

Closer to home, the tool delivers a detailed assessment of the local dangers of sea-level rise.

Residents of Ocean County, for example, will find that more than $29 billion worth of real estate would be flooded by a rise in sea level of five feet, a margin that is within scientists’ expectations for the end of the 21st century.

In Middlesex County, two power plants, or about a fifth of the county, lies below the level that a combination of tides, storm surges, and higher seas would drive water five feet above the high-tide line.

And in Atlantic County, 86 hazardous waste sites, or 22 percent of the total land area, would be inundated by a five-foot rise in waters.

Categorizing Risk

Users can assess their exposure by choosing from six categories — socioeconomy, population, buildings, infrastructure, contamination risks, and land — and then selecting from subcategories ranging from roads to military bases to social groups in differing levels of vulnerability.

For instance, a community is judged to be highly vulnerable to sea-level rise if it is exposed to coastal floods and its residents have insufficient income to pay for flood insurance or alternative homes on higher ground. Different levels of vulnerability refer to a community’s resilience to natural hazards.

In Cape May County, more than a third of the high-vulnerability population would be threatened by five feet of sea-level rise, making the county the most vulnerable by that measure.

The tool also calculates the exposure of different ethnic groups. In Salem County, the homes of 25 percent of African-Americans would be flooded out by a five-foot increase, it says.

Similarly, it shows that 52,487 Caucasians in Ocean County will be in flooded areas if water levels rise by five feet.

Ben Horton, a sea-level rise scientist at Rutgers University, welcomed the new tool as an aid to understanding the practical effects of sea-level rise, and encouraging them to think more seriously about adaptation.

“The problem sea-level rise projections is that they are rather abstract,” Horton said. “This tool takes it down to regional, county and local levels.”

If it becomes widely disseminated, the tool will help local planners decide whether to build, for example, an electrical substation that might have a lifespan of 50 years in an area that would be subject to coastal floods within that period.

“We can start thinking about risk,” he said. “Are we planning our infrastructure in regions that are exposed to sea-level rise?”

In 2013, climate scientists at Rutgers released an online tool that allows users to visualize the effects of different levels of sea-level rise at selected points along the Jersey Shore.

Users of the new tool wanting to anticipate the effects of a two-foot rise — a margin that’s in the range of expectations by the middle of the century — can specify that level and discover their own vulnerability. In Ocean County, five percent of all real estate and two percent of roads would be under water in the event of a two-foot rise.

The tool builds on an earlier version published in 2012, and is part of a broader project that will offer the same analysis for every U.S. state later this year, said Strauss, who is director of the project. The latest release also updates previous work on New York, and publishes an assessment for New England for the first time.

New Jersey’s edition adds features including military bases, protected lands such as wildlife refuges, and rail yards, some of which were flooded by Sandy. In recognition of the importance of municipalities in New Jersey government, the tool also drills down for the first time to township level.

In Burlington County’s Riverside Township, for example, it shows that $57 million in property would be affected by a five-foot rise in sea level. Vulnerabilities are also broken down for the first time by state Senate and Assembly districts and by city wards.

The tool also adds planning authorities such as the Delaware Valley Regional Planning Commission to its analysis. It shows that within that organization’s jurisdiction, $2.5 billion worth of property would be affected by a five-foot rise in sea level.

“We want this tool to be useful to all these groups,” Strauss told NJ Spotlight.

An accompanying report takes a broader view, noting that 295,000 people live less than five feet above the high-tide line, in an area that contains property worth $112 billion, 2,100 miles of road, and 45 public schools.

The numbers of threatened facilities more than double if the water level is assumed to rise by nine feet, the peak flood elevation during Sandy at the Battery in New York.

“We find that sea-level rise from warming has already increased the likelihood of extreme flooding in the area — flooding high enough to seriously threaten the PATH transit system — by 50 percent,” the report said.

Among the broader effects of sea-level rise will be the dislocation of people from vulnerable coastal zones, and the higher insurance payouts that will be funded by taxpayers, Strauss said.

The tool, which took about two years to complete, follows the recent release of two reports from the U.N.’s International Panel on Climate Change which warned of worsening effects, including sea-level rise, from warming global temperatures and melting polar ice caps.

Unchanged from the 2012 edition of the tool are the sea-level rise projections themselves. For the Battery at New York City, a common benchmark in the New York-New Jersey area, seas are projected to rise by 0.6 feet to 1.8 feet by 2050 and by 1.9 feet to 6.3 feet by 2100. Projections for Atlantic City and Cape May are slightly higher. For the shore as a whole, the sea level is rising at about twice the global rate because the land is sinking at the same time, the report said.

The forecasts represent a combination of data from global and national groups, including the IPCC and the National Oceanic and Atmospheric Administration, Strauss said.

Sea-level rise has not yet redrawn local maps but it is already contributing to increased coastal flooding the report said. It urged people to begin planning for higher waters in years to come.

“It will not require another Sandy to cause extensive economic damage and suffering in the future,” the report said. “Knowledge of vulnerabilities can lead to better preparation for the next storm, and the ones after.”