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NJ could need 2,700 miles of sea walls to defend against rising waters

New study says building defenses along Jersey Shore would cost billions and suggests the fossil-fuel industry should pay

sandy sea level rise

New Jersey would have to pay almost $25 billion to build almost 2,700 miles of seawalls to protect its coastal communities from anticipated sea-level rise by 2040, according to the latest study on the state’s vulnerability to rising ocean levels.

The Center for Climate Integrity, a Washington, DC-based advocacy group, said New Jersey faces the sixth-biggest bill for sea-wall construction of any state, while low-lying Cumberland County would have to pay the most — $5.8 billion for 532 miles of seawalls — among New Jersey’s counties.

Atlantic City would have to build 49 miles of sea walls to prevent persistent flooding, at a cost of some $365 million, while Mystic Island and North Beach Haven would also be faced with multimillion-dollar bills for sea defenses, according to the national report, titled “High Tide Tax,” published on Thursday.

“This looming climate and financial threat exist for every coastal community, regardless of size, population or financial position,” the report said. (The report’s estimate of the amount of coastline that would need defending from sea-level rise is based on New Jersey’s numerous inlets, bays, estuaries and islands that are expected to be flooded with sea water by 2040. By comparison, the U.S. Army Corps of Engineers says that its current study of how to defend New Jersey's back bays from future flooding covers 3,400 miles of coastline.)

It follows a warning from the Union of Concerned Scientists last year that some 250,000 coastal properties in New Jersey are at risk from seas that, by some scientific estimates, are projected to rise 10 inches by 2030 and 1.5 feet by 2050.

Danger to metropolitan areas

In 2016, another report on the vulnerability of metropolitan New Jersey, New York and Connecticut said rising seas will in future permanently flood large areas of the Jersey Shore, Hoboken and Teterboro Airport, for example.

hoboken  flood
Flooding in Hoboken during superstorm Sandy.

As melting polar ice caps and rising temperatures swell ocean volumes in response to high levels of human-caused carbon dioxide in the earth’s atmosphere, New Jersey and other mid-Atlantic states are experiencing about twice the global rate of sea-level rise because their land mass is sinking at the same time as seas are rising, scientists say.

The new report said it is the first to estimate the costs of armoring coastal areas that contain infrastructure like roads, bridges, airports, rail lines, ports and drinking-water supply systems.

But it warned that the projections are likely to be the “bare minimum” that cities and states will have to pay to stop themselves being flooded by ocean waters in coming years, and may represent only 10-15 percent of total adaptation costs.

The authors based their projections on conservative estimates for CO2 emissions and the effects they are expected to have on ocean levels, in an effort to focus discussion on baseline costs for defending coastal communities rather than looking at the consequences of higher emissions levels, even if they are seen as more realistic.

The sea wall cost estimates are based on national standards followed by engineers plus local estimates from sea wall construction companies, leading to per-foot cost estimates, the report said.

Based on conservative projections

The cost estimates, based on projections from Resilient Analytics, an engineering firm that specializes in climate adaptation, assume relatively low levels of Representative Concentration Pathways (RCPs) for carbon emissions, and their climate effects, as calculated by the Intergovernmental Panel on Climate Change.

Under the IPCC’s two lowest emissions scenarios, the global mean sea level will likely rise 11-24 inches, and 14-28 inches, respectively, by 2100, the report said.

But under the IPCC’s two higher scenarios — which the new report called “more plausible” given current global policies on curbing emissions — seas are projected to rise between 15 and 39 inches by the end of the century.

The cost estimates are based on projected sea-level rise under the two lower RCP projections, combined with a “one-year storm surge,” or the level to which coastal water rises in a typical storm.

This week, the U.S. Environmental Protection Agency finalized a rule that allows states to set their own emissions for coal-fired power plants, a move that environmentalists say will boost U.S. carbon emissions, and which the EPA itself says could result in 1,400 more premature deaths from air pollution each year than under the Obama-era Clean Power Plan to curb power-plant emissions.

In New Jersey, the Commissioner of the Department of Environmental Protection, Catherine McCabe, attacked the rule as a regressive step. “Instead of facing up to the urgent challenge of reducing carbon emissions, as New Jersey and many other states are doing, the Trump Administration is taking us backwards,” she said after the EPA’s announcement.

Mapping coastal vulnerability

In March, the DEP released a Coastal Vulnerability Index, a mapping system that combines indicators like flood-prone areas and storm-surge inundation scenarios to indicate the flooding threat faced by specific communities.

Jersey Shore
Credit: USACE

Ben Strauss, president of Climate Central, a Princeton-based research group that provided flood maps for the study, said it probably sharply underestimates the costs of defending coastal communities because it only covers sea walls and levees rather than an array of other measures that are under consideration by some administrations.

“Except where ingenious and less expensive other approaches can be found, such as boosting natural wetlands as defenses, we can anticipate many other expenses, such as moving or upgrading existing infrastructure, and adding needed new infrastructure such as pumping systems,” Strauss wrote in an email.

He noted that New York City Mayor Bill de Blasio this year estimated that it would cost $10 billion just to build out Lower Manhattan in a way that would stop ocean waters inundating the financial district and other sites.

Nationwide, the cost of defending the coast from rising seas is estimated at $400 billion, or about half of the federal stimulus package provided by the Obama administration to stimulate the economy during the 2008-2009 recession.

Ocean City, for example

For individual communities such as Ocean City — a barrier-island community of about 11,000 people which needs 33 miles of sea walls costing $247 million, according to the report — the bill will far exceed their ability to pay, raising the question of whether to find the money elsewhere or simply abandon the town and retreat to higher ground. In 43 communities including Strathmere, the cost of sea walls would exceed $500,000 per person.

The bill, the report says, should be paid by the fossil-fuel industry which has known for at least 50 years that its products caused climate change but has maintained an “exquisitely effective” denial campaign for the last 30 years, saying it should not have to pay climate-related costs.

“Failing to hold polluters to this basic responsibility would be to knowingly bankrupt hundreds of communities, standing idly by as they are slowly and inexorably swallowed up by the sea,” the report said.

The American Petroleum Institute, the oil industry’s leading trade group, declined to respond to the report’s arguments that it should pay to defend coastal towns against sea-level rise, and that it had for decades ignored evidence that its products cause climate change. But it issued a statement saying that the industry is helping to drive down emissions by using cleaner technology and natural gas, which emits less carbon than coal or oil.

“The U.S. natural gas and oil industry is meeting the climate challenge head-on, investing billions in high-tech innovation, efficiency improvements, and cleaner fuels,” the API said. “Our industry is leading the charge driving CO2 emissions in the United States to their lowest level in a generation, while reducing its environmental footprint.”

The Center for Climate Integrity, a project of the Institute for Governance and Sustainable Development, is funded by the MacArthur Foundation, Patagonia Inc., the Tortuga Fund, the Rockefeller Family Fund, and the Wallace Global Fund.

Jon Hurdle is a freelance writer who lives in Philadelphia and regularly reports on water and other environmental issues for NJ Spotlight.

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