Thousands of NC, SC homes totaling billions could be flooded by sea level rise in years ahead, study finds

In the next 30 years – the lifespan of a typical mortgage – tens of thousands of homes in North and South Carolina could be at risk of chronic flooding.

Residents of coastal communities most often feel the effects of sea level rise during tidal flooding, which is expected to worsen because of accelerating sea level rise, primarily driven by climate change.

That flooding puts 2.5 million homes and businesses valued at $1 trillion at risk by the end of the century, according to a new report from the Union of Concerned Scientists.

Sea levels are rising at a rate of about an inch per year (5 inches from 2011-15) in some areas along the East Coast, from North Carolina to Florida, according to one study— and that’s faster than researchers expected.

Tidal flooding, also known as “sunny day flooding” is the temporary inundation of low-lying coastal areas during high tide events.

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The new UCS study uses property data from online real estate company, Zillow, combined with a peer-reviewed methodology developed by UCS for analyzing coastal areas at risk for frequent flooding.

The study uses three sea level rise scenarios developed by the National Oceanic and Atmospheric Administration. UCS found out how many homes and commercial properties along coastline of the lower 48 states are at risk of becoming chronically flooded by high tides — flooding an average of 26 times per year or more in coming years, even without major storms to cause additional flooding.

The core findings of the UCS study use the high sea level rise scenario, which UCS says is “an appropriately conservative projection to use when estimating risk to homes, which are often the owner’s single biggest asset. “

“What’s striking as we look along our coasts is that the significant risks of sea level rise to properties identified in our study often aren’t reflected in current home values in coastal real estate markets,” said Rachel Cleetus, an economist and policy director for the climate and energy program at UCS, and report co-author. “Unfortunately, in the years ahead many coastal communities will face declining property values as risk perceptions catch up with reality. In contrast with previous housing market crashes, values of properties chronically inundated due to sea level rise are unlikely to recover and will only continue to go further underwater, literally and figuratively.”

Carolinas homes at risk, and what that means

Satellites and tide gauges have been used to report sea level at regular intervals in North Carolina.

That data shows that the sea level has been gradually rising consistently along the North Carolina coast for the past 30 years or more since those gauges were installed, according to the N.C. Department of Environmental Quality.

But sea levels aren’t rising equally “like water in a bathtub,” according to a report from Yale Environment 360. “The oceans are more akin to a rubber kiddie pool where the water sloshes around unevenly, often considerably higher on one side than another.”

As sea levels continue to rise, the frequency, depth and extent of coastal flooding will continue to worsen, according to NOAA. Some areas, including the Carolinas, could see worse flooding than others, and stand to lose much more.

In 2016, Charleston saw 50 days of tidal flooding.

Fifty years ago? Just four days.

Flooding projections are set at about 25 percent above average for 2017-18 for areas including Wilmington, according to a recent NOAA report.

Wilmington had 84 days of high-tide flooding in 2016, according to NOAA.

Living in cities threatened by sea-level rise could be like living near an active volcano, according to NOAA oceanographer William Sweet.

In North and South Carolina, billions of dollars in valuable property are at risk, according to the study, and thousands could potentially be displaced from their homes.

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In North Carolina, there are 15,582 homes valued at nearly $4 billion at risk in the next 27 years, according to the study. There are nearly 23,000 people housed in those at-risk homes.

In South Carolina, there are 16,614 homes at risk in the same time period, valued at close to $9 billion. About 24,000 people live in those at-risk homes, the study says.

Because those homes are at risk, that also means the property taxes their owners pay is at risk. In North and South Carolina, that amount totals more than $96 million in the next 27 years, according to the study.

That’s $96 million that would no longer be available to local governments should those homes become unlivable, meaning less funding for schools, roads and emergency services in those places.

By 2100, those numbers increase to nearly 100,000 homes in North Carolina valued at more than $28.5 billion and more than 150,000 people living in those at-risk homes, according to the study data. In South Carolina, more than 115,000 homes valued at nearly $52.7 billion and more than 186,000 people in chronically flooded homes by 2100.

Nationwide, the 311,000 coastal homes at risk by 2045 house about 550,000 people and contribute nearly $1.5 billion toward today’s property tax base, according to study data. In the next century, those numbers increase to about 4.7 million people in homes that contribute $12 billion in taxes. Things get even worse if at-risk commercial properties are included.

“For some communities, the potential hit to the local tax base could be staggering,” said Kristy Dahl, senior climate scientist at UCS and report co-author. “Some smaller, more rural communities may see 30, 50, or even 70 percent of their property tax revenue at risk due to the number of chronically inundated homes. Tax base erosion could create particular challenges for communities already struggling with high poverty rates.”

Who lives in the at-risk communities?

Nationwide, nearly 175 communities could expect to see 10 percent or more of their homes at risk of chronic flooding in the next 27 years, the study said.

Nearly 60 of those communities have poverty levels above the national average.

Of the 75 communities with 30 percent or more of their property tax base at risk because of chronic flooding in the next few decades, about one-third have poverty rates above the national average.

North Carolina is among those, and is one of the “places that could be hit hardest,” the study said.

Similarly, communities at risk that have large African American or Hispanic populations, including those in the Carolinas, could also be “at an inherent disadvantage in taking steps to prevent or recover from chronic flooding, due to longstanding social and economic inequities,” the study said.

Many of the communities with at-risk homes have high percentages (60 percent or more) of seniors — far above the national average, according to UCS data.

Croatan in Craven County, North Carolina is one of those. About 20 percent of Croatan’s homes, value and tax base are at risk of chronic flooding in the next 15 years, the study said.

UCS built an interactive map to help communities determine their risk.

Nags Head and Hatteras together have nearly 2,000 at-risk homes in the next 30 years, the study said.

Crawford has 504 homes and more than 1,200 people affected. Atlantic beach has 200 homes and more than 200 people affected.

In Kinnakeet, 34 percent of homes are at risk, or about 1,099 homes.

In South Carolina, nearly 1,500 homes on Kiawah Island would be at risk, and more than 2,700 on Hilton Head.

On Kiawah Island, those homes represent nearly one-quarter of the local property tax base.

In Charleston, 1,629 homes are at risk of becoming chronically flooded by 2045, about 16 percent of the entire community, all valued at a collective $1.3 billion and housing nearly 3,000 people.

In seaside communities such as Nags Head, many homes are physically elevated off the ground. But even if a home stays dry, access roads, surrounding land and other infrastructure will be flooded.

“While wealthier homeowners may risk losing more of their net wealth cumulatively, less-wealthy ones are in jeopardy of losing a greater percentage of what they own,” Cleetus said. “Homes often represent a larger share of total assets for elderly or low-income residents. Renters too might find themselves in a tight market or having to put up with decaying buildings and increased nuisance flooding. Hits to the property tax base in low-income communities, which already experience significant underinvestment in critical services and infrastructure, could prove especially challenging.”

Meanwhile, the loss of coastal property values will have reverberations throughout the economy — affecting banks, insurers, investors, and developers — potentially triggering regional housing market crises or a more widespread economic crisis, the study said.

Homeowners whose properties become chronically flooded could find themselves with mortgages that exceed the value of their homes, face steeply rising flood insurance premiums or even default on their loans. Lenders carrying large numbers of these risky mortgages could lose money or eventually become insolvent, with smaller banks concentrated in regions with high flood risk being especially exposed, according to the study. Coastal real estate investors and developers may similarly experience financial losses in some coastal areas.

What can we do?

When a North Carolina state science panel reported in 2010 that seas on the coastline could rise by as much as 39 inches over the next century, legislators passed a law forbidding communities from using the report to make new rules.

A new report in 2015 looked only 30 years to the future and forecast a rise of 2 to 10 inches, depending on location.

UCS says local and state governments can help minimize risk and prevent additional risk by using accurate, science-based flood risk data, improving zoning and building codes, removing incentives for building in at-risk areas and more.

“Actions today, especially the amount of global warming emissions we release, will help determine what our coasts will look like at the end of the century,” said Astrid Caldas, senior climate scientist at UCS and report co-author. “If we manage to meet the goals of the Paris Agreement by keeping warming to between 1.5 and 2 degrees Celsius and if ice loss is limited, 85 percent of all affected residential properties—valued at $782 billion today and currently accounting for more than $10.4 billion in annual property tax revenue to municipal governments—could avoid chronic flooding this century. The longer we wait to drastically reduce emissions, the less likely it is that we will achieve this outcome.”

“Not all affected communities will share the same experience,” said Erika Spanger-Siegfried, senior analyst in the climate and energy program at UCS and report co-author. “Some may see sharp adjustments to their housing market in the not-too-distant future; some could see a slow, steady decline in home values; and others could potentially invest in protective measures to keep impacts at bay for a few more decades. In any case, by knowing how much time they have before a significant number of properties will be regularly flooded, communities can start planning and implementing responses now, while they still have a range of options from which to choose.”

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