Coastal Flooding-A Trillion-Dollar Threat

Report: 40 percent of Florida property will be 'highly exposed' to flooding

Zillow Data Used To Project Impact Of Sea Level Rise On Real Estate

As many as 311,000 coastal homes in the continental United States with a collective market value of approximately $117.5 billion are at risk of climate change-induced chronic flooding within the next 30 years-the lifespan of a typical mortgage- according to new data released by the Union of Concerned Scientists (UCS), which also noted that about 14,000 coastal commercial properties assessed at a value of roughly $18.5 billion also are at risk during that timeframe. By 2100, about 1 million properties — worth $351 billion — will be at risk, the report said.

Florida would be the state most impacted by coastal flooding, losing more than 10 percent of its residential properties-about one million homes-by 2100 in a high sea level rise scenario.

A map shows 10 percent of homes in St. Augustine and Brunswick are potentially at risk from chronic flooding in 2045, a time frame chosen since it falls within the lifetime of a 30-year mortgage issued today. Homeowners whose properties become chronically inundated could find themselves with mortgages that exceed the value of their homes, face steeply rising flood insurance premiums, or even default on their loans.

A study by the Union of Concerned Scientists examined how real estate values were affected in 23 coastal states.

Using three scenarios developed by the National Oceanic and Atmospheric Administration, the UCS estimated the number of properties in the 48 mainland states that could be affected by high tides and regular flooding, not counting major storms. Under NOAA's calculations for a moderate level of sea level rise, around 140,000 homes would be at risk by 2035 and more than 2.1 million by 2100. The total number of at-risk residential properties jumps to roughly 68,000-home to about 102,000 people-by 2100.

With lower home values, comes lower property taxes. Previous research has suggested that about 13 million Americans may have to move due to sea level rise by the end of the century, with landlocked states such as Arizona and Wyoming set for a population surge.

"Even if it takes till 2045 for $135 billion in property value to experience chronic flooding, the economic ramifications could be far more significant than even the largest estimates presented in this report and occur substantially earlier than the flooding itself", Bernstein wrote in a statement to CNN.

The report warns of a potential housing market crisis, once risk perceptions catch up with reality. "People on the waterfront won't be able to stay unless they are very wealthy". And what we've found through our research is it's a real threat to coastal real estate.

'The impact could well be staggering, ' said Kristina Dahl, a senior climate scientist at the Union of Concerned Scientists (UCS) told The Guardian.

Many of Maryland's most exposed communities are home to residents who have fewer resources to adapt to chronic flooding.

There are now many well-intentioned federal, state and local policies that mask risk and create incentives that reinforce the status quo or even expose more people and property to risk.

The report includes a risk assessment for a variety of coastal ZIP codes.

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