High tides threaten California homes; Marin County has greatest risk

"At the local level, coastal communities must no longer allow construction that can not accommodate sea level rise", he said.

Of course, coastal states would be the most affected, particularly low-lying states.

The report further found that around 14,000 commercial properties worth $18.5 billion would also be at risk by 2045.

According to Desiree Companion, a certified floodplain manager employed by Sarasota County, the United States government-issued flood maps that people consult when building or buying a home are decades old in many places.

If this is the case, then 310,000 U.S. homes would be threatened by 2045, flooding as often as once every other week. Currently, those homes are worth about $353 million, contribute $3 million annually to the property tax base, and house an estimated 670 people.

Florida's municipalities could take a large hit to their property tax revenues by 2045, and the state will be the greatest hit of all coastal states in the lower 48 by the end of the century, according to the report. Also, the San Francisco Bay Area, coastal Louisiana, the Eastern Shore of Maryland and beach communities from Texas to MA. By 2100, that increases to 37,500 properties valued at $46 billion. By the end of the century, homes and businesses now worth more than $1 trillion could be at risk: as many as 2.4 million homes-roughly the equivalent of all the homes in Los Angeles and Houston combined-valued at approximately $912 billion and 107,000 commercial properties assessed at $152 billion.

Florida, New York and New Jersey may have the most to lose.

Under this scenario, where planet-warming emissions are barely constrained and the seas rise by about 6.5ft globally by the end of the century, 311,000 homes along the USA coastline would face flooding on average 26 times a year within the next 30 years-a typical lifespan for a new mortgage.

Factoring Zillow home prices with National Oceanic and Atmospheric Administration sea level rise scenarios, UCS scientists rank Miami as most vulnerable in Florida followed by Tampa Bay. Flood insurance premiums could rise sharply, with people faced with the choice of increasing clean-up costs or retreating to higher ground inland. The authors of the research say that this could potentially lead to the most extreme housing crisis the country has ever seen.

If properties flood regularly, homeowners risk steep financial losses, along with local services becoming jeopardized, as tax bases erode. The combination of poverty and chronic flooding creates hotspots of heightened risk in Louisiana, North Carolina, New Jersey and Maryland. UCS said by the end of the century, 2.4 million homes and 107,000 commercial properties now worth more than $1 trillion altogether could be at risk, with Virginia's coastal real estate a big part of that number.

The study was published Monday by the Union of Concerned Scientists. They also pointed out that the vegetable supply could shrink by a third in 2050 if people do not do something about climate change.

About 175 communities nationwide can expect significant chronic flooding by 2045, threatening 10 percent or more of their housing stock.

"The longer we wait to drastically reduce emissions, the less likely it is that we will achieve this outcome".