In the span of a 30-year mortgage signed today, 2,400 Palm Beach County homes could face a month’s worth of flooding each year as sea levels rise and tides creep farther inland, according to a study released Monday by the Union for Concerned Scientists.
By the year 2100, the number of homes from Boca Raton to Jupiter that are vulnerable to the slow-motion threat of tidal inundation skyrockets to 60,026 properties worth a staggering $36.2 billion in today’s dollars.
The nationwide report, which used housing information from the online real estate company Zillow, looked at the years 2045 and 2100 to emphasize that sea level rise is not just a faraway challenge. A home buyer signing a 30-year loan this year for a property vulnerable to flooding could still be paying the mortgage when rising water becomes a problem.
“For people who are making decisions right now about where they are going to live and where they will invest, 2045 is an important date,” said Nicole Hernandez Hammer, a biologist and consultant to the Union of Concerned Scientists. “If this report gets the attention of any state, it should be Florida.”
The key results of the study, titled “Underwater: Rising seas, Chronic floods and the implications for US Coastal Real Estate,” are based on the worse-case sea level rise scenario presented by the National Oceanic and Atmospheric Administration — “an appropriately conservative projection to use when estimating risk to homes,” a press release notes.
Statewide, about 64,000 homes are at risk of chronic flooding by 2045. The report defines chronic flooding as an average of 26 flood events or more per year, even in the absence of major storms.
By 2100, Monday’s report says 1 million Florida homes will be at risk. That’s about 10 percent of the state’s current residential properties and 40 percent of the homes at risk nationally.
Founded in 1969, the Union of Concerned Scientists explores how public policy and welfare are affected by science-based issues — such as nuclear power, food production and climate change. The organization has 200 staff members and 23,000 science network members.
Miami, the Florida Keys, Tampa and St. Petersburg stand out as the most at risk flooding areas in Florida the next 30 years, according to the report.
Palm Beach County is better protected from sea level rise than other areas of the state because part of its shoreline is an elevated coral ridge, said Leonard Berry, a professor emeritus at Florida Atlantic University and the former director of the Florida Center for Environmental Studies.
But tidal flooding is an issue for Palm Beach County properties along the Intracoastal waterway, some of which already see days of flooding each fall during the king tides.
West Palm Beach, which has no oceanfront, has 183 homes in danger of chronic flooding by 2045, but that increases to 2,176 homes worth $1.35 billion by 2100.
In Delray Beach, the study lists 325 homes at risk of chronic flooding by 2045. That balloons to 5,121 homes worth $3.74 billion by 2100.
The study counted each unit in a condominium as an individual home if the building fell within inundation limits even if only the bottom floor would be flooded.
“The answer is to not get panicky, but to look carefully at the situation and understand the options,” said Berry, who agreed using the worse-case scenario is legitimate as long as it’s disclosed. “It’s better to be forewarned and prudent about what the future may bring.”
If nothing changes to reduce the rate of global warming, Monday’s study estimates there will be an average of 1.8 feet of sea level rise in Florida by 2045 and 6.4 feet by 2100. The estimates are above 1992 levels.
Jayantha Obeysekera, director of Florida International University’s Sea Level Solutions Center, cautions against taking any prediction as fact. Models that determine ice sheet melt are not perfect, and zeroing in on how sea level rise will affect a single home is tricky, he said.
“When you do this kind of large analysis, you lose the resolution in the scale that you are most interested in,” said Obeysekera, who previously worked as an engineer and chief modeler for the South Florida Water Management District. “At some point, the rapid acceleration of sea level rise will inundate the coastal areas pretty much 365 days a year, but the question is when will that happen.”
While Florida has the most properties at risk by 2100, New Jersey is listed as runner-up with 250,000 impacted homes with current market values of $108 billion. New York ranks third with 143,000 impacted homes with current market values of nearly $100 billion.
“The good news is we can avoid the worse scenario and the majority of homes at risk could be spared if as a global community we move forward with the Paris agreement,” said Hernandez Hammer.
President Donald Trump withdrew from the U.S. from the Paris climate accord last year. The accord is a multi-nation agreement to keep global warming below 2 degrees Celsius (3.6 degrees Fahrenheit.)
Local governments are moving forward with efforts to mitigate climate change, including in South Florida where Palm Beach, Broward, Miami-Dade and Monroe counties work together as the Southeast Florida Regional Climate Change Compact.
“The compact is unique in the country and having that involvement and community engagement is wonderful,” said Obeysekera. “Speaking as an engineer, this is not an easy problem to solve.”