The US woke up this morning to the impacts of Hurricane Helene: Beyond the still uncounted deaths, entire communities are leveled and hundreds of thousands of homes and buildings are damaged or destroyed. Millions of Americans are suffering and there’s no end game, just bigger and more frequent storms in the future.
We wrote the following piece in 2022 about Hurricane Ian and it’s just as relevant today:
September 29, 2022
Hurricane Ian came ashore on the west coast of Florida and did its damage - time will tell how many people die and how many billions it will cost to rebuild. Hurricane Harvey dumped 40 inches of rain over four days over Houston in 2017 and caused $125 billion in damages and 68 people died. Katrina was also $125 billion in damage with 1800 deaths.
We recently wrote about the impact of sea level rise but found that the near-term danger is hurricanes with their rainfall, wind and storm surge. We predicted that someday soon, a major hurricane would hit the east coast of Florida and do untold damage. We picked the wrong coast.
Increasingly intense hurricanes are mainly driven by hotter ocean water temps. Florida has been lucky to avoid the worst hurricanes of the past decade - its west coast fronts onto the Gulf of Mexico, which is about 4 degrees F hotter than a hundred years ago. Hurricanes really get going with ocean water temperatures in excess of 82 degrees F. Temps on Ian’s path across the Gulf were in the 87 degrees F range. (The seawater temp under Helene is believed to have been 89 degrees F.) That’s as hot as the Gulf has ever been. It’s estimated that a one-degree Fahrenheit rise in ocean temperature can increase a hurricane’s wind speed by 15 to 20 miles per hour. Water that’s 4 degrees hotter will generate an additional 70 mph of wind speed, which also drives storm surge. This is the main reason forecasters predicted the intensification of Ian.
As to general sea level rise, predictions vary. Sea levels are rising because warmer water takes up more space than cold water and because melting ice sheets and glaciers are creating a larger overall volume of sea water. The largest, most vulnerable ice sheets are over Greenland and the Western Antarctic. We do know the rise to date is about 9 inches since 1880 and the rate is accelerating. Before the 1990s, the increase was .07 inches per year. By 2020 it had doubled to around .15 inches per year. There are estimates sea level could rise anywhere from 3 to 10 feet by 2100 largely depending on the path of fossil fuel emissions over the next 30 years. Large chunks of heavily populated global coastlines are already at or very close to present day sea level and sea level migration is underway.
Many places in the US are subject to sunny day flooding. Miami real estate agents now take clients to higher ground (“sell low, buy high”) and since 2000, prices have been rising in poorer neighborhoods at higher elevations in a form of “climate gentrification.”
In “Unlimited Sand and Money Still Won’t Save the Hamptons”, Bloomberg reports that over the next 30 years, the U.S. will spend at least $1.5 billion to restore about 80 miles of Long Island’s shoreline, as part of the “From Fire Island to Montauk Point project”. Coastal cities and shoreline communities are spending hundreds of millions installing pumping stations, raising streets and sidewalks, requiring all new houses to be built on stilts, expanding drainage systems and building sea walls.
Insurance companies won’t cover flood damage so homeowners who need insurance to get a mortgage turn to FEMA. Claims have far exceeded premiums for many years, so FEMA has updated its formula for evaluating flood insurance risk resulting in skyrocketing premiums for coastal properties. Under FEMA’s “Risk Rating 2.0” single-family homes will see increases as high as $1,200 next year. By law, annual increases are capped at 18% so premiums could go as high as $6,000 in ten years.
