Climate Change Speeds Erosion With Huge Storms (Bloomberg.com)

Climate Change Speeds Erosion With Huge Storms

https://bloom.bg/2wMKjCp

Six months ago, the U.S. Army Corps of Engineers finished a $12 million project to rebuild some of Florida’s prettiest shoreline. About 220,000 cubic yards of sand was poured onto tourist-friendly stretches of world-famous Miami Beach, widening it to 230 feet. It’s part of a 42-year-old federal program designed to combat gradual erosion and ensure there’s a buffer between inland communities and the leading edge of tropical storms. 

Scientists will tell you that beaches and their shoreline cousins—wetlands, mangroves, bays, and sounds—are always on the move. They live at the whim of tides, winds, rivers, and waves. There have always been lovely beaches, historically speaking, but they haven’t always been where the iconic Fontainbleau hotel now stands in Miami Beach. This geographic reality didn’t hit home until people laid down beach towels, put up resorts, and cut navigation inlets.

Miami Beach and South Beach, Fla.

Photographer: Chris Condon

As Hurricane Irma careers into Miami Beach’s neighborhood, the recently completed project is emblematic of the increasingly expensive chasm between what beaches are supposed to be and what vacationers and property-owners want them to be. And global warming is fast expanding that gulf.

It becomes “erosion” only when you want to keep something the way it is, according to Robert Young, director of the Program for the Study of Developed Shorelines at Western Carolina University. He and other experts call changing shorelines just “shoreline change,” because it’s never going to stop. Proponents of fighting nature, meanwhile, call battling erosion the more healthy sounding “beach nourishment.” The problem with beach nourishment, though, is that it gets consumed—sometimes quickly.

“It’s not uncommon for a beach nourishment project to disappear—very shortly after it was placed—in a big storm,” Young said. “This happens all the time.” Like last year, when Hurricane Matthew brushed away a $30 million restoration project in South Carolina that was completed in 2014, stripping sand away from a shoreline called—wait for it—Folly Beach. 

Accelerating sea-level rise and intensifying storms are speeding up erosion 

A slow-burning tension is inherent in local economies built on disappearing beaches. Hotels are built near the sand so guests will stay. The Corps of Engineers or local authorities rebuild beaches to protect hotels and everything else behind and around them. “That is why the berm [corps shorthand for dunes and beach] is there in the first place, for that catastrophic event,” said Laurel Reichold, project manager for the Miami-Dade County Beach Erosion Control & Hurricane Protection Project. “That’s what takes the brunt of the storm, so your infrastructure behind it doesn’t take that big a hit.” 

This cycle, however, seals in a political dynamic that runs counter to nature, which has a tendency of winning in the end.

Florida, with its $109 billion tourism industry and a shoreline length second only to Alaska’a among U.S. states, leads the country in beach-fixing. Almost 500 projects have spread 293 million cubic yards of sand over its shores, at a cost of $2.4 billion in real dollars, according to a database of 2,000 beach nourishment projects going back to 1923. These days, there’s even an international sand trade, one that’s become more lucrative as beaches around the world are slated for face-lifts.

Hurricane Irma.

Source: National Oceanic and Atmospheric Adminsitration

More of Florida’s beach communities may be joining that list soon. Current projections suggest that Hurricane Irma will dogleg right toward Florida this weekend, putting the state’s lengthy shoreline squarely in its path. 

Days before meteorologists could say with high confidence where the storm might hit, the Dade County erosion project had already assembled an emergency team. Vessels were prepared to survey the 13 miles of shoreline it’s charged with monitoring in the aftermath of a hurricane. Shoreline damage that meets certain criteria may qualify for federal funds to pay for more beach nourishment. Parts of Miami Beach received such emergency restoration work after Hurricane Andrew in 1992 and twice from 2000 to 2010 in addition to planned projects.

It would be tough enough for shoreline communities if erosion proceeded at the same pace as it did in the late 20th century. More serious challenges, including accelerating sea-level rise and intensifying storms, have greeted them in the new century.

Miami Beach has already run out of sand 

The global average sea level is rising at about 3.4 millimeters a year, because of higher temperatures, which melt ice sheets and cause water to expand. The world’s oceans don’t rise uniformly, though: Water sloshes around the planet, creating “hot spots.” The U.S. East Coast below North Carolina’s Cape Hatteras saw an unusual sea level increase from 2011 to 2015, rising three times higher than the global average, according to University of Florida research published last month. In southeastern Florida from 2011 to 2015, sea levels rose six times faster than the rate measured from 1996 to 2010. Anomalies such as these, though not a function of human-driven climate change, make an already bad situation worse for a part of the U.S. particularly susceptible to hurricanes.

For decades, beach communities, local and federal governments, contractors, sand merchants, and the Army Corps have worked to keep beaches where and how people have grown accustomed to them. Whether coastline restoration can continue in the face of rising seas, from the northern tip of Maine to the southern tip of Texas, remains to be seen.

Back in Miami Beach, however, they’ve already run out of sand. The most recent beach nourishment projects brought the precious stuff in from mines near Lake Okeechobee, Florida’s largest inland lake. 

    via Bloomberg.com

    September 7, 2017 at 01:31PM