Vast swathes of California beaches could be lost to climate change, a recent paper predicted, with 25 to 70 percent of the state’s beaches completely eroded by the end of this century.
The study, published in marchwas produced by five scientists from the USGS Pacific Coastal & Marine Science Center, the University of Illinois at Chicago, and the University of New South Wales – Sydney.
The five watched Ocean Beach in San Francisco and studied satellite imagery of the beach for two decades.
They then took the entire 1,100 mile coastline of California and used their models to predict how climate change would affect the beaches, using a projected sea level rise of 1.6 to 10 feet over the course of of the next 80 years.
They found that 25-70% of the state’s beaches could be lost.
Pismo Beach in California, near San Luis Obispo, is among those cited by researchers as being at risk
Newport Beach, just south of Los Angeles, is also considered at risk, as research predicts that 25 to 70 percent of California’s beaches could be eroded by rising sea levels.
“By 2100, the model estimates that 25 to 70 percent of California’s beaches could be completely eroded due to sea level rise scenarios of 0.5 to 3.0 m, respectively,” the authors wrote. authors.
“The satellite-like modeling system presented here is generally applicable to a variety of coastal settings around the world due to the global coverage of satellite imagery.”
The authors warned that several well-known beaches were at risk – including Point Arena and Humboldt Bay in Northern California; Pismo Beach and Morro Bay in Central California; and Newport Beach and San Clemente in Southern California.
The study, quoted by news site SFGatehas not yet been peer reviewed.
It follows a similar 2017 study by the same group of researchers, which then found that 31 to 67 percent of Southern California beaches were at risk of destruction.
“The model predictions, although subject to considerable uncertainty, indicate that significant impacts on the coastline may occur due to accelerated sea level rise,” the authors conclude.
“It is likely that many California beaches will require substantial management efforts (e.g., beach nourishment, sand retention, shielding, dune restoration as well as other engineering and nature-based solutions) in order to maintain existing beach widths and the many services they provide.’
San Clemente, another Los Angeles-area beach, is vulnerable for the next 80 years, researchers concluded in a study that has yet to be peer-reviewed.
Morro Bay, 200 miles north of Los Angeles, is at risk from rising sea levels, the team said
Experts are deeply concerned about sea level rise, but disagree on the predicted rise.
The National Oceanic and Atmospheric Administration predicted last year that sea levels would rise up to eight inches in California and along the West Coast over the next 25 years.
Mark Merrifield, coastal oceanographer at the Scripps Institution of Oceanography in La Jolla, said The Guardian the satellite models used by the five researchers should be taken with some skepticism because they are new.
“Beach morphology models in general have limited skill in predicting contemporary changes, there are few datasets available for validation of the methodology, and projections of future wave and water level conditions introduce another level of uncertainty,” he said.
But Sean Vitousek, the lead author of both studies, said they proved the need to act now, even if people disagreed on the precise extent.
“The beaches are perhaps California’s most iconic feature, and the potential for losing that identity is real,” he wrote in 2017.
“The effect of California losing its beaches is not just a matter of affecting the tourism economy.
“The loss of the protective strip of beach sand between us and the crashing waves exposes critical infrastructure, businesses and homes to damage.”
