A new study from the U.S. Geological Survey (USGS) has found that 25% to 70% of California’s beaches could disappear by the end of this century. It follows a similar study from 2017 that found 31% to 67% of beaches in Southern California were at risk.
The research, which is currently undergoing the peer-review process, looks at satellite data from the past 20 years along with climate models of sea level rise. USGS researchers reviewed satellite data on about 1,350 kilometers of coastlines and modeled sea level rise from 1.6 feet to 10 feet.
“By 2100, the model estimates that 25% to 70% of California’s beaches may become completely eroded due to sea-level rise scenarios of 0.5 to 3.0m, respectively,” the authors wrote in the paper. “The satellite-data-assimilated modeling system presented here is generally applicable to a variety of coastal settings around the world owing to the global coverage of satellite imagery.”
According to National Oceanic and Atmospheric Administration (NOAA), sea levels have risen about 8 to 9 inches since 1880, but the rate of sea level rise is quickly increasing. It remained around 0.06 inches per year in the 20th century, but from 2006 to 2015, sea level rise reached 0.14 inches per year.
NOAA estimated that sea level rise around the U.S. would reach around 2 feet higher than the average in 2000 by 2100 with major reductions in emissions. But continuing forward with high greenhouse gas emissions could result in sea level rise of 7.2 feet by 2100.
In California, vanishing beaches would leave coastlines with only cliffs or infrastructure to protect the coast, as The Guardian reported. Some of the highest risk locations for coastal erosion include Humboldt Bay, Morro Bay, Newport Beach, Pismo Beach, Point Arena and San Clemente.
The 2017 study already estimated erosion for Southern California, but this latest study shows erosion for beaches all along the coast, and it could become a similar problem for other states. In a USGS study from 2009, researchers found that 66% of California’s beaches were experiencing short-term erosion and 40% experienced long-term erosion.
While the latest study results are concerning, the authors noted that the results from the analysis and climate modeling are still uncertain. Still, it shows an urgent need for more conservation efforts for the state’s beaches.
“The model predictions, although subjected to considerable uncertainty, indicate that significant impacts to the shoreline may occur due to accelerated sea-level rise,” the authors in the most recent study wrote. “It is likely that many beaches in California will require substantial management efforts (e.g., beach nourishments, sand retention, armoring, dune restorations as well as other engineering and nature-based solutions) in order to maintain existing beach widths and the many services they provide.”