At a Glance

More than 130 feet of Southern California's coastal cliffs could be lost, USGS researchers say.And these projections could be on the conservative side, an author of the study notes.

More than 130 feet of Southern California's coastal cliffs could be lost by the turn of the century if nothing is done to curb rising seas, a new study says.

According to thestudypublished last week by the U.S. Geological Survey, researchers for the agency used five different and sea level rise projections of1.6 to 6.6 feet to determine that an average of 62 to nearly 138 feet of coastal cliffs is expected to recede along California's highly populated southern coastline by 2100.

Cliffs like these in Southern California will likely be compromised by rising seas in the years for come.

(Harrie Den Otter/EyeEm/Getty Images)

The study focused on the coastal cliffs fromSan Diego to Point Conception, about 150 miles north of Los Angeles.

Patrick Barnard, research director of the USGS Climate Impacts and Coastal Processes Team and a co-author of the study, noted that while 130 feet may not seem like much, an average of 1.7 feet per year over 80 years puts it into perspective.

“This is a significant amount of erosion, and it's something that we need to be preparing for now, not later,” Heather Cooley of the Pacific Institute told the Los Angeles Times.“We’re talking about — there's private properties, there's public infrastructure, we have roads, we have treatment plants, there's even consideration of building desalination plants in some of these areas. All of those facilities would be at risk from this erosion.”

The authors noted in the study that the amount of cliff erosion is particularly difficult to predict because of different variables, including the slope of the cliffs, the sediment composition, human intervention andwave action, among others.

The purpose of the study and others like it, the agency said, is to provide model results to coastal managers and the general public for use as a hazard assessment tool and coastal management.

“Hopefully, this model will give coastal managers a broad-scale picture of how the cliffs might respond to sea-level rise so that they can start planning for the future,” Pat Limber, a coastal geomorphologist, told the Times.

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The new study published in the Journal of Geophysical Research: Earth Surface supports another USGS study conducted in 2017, which found that between 31 to 67 percent of may become completely eroded by 2100 because of to rising seas.

“Beaches are perhaps the most iconic feature of California, and the potential for losing this identity is real," said lead author of the 2017 studySean Vitousek. "The effect of California losing its beaches is not just a matter of affecting the tourism economy. Losing the protecting swath of beach sand between us and the pounding surf exposes critical infrastructure, businesses and homes to damage. Beaches are natural resources, and it is likely that human management efforts must increase in order to preserve them."

The team is now finishing up its projections for the state's Central Coast before beginning a new study on Northern California.