The impact of historic weather and changing climate trends threaten up to 70% of California beaches, which could be lost to erosion by the end of this century, a recent U.S. Geological survey found.

The government report released earlier this year, which is in the process of being peer-reviewed for publication, found that between 25% and 70% of California’s beaches – and up to two-thirds of the state’s approximately 840 miles of coastline – could be washed away by 2100 due to rising sea levels caused by global temperature increases and greenhouse gas emissions. 

In 2017, a study conducted by the same researchers found that between 31% and 67% were at risk of disappearing.

“Beaches are perhaps the most iconic feature of California, and the potential for losing this identity is real,” Sean Vitousek, the lead researcher, said in 2017. “Losing the protecting swath of beach sand between us and the pounding surf exposes critical infrastructure, businesses and homes to damage.”

In the next 25 years, the West Coast faces a potential sea level rise of up to eight inches, according to the National Oceanic and Atmospheric Administration. 

The report’s estimates of how the entire state’s coastline will shift were determined by combining rising sea level models due to global temperature increases with two decades of satellite imagery of Ocean Beach in San Francisco.

Severe coastal bluff erosion, along the southern end of Ocean Beach, San Francisco, California on Jan. 19, 2010. This storm damage occurred during the 2009-2010 El Niño, which, on average, eroded the shoreline 55 meters that winter.

Researchers say the report can help guide the state’s coastal preservation and monitoring efforts. To maintain existing beach widths, the state will need to “ require substantial management efforts,” including beach nourishments, sand retention, armoring, dune restorations as well as other engineering and nature-based solutions, the survey said. 

“Beaches are natural resources, and it is likely that human-management efforts must increase in order to preserve them,” Vitousek said in 2017.

‘A balancing act’: Band aids versus longterm solutions to coastal erosion

Bluff erosion during the 2009–10 El Niño undermined the Great Highway guardrail at the southern end of Ocean Beach, San Francisco, California on January 20, 2010. The shoreline eroded, on average, 55 meters that winter, leading to lane closures on the highway and an emergency $5-million revetment along the base of this bluff.

Shalini Vajjhala, Executive Director of the nonprofit PRE Collective, says that determining a sustainable plan to address coastal erosion and beach maintenance is “a balancing act” between allocating resources towards “urgent needs” that arise from something like extreme weather, while also reducing the overall root causes of climate change’s impact on the landscape. PRE Collective works with communities across the U.S. to help them plan resilient and sustainable infrastructure development. 

“The balancing act is making sure that we address the urgent needs and help folks who are suffering and still reduce the underlying risks and damages,” Vajjhala said.

Nourishment is not a long-term solution to beach erosion but protects property, ports and tourist destinations in the short-term, according to the U.S. Army Corps of Engineers.