NASA Finds Big Gap in California Shoreline Changes

Surf’s up in SoCal — in some places, quite literally.

Some parts of California’s coastline are shrinking, while other parts of the state’s coast are growing, the Los Angeles Daily News reported, citing a study by the University of California, Irvine and the United States Geological Survey.

The state has added roughly 500 acres of coastline over the past four decades, per NASA satellite data tracking shoreline changes from 1984 to 2024.

The results challenge the long-standing assumption that California’s coast has been in steady retreat. According to the researchers, beaches across nearly 200 miles of Southern California widened by an average of more than 23 feet during the study period. Nearly 50 percent of the coastline expanded significantly, while 31 percent saw its shores shrink.

Beaches in San Clemente, San Onofre and Doheny eroded sharply, narrowing by more than 3 feet per year in some cases. Meanwhile, stretches such as Huntington Beach and Venice have ballooned to more than 600 feet wide, often because they sit near harbors, jetties or engineered sand-replenishment projects that trap sediment, according to the study authors.

Property owners and developers along the coast can benefit from wider beaches that buffer oceanfront homes, hotels and infrastructure from storm surge and rising seas. Parts of Sunset Beach, Huntington Beach and Newport Beach have benefitted from beach nourishment projects that created wider beaches, but often those projects end up having unintended consequences in other parts of the seaside.

“The gains occurring in Santa Monica and Venice are resulting in erosion down the coast,” study lead author Jonathan Warrick, research geologist at the U.S. Geological Survey’s Pacific Coastal and Marine Science Center, told the outlet. “There are human fingerprints in all this.”

This push-and-pull dynamic has direct implications for real estate risk modeling and public investment.

Several Southern California harbors already operate sediment bypass systems to move sand past jetties, and researchers suggest expanding such programs could mitigate erosion hot spots more strategically. Moving forward, using satellite monitoring tools to track shoreline shifts could change how cities and coastal developers plan for future projects.

— Chris Malone Méndez