San Francisco’s Ocean Beach, pictured in 2024, is one of the California beaches that are at risk of eroding away by 2100.

A powerful El Niño is forming in the Pacific. The real threat to California’s beaches isn’t the waves — it’s the concrete we pour after they hit.

Some forecasters are already calling the coming El Niño “Godzilla.” The National Oceanic and Atmospheric Administration’s Climate Prediction Center now puts the odds at greater than 90% that this will be a “very strong” event this fall and winter — and a 69% chance it exceeds the strength of every El Niño on record since 1950. The subsurface ocean heat that drives it is already measurable. We can see it coming.

For California’s coast, where up to 75% of our beaches are at risk of disappearing by 2100, each El Niño presents another moment of reckoning. When warm water masses shift across the equatorial Pacific, the resulting atmospheric changes bring larger waves, elevated sea levels and powerful storms in rapid succession — each hitting a shoreline already battered by the last. Wave energy along California’s shore can run 50% above average. Sea levels climb half a foot to a full foot, pushing the ocean inland and flooding coastal homes, roads and infrastructure.

Article continues below this ad

The record is unambiguous. The 1997-98 El Niño claimed 17 lives and condemned entire cliff faces in communities like Pacifica. The 2015-16 event produced the worst coastal erosion ever measured across six West Coast regions. U.S. Geological Survey research has documented that coastal erosion in California increases by more than 69% during extreme El Niño events. These are not anomalies.........

© San Francisco Chronicle