California regulators are urging local officials to brace for retreat as scientists continue to predict sea levels will rise in coming decades and pummel beachfront communities from San Diego to Arcata.

With the prospect of ever more harrowing storms and flooding brought on by climate change, officials say cities and towns need to start planning to eventually abandon or relocate everything from highways to underground utilities to beachfront homes.

“The reality is seas are rising, eroding and inundating our coast and, in some places, that means homes and critical infrastructure will be lost,” said Jack Ainsworth, executive director for the California Coastal Commission. “Just look at the apartment buildings leaning off the crumbling cliffs of Pacifica or the homes tumbling onto Gleason Beach. These are windows into California’s future, and we must plan for that.”

But some local leaders and landowners say they have no intention of sacrificing private property to the ocean. Del Mar officials said they will try every other option — specifically, dumping massive amounts of sand on their beach — before even drafting a strategy to purchase and ultimately demolish homes and businesses hemmed in by the San Dieguito Lagoon and the Pacific Ocean.

“Managed retreat is not feasible for us,” said Del Mar Mayor Dwight Worden. “The best strategy is to build up a good wide beach. That’s feasible, and we can make it work for up to 3 feet of sea level rise.”

Conservative estimates range from about 1 to 4 feet of sea-level rise by the end of the century. Although experts warn that it could be as much as 8 feet, depending on how fast ice sheets in Greenland and Antarctica melt.

Some cities, such as Imperial Beach, have taken a different tack, engaging in hard conversations about when and how to start retiring homes.

“Doing our economic impact study we identified many options for (addressing) sea level rise, and the most cost-effective thing we can do is managed retreat,” said Imperial Beach Mayor Serge Dedina. “The more that we work with nature and not against it, the more successful we are.”

Dumping sand on shorelines can be costly and is expected to get even pricier as cities increasingly compete for limited resources to save their beaches. Solana Beach and Encinitas, for example, plan to spend $165 million over the next 50 years to add sand to their shores.

Beach “nourishments,” as they are called, are also not guaranteed to work. Sand poured on the shores of Torrey Pines in 2001 washed away after just one storm. On the other hand, projects in Solana Beach and Cardiff in 2012 used a coarser grain sand and have proven somewhat resilient, even through El Niño-driven weather two years ago.

“We still have a lot to learn about how these beach nourishments behave,” said Scripps researcher Bonnie Ludka. “We’ve found that they can behave drastically different.”

“It scares everybody here,” said longtime resident Kim Fletcher, 90. “Of course, I won’t be here, but I’ve got grandchildren and great grandchildren.”