"The costs are a worst-case situation," said City Councilman Ed Selich, who represents Balboa Island, where a projected 4-foot rise by 2100 would inundate homes. "We don't know whether those projections are going to hold over the long haul, so we have to come up with a phased approach."
Already, Newport's islands flood during extreme high tides. Crews pumped water from streets last winter after an 8-foot tide, coupled with storm surges, breached seawalls.
Officials want to extend the walls, from 9 feet to 10 feet above the average sea level, to brace for an expected 1-foot rise by 2050. On Balboa Island, that could mean replacing the 1930s-era concrete barriers with steel ones, or extending the current structures.
Most of the city's seawalls have begun to show "widespread cracking," a public works report says.
Replacing aging infrastructure is reason enough to act now, officials say.
Newport Beach has 17 to 18 miles of seawalls, about 4.5 miles of which are in public control and 13 miles of which are privately owned.
In the conservative city, politicians often avoid talk of climate change — especially its causes — and instead point to a demonstrated sea level rise and its threat to real estate.
Selich, who drives a Hummer, said he doesn't know if climate change is "man-made or simply a long-term cycle."
"I just know that the evidence is there that [the sea] is rising," he said, "and we have the responsibility to deal with it."
Selich hopes that in five years the city can build up Balboa Island's walls already prone to flooding.