SAN CLEMENTE, Calif.—The San Clemente City Council unanimously adopted a plan in December, which it said was aimed at staving off future potential impacts to its beaches and shores due to rising sea levels, and coastal erosion. The so-called Coastal Resilience Plan seeks to address a range of issues—everything from easing incremental shoreline erosion all the way to a worst-case scenario where the region’s sea wall—which protects homes, for example—would be gone. According to the plan, the wearing away of beaches is due to the gradual rise of the ocean. But one councilman—who ultimately voted for the plan—disagreed with the overall plan’s assessment that the issue was due to rising sea levels. Councilman Steve Knoblock said erosion is the man-made result of officials no longer moving sand from two nearby rivers to San Clemente beaches, a remedy called “sand replenishment.” He additionally said too much residential development has disrupted how …