The camera zooms in on the majestic sandy bluffs that make this stretch of the San Diego County coast so iconic: a close-up, everyone realizes, of that cliff crumbling in real time — ancient sand and soft, somewhat cemented rocks tumbling onto the beach below.

Moments later, a popular commuter rail rumbles by. Some in the room gasped. Lawmakers watched in sober silence.

“This is a natural phenomenon; it’s feeding the beaches, but it’s happening more and more frequently in part because of sea level rise,” said Merrifield, director of Scripps’ Center for Climate Change Impacts and Adaptation. “So what can do? That’s why we’re here, right?”