This year, an extraordinary amount of warm water has built up in the equatorial Pacific and beyond, driving what promises to be the most intense El Niño ever recorded. When Snodgrass and I talked on Tuesday, the water temperature at the pier was 75 degrees, 11 degrees warmer than the daily average and the warmest November 3 ever recorded. This would have surprised him more if daily records hadn’t already been broken 65 times this year. ... For some of California’s more familiar life forms, the conditions this year have been deeply alarming. April Ridlon, the director of science at the Monterey Bay Aquarium, in Monterey, has deployed extra divers to monitor kelp forests that can suffer in warmer temperatures, deprived of nutrients from cold upwelling waters. Just over a decade ago, amid the marine heat wave known as “the blob,” which coincided with another El Niño, Central California lost more than half of its kelp forests, she says, and Northern California lost even more. In some areas, the kelp has still not returned. She expects to lose kelp now, too, which means potentially losing populations of hundreds of other species that rely on them for habitat and nursery grounds.