A strange phenomenon is currently occurring along the equator, but most people won’t notice it unless they work with satellite data. The height of the Pacific Ocean has increased. Not everywhere, but in a long, warm area close to the equator, a satellite known as Sentinel-6 Michael Freilich has been surreptitiously recording sea surface elevations that, to be honest, seem a little strange. Whether California is prepared or not, that bump in the ocean is El Niño making its presence known.
The official development of El Niño conditions was confirmed by NOAA earlier this month, and forecasters are now placing a good chance—more than 60 percent—that this one will develop into what scientists refer to as a “Super El Niño.” Only a few times in recorded history have sea temperatures in the central and eastern Pacific risen more than two degrees Celsius above average. The 1997–1998 event, which is still the standard for these things, caused devastating flooding and landslides throughout California and cost the world economy trillions of dollars.
The water itself is what makes this year unique, or at the very least deserving of more attention. Sea levels in Peru have already risen by about eight inches above normal due to a warm pulse that pushed across the Pacific and crashed into the South American coast. It may seem insignificant, but keep in mind that this is on top of already high tides. The same warm mass is predicted by scientists monitoring the satellite data to continue moving northward across the Americas, eventually arriving at the coast of California later this year.
Climate scientist Daniel Swain of UC’s Agriculture and Natural Resources program has been direct about the implications of that. He warns that during a major storm event, king tides colliding with storm surges could push water levels two to three feet above normal. He has predicted a temporary sea-level rise along the California coast of between six inches and two feet this year. That’s not a hundred-year forecast, but it’s worth pondering for a moment. This winter, that is.
Bay waters have already risen by roughly ten inches, according to San Francisco’s tidal gauge, which has been recording data since 1900. When long-term climate trends are combined with El Niño’s brief surge, you can see conditions that scientists would otherwise anticipate in decades. Michael Beck of UC Santa Cruz presented it in an almost upbeat manner, speculating that this winter might serve as a practice run for the sea levels that California will need to prepare for by the 2050s. Even though it’s a peculiar kind of silver lining, there is something to that.
Rain is more important right now for the majority of Californians. Forecasters are keeping a close eye out for an active storm season because El Niño tends to push the jet stream in ways that favor wetter winters throughout Southern California. This is good news for reservoirs and drought concerns, but less good news for hillsides that are already vulnerable to mudslides following dry summers.
The exact strength of this event and how closely it will resemble past Super El Niños are still unknown. These comparisons are now more difficult than they were in the past due to climate change; the old thresholds don’t always behave the same way because of warmer baseline oceans. Although NOAA’s revised index makes an effort to take that change into consideration, all forecasts still contain some degree of uncertainty. The fact that the ocean is already shifting, that satellites are already observing it, and that California’s coastline will have a noisy few months ahead of it all seem fairly certain.
