After a year of dominance, El Niño’s wrath has ended, but its climate-changing counterpart, La Niña, is nipping at its heels and could signal a return to drought for California.
El Niño is the warm phase of the El Niño Southern Oscillation, also called ENSO. The tropical Pacific climate pattern is the biggest driver of weather events worldwide and has been actively disrupting global temperatures and precipitation patterns since its arrival last summer.
The El Niño event has contributed to months of record temperatures in the oceans, extreme heat stress for coral reefs, drought in the Amazon and Central America, and record-breaking atmospheric rivers on the US west coast, the National Oceanic and Atmospheric Administration said in its latest ENSO update.
The system is now offering a short reprieve as it has moved to a ‘neutral’ pattern – but it won’t stay that way for long.
There is a 65% chance that La Niña will develop between July and September and last into the Northern Hemisphere winter, NOAA said. There is an 85% chance that the installation will take place between November and January.
Along the West Coast, and especially in Southern California, La Niña is often associated with cooler, drier conditions. La Niña was last present during the state’s three driest years on record — 2020 through 2022 — when drought and unprecedented water restrictions decimated millions of people.
Bill Patzert, a retired climatologist at NASA’s Jet Propulsion Laboratory in La Cañada-Flintridge, noted that Southern California has experienced 25 weak to strong La Niña years since 1950, when the modern record began. Nineteen of those years were drier than normal.
“So for Angelenos, La Niña has all the makings of a drier than average winter and is rightly often referred to as ‘the Diva of Drought,'” he said.
“But it’s not certain,” Patzert added. “La Niña could catch us by surprise. It’s still a nonsense, but firefighters, water managers and farmers would be wise to be prepared.”
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State water managers are indeed preparing — but for both wet and dry conditions later this year, according to Jeanine Jones, interstate resources manager at the California Department of Water Resources.
That’s because La Niña is just one of many factors that can affect California’s weather, and its outcomes are never a guarantee.
“Historically, most La Niña years have been dry, but in itself this is not a good predictor because there are other things going on,” Jones said. “We always like to say that in any given year, because of the extreme variability in precipitation in California, we should prepare for wet or dry.”
Those preparations include ongoing discussions about a state climate bond, which would provide more financial support to prepare for either extreme, she said. State officials also continue to implement Governor Gavin Newsom’s strategy – unveiled in 2022 – for a hotter, drier future.
But images of the most recent drought remain fresh in the minds of many Californians, including dead, brown lawns and dangerously low water levels in Lake Oroville and Lake Mead.
Jones noted that the severe water restrictions Southern California experienced during that drought were the result of cuts to the State Water Project and prolonged drying conditions on the Colorado River. The good news is that California’s reservoirs are currently at above-average levels after two consecutive wet winters fueled by El Niño.
“Most water users in California are equipped and accustomed to dealing with one dry year,” she said. “It is when conditions persist for several dry years in a row that life becomes more difficult.”
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La Niña is not just a factor when it comes to precipitation. The pattern could also indicate a slight break from the El Niño-driven trajectory record high temperatures on earth that have gripped the planet over the past 12 months, NOAA officials said.
Long-term warming trends driven by climate change could still make 2024 one of the warmest years on record, according to Michelle L’Heureux, a climate scientist at NOAA’s Climate Prediction Center.
“La Niña generally results in lower average global temperatures,” L’Heureux said in an email. “However, we are still feeling the effects of the previous El Niño on global average temperatures, so it is not entirely clear where this year will rank, except probably in the top 5. Because climate change is increasing temperatures over time I can expect La Niña to put a small dent in that upward trend, but it probably won’t be much.”
La Niña also brings other challenges, including ties to the forecast active Atlantic hurricane seasonwhich is expected to produce as many as 25 named storms.
L’Heureux said the immediate effects of La Niña will be limited because ENSO has “very minimal impact on U.S. summer temperature and precipitation anomalies,” and its effects only really become apparent in the fall or winter.
NOAA’s latest winter outlook currently points to warmer and drier conditions across the southern half of the US, including Southern California. Parts of the Midwest, Montana, Idaho and Washington could see wetter weather.
“The trend toward increased chances of below-average precipitation and above-average temperatures for the Southwest and California is quite typical of a La Niña-influenced winter,” L’Heureux said.
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It’s too early to say how strong this La Niña is likely to be, with a wide range of possible outcomes still in play, forecasters said.
In fact, it is somewhat unusual for ENSO to switch from El Niño to La Niña within a year, which has only happened 10 times in history, Rebecca Lindsey of NOAA’s Climate Program Office wrote in the agency’s blog.
Of those cases, four of the six ‘strong’ El Niños evolved into strong La Niñas. But the strongest El Niño of them all eventually developed into the weakest La Niña, so “it’s complicated,” Lindsey wrote, noting that the strength of the coming event will become clearer as it gets closer.
JPL’s Patzert also warned that La Niña is not the only player when it comes to predicting rainfall and temperature – and that global warming is “certainly impacting the impacts of El Niño and La Niña in ways that are not yet fully understood.” are understood.”
“The reach of La Niña, amplified by climate change, is global,” he said. “In many parts of the world, last year’s rainfall and temperature patterns could be reversed from drought to floods, from wet to wildfires, from economic benefits to severe disasters. La Niña is a big problem.”
This story originally appeared in the Los Angeles Times.