After a year of dominance, El Niño’s rampage is over; But its climate-wrecking counterpart, La Niña, is immediately warming and could signal a return to dryness for California.
El Niño is the warm phase of the El Niño Southern Oscillation, sometimes called ENSO. The climate pattern in the tropical Pacific is the largest driver of weather patterns around the world and has been actively disrupting global temperatures and precipitation patterns since its arrival last summer.
The El Niño event contributed to months of record-breaking global ocean temperatures, extreme heat stress on coral reefs, drought in the Amazon and Central America, and record-breaking atmospheric fluxes on the U.S. West Coast, National Oceanic and Pacific Oceans, among other effects. The Atmospheric Administration said in its latest ENSO update.
The system now offers a short period of time as it switches to a “neutral” setup, but it won’t stay that way for long.
NOAA said there is a 65% chance that La Niña will develop between July and September and continue into winter in the Northern Hemisphere. There is an 85% chance that it will be valid between November and January.
Along the West Coast and especially in Southern California, La Niña is generally associated with cooler, drier conditions. La Niña was last there during the state’s three driest years on record (2020 to 2022), which saw drought conditions ease and unprecedented water restrictions for millions of people.
Bill Patzert, a retired climatologist at NASA’s Jet Propulsion Laboratory at La Cañada-Flintridge, noted that Southern California has experienced 25 weak-to-strong La Niña years since the modern record began in 1950. 19 of these years were drier than normal.
“So for Angelenos, La Niña rolls the dice for a drier-than-average winter and is often referred to as the ‘Diva of Drought,’ for good reason,” he said.
“But that’s not a sure thing,” Patzert added. “La Niña could surprise us. It’s still bullshit, but firefighters, water managers and farmers would be wise to be prepared.”
Read more: The world is once again breaking heat and CO₂ records: ‘Our planet is trying to tell us something’
According to Jeanine Jones, director of interstate resources for the California Department of Water Resources, state water managers are indeed preparing; but for either wet or dry conditions towards the end of this year.
That’s because La Niña is just one of many factors that can affect California’s weather, and its consequences are never guaranteed.
“Historically, most La Niña years have been dry, but that alone is not a good prediction because there are other things going on,” Jones said. “We always like to say that due to California’s extreme variability in precipitation, we should prepare for wet or dry in any given year.”
Among those preparations, he said, are ongoing discussions about a state climate bond that would provide more financial aid to help prepare for both extremes. State officials also continue to implement Gov. Gavin Newsom’s strategy for a warmer, drier future announced in 2022.
But images of the latest drought remain fresh in the minds of many Californians, including dead, brown grass and dangerously low water levels in Lake Oroville and Lake Mead.
Jones noted that the severe water constraints Southern California is experiencing during this drought are due to cuts to the State Water Project as well as long-term drying conditions in the Colorado River. The good news is that after two consecutive wet winters triggered by El Niño, California’s reservoirs are now at above-average levels.
“Most water users in California are equipped and accustomed to dealing with a single dry year,” he said. “Life becomes even more difficult when conditions persist for multiple consecutive dry years.”
Read more: The U.S. Drought Monitor is a critical tool for the arid West. Will it be able to keep up with climate change?
La Niña isn’t just a factor when it comes to precipitation. This pattern could also signal a slight break from the El Niño-driven trend. record global temperatures NOAA officials said this situation has been affecting the planet for the last 12 months.
But long-term warming trends driven by climate change could still make 2024 among the hottest years on record, according to climate scientist Michelle L’Heureux of NOAA’s Climate Prediction Center.
“La Niña generally results in cooler global average 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’s not entirely clear where this year will rank other than in the top 5. Since climate change increases temperatures over time, this year’s La Niña will contribute to this upward trend.” “We can expect it to make a small impact, but probably not too much.”
La Niña comes with other challenges, including connections to predicted conditions. active Atlantic hurricane seasonIt is expected to produce up to 25 named storms.
La Niña’s immediate effects will be limited because ENSO “has little impact on U.S. temperature and precipitation anomalies during the summer months” and its effects don’t begin to show up until the fall or winter, L’Heureux said.
NOAA’s latest winter outlook currently points to warmer, drier conditions across the southern half of the United States, including Southern California. Parts of the Midwest, Montana, Idaho and Washington may experience wet weather.
“The increased likelihood of below-average precipitation and above-average temperatures for the Southwest and California is pretty typical of a La Niña-influenced winter,” L’Heureux said. said.
Read more: Forecasts call for an active hurricane season. Could California see another Hilary?
Forecasters said it was too early to tell how strong La Niña would be, and a wide range of possible outcomes were still in play.
Rebecca Lindsey of NOAA’s Climate Program Office wrote on the agency’s blog that it’s actually unusual for ENSO to change from El Niño to La Niña within a year, having happened only 10 times in the historical record.
Of these examples, four of the six “strong” El Niños turned into strong La Niñas. But the strongest El Niño turned into the weakest La Niña, so “it’s complicated,” Lindsey wrote, noting that the strength of the upcoming event will become clearer as it gets closer.
JPL’s Patzert also cautioned that La Niña is not the only player in predicting precipitation and temperature, and that global warming “certainly impacts the effects of El Niño and La Niña in ways that are not yet fully understood.”
“La Niña’s increased reach with climate change is global,” he said. “In many parts of the world, last year’s rainfall and temperature patterns may be reversible, from drought to floods, from precipitation to wildfires, from economic benefits to punishing disasters. La Niña is a big deal.”
This story was first published in the Los Angeles Times.