by After a year of dominance, El Niño’s fury has ended — but its climate counterpart, La Niña, is hot on its heels and could signal California’s return to drought.
El Niño is the warm phase of the El Niño Southern Oscillation, sometimes called ENSO. The tropical Pacific climate pattern is the biggest driver of weather conditions around the world, and has been actively affecting global temperatures and precipitation patterns since it arrived last summer.
Among other effects, the El Niño event contributed to months of record global ocean temperatures, extreme heat stress on coral reefs, drought in the Amazon and Central America, and record-setting atmospheric rivers on the US West Coast, the National Oceanic and Atmospheric Administration said in its latest ENSO update.
The system is offering brief relief now that it has moved into 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 persist into the Northern Hemisphere winter, NOAA said. There is an 85% chance that it will be in place between November and January.
Along the West Coast, and in Southern California in particular, La Niña is often associated with cooler and drier conditions. La Niña was last in effect during the state’s three driest years on record – 2020 to 2022 – when drought conditions worsened and unprecedented water restrictions for millions of people.
Bill Patzert, a retired climatologist with NASA’s Jet Propulsion Laboratory in La Canada-Flintridge, noted that there have been 25 strongly weak La Niña years in Southern California since 1950, when the modern record began. Nineteen of those years were drier than normal.
“So for Angelenos, La Niña loads the dice for a drier-than-average winter and, with good reason, is often called the ‘Drought Diva,'” he said.
“But it’s not a sure thing,” Patzert said. “La Niña can surprise us. It’s still a contraction, but it would be wise for firefighters, water managers and farmers to be prepared.”
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State water managers are indeed preparing — but for wet or dry conditions later this year, according to Jeanine Jones, interstate resource manager with the California Department of Water Resources.
That’s because La Niña is only one of many factors that could affect California’s weather, and its results are not guaranteed.
“Historically, most La Niña years are dry, but by itself, it’s not a good predictor because there are other things going on,” Jones said. “We always like to say that we should prepare for wet or dry in any given year, because of the great variability of California’s precipitation.”
Those preparations include ongoing discussions about a state climate bond, which would provide more financial aid to help prepare for the latter two, she said. State officials are also continuing to implement Gov. Gavin Newsom’s strategy — unveiled in 2022 — for a warmer, drier future.
But images of the most recent drought are still fresh in the memories 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 in Southern California during that drought were caused by cuts from the State Water Project as well as long-term dry conditions on the Colorado River. The good news is that California reservoirs are currently at above-average levels after two back-to-back wet El Niño-induced winters.
“Most water users in California are equipped and used to dealing with one dry year,” she said. “It’s when the conditions remain for multiple dry years in a row that life becomes more difficult.”
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La Niña is not the only factor in precipitation. The pattern could also indicate a slight El Niño-driven break record-warm global temperatures that have affected the planet in the past 12 months, NOAA officials said.
However, long-term warming trends driven by climate change could make 2024 among the warmest years on record, according to Michelle L’Heureux, a climate scientist with NOAA’s Climate Prediction Center.
“La Niña typically 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 is not entirely clear where this year will rank other than in the top 5. Because climate change is increasing temperatures over time, we can expect that La Niña could put a small dent in that upward trend, but it probably won’t be for long.”
La Niña also comes with other challenges, including links to the projections active Atlantic hurricane seasonwhich is expected to have up to 25 named storms.
L’Heureux said the immediate effects of La Niña will be limited because ENSO has “very little influence on US temperature and precipitation anomalies during the summer,” and their impact won’t really emerge until the fall or winter. .
NOAA’s latest winter outlook currently shows 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 pretty typical of a La Niña-influenced winter,” L’Heureux said.
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It’s too early to tell how strong this La Niña is likely to be, with a wide range of possible outcomes still in play, forecasters said.
In fact, it’s rare for ENSO to go from El Niño to La Niña within a year, happening only 10 times in the historical record, Rebecca Lindsey of NOAA’s Climate Program Office wrote in the agency’s blog.
Of those cases, four of the six “strong” El Niños developed into strong La Niñas. But the strongest El Niño of all is evolving into the weakest La Niña, so “it’s complicated,” Lindsey wrote, noting that the strength of the upcoming event will become clearer as time goes on. it comes closer.
Patzert, of JPL, also warned that La Niña is not the only player in predicting rainfall and temperature – and that global warming “is affecting the impacts of El Niño and La Niña in ways that are not yet fully understood .”
“The arrival of La Niña, enhanced by climate change, is global,” he said. “In many parts of the globe, last year’s rainfall and temperature patterns can be reversed from drought to floods, from wet to wildfires, from economic benefits to punishing disasters. La Niña is a big deal. “
This story originally appeared in the Los Angeles Times.
