Fifth La Niña in Six Years to Disrupt Crops and Supply Chains

Deadly flooding in Asia and early snowstorms across the US are signaling the return of a weather-roiling La Niña, a cooling of Pacific waters that can disrupt economies and trigger disasters worldwide.

In recent La Niña years, global losses have ranged from $258 billion to $329 billion, according to Aon, a reinsurance broker and data analysis firm. Despite year-to-year swings in damage totals, the overall trajectory is unmistakable: Extreme weather is pushing losses higher. The La Niña phenomenon is often linked with droughts in California, Argentina and Brazil, and the destructive flooding that recently swept Southeast Asia. These types of catastrophes have become a larger factor in setting terms for insurers, farmers and energy providers.

La Niña can intensify both droughts and downpours, fuel more active storms across the tropical Pacific and strengthen Atlantic hurricanes. During past episodes, the pattern may have helped drive the Los Angeles fires in January and Hurricane Helene, which killed more than 250 people across the southern US in 2024. Not every extreme event can be tied directly to La Niña, but scientists say the fingerprints are familiar.

“La Niña is like a traffic cop in the middle of rush hour, aiding the flow of cars or weather systems in certain preferred directions,” said Michelle L’Heureux, a forecaster with the US Climate Prediction Center. She has also likened it to “the conductor of a weather symphony” or an American football quarterback calling plays. Even though La Niña tends to follow a general pattern, L’Heureux points out that each event is different and other factors can influence the ultimate outcome. La Niña doesn’t typically have a major influence on weather in Europe, L’Heureux said.

The current La Niña marks the fifth in six years, part of a broader tilt toward more La Niñas than El Niños (the warming of Pacific waters) across the past quarter century. Scientists are still studying the shift. Some suggest climate change may be influencing the cycle, while others attribute it to natural variability, L’Heureux said.

The ripple effects can even reach deep into global markets. La Niña is often associated with lower yields for corn, rice, and wheat, according to research published in the journal “Environmental Development.” Energy demand usually climbs as colder temperatures settle over northern parts of the US, China and Japan, raising fuel consumption and straining utilities. These outcomes can simultaneously lift prices for some commodities while squeezing others.

Asia’s Toll

Even a weak La Niña can leave a heavy footprint. The weather pattern was likely part of the recipe for a sequence of tropical cyclones and destructive flooding that killed more than 1,600 people and caused at least $20 billion in losses in South and Southeast Asia, according to a team of researchers who investigated the storm as part of a World Weather Attribution analysis.

Flooding across Vietnam and Thailand in November and December has killed at least 500 people and caused more than $16 billion in damage and losses, according to data compiled by Bloomberg. While the role of La Niña in these disasters isn’t certain, the pattern is consistent with its past behavior, L’Heureux said.

“The contribution of La Niña to above-normal rainfall across Southeast Asia is costing lives and damaging infrastructure,” said Bill Hare, chief executive officer of Climate Analytics.

China faces its own risks. Below-average temperatures could threaten winter wheat production, said Luiz Roque, market intelligence coordinator at Hedgepoint Global Markets. That threat, as well as impacts elsewhere, will likely be mitigated by the weakness of the current La Niña.

Palm oil producers in Southeast Asia may see heavier rainfall disrupt harvesting and transportation, weighing on monthly output and oil extraction rates, said Kang Wei Cheang, an agricultural broker at StoneX Group Inc. in Singapore. At the same time, increased moisture could benefit the crops in about five to 12 months by promoting tree recovery and bunch formation.

US Outlook

In North America, La Niña typically produces colder and snowier conditions across western Canada, the Pacific Northwest, the northern Rockies and the Great Lakes region, said Abby Frazier, a geography professor at Clark University. Chicago has already posted its snowiest November day on record this year and central and northern New England saw more than seven inches across wide areas, with some locations approaching a foot, according to the National Weather Service.

By the heating-degree-day measure, a method of tracking temperature-driven energy demand, November was colder than last year but warmer than the 10-year average, said Matt Rogers, president of the Commodity Weather Group. The densely populated US Northeast was colder than normal.

The colder, snowier conditions across the northern US are being helped by La Niña, said Paul Pastelok, a long-range forecaster at AccuWeather Inc. “It’s helping, it is not the total reason but it is helping,” he said.

La Niña’s influence in the US Southwest usually tilts toward drought, a pattern that can extend into Southern California, Clark University’s Frazier said. However, there are instances where other weather patterns, such as intense maritime heatwaves across the Pacific, can upend expectations, according to Jennifer Francis, a climate scientist with the Woodwell Climate Research Center.

“An excellent example was the winter of 2022-23, the third in a row of La Niña conditions,” Francis said. “That winter was the wettest in California in over two decades.”

Global Risks

Brazil, the world’s top soybean exporter, is watching for signs La Niña could reduce rainfall in parts of its southern growing regions. The forecast indicates irregular rains in the center and southern parts of the country, said meteorologist Marco Antonio dos Santos, adding that concerns are reduced for now because there’s no sign of prolonged drought periods lasting more than 20 days.

In the country’s southernmost state of Rio Grande do Sul, soy plantings are slightly delayed but progressing, agronomist Alencar Paulo Rugeri said. “The tension is that we could have a drier December, but it will all depend on the intensity” of the dryness, he added.

Conditions across the Maritime Continent are expected to dry in December while rains continue across Vietnam, according to forecasts from commercial forecaster Ignitia.

Erratic rainfall can help some fields and hurt others but the risk comes when showers arrive off-season or skip key growth periods, “turning a professional activity into a lottery game with bad odds,” said Andreas Vallgren, Ignitia’s chief science officer.

The Climate Layer

While La Niña is a naturally occurring cycle, their impacts are “being modified and amplified by global warming,” according to Climate Analytics’ Hare.

“Whilst they are distinct from the long-term warming trend caused by human activities — especially the continued burning of fossil fuels, which is driving devastating changes in extremes of temperature and rainfall worldwide — they are modulating and to some extent exacerbating the underlying global warming trends,” Hare said.

As for the current La Niña, it is likely peaking now, or will be in the next few weeks and then conditions across the equatorial Pacific are forecast to drop to neutral, he said. Even if the Pacific returns to a more normal state, that doesn’t mean the changes to the globe’s weather will end. La Niña conditions may linger for months.