The U.S. National Oceanic and Atmospheric Administration (NOAA) has officially confirmed the arrival of a weak La Niña in late December 2024, a natural climate phenomenon expected to last until February to April. This shift could influence global weather patterns, potentially offering respite from the extreme heat experienced in recent years.
La Niña the cooler counterpart of El Niño, is part of the El Niño Southern Oscillation (ENSO), a natural climate dynamic that alternates between warm (El Niño), cool (La Niña), and neutral phases. During La Niña, cooler-than-average sea surface temperatures in the tropical Pacific Ocean typically interact with the atmosphere, driving changes in global weather.
For most of 2024, scientists observed La Niña-like atmospheric patterns, such as stronger east-to-west winds and drier Pacific conditions, but the accompanying cooler ocean temperatures were absent an unusual occurrence. Emily Becker, associate director of NOAA’s Cooperative Institute for Marine and Atmospheric Studies, noted the rarity of this disconnect.
Now, with ocean surface temperatures finally catching up, NOAA estimates a 59% likelihood of La Niña persisting until early spring and a 60% chance of ENSO transitioning to a neutral state by mid-2025.
Weather Implications
La Niña is typically associated with wetter conditions in Southeast Asia, the Brazilian Amazon, parts of Southern Africa, and the U.S. Pacific Northwest, while cooling global average temperatures slightly. After a record-breaking El Niño in 2023-2024, one of the strongest on record, the arrival of La Niña may signal less extreme weather for some regions.
Wetter conditions in the Amazon and Southeast Asia could help alleviate the droughts exacerbated by El Niño, while cooler temperatures may provide a temporary reprieve from rising global heat.
Caution Amid Relief
Ben Clarke, a researcher at Imperial College London’s World Weather Attribution, cautioned against viewing La Niña as a cure-all for climate woes. “Even with La Niña’s cooling effect, 2025 will likely still be a hot year due to ongoing greenhouse gas emissions,” Clarke explained.
The recent El Niño, amplified by climate change, led to unprecedented droughts in regions like the Amazon and Indonesia. While La Niña often reverses these conditions, it doesn’t eliminate the underlying drivers of climate volatility. Moreover, regions unaccustomed to La Niña impacts could still face unusual weather events.
The arrival of La Niña offers both hope and a stark reminder of the ongoing climate crisis. While cooler temperatures and wetter conditions in key regions may bring temporary relief, the broader trend of rising global temperatures remains unshaken.
With countries continuing to emit greenhouse gases at unsustainable levels, the planet’s future hinges on collective action. The ENSO cycle, while powerful, is no match for the long-term impact of human-driven climate change. Scientists urge governments and individuals alike to prioritize mitigation and adaptation strategies to navigate the challenges ahead.