Environmental (Commonwealth Union)_ The world climate system is sending mixed signals: even though the La Niña cooling trend appears poised to return this fall, its effect can come too little, too late to stall the runaway rate of global warming. The UN’s World Meteorological Organization currently estimates the probability of Pacific Ocean temperatures falling to La Niña levels during September-November at 55-60%, yet even if this cooling trend materializes, global temperatures should remain obstinately above average. This contradiction indicates just how powerful human-caused climate change has grown, capable of overriding even potent natural climate occurrences.
La Niña is the cold phase of the El Niño-Southern Oscillation (ENSO) cycle, characterized by unusually cold surface waters in the central and east equatorial Pacific. It tends to bring a predictable weather shift: increased rain in Southeast Asia and Australia and dryness in the southern United States, with generally moderate cooling effects globally. This subsequent event would be the follow-up to the unusual 2020-2023 “triple-dip” La Niña, only the third such long-lasting event since 1950, which, though lengthy, was not even sufficient to prevent the last decade from being the hottest on record. This precedence in the record makes the point that even a strong La Niña would only moderately cool, but not counteract, the current warming trend.
The WMO prediction points to a new climate reality: human-caused warming has become the stage against which natural variability unfolds. “We’re trying to cool a boiling pot with an ice cube, climatically speaking,” comments Dr. Maria Rodriguez, a climate scientist at the University of Lisbon. “The fundamental temperature baseline has shifted so fundamentally that even our cooling episodes now occur at what would have been considered to be warm temperatures a few decades previously.” The numbers confirm: 2024 remains on track to be the all-time hottest year ever as the El Niño circumstances that drove 2023’s record heat start to subside.
The implications reach far beyond temperature records. La Niña’s potential return would bring drought-stricken regions like Southeast Asia much-needed rainfall but potentially make drought worse in the southern US. These trends, however, will manifest in a hotter atmosphere capable of holding more moisture, so even typical La Niña-related precipitation may arrive in the form of more frequent heavy, flood-causing showers. Likewise, temperature moderation can temporarily alleviate the conditions in certain spots but won’t alter the general trend toward warmer temperatures on a global basis.
The WMO seasonal forecast states that well above-normal temperatures are likely in most of the northern hemisphere and much of the southern hemisphere in November, a prediction that will unfold whether La Niña shows up or not. This consistency shows that the buildup of greenhouse gases is now the main cause of climate change, making natural changes less important. As the agency notes, global warming is “ramping up global temperatures, intensifying extreme weather, and affecting season patterns of rainfall and temperature” regardless of the state of ENSO.
Therefore, the desired La Niña does not represent a return to cooler conditions, but rather illustrates how significantly human activity has altered the planetary climate system. Even our own cooling episodes now occur at warm temperatures, delivering at best temporary relief rather than genuine reversal. As the planet watches while Pacific temperatures drop towards La Niña values, the underlying message remains unequivocal: natural variability can modulate but no longer control the deep warming trend under way.
