El Niño expected to smash heat records in 2024

There’s a 90 percent chance that global average surface temperatures will reach a record high for the year leading up to June 2024, according to new research published today in the journal Scientific Reports. Some places will be more sweltering than others, particularly in parts of Asia. The heat has cascading effects, like raising the risk of drought and wildfire.

A weather pattern known as El Niño is to blame. El Niño is part of a natural, cyclical phenomenon, but climate change heightens the stakes by raising baseline temperatures before El Niño swoops in to push the mercury up even higher.

“We have seen that this type of warming can cause a lot of troubles in the world, so we want to give people a heads up,” says Deliang Chen, one of the authors of the new research and a professor in the department of earth sciences at the University of Gothenburg.

There are three phases to the El Niño–Southern Oscillation (ENSO), with El Niño being the extreme warm phase of the cycle. During a neutral phase, trade winds over the Pacific Ocean push warm waters near South America west toward Asia, allowing cooler water to rise from the deep toward the surface of the ocean. Those winds weaken during El Niño, creating a large area in the Pacific that is much warmer than usual. As a result, heat that’s been stored in the ocean is released into the atmosphere.

That’s why El Niño can lead to weird weather, although its effects tend to vary from region to region. Before the current El Niño developed last June, forecasters were already heralding the havoc it could cause. The World Meteorological Organization said that along with climate change, it would “push global temperatures into uncharted territory.” Unsurprisingly, 2023 wound up being the hottest year since record-keeping began in 1850 — with temperatures unofficially thought to be the hottest in at least the last 100,000 years.

To predict what’s in store for 2024, Chen and his colleagues modeled two possible scenarios: one under a moderate El Niño and another under a strong El Niño. With a moderate El Niño, the Bay of Bengal and the Philippines can expect to be the hardest hit this year. The Philippines, a tropical archipelago in the Pacific, faces continued drought over the next several months. In the Bay of Bengal, which borders several countries in South and Southeast Asia, El Niño often leads to marine heatwaves that can bleach and kill coral reefs that nearby communities rely on for their livelihoods and that provide a buffer against tropical storms.

Image: Ning Jiang and Congwen Zhu via Scientific Reports

A strong El Niño would also break temperature records across the Caribbean, South China Sea, Amazon, and Alaska this year, according to the new research. The Caribbean, South China Sea, and Bay of Bengal could all face year-round marine heatwaves under this more extreme scenario. Severe drought could fuel wildfires in the Amazon, while sky-high temperatures might speed the loss of glaciers and permafrost in Alaska. Strong El Niños in the past have cost the global economy trillions of dollars.

Fortunately, the world might dodge a bullet this year with a moderate El Niño now looking most likely. But even that is expected to be enough to push the world past a new record for global average surface temperature by June. El Niño is forecast to end by then, but typically rolls back around every two to seven years.