Pacific heat pulse is temporary, but scientists warn that its climate impacts are not.

The 2024 El Niño in the Tropical Pacific, combined with human-caused warming, dried out vast tracts of the Amazon region, crushing livelihoods and displacing people, and also flipped some forests to release more carbon dioxide than they absorb and store, a “regime shift” in the Amazon carbon cycle.

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Luis Acosta/AFP via Getty Images

The Pacific Ocean is a giant climate cauldron, with a powerful heat engine that affects storms, fisheries, and rainfall patterns half a world away, and scientists are watching closely to see if it’s about to boil over.

Their projections suggest the tropical Pacific is simmering toward a strong El Niño , the warm phase of an ocean-atmosphere cycle that can intensify and shift those impacts.

In a world already superheated by greenhouse gases, a strong El Niño during the next 12 to 18 months could permanently push the planet’s average annual temperature past the 1.5 degrees Celsius…