This article was originally published by Inside Climate News and is reproduced here as part of the Climate Desk collaboration.

Unusually warm waters in the eastern Pacific at the onset of the last El Niño in 2023. NOAA

El Niño is temporary, but scientists warn that its climate impacts are not.

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 warming threshold enshrined in scientific documents and political agreements as a turning point for potentially irreversible climate…