El Niño raises fresh fears for reefs and harvests

The return of the El Niño climate pattern this year raised fresh fears for the natural world, threatening renewed coral bleaching, drought and strain on ecosystems and agriculture across large parts of the globe, as the warming phase added its influence atop an already heated planet.

El Niño, marked by unusually warm waters in the tropical Pacific, reshapes weather patterns worldwide and tends to push global temperatures higher. Layered on top of the long-term warming from greenhouse gases, its arrival heightened the risk of record heat and of the extremes that come with it.

Among the gravest concerns was the threat to coral reefs, already battered by repeated mass bleaching events in recent years. The additional ocean heat associated with El Niño raised the danger of further widespread bleaching, giving stressed reefs little time to recover.

On land, the pattern threatened drought in regions prone to it during El Niño years, with implications for water supplies, wildfire risk and agriculture, potentially straining harvests and food security in vulnerable areas, even as other regions faced heightened flood risk.

Scientists and disaster planners watched the pattern's development closely, as its effects on seasonal weather can be anticipated months in advance, offering some lead time to prepare. But the return of El Niño underscored a sobering reality: that natural climate cycles now play out against a backdrop of human-caused warming, amplifying their impacts and raising the stakes for ecosystems and communities already under growing pressure from a changing climate.