El Niño returns, reshaping the global forecast

Forecasters declared the arrival of El Niño this June, confirming the return of the periodic warming of the tropical Pacific that reshapes weather patterns across the globe and signalling the likelihood of record-breaking global heat in the months to come.

El Niño, characterised by unusually warm ocean temperatures in the central and eastern tropical Pacific, influences weather far beyond its origin. Its arrival, after a prolonged stretch of its cooler counterpart La Niña, pointed to significant shifts in rainfall and temperature patterns worldwide.

Forecasters noted that El Niño tends to add extra warmth to global temperatures, raising the prospect that the following period could set new records, layered on top of the long-term warming trend. It also typically suppresses Atlantic hurricane activity by increasing wind shear, while favouring more storms in the Pacific.

Around the world, El Niño is associated with drought in parts of Asia, Australia and Africa, heavier rainfall in parts of the Americas, and disruptions to agriculture, fisheries and ecosystems. Governments and farmers watch its development closely to anticipate the risks.

The declaration prompted warnings that the combination of El Niño and human-caused climate change could drive dangerous extremes in the year ahead. Indeed, the months that followed would go on to shatter global heat records, a vivid demonstration of how this natural cycle, superimposed on a warming baseline, can push the climate system to new and alarming extremes.