Record weather
After a year of driving extreme weather, the El Niño pattern in the Pacific Ocean is subsiding, but this year may not be any cooler, says James Dinneen
THE El Niño climate pattern is coming to an end after boosting record temperatures and extreme weather across the planet over the past year. But it is uncertain how soon a transition to a cooler La Niña will bring respite from the heat.
“La Niña should stop that streak of record-breaking temperatures,” says Pedro Dinezio at the University of Colorado Boulder. “If it doesn’t, are our models wrong? Are we underestimating global warming?”
El Niño conditions are characterised by above-average sea surface temperatures in parts of the tropical Pacific. These waters usually oscillate between a warm El Niño temperature pattern, neutral conditions and a cool La Niña every two to seven years, a cycle that is one of the strongest factors influencing the global climate. El Niño is associated with hotter average temperatures and a distinctive pattern of weather conditions in much of the world.
The current El Niño first appeared in June 2023, following a rare three-year-long La Niña. Temperatures in the Pacific Ocean are now expected to return to neutral conditions within the next month, according to the latest forecast from the US National Oceanic and Atmospheric Administration (NOAA). Cool La Niña conditions are then likely to appear between June and September.
“You can already see [La Niña] emerging,” says Dinezio. “You can see it there in the Pacific right now.”
Early last year, researchers were alarmed that the developing El Niño might reach historic strength, comparable to the powerful ones of 2015-2016 or 1997-1998. A very strong event could have an outsized influence on weather around the world.
What emerged was a strong El Niño – the temperature anomaly in the Pacific reached 2°C above average at its peak – but not a record-breaking one. However, combined with background global warming from human-caused climate change and other factors, the outcomes of this year’s El Niño were unprecedented.
The heat pouring out of the Pacific helped make global average temperatures in 2023 the hottest on record, with shocking heat anomalies on land and in the oceans. Each of the past 11 months since El Niño emerged has also been the hottest of that month on record, according to NOAA.
Global trade disruption
Many of the regions that normally see weather influenced by El Niño also saw those effects amplified by background warming. For instance, drought and heat drove intense fire seasons in South America and Indonesia. In Central America, low water levels linked to El Niño created a traffic jam in the Panama Canal, disrupting g
