The United Nations has officially confirmed what months of forecasts have been pointing to: there are overwhelming odds that the next El Niño will be one for the history books.

On Tuesday, the UN’s World Meteorological Organization issued a stark warning that there’s now an 80 percent chance that El Niño conditions emerge between June and August, and over a 90 percent chance that they appear before November.

“This update matters because El Niño is a major driver of global weather and climate patterns,” Celeste Saulo, secretary-general of the WMO said in a statement. “The footprint of an El Niño travels far beyond its origins in the Pacific Ocean, impacting agriculture, energy supplies, trade, water resources, supply chains, and livelihoods across entire regions.”

As part of the warning, UN secretary-general António Guterres delivered a video statement urging the world’s governments to start preparing for an extreme warning period, in addition to prolonged droughts in some areas and heavier rainfall in others.

“The science is clear: El Niño is arriving on our doorstep in the coming months with 90 percent certainty,” Guterres said. “The world must treat it as the urgent climate warning it is. El Niño conditions will pour fuel on the fire of a warming world.”

El Niño refers to a phase of the El Niño Southern Oscillation, a naturally occurring climate pattern characterized by unusually warm ocean surface temperatures throughout the Pacific. That pocket of warm water then drifts eastward, weakening tropical trade winds, which has a domino-like effect on weather patterns throughout the world.

What those impacts are depends on how strong El Niño is, and where exactly you are in the world. Southern Africa, Central America, and the South Pacific can expect drier conditions, for example, while those in East Asia, the Gulf of Mexico, and the Southern Cone tend to see much more precipitation.

The relative strength of El Niño will be difficult to parse until more data emerges, but numerous models have predicted a “super El Niño,” where sea surface temperatures rise 4.5 degrees Fahrenheit above average before November. If that happens, we could easily be facing one of the worst such climate shifts in history — a record set in 1877 when El Niño-fueled climate disasters killed millions.

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