CNN  — 

Governments must prepare for more extreme weather events and record temperatures in the coming months, the World Meteorological Organization warned Tuesday, as it declared the onset of the warming phenomenon El Niño.

El Niño is a natural climate pattern in the tropical Pacific Ocean that brings warmer-than-average sea-surface temperatures and has a major influence on weather across the globe, affecting billions of people.

“The onset of El Niño will greatly increase the likelihood of breaking temperature records and triggering more extreme heat in many parts of the world and in the ocean,” said WMO Secretary-General Petteri Taalas.

The declaration “is the signal to governments around the world to mobilize preparations to limit the impacts on our health, our ecosystems and our economies.”

To save lives and livelihoods, governments must establish early warning systems and prepare for further disruptive weather events this year, he said.

The last three years have been some of the warmest on record, even with El Niño’s sister phase, La Niña – which is marked by cooler-than-average ocean temperatures.

A “double whammy” of a very strong El Niño and human-caused warming from the burning of fossil fuels led to 2016 becoming the hottest year on record, according to the WMO, the United Nations’ agency for weather, climate and water resources.

But the first El Niño to develop in seven years layered on top of human-caused global heating, could push 2023 or 2024 to break 2016’s heat record, the WMO said.

The WMO said there was a 90% probability of El Niño continuing during the second half of 2023 at moderate strength.

Along with increased ocean warming, El Niño events are usually associated with increased rainfall in parts of southern South America, the southern United States, the Horn of Africa and central Asia.

But it can also amplify severe droughts, heat waves and wildfires over Australia, Indonesia, parts of southern Asia, Central America and northern South America.