Noah
Although the Earth's climate has been hot in recent years, it's about to get even hotter: El Niño is on the way, with warmer sea temperatures heralding new extreme weather events, say U.S. and international meteorologists.
For several years, a persistent La Niña pattern in the tropical Pacific has been mitigating some of the worst temperature rises, as well as upsetting precipitation patterns. But the World Meteorological Organization says all that is about to change.
“We have just experienced the eight hottest years on record, although we have had a cold La Niña for the past three years,” said Petteri Taalas, Secretary-General of the World Meteorological Organization.
In the United States, this shift promises relief in other forms, as the ending La Niña is associated with more hurricane activity in the east and drought in the west.
Here's a quick guide to these two influential climate patterns:
They affect hurricanes and other weather conditions
El Niño typically brings a quieter hurricane season in the Atlantic and more hurricane activity in the Pacific, while La Niña does the opposite — a dynamic that the National Oceanic and Atmospheric Administration likens to a see-saw.
Warmer El Niño waters can also push the Pacific Jet Stream south. When this happens, NOAA says, “Areas in the northern U.S. and Canada are drier and warmer than normal. But in the U.S. Gulf Coast and Southeast, these periods are wetter than normal and lead to increased flooding.” .
She called the La Niña phenomenon in March; Since then, American forecasters have installed an El Niño monitor.
“There is a 62% chance of an El Niño developing from May to July, and more than an 80% chance of an El Niño developing by the fall,” says Emily Baker of the National Oceanic and Atmospheric Administration (NOAA).
La Niña cools and El Niño warms
Taalas said La Niña “acted as a temporary brake on rising global temperatures.” This is because this pattern occurs when sea surface temperatures are unusually cold, and are expected to stay that way for several months.
We've seen La Niña conditions since late 2020, leading to forecasts of below-normal winter temperatures across much of the northern United States and warmer temperatures across much of the South.
But because of the new trend of warmer sea surface temperatures, Talas added, “El Niño will likely lead to a new spike in global warming and increase the chance of breaking temperature records” that were only recently recorded.
It usually takes time for changes to achieve their full effects. The World Meteorological Organization says the biggest impact on global temperatures is unlikely to become apparent until 2024.
Patterns change regularly, and irregularly
The rule of thumb is that El Niño patterns occur more often, but El Niño usually lasts longer — sometimes for years. Most cases of either form usually last only nine to 12 months.
“El Niño and La Niña occur every two to seven years on average, but they do not occur on a regular schedule,” says the National Oceanic and Atmospheric Administration (NOAA). In addition to the two patterns, ocean temperatures are sometimes considered “neutral,” meaning they are neither abnormally warm nor cold.
While confidence is growing that a new pattern is taking hold, it is not yet known how strong the next El Niño will be.
However, the World Meteorological Organization is urging people and governments to prepare for hotter and more volatile conditions, pointing to the possibility of a repeat of 2016 – the warmest year on record, thanks to what the World Meteorological Organization calls the “double whammy” of an extremely powerful electrical storm. “El Niño event and human-caused warming due to greenhouse gases.”