What a ‘super’ El Niño means for the planet

Forecasters are increasingly predicting the possibility that a powerful “super El Niño” will take effect this year. The phenomenon, which could be the strongest El Niño in at least a decade, may spur punishing drought in some regions and severe storms in others, while also causing the Earth’s temperature to rise. 

The National Oceanic and Atmospheric Administration predicted this week with growing confidence that El Niño could begin this spring or summer. The latest report added that there is a 25 percent chance of a “very strong” El Niño and a 50 percent chance of a “strong” El Niño, with Pacific Ocean temperatures rising to at least 1.5 degrees Celsius warmer than average. 

The phenomenon—which typically occurs every two to seven years—is often characterized by chaos because it shifts global weather and introduces new extremes. Yet some scientists paradoxically view it as a chance to prepare for what’s to come.

“When we have an El Niño it influences the global atmosphere in such a way that we have a greater chance of knowing where things are going to happen,” says Emily Becker, a research professor at the University of Miami who is part of NOAA’s El Niño—Southern Oscillation forecast team. “So, it’s that added capability of seeing potential outcomes that really gives us a nice advantage.

What is El Niño and how do we know it’s coming? 

The naturally recurring weather pattern has been transforming the Earth’s climate for what scientists believe to be hundreds of millions of years. It typically lasts between nine and 12 months. 

The seed of this transformative phenomenon lies in the tropical Pacific Ocean, where winds usually blow from the east to the west, pushing warmer water and stormy weather away from Ecuador and Peru, toward Indonesia. When those winds weaken, the warmer water moves east, and with it, the stormy weather. Surface temperatures across that patch of ocean increase, changing the Earth’s atmospheric circulation.  

(This ancient society tried to stop El Niño—with child sacrifice)

Satellites track these ocean temperatures, while an array of research buoys in the middle of the sea deploy probes more than a thousand feet underwater to monitor how deeply it is warming. Warmer water underneath the surface rises over the course of several months to feed potential El Niño conditions. The larger the temperature increase, the stronger the El Niño could be. 

What is a super El Niño? 

A super El Niño is not a scientific term but rather a label that forecasters use for a very strong El Niño, when Pacific Ocean temperatures increase at least 2 degrees Celsius above average. They are rare; the last one occurred around 10 years ago. It was on par with other record strong events in the late 90s and early 80s.

These can have devastating effects. The most recent super El Niño from 2015 to 2016 was connected to a record-breaking hurricane season in the central North Pacific, water shortage in Puerto Rico, drought in Ethiopia, and the hottest global surface temperature on record at that time, according to NOAA. 

(How warm oceans supercharge deadly hurricanes)

As for this year, Becker says it’s unusual to have a 25 percent chance of a very strong El Niño so far out, but when it comes to spring forecasting, she added, “there is a very well-documented tendency for [computer models] to predict way stronger surface temperatures than actually occur in the tropical Pacific.” 

We’ll probably know in the early fall if a very strong El Niño will occur, she adds.

How does El Niño affect our planet? 

Depending on its strength, El Niño’s effects can be far-reaching, influencing storm patterns, drought, wildlife populations, and even how fast the Earth spins.

Warmer waters in the central and eastern parts of the tropical Pacific could mean more intense storms there—and those storms can influence weather across the globe. 

El Niño pushes jet streams further south, says Becker. In the past some places including the southeastern United States and Texas have seen more rain, while other places including southern Africa experienced more heat and drought, which hurt food crops and led to hunger. Less rainfall and warmer temperatures in Indonesia and Australia have also meant more wildfires there.

Warmer water in the Pacific ultimately leads to warmer air as well. In the past, El Niño years have been some of the warmest on record. 

The reverberations of El Niño can also have trickle-down effects on wildlife populations. The penguin population on the Galápagos Islands severely crashed after two strong El Niño events in the 80s and 90s, according to a 2006 study in Biological Conservation. The warming oceans caused by the weather patterns reduced the number of macronutrients and fish in the water, which in turn may have starved the penguin population. 

Will El Niño affect the Atlantic hurricane season?

This year’s first Atlantic hurricane forecast, released this week by scientists at Colorado State University, predicted a near or below average season. 

“The primary reason why we're going a little bit below normal is because of the potential for a pretty strong El Niño event this summer and fall,” says Phil Klotzbach, a senior hurricane research scientist at CSU. 

Across the Atlantic, El Niño increases wind shear, strong vertical gusts that break apart storms as they form. That combined with the fact that parts of the Atlantic Ocean aren’t as warm as they were last year could make for a less intense season, Klotzbach says.

Despite the potentially catastrophic effects, being able to track these long-entrenched weather patterns can better prepare us, scientists say.

“I always hesitate to characterize El Niño or La Niña as good or bad,” says Becker. “They just are, and pretty much always have been.”