The weather phenomenon La Niña ended after a three-year run, leaving scientists in anticipation of its sister phenomenon, El Niño. Now there are signs indicating that this year's El Niño will be far more extreme than usual. Oceans have been warming at a "rapid" rate leaving scientists concerned about what El Niño will bring. It could be enough to push average global temperatures above the 1.5-degree-Celsius threshold detailed by the United Nations.
What is El Niño?
The El Niño Southern Oscillation (ENSO) is a weather phenomenon in which "sea temperatures at the surface in the central and eastern tropical Pacific Ocean become substantially warmer than normal," according to the World Meteorological Organization (WMO). As a result, it causes "extreme heat, dangerous tropical cyclones, and a significant threat to fragile coral reefs," along with overall warmer temperatures, according to CNN.
ENSO is expected to make an appearance sometime this year, and the phenomenon typically lasts between nine and 12 months. "Right now, the atmosphere and the ocean are both in sync and screaming 'El Niño rapid development' over the next few months," climate scientist Daniel Swain tells CNN. The phenomenon is said to be "like a natural form of climate change," according to Time.
However, this year scientists are warning of a potential "super El Niño, which could cause "very high temperatures in a central region of the Pacific around the equator," reports The Guardian.
What does this entail?
While models have shown "a very large spread" of ENSO strength predictions, "the really big ones reverberate all over the planet with extreme droughts, floods, heatwaves and storms," says Mike McPhaden, a senior research scientist at the U.S. National Oceanic and Atmospheric Administration (NOAA) to The Guardian.
One of the largest potential consequences is that average global temperatures could reach 1.5 degrees Celsius over preindustrial levels, a threshold the United Nations warned against. "We will probably have, in 2024, the warmest year globally on record," Josef Ludescher, a senior scientist at Potsdam Institute for Climate Impact Research, tells CNN. The previous hottest year was 2016, which also had a strong El Niño.
California could also see a continuation of the unprecedented precipitation. A head forecaster at NOAA's Climate Prediction Center Jon Gottschalck described that the phenomenon could "elevate odds for atmospheric river-type events for the West Coast," which was responsible for much of the state's rain and snow.
What about the ocean?
One of scientists' biggest concerns is how quickly the ocean is warming. The warmer ocean temperatures could wreak havoc on coral reefs and intensify the hurricane season in the Pacific. "What's being predicted here is very scary," says Peter Houk, a professor at the University of Guam, to CNN. "Every time one comes, it grows a little bit more in intensity."
However, recently oceans have hit record levels of warmth, according to The Associated Press. "This is an unusual pattern. This is an extreme event at a global scale," says climate scientist Gabe Vecchi to The AP. "That is a huge, huge signal. I think it's going to take some level of effort to understand it," he says, adding that the level of warming is likely not only attributed to an El Niño event.
One of the consequences of this extreme warmth is the disappearance of the ocean's "twilight zone," which is "located between 656 feet and 3,280 feet (200 meters to 1,000 meters) below the surface," per CNN. A quarter of the ocean is included in this region, and it contains a high level of biodiversity. Historically, "in these warm periods, far fewer organisms lived in the twilight zone, because much less food arrived from surface waters," says Paul Pearson, an honorary professor at Cardiff University.
"La Niña's temporary grip on rising global temperatures has been released," NOAA oceanographer Mike McPhaden tells The AP. "One result is that March 2023 was the second-highest March on record for global mean surface temperatures." He adds, "What we are seeing now is just a prelude to more records that are in the pipeline."
Is climate change playing a role?
Scientists believe that climate change is causing El Niño to come more frequently and more intensel than before, despite being a natural phenomenon. According to a 2019 study, "if the currently observed background changes continue under future anthropogenic forcing, more frequent strong El Niño events are anticipated."
The outcomes of ENSO events are also more intense in the backdrop of climate change because the warmth of the ocean and atmosphere are exacerbated. "Extreme El Niño and La Niña events may increase in frequency from about one every 20 years to one every 10 years by the end of the 21st century under aggressive greenhouse gas emission scenarios," says McPhaden. "The strongest events may also become even stronger than they are today."
