The tropical Pacific has seen heat build for months as a “super” El Niño takes shape.
A climate phenomenon that forms every few years, this year’s iteration of El Niño has been on a tear of daily records and is forecast to reach unprecedented strength this winter. While it’s characterized by hotter-than-normal waters in the eastern tropical Pacific, El Niño is a global problem.
It’s fair to wonder how another global problem is interacting with El Niño: climate change, driven by burning fossil fuels. While a hotter climate begetting a hotter El Niño might seem like a done deal, “I have more questions than I have reactions” to what’s happening, says Christopher Callahan, a climate researcher at Indiana University. In other words, the relationship is still an area of active research—and this year’s event could provide vital insights.
El Niño’s added ocean heat affects the atmosphere, causing weather patterns around the world to shift. Consider it kind of like a domino run, where one tile starts a chain reaction. Such a major slug of heat in the Pacific will act more like a shove then a light flick on the atmosphere, and the resulting shifts in weather are expected to be generationally intense.
The US National Oceanic and Atmospheric Administration is forecasting 100 percent odds of an extremely strong El Niño through December and above 80 percent odds it stays that way through February. Data shows this El Niño has already set multiple all-time daily heat records including a recent peak of 3.4 degrees Celsius.
NOAA issues its El Niño forecast as a three-month rolling average, and the agency predicts heat could peak at 2.7 degrees Celsius above normal for the period from October to December. (It’s not out of the question that heat could surpass 3 degrees Celsius, though.) If the forecast holds true, it would smash the previous record of 2.4 degrees Celsius, which was set during the 1982-1983 event.
How Is Climate Change Impacting El Niño?
There is a growing body of evidence that climate change is likely playing at least some role in influencing El Niño. The magnitude and frequency of the phenomenon has increased over the past 60 years, says Francisco Estrada, coordinator of the Climate Change Research Program at the National Autonomous University of Mexico, and so has the variability and how the effects are distributed around the world. He says there shouldn’t be a debate framed as a choice between a “natural El Niño” and an “El Niño caused by climate change” but rather as an interaction between the two processes.
“You can’t separate El Niño from global warming—they’re inextricably linked,” he explains.
Modeling also indicates that El Niño is likely to strengthen as the planet warms, though Callahan notes that many models struggle to accurately represent long-term temperature trends in the eastern tropical Pacific. That can give researchers some pause, but there’s also other evidence that climate change is juicing El Niño.