Just over 10 years ago I interviewed Kevin Trenberth in San Francisco, in the midst of what turned out to be a strong El Niño event, when global temperature rose smartly through 2015-16, in a pattern that Dr. Trenberth described as a “step function”, and he hypothesized that successive El Niño events, since they represent a major cycle in ocean absorption and release of heat to the atmosphere, were important markers of the global heating process.
We have enough of a record now to see that Dr Trenberth was broadly correct. The El Niño cycle seems to be an important one in which planetary temperature equilibrates to a somewhat higher level.
The cycles historically recur on a 2 to 7 year cycle, the last one was 2023-24, with 2024 being the warmest year in the record.
This year’s El Niño is looking increasingly likely to have wide-reaching impacts across the planet.
It’s still in its developmental stages and it’s too early to confidently say just how strong it may become, but its tendencies have been similar to major events in the past — boosted by record-breaking westerly wind bursts in the Pacific, which blow warm water eastward.
No two El Niño events are exactly alike, but here are some of the possibilities.
Atlantic hurricane season impacts
Harsh winds in the middle and upper atmosphere during formidable El Niño events can create conditions that are less conducive to hurricane formation.
“Overall, this would be about as unfavorable an Atlantic look as you could get for the peak of hurricane season,” wrote meteorologist Andy Hazelton, who has been tracking this potential El Niño’s impact on the upcoming Atlantic hurricane season, which starts June 1.
Even if there are fewer storms, El Niño doesn’t tell you where hurricanes may go. It only takes one landfall — as demonstrated by Hurricane Andrew in Florida in 1992 — for it to be a memorable season.
The strongest El Niño events almost always cause a record warm year. That’s because heat comes out of the ocean during El Niño, overspreads the tropics in the Pacific, then gets redistributed across the planet.
“The El Nino cometh,” wrote climate scientist Zeke Hausfather.
“This would push up our estimate for 2026 global temperatures (though it’s still unlikely to surpass 2024 as the warmest year), and make 2027 very likely to be the warmest year on record,” he said, citing that air temperature increases lag behind El Niño’s development.
Strong El Niño periods often appear as an upward stairstep in long-term plots of global temperatures.
“Due to the increasing concentration of greenhouse gases, the climate system cannot effectively exhaust the heat released in a major El Niño event before the next El Niño comes along and pushes the baseline upward again,” Defense Department meteorologist Eric Webb said.
The scary part about Dr. Swain’s 1998 comparison is that 1998 was a hot year like no other that preceded it in the modern record.
For almost 2 decades afterward, that spike in the temperature record offered a visual hook for climate deniers to claim that “Global Warming Stopped in 1998”- simply because, although the planet kept warming, that striking point on the graph could be displayed in a way so as to fool the unschooled eye.
By 2016, that apparent “hiatus” was over, and even the untrained observer could see the obvious steady global rise.
When we attended the local Austin cabaret Esther’s Follies in 1998, it seemed to have been raining forever. The revue that season had the song “El Niño” sung by the brassy Chi Chi Labamba while other performers danced in the rain outside the window behind the stage.