Posts misrepresent effects of El Niño, humans on record heat

As El Niño ends, posts on X are blaming the natural phenomenon for record heat in 2023. This is misleading; while the climate pattern did affect average temperatures, the claims omit the impact of human-caused greenhouse gas emissions -- which climate scientists say are the single largest contributor to global warming.

"Weird narrative that we don't know what caused the global warmth in 2023. It's undeniably El Niño which rapidly emerged after 3 consecutive La Niña years," says Ryan Maue, a meteorologist and internet personality, in a March 20, 2024 post on X.

"There should be zero confusion about the proximate, dominant cause of 2023's global temperature."

<span>Screenshot of a post on X taken April 1, 2024</span>
Screenshot of a post on X taken April 1, 2024

Other posts have made similar claims about El Niño, which began in mid-2023 (archived here). El Niño is marked by warmer-than-average sea surface temperatures in Pacific Ocean and occurs on average every 2-7 years (archived here). The current round of the natural climate phenomenon will likely end in the next few weeks or months, with a potential new shift to the opposite cycle of La Niña, according to calculations from the National Weather Service (archived here).

NASA analyses have determined both human-caused global warming and El Niño are behind the rise in atmospheric and ocean temperatures over the past year (archived here and here).

However, "El Niño alone cannot explain the record high temperatures of 2023 and early 2024," said Josh Willis, principal scientist at NASA's Jet Propulsion Laboratory (archived here).

"The warming caused by human interference with the climate has actually contributed much more to the record than the El Niño," he told AFP on March 28.

Human-caused warming is 'dominant root cause'

NASA estimates global average sea levels rose by about 0.3 inches between 2022 and 2023, the hottest year on record. That is equivalent to draining a quarter of Lake Superior -- the largest freshwater lake in the world -- into the ocean over the course of a year (archived here).

Nature Conservancy chief scientist Katharine Hayhoe (archived here) said that multiple human and natural factors contribute to annual average temperatures.

"When we have the global temperature increasing due to human emissions, plus we have El Niño, we know in advance that this is gonna be an even warmer than average year," she said on March 27 .

<span>Graphic explaining the El Niño climate pattern in the Pacific Ocean that can significantly impact weather </span><div><span>Gal ROMA</span><span>Sophie RAMIS</span><span>AFP</span></div>
Graphic explaining the El Niño climate pattern in the Pacific Ocean that can significantly impact weather
Gal ROMASophie RAMISAFP

Russell Vose, chief of the Monitoring and Assessment Branch at NOAA's National Centers for Environmental Information, also pointed to factors such as heat-trapping gases in the atmosphere, a reduction of aerosol particles and the potential aftereffects of a 2022 volcanic eruption in Tonga (archived here and here).

"Present-day concentrations of carbon dioxide are higher than the last two million years and may possibly be higher than the last 14 million," he said in an April 1 email (archived here).

Climate researcher Pushker Kharecha (archived here), who recently co-authored a report on record heat in 2023 (archived here), told AFP on April 1 that it is "factually incorrect and thus very misleading to claim that the sole underlying cause is the recent El Niño."

Kharecha said: "The dominant root cause remains the underlying human-caused warming trend, which we have argued in recent peer-reviewed papers and articles" (archived here).

"Broadly speaking, El Niño/La Niña are simply fluctuations superimposed on the underlying global warming trend, which is indisputably and overwhelmingly caused by greenhouse gas (GHG) emissions from fossil fuel burning and deforestation."

<span>Graphic showing the annual change in CO2 concentrations with and without influence from El Niño and La Niña, as well as the projected CO2 concentration rise in 2024, along with the three IPCC scenarios that aim to limit warming to 1.5°C</span><div><span>Julia Han JANICKI</span><span>Anibal MAIZ CACERES</span><span>AFP</span></div>
Graphic showing the annual change in CO2 concentrations with and without influence from El Niño and La Niña, as well as the projected CO2 concentration rise in 2024, along with the three IPCC scenarios that aim to limit warming to 1.5°C
Julia Han JANICKIAnibal MAIZ CACERESAFP

Jayantha Obeysekera, director of the Sea Level Solutions Center at Florida International University (archived here), agreed.

"The global warming trend is persistent. Around that warming trend, there is natural variability due to such phenomena as El Niño," he told AFP on March 27 (archived here).

"We know that 2023 was the warmest on record," he added, "but nine out of 10 last years have been warmer" than before.

AFP has previously fact-checked other claims about the role of climate change in extreme weather events.