SAN FRANCISCO (KCBS RADIO) – By the time the latest El Niño weather pattern slowed to an end this summer, it became one is the strongest on record. Going forward, we could see even more extreme El Niño events.
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Strong El Niño events can cause destructive weather patterns. Examples include record rainfall in California in the late 1990s that in turn caused devastating landslides. As those landslides killed more than a dozen people, prolonged warming on the planet resulted in the loss of about 15% of our reefs.
Study findings published Wednesday in the Nature journal indicate that that Earth will have more frequent and extreme El Niño patterns by 2050 – one in every two that occur, in fact – if greenhouse gas emissions continue to increase. Greenhouse gasses include carbon dioxide, methane, nitrous oxide and others. They trap heat in the Earth’s atmosphere.
“It’s pretty scary that 2050 is not very far away,” said Pedro DiNezio, co-lead author of the new study and associate professor in the University of Colorado Boulder Department of Atmospheric and Oceanic Sciences. “If these extreme events become more frequent, society may not have enough time to recover, rebuild and adapt before the next El Niño strikes. The consequences would be devastating.”
Although greenhouse gas emissions dropped 3% in 2022 compared to 1990, they also increased by 5.7% from 2020 to 2022, according to the U.S. Environmental Protection Agency. That jump was mostly due to a rebound in fossil fuel combustion emissions after COVID-19 pandemic restrictions eased.
While the recent El Niño pattern was flowing, Earth saw record temperatures and 11 billion-dollar weather and climate events. According to CU Boulder, global temperatures broke records for 12 months in a row during 2023 and 2024.
El Niño is a regular occurrence that shifts back and forth regularly with a cooler (in the North) weather pattern called La Niña every four to seven years, as explained by Climate.gov. For El Niño to occur, the water temperatures along the equator in the Pacific Ocean rise by at least 0.9 degrees above average for an extended period. If this area warms by 3.6 degrees above average, scientists classify the El Niño event as extreme.
A model created by DiNezio and their team showed that extreme El Niño events were very rare during the Ice Age, when the planet was cooler. As the planet warmed, the frequency and intensity of El Niño have increased. In the 1950s, the U.S. National Oceanic and Atmospheric Administration has recorded three to four extreme El Niño events. Other research published this month in the Science journal found that a “Mega El Niño” instigated the end-Permian mass extinction, way before our time.
“El Niño events are difficult to simulate and predict because there are many mechanisms driving them. This has hindered our ability to produce accurate predictions and help society prepare and reduce the potential damage,” DiNezio explained.
So, they created a model to simulate El Niño events going back 21,000 years using a computer model. Then, the team validated the model by comparing its simulated data with past ocean temperature data retrieved from fossilized shells of foraminifera. Those are a group of single-celled organisms that filled Earth’s oceans long before human existence, CU Boulder said.
With the model, DiNezio and their team found that a single mechanism has been controlling the complex El Niño pattern since the last Ice Age thawed – something called the Bjerknes feedback. As its name suggests, this is a feedback loop, and it impacts the flow of air over the Pacific Ocean. During El Niño, winds are weakened and allow warmer water to flow east, thus fueling the loop. Rapidly warming temperatures due to greenhouse gas emissions cause the Bjerknes feedback to become stronger and cause more intense El Niño events, the research suggests.
“We are the first to show a model that can realistically simulate past El Niño events, enhancing our confidence in its future predictions. We are also proud of the robust technique we developed to evaluate our model,” said DiNezio. “But unfortunately, it brought us no good news,” he added.
They said the findings stress the importance of taking measures to reduce the impact of these events by cutting emissions, helping communities and more. One way to do that is to move away from our reliance on fossil fuels, said the study author.
In the U.S., President Joe Biden and the current administration have been working on finding ways to reduce fossil fuel use.
“I just hosted a three-day conference with the Quad in Delaware, it — with the prime minister of India, Australia, and Japan, three of the fastest-growing economies in the world,” Biden said this week. “They understand you can’t remain dependent on fossil fuels. They need to lead the clean energy future.”
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