In 2016, waves supercharged by El Niño impacted the California coast.
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Recent headlines have been buzzing with news about the impending “Godzilla El Niño.” In reality, there’s an 80% chance of an El Niño developing by September. While most climate models forecast a moderate event, some hint at the possibility of a stronger Super El Niño.
However, the broader outlook remains concerning. Regardless of its intensity, we can expect more damaging El Niño events in the coming decades. Even if these events are less powerful, their effects will be pronounced in an increasingly warmer world.
As Axel Timmermann from the Busan National University states, “Even a standard El Niño could create larger regional and global impacts.” His research indicates that both El Niño and La Niña events—collectively referred to as ENSO events—are predicted to become stronger and will increasingly influence weather patterns across the Atlantic Ocean.
Timmermann’s team has found that computer model simulations predict intensified extremes for El Niño-La Niña phenomena, leading to a more pronounced impact in remote regions, especially Europe.
The El Niño phenomenon is fundamentally about the water and wind dynamics in the Pacific Ocean. During the neutral state, trade winds push surface water westward, creating warm water accumulations in the western Pacific. Meanwhile, cold water rises near South America, replacing the warm water displaced by these winds, leading to increased rainfall.
However, when trade winds weaken or reverse, warm water can flow eastward, shifting rain patterns and triggering positive feedback loops that amplify El Niño events. This shift can cause droughts in countries like Australia and Indonesia while leading to floods in South America.
This is also why El Niño contributes to rapid global warming. A larger expanse of warm water enhances evaporation, releasing energy as latent heat and transferring heat into the atmosphere.
El Niño’s intensity is gauged by how much warm water flows east towards South America, often indicated by sea surface temperature anomalies exceeding 0.5°C. While “Super El Niño” is not a scientific term, it is often defined by temperature increases above 2 degrees Celsius; “Godzilla El Niño” references temperatures above 3 degrees Celsius, as noted by Adam Scaife from the Met Office Hadley Centre.
As El Niño unfolds, negative feedback loops can emerge, such as increased cloud cover over the central Pacific, which can lead back to neutral conditions or even shift to La Niña, where stronger westerly winds push cold water westward.
The three strongest El Niño events recorded occurred in 1982-83, 1997-98, and 2015-16, each causing significant harm to ecosystems and human populations, including mass mortality of corals and marine life.
Each Super El Niño has resulted in economic damages amounting to trillions of dollars. A 2023 study by Christopher Callahan from Indiana University found a direct correlation between the magnitude of economic loss and the intensity of Pacific ocean temperatures: “If a major El Niño occurs this year, we should anticipate economic losses in the trillions, similar to past events.”
As global temperatures rise, future El Niños and Super El Niños will likely become increasingly damaging. Richard Allan from the University of Reading, UK, states, “The science is clear.” He emphasizes that ENSO-related flooding is expected to worsen due to increased atmospheric moisture, leading to more intense rainfall during storms. Hotter conditions will also exacerbate droughts, causing longer and more severe dry spells.
Some climate models propose that warming could amplify the feedback mechanisms driving ENSO events, possibly leading to greater intensity in both El Niño and La Niña, and quicker transitions between the two, referred to as “climate whiplash.” This may complicate society’s adaptation to environmental changes.
“This means greater fluctuations between wet and dry years for numerous regions,” explains Malte Stucker, a member of Timmermann’s team at the University of Hawaii.
Worse yet, the team’s research suggests that these intensified fluctuations could synchronize ENSO events with the North Atlantic Oscillation. If this occurs, Europe may experience significant variability in flooding and drought patterns.
“Such a change would be a major shift for Europe since El Niño typically has minimal influence on its weather patterns under current conditions,” Stucker notes.
Though there is strong evidence suggesting that future El Niños of similar magnitude will cause more destruction, the likelihood of El Niño events intensifying remains highly debated. “There are substantial disagreements regarding the future behavior of El Niño and La Niña,” Scaife points out.
Not all climate models predict an intensification of El Niño, yet many do connect it closely with regions like the Atlantic Ocean, suggesting that El Niño’s impacts across the Pacific may strengthen in the coming years.
Even if ENSO events do intensify, they won’t continue to do so indefinitely, according to Timmermann. He notes that this intensification is partly due to rapid warming of water approximately 100 meters deep across the Pacific; ENSO events may weaken as groundwater temperatures equilibrate and differentials decrease.
What about the fish stocks? Such a decline may not materialize until after 2150, so fasten your seatbelts for a turbulent ride ahead.
Topics:
- Climate Change/
- Extreme Weather Events
Source: www.newscientist.com
