Extreme El Niño events might become the new norm, according to new research. During these powerful El Niños, the west coast of South America experiences severe rainfall that can cause floods and landslides, while regions in the western Pacific, such as Indonesia and Australia, endure prolonged droughts.
A 2023 United Nations report warns that if current greenhouse gas emission trends persist, the world is on track to warm by 5.2 degrees Fahrenheit (2.9 degrees Celsius) by 2100. However, the new modeling study suggests that if global temperatures rise slightly more—by 6.6°F (3.7°C)—90% of El Niños could be as severe as the strongest ones recorded, such as the devastating El Niño of 1997-1998. This historical El Niño event led to 23,000 deaths and billions of dollars in damage from storms, droughts, floods, and disease outbreaks, according to a 1999 estimate published in Science.
“If we would end up in a state where each El Niño is an extreme eastern Pacific El Niño, this would just have huge socio-economic impacts in the Pacific region,” said the study’s lead author, Tobias Bayr, who conducted the research while a scientist at the GEOMAR Helmholtz Centre for Ocean Research in Germany.
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Climate Change and the El Niño-La Niña Cycle
The impact of climate change on the El Niño and La Niña cycles has been a subject of intense debate. Some early models suggested that a warming world might lead to a permanent El Niño state, characterized by weakened trade winds and warmer waters in the eastern Pacific.
This ocean warming triggers broad climate and weather effects. It transfers heat to the atmosphere, raising global temperatures. The jet stream over North America shifts south, leading to drier conditions in the Pacific Northwest and increased rainfall in the southern U.S. In the Southern Hemisphere, the consequences are more severe: extreme precipitation in South America and droughts and wildfires across the Pacific.
Recent studies, however, have presented different scenarios. Bayr explained that their model, which excels at simulating the complex patterns of the El Niño/La Niña cycle, did not predict a permanent El Niño but rather more intense and frequent El Niño events.
Under current conditions, the model projects eight or nine extreme El Niños per century. With a 6.6°F increase in global temperatures, this number could soar to 26 extreme El Niños every 100 years, occurring on a nearly regular four-year cycle. In such a scenario, the model forecasts that 90.4% of El Niños would be classified as extreme by today’s standards due to extra-warm conditions in the eastern Pacific over the equator.
Ongoing Research and Future Directions
The findings, published on July 4 in Geophysical Research Letters, stem from just one model, so further validation in other climate models is needed. The study also revisits the idea of El Niño as a potential “tipping point” in the climate system. Climate tipping points are thresholds that, once crossed, lead to rapid and potentially irreversible changes.
“It has a really very different behavior in the colder and the warmer climate and therefore we say that there is a tipping point-like behavior,” Bayr said. “It would be good if other institutes could also do similar experiments and investigate if other models show a similar behavior.”
Impact of El Niño and La Nina on India
Since 1950, India has faced 13 major droughts, and notably, 10 of these occurred during El Niño years, while just one occurred in a La Niña year. This pattern is largely due to the fact that El Niño typically brings less rainfall to India compared to average conditions. Indian agriculture relies heavily on the monsoon rains, so a reduction in rainfall during these critical months usually results in below-average crop yields.
El Niño and La Niña, together known as the ENSO (El Niño-Southern Oscillation), are crucial phenomena in climatology hese climatic events have a profound impact on both Indian and global weather patterns, influencing everything from precipitation levels to agricultural productivity.
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