Models of climate change predict that El Niño will occur more often as the global temperature rises. A new study provides long-term data to prove it.
Researchers from Australia procured 400 years worth of data on El Niño from coral records. They found that a new category of El Niño has become more prevalent in the last few decades.
The study offers better understanding of the El Niño and the patterns that have emerged due to climate change. The paper was published in the journal Nature Geoscience.
El Niño Becoming More Frequent, More Intense
The new category of El Niño, characterized by warm sea surface temperature in the central Pacific instead of the usual far eastern Pacific, has been observed more in recent decades, including the 2014-2015 event and, more recently, 2018-2019.
By the end of the 20th Century, the researchers reported that the world saw a sharp increase in central Pacific El Niño events. Meanwhile, the eastern Pacific El Niño events stayed relatively low, but the most recent occurrences (1982-1983, 1997-1998, 2015-2016) were more intense than usual.
They found the emergence of the new trend by looking at corals found in the tropical Pacific.
"The corals started growing decades to centuries before we began routinely measuring the climate with instruments," the researchers wrote in The Conversation. " The corals are an excellent archive of changes in water conditions they experience as they grow, including ocean changes related to El Niño."
Using data collected from coral cores, the researchers trained an algorithm to recognize characteristic patterns of El Niño events, when it happened, and what type occurred. The team was able to reconstruct a history of El Niño events from the past 400 years.
What Changing El Niño Trends Mean For The World
El Niño is associated with reduced rainfall in Asia and Australia, but it also affects the weather in North America. During an El Niño event, the U.S. Gulf Coast and Florida might experience wetter-than-average conditions while Ohio Valley and the Pacific Northwest might see drier-than-average conditions.
Changes to El Niño behavior will have implications to the weather patterns around the world, affecting not only the human population but also ecosystems. For example, the researchers pointed out the 2015-2016 Eastern-Pacific El Niño event which led to disease outbreaks in several parts of the planet.
"With the impacts of climate change continuing to unfold, many of the hottest years on record also coincide with El Niño events," they warned.