Paris: Global warming periodically shifts El Nino thousands of miles to the west, potentially intensifying Asian droughts and weakening its dampening effect on Atlantic hurricanes, reports a study published on Thursday.
Up to now, the tropical weather phenomenon, which strikes on average every four or five years, has generally occurred along a wide stretch of the Equator in the eastern Pacific. Such is the case with the current El Nino, which is likely to remain in place well into next year, the World Meteorological Organisation said last month.
El Nino disrupts weather patterns around the world, causing drought in Indonesia, Australia, India and eastern Brazil, and unusually heavy rainfall in the US Gulf Coast and parts of South America. It also lowers sea surface temperatures in the Caribbean and Atlantic, which helps prevent the formation and intensity of hurricanes in that region.
But climate change has apparently given rise to an alternate form of El Nino that is likely to become more frequent over the coming decades, according to the new research, published in Nature. “There are two El Ninos,” said Ben Kirtman, a professor at the University of Miami and a co-author of the study.
“In addition to the eastern Pacific El Nino ... a second El Nino in the central Pacific is on the increase,” he said. The two do not occur at the same time, he added. This could be bad news on at least two fronts, the researchers said.
In Asia, it could intensify droughts that have already wreaked havoc in recent decades. And in the Atlantic, it could weaken the positive effect it has had up to now in mitigating the intensity of hurricanes that strike the Caribbean and the US east coast.
Researchers at the Korea Ocean Research and Development Institute in Ansan matched sea surface temperature data from the last 150 years against future global warming scenarios. Most of the models showed that global warming will boost the frequency of the central Pacific El Nino.