The 400-year record revealed a clear change in El Niño types, with an increase of Central Pacific El Niño activity in the late 20th Century and suggested future changes to the strength of Eastern Pacific El Niños.
"We are seeing more El Niños forming in the central Pacific Ocean in recent decades, which is unusual across the past 400 years," said lead author Dr. Mandy Freund.
"There are even some early hints that the much stronger Eastern Pacific El Niños, like those that occurred in 1997/98 and 2015/16 may be growing in intensity."
This extraordinary result was teased out of information about past climate from coral cores spanning the Pacific Ocean, as part of Dr. Freund's Ph.D. research at the University of Melbourne and the Centre of Excellence for Climate Extremes. It was made possible because coral coreslike tree ringshave centuries-long growth patterns and contain isotopes that can tell us a lot about the climate of the past. However, until now, they had not been used to detect the different types of El Niño events.
https://phys.org/news/2019-05-impossible-year-el-nino-revealing.html