Extreme El Niño still expected, even if global warming halts

An international research group has found that the number of extreme El Niño events will increase, even if global warming stabilises.

Extreme El Niño still expected, even if global warming halts

Dr Guojian Wang, from the Commonwealth Scientific and Industrial Research Organisation, and lead author on the research, said: “Currently, the risk of extreme El Niño events is around five events per 100 years.”

But the researchers have found that even if signees to the Paris Agreement, manage to hold: “the increase in the global average temperature to well below 2°C above pre-industrial levels and … limit the temperature increase to 1,5°C above pre-industrial levels”, the frequency of extreme El Niño events will still increase because of a continuation of faster warming in the eastern equatorial Pacific.

According to the researchers’ simulations, the increase could double “to approximately 10 events per 100 years by 2050”, Wang said, adding, “After this, as faster warming in the eastern equatorial Pacific persists, the risk of extreme
El Niño continues upwards to about 14 events per 100 years by 2150.”

Wang said the research result was unexpected and “shows that future generations will experience greater climate risks associated with extreme El Niño events than seen at 1,5°C warming”.

Extreme El Niño events occur when the usual El Niño Pacific rainfall centre is pushed east toward South America, sometimes up to 16 000 km, causing massive changes in the climate. The further east the centre moves, the more extreme the event.

“This pulls rainfall away from Australia, bringing conditions that have commonly resulted in intense droughts across the nation,” Dr Wenju Cai, co-author, and director of the Centre for Southern Hemisphere Oceans Research, explained.

“Other countries like India, Ecuador, and China experience extreme events with serious socio-economic consequences.

“The most severe previous extreme El Niño events occurred in 1982/83, 1997/98 and 2015/16, years associated with worldwide climate extremes.”

The study was conducted at the Centre for Southern Hemisphere Oceans Research, in collaboration with CSIRO, Qingdao National Laboratory for Marine Science and Technology in China, the University of New South Wales, and the University of Tasmania, and published in Nature Climate Change.