The frequency of extreme El Niño events is projected to increase for a further century after global mean temperature is stabilised at 1.5°C above pre-industrial levels.
Research published today in Nature Climate Change by an international team shows that if warming was halted to the aspirational 1.5°C target from the Paris Agreement, the frequency of extreme El Niño events could continue to increase, due to a continuation of faster warming in the eastern equatorial Pacific.
CSIRO researcher and lead author Dr Guojian Wang said the growing risk of extreme El Niño events did not stabilise in a stabilised climate.
"Currently the risk of extreme El Niño events is around five events per 100 years," Dr Wang said.
"This doubles to approximately 10 events per 100 years by 2050, when our modelled emissions scenario (RCP 2.6) reaches a peak of 1.5°C warming.
"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.
"This result is unexpected and shows that future generations will experience greater climate risks associated with extreme El Niño events than seen at 1.5°C warming."
The research was based on five climate models that provided future scenarios past the year 2100.
The models were run using the Intergovernmental Panel on Climate Change’s lowest emissions scenario (RCP2.6), which requires negative emissions late in the century.