Under the Paris Climate Agreement, the international community is aiming to limit warming to 2 degrees celsius.
But the Australian-led study in the Nature Climate Change Journal found increases in global temperatures causing extreme El Niños would continue to see extreme weather events, even if the global temperature stopped rising.
The lead scientist from the Australia research institute CSIRO, Wenju Cai said the study indicates that extreme weather events are likely to become twice as common in the future.
"The South Pacific countries, these are the countries where the capacity to deal with extremes is probably lower than for example in New Zealand or Australia," he said.
"However, they are more vulnerable climate change induced, extreme weather, extreme climate and so cutting greenhouse is always good."
"What we are saying in this paper is that even if we could achieve, say 1.5 [degree celsius] the risk will continue to increase for another century," Mr Cai said.