An international study by Australia's national science agency, CSIRO, has found that climate change will lead to more extreme floods and droughts in the South Pacific.
The study, led by CSIRO oceanographer Dr Wenju Cai, examined the movement of the South Pacific rain band, which spans the Pacific from south of the equator southeast to French Polynesia and can move north up to 1000 kilometres towards the equator.
It found the frequency of this movement will almost double in the next 100 years, with rain intensifying at a corresponding rate.
In a statement, the CSIRO said Pacific countries will experience more extreme floods and droughts, in response to increasing greenhouse gas emissions
The study also found greenhouse gases are projected to enhance equatorial Pacific warming, which will lead to increased frequency of extreme excursions of the rain band.
The study says it is the largest and most persistent rain band in the southern hemisphere.
Dr Cai says during extreme El Nino events, such as the 1982/83 and 1997/98, the band moved northward by up to 1000 kilometres.
He says this shift brings more severe extremes, including cyclones to regions such as French Polynesia that are not accustomed to such events.
The study found during moderate El Nino events the rain band moves northeastward by 300 kilometres and countries located in its normal position, such as Vanuatu, experience forest fires and droughts and increased tropical cyclones.