El Nino could pack a long-term punch for small Pacific island states

Heavy rains such as the ones in Fiji this week that created flooding in the northern Viti Levu town of Rakiraki are expected to be more likely as climate change brings more cyclones during El Nino weather patterns.

Small Pacific island states could be hit by more tropical cyclones during future El Nino weather patterns due to climate change, Australian scientists say.

El Nino is a warming of sea-surface temperatures in the Pacific occurring every two to seven years which can trigger both floods and drought in different parts of the world.

Its opposite phase, a cooling of the same waters known as La Nina, is associated with the increased probability of wetter conditions over much of Australia and increased numbers of tropical cyclones.

Between 2070 and the end of the century, Fiji, Vanuatu, Solomon Islands, Marshall Islands and Hawaii could face an increased frequency in powerful storms during El Nino of up to 40 per cent, Australian meteorologists said in a study.

However cyclones may be up to 60 per cent less frequent during the opposite La Nina pattern, according to the study published in Nature Climate Change magazine.

Cyclones bring destructive winds, torrential rain and storm surges that are likely to be exacerbated by rising sea levels caused by global warming, posing a serious threat to Pacific islands, the authors said.

"Storm surge ... can lead to massive waves propagating far inland, devastating structures and vegetation in its path," co-author Kevin Tory, of the Australia's Bureau of Meteorology (BOM) told the Thomson Reuters Foundation.

"Salt water inundation can also damage soil, leading to years of reduced agricultural yield," he said.

Researchers said in the last three decades of the century, the ocean's surface waters will be hotter than usual in the Western Pacific due to global warming, resulting in more frequent cyclones during El Nino.

"These results suggest tropical cyclone activity in these regions will increase in a future warmer climate," one of the study's authors, Savin Chand, of Federation University Australia said in an email.

The latest El Nino, which emerged in 2015 and ended in May this year resulted in sea temperatures rising to the highest levels in 19 years.

Small island developing states are already suffering the impacts of climate change, including rising seas and worsening extreme weather, and have pushed hard for more ambitious international efforts to reduce planet-warming emissions.

The Marshall Islands, Fiji and Palau were the first three countries to ratify the Paris climate change agreement to limit global temperature rise to "well below" 2 degrees Celsius earlier this year.

- AAP