World Video | Defence | Foreign Affairs | Natural Events | Trade | NZ in World News | NZ National News Video | NZ Regional News | Search

 

Warming causes more extreme shifts


Warming causes more extreme shifts of the Southern Hemisphere’s largest rain band


South Pacific countries will experience more extreme floods and droughts, in response to increasing greenhouse gas emissions, according to a paper out today in the journal Nature.

The changes will result from the South Pacific rain band responding to greenhouse warming The South Pacific rain band is largest and most persistent of the Southern Hemisphere spanning the Pacific from south of the Equator, south-eastward to French Polynesia. Occasionally, the rain band moves northwards towards the Equator by 1000 kilometres, inducing extreme climate events.

The international study, led by CSIRO oceanographer Dr Wenju Cai, focuses on how the frequency of such movement may change in the future. The study finds the frequency will almost double in the next 100 years, with a corresponding intensification of the rain band.

Dr Wenju and colleagues turned to the extensive archives of general circulation models submitted for the fourth and fifth IPCC Assessments and found that increases in greenhouse gases are projected to enhance equatorial Pacific warming. In turn, and in spite of disagreement about the future of El Niño events, this warming leads to the increased frequency of extreme excursions of the rain band.

During moderate El Niño events with warming in the equatorial eastern Pacific, the rain band moves north-eastward by 300 kilometres. Countries located within the bands’ normal position such as Vanuatu, Samoa, and the southern Cook Islands experience forest fires and droughts as well as increased frequency of tropical cyclones, whereas countries to which the rain band moves experience extreme floods.

“During extreme El Niño events, such as 1982/83 and 1997/98, the band moved northward by up to 1000 kilometres. The shift brings more severe extremes, including cyclones to regions such as French Polynesia that are not accustomed to such events,” said Dr Cai, a scientist at the Wealth from Oceans Flagship.

A central issue for community adaptation in Australia and across the Pacific is understanding how the warming atmosphere and oceans will influence the intensity and frequency of extreme events. The impact associated with the observed extreme excursions includes massive droughts, severe food shortage, and coral reef mortality through thermally-induced coral bleaching across the South Pacific.

“Understanding changes in the frequency of these events as the climate changes proceed is therefore of broad scientific and socio-economic interest."

The paper, More extreme swings of the South Pacific Convergence Zone due to greenhouse warming, was co-authored by Australian scientists Dr Simon Borlace, Mr Tim Cowan from CSIRO and Drs Scott Power and Jo Brown, two Bureau of Meteorology scientists at the Centre for Australian Weather and Climate research, who were joined by French, US, UK, and Cook Island scientists.

The research effort from Australian scientists was supported by the Australian Climate Change Science Program, the CSIRO Office of Chief Executive Science Leader programme, and the Pacific-Australia Climate Change Science and Adaptation Planning Program.


Resources

© Scoop Media

 
 
 
World Headlines

 




UN: “COVID-19 Is Not Over”, Tedros Warns World Health Assembly

The head of the World Health Organization (WHO) told global health Ministers on Sunday that although reported COVID-19 cases and deaths have declined significantly, it is not time to lower the guard... More>>



UN: Bachelet Calls On Mexico To Step Up Efforts As Tragic Milestone Reached Of More Than 100,000 Disappearances

UN High Commissioner for Human Rights Michelle Bachelet on Tuesday called on the Mexican authorities to step up efforts to ensure truth and justice for victims of disappearances, who now number more than 100,000, according to official data... More>>


ADC: Statement On The Assassination Of Shireen Abu Akleh

Early this morning in Jenin, Occupied Palestine, revered Palestinian voice Shireen Abu Akleh, a Palestinian American journalist for Al Jazeera, was assassinated by Israeli Occupation Forces snipers...
More>>





Access Now: Elon Musk’s Twitter Buyout Must Not Come At The Expense Of Human Rights

Following today’s announcement that Elon Musk will acquire complete ownership of Twitter in a cash sale of around 44 billion USD, pending shareholder approval, Access Now urges Twitter’s Board, employees, and shareholders... More>>



UN: Biodiversity And Ecosystem Protection Highlighted On Mother Earth Day

Marking International Mother Earth Day, UN General Assembly President Abdulla Shahid urged on Friday, for collective action to safeguard biodiversity and protect ecosystems... More>>

Ukraine: Hundreds More Reach Safety After Fleeing Besieged Mariupol
In Ukraine, humanitarians said on Wednesday that hundreds of people have managed to reach safety after fleeing Mariupol, where there’s also been condemnation for the killing of Lithuanian filmmaker Mantas Kvedaravicius... More>>