Regional climate monitoring hub warns of La Niña impact

By Alexander Rheeney 20 September 2022, 7:09PM

A regional climate monitoring hub has warned Pacific Island nations including Samoa to prepare for drier and more rainfall than normal conditions as La Niña impacts the region.

Coming on the back of the declaration of a La Niña for the third consecutive year in the Pacific by the World Meteorological Organisation (WMO), a statement issued by the Apia-based Secretariat of the Pacific Regional Environment Programme (SPREP) included a warning from the WMO Pacific Regional Climate Centre Network (RCC-N) for communities in the northwest and southwest Pacific.

Communities in the central equatorial Pacific were advised to prepare for a return to drier than normal conditions and communities in the northwest and southwest Pacific for higher than normal rainfall, according to the SPREP statement.

SPREP COSPPac Climatology Officer, Philip Malsale, said La Niña refers to the large-scale cooling of the ocean temperatures in the central and or eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation, namely wind, pressure and rainfall.

“It is important to note that every La Niña event is different and impacts vary from country to country,” Mr Malsale said.

During La Niña Pacific countries in the west, namely Palau, mainland Papua New Guinea (PNG), Solomon Islands, New Caledonia, Vanuatu, Fiji, Tonga, Wallis and Futuna, Samoa, American Samoa, Niue, southern Cook Islands and southern French Polynesia, tend to receive higher than normal rainfall. The opposite impact is experienced in countries in the central Pacific. These include Nauru, Kiribati, Tuvalu, Tokelau, northern Cook Islands and northern French Polynesia.

In preparation for these weather events, SPREP Meteorology and Climatology Adviser, Salesa Nihmei said taking note of the advice from national meteorological services is recommended. 

“People can best prepare for such an event by taking the advice from national meteorological services seriously," Mr. Nihmei said. 

"This is a slow onset climate event, which brings risks to the community. Sectors need to communicate with national meteorological services on how best they can prepare for such events.

"There is the risk of water borne diseases, placing a burden on health systems. On the other hand, there are communities in the Pacific who are facing drier than normal conditions and are facing drought and shortage of water such as PNG Islands, Kiribati and Tuvalu. 

"There is a great risk of damage to infrastructure, crops and livestock as well as food security. These impacts coupled with higher temperatures and sea level associated with climate change means people will struggle to make end meets."

Australia Bureau of Meteorology (BoM) COSPPac Technical Science Lead, Dr. Simon McGree, expressed similar sentiments and urged Pacific communities to take heed of the correct information and warnings from their national meteorological services as the climate event sets in affecting weather patterns in the region.

“A La Niña has been declared and is underway according to WMO and the WMO Pacific RCC-N Node for Long-Range Forecasting members, specifically the United States National Oceanic and Atmospheric Administration (NOAA), the Australia Bureau of Meteorology (BoM), New Zealand National institute of Water and Atmospheric Research (NIWA) and Republic of Korea APEC Climate Centre (APCC),” said Dr. McGree.

"La Niña is a normal part of our climate system. El Niño and La Niña events swing back and forth every three to seven years on average but recently we have seen a series three La Niña events, which is very unusual.”

The WMO Pacific Regional Climate Centre Network (RCC-N) said best for form of protection is to stay vigilant and be prepared and being in touch with national meteorological services is critical.

“People need to contact their national meteorological services for latest information on the La Niña event and get in touch with sector leaders on how well they can prepare before, during and after a La Niña. 

"Don't act on information from social media unless this is from national meteorological services or another reliable source. 

"A key message from us is the importance of having the communities and sectors work closely with national meteorological services to use information for decision-making. We encourage them to know your risk, know your action.”

The national meteorological services community in the Pacific together with Pacific RCC-N nodes will further discuss the triple dip La Niña event during the upcoming Pacific Island Climate Outlook Forum on 25 October 2022.

The first triple-dip la Nina since 1950 and the first of this century, according to the WMO, is expected to bring excessive rainfall to some parts of the Pacific which could cause flooding impacting agriculture, aviation, infrastructure, health, water and indirectly affect other sectors.

The onset the triple-dip La Niña adds to the challenges already faced by Pacific communities struggling with ongoing impacts from the previous La Niña. Many of them will also be directly impacted by a La Niña influenced South Pacific cyclone season up ahead. 

Climate models show a general cooling to La Niña thresholds (−0.8 °C) by October, and peak towards end of 2022. Most models indicate a return to ENSO-neutral conditions in early 2023, indicating a relatively short-lived event, though model accuracy reduces at longer-lead times.

By Alexander Rheeney 20 September 2022, 7:09PM
Samoa Observer

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