Study shows Pacific nations 'sandwiched' between storm bands
Storm clouds rolling into Wellington on 12 August, 2024.
Photo:
Supplied / James Bass
A climate scientist has discovered that two specific bands of the globe are warming faster than elsewhere.
Auckland University's Dr Kevin Trenberth led a study examining where heat - captured by the ocean - travels and accumulates.
The first band - at 40 to 45 degrees latitude south - is heating at the world's fastest pace, with the effect especially pronounced around New Zealand, Tasmania, and Atlantic waters east of Argentina.
The second band is around 40 degrees north, with the biggest effects in waters east of the United States in the North Atlantic and east of Japan in the North Pacific.
Dr Trenberth said it could be why storms that track to New Zealand - from an area warming at a slower rate - seem to strengthen once they get there.
He said it's "striking" and "unusual" to see such a distinctive pattern.
"It turns out there are changes in ocean currents going on, coupled with changes in the atmospheric circulation - changes in the jet stream - and where all of the storm tracks are going."
The heat bands have developed since 2005 in tandem with poleward shifts in the jet stream (powerful winds above the Earth's surface that blow from west to east) and corresponding shifts in ocean currents, according to Trenberth and his co-authors in the
Journal of Climate
.
Trenberth said most Pacific Island nations fall within the subtropics, which are "still quite warm" but heating at a slower rate.
But they are effectively sandwiched between the two bands where harsher storms form more frequently.
In areas which are warmer, Dr Trenberth said that stronger storms with heavier rainfall are fuelled as they pick up more moisture, taking heat out of the ocean, and sending off along their track.
"No doubt the heat will come back into these regions, because of the way in which the winds are changing in the atmosphere."
For New Zealand and its neighbours, Dr Trenberth said that these findings could help explain why each new year breaks heat records.
"It comes back to what is really going on in the oceans," he said.
"They have now warmed up so that they are major players in the global warming picture."
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
RNZ News
9 hours ago
- RNZ News
Road closures for parts of State Highway 8 and State Highway 80 due to snowfall
State Highway 8 between Twizel and Fairlie and State Highway 80 between Lake Pukaki and Aoraki/Mt Cook will be closed to motorists because of extremely icy conditions. Photo: Supplied / New Zealand Transport Agency Two areas of state highway in the Mackenzie Country will be closed again on Saturday night due to dangerous driving conditions caused by snowfall. New Zealand Transport Agency (NZTA) said State Highway 8 between Twizel and Fairlie and State Highway 80 between Lake Pukaki and Aoraki/Mt Cook would be closed to motorists because of extremely icy conditions caused by snow flurries, snow melt and freezing temperatures. Crews would be working on the roads, breaking up ice and spreading grit, NZTA said. A decision would be made in the morning about when the roads would open again. On Friday night, motorists were stranded in Lindis Pass when sections of SH8 became blocked by snowfall, prompting a rescue mission. Firefighters were called as a polar blast struck Canterbury and Otago, dumping up to a metre in some areas. The occupants of five cars and a couple of trucks had to abandon their vehicles and were taken to Tekapo for the night, with specialist Fire and Emergency vehicles being used to extract the vehicles. The motorists were reunited with their vehicles Saturday morning. Elsewhere, SH73 from Otira to Springfield (Arthur's Pass and Porters Pass) and SH85 from Kyeburn to Palmerston were both re-opened earlier on Saturday. A slip at Gorge Stream on SH7 was now clear, meaning the highway from Hanmer Springs to Springs Junction had been re-opened. State Highway 87 between Mosgiel and Kyeburn was also open. Fears of an extreme cold snap did not eventuate, despite chilly temperatures around the motu. The country went into the latter part of the week with almost two dozen weather warnings in place, but rain eased on Friday in Tāupo and the Bay of Plenty, and the South Island avoided heavy snowfall. On Saturday, a strong wind watch was issued for the Chatham Islands through to Sunday due to a nearby deep low, bringing northerly gales. MetService meteorologist Sylvia Martino told RNZ Dunedin Airport and Takapō took out the chilliest spots, at minus five overnight, while Christchurch dropped to minus one. Sign up for Ngā Pitopito Kōrero , a daily newsletter curated by our editors and delivered straight to your inbox every weekday.
RNZ News
18 hours ago
- RNZ News
Farmers risk being cut off as bridge funding dries up
The Wharekiri Stream can be impassable in a flood. Photo: Supplied / Shirley Millard Clarence Valley farmers have been left high and dry following a decision not to extend a funding deadline for replacing a quake-damaged bridge north of Kaikōura. Waka Kotahi - the New Zealand Transport Agency (NZTA) - has informed the Kaikōura District Council it will not extend the 30 June sunset clause or offering additional funding for a replacement for the Glen Alton Bridge on Waiau Toa Clarence River, which was destroyed in the 7.8 magnitude earthquake in 2016. Property owners now face an uncertain future, without year-round, all weather access to the valley. Steve and Shirley Millard have been farming in the valley for 13 years, with Mrs Millard commuting to work in Kaikōura. ''It should have been done way before now,'' Steve said. ''They said they are looking at other options, but I can't see many.'' The Clarence Valley is home to several properties, including forestry blocks, large hill country properties and Department of Conservation land. For now access in and out is via Waipapa Road, Wharekiri Stream and a paper road through several properties. But the Wharekiri Stream is prone to flooding in heavy rain events and can be impassable for up to two weeks. Access is by four-wheel-drive only. Kaikōura District Council chief executive Will Doughty said NZTA's decision is a major setback and left the council with few options. ''The project has had a number of complex issues and stakeholder challenges that, despite best efforts, council has not been able to fully overcome.'' The remains of the Glen Alton bridge in the Clarence Valley, north of Kaikōura. Photo: Supplied / Kaikōura District Council The NZTA board approved emergency works funding of $12.6 million from the National Land Transport Programme in 2019 to replace bridge - a 95 percent subsidy, but the project has been beset by challenges. The council initially applied to Environment Canterbury (ECan) for a resource consent to build a $13.5m bridge, 500 metres upstream from the previous bridge. But this was opposed by Te Rūnanga o Kaikōura on cultural grounds. Last year, the council asked its contractor, Contract Structures Ltd, to provide a cost estimate for building a bridge at the original site. Going to the original site will require the council to acquire land for an access road to the new bridge, a process expected to take up to 18 month. The council will leave the local share funding of around $500,000 in the 2025/26 annual plan budget while the next steps are considered, Doughty said. NZTA regional manager central and lower South Island Peter Brown said the agency advised the council in December its application for an extension would likely be declined unless it could provide evidence by 28 February the challenges it faced could be overcome. ''Despite some progress being made on key issues, there remained significant ongoing risks and a lack of a clear path forward.'' The NZTA board met last month and declined an extension and a funding increase to $16.5m. ''We understand there will be disappointment over this decision for Clarence Valley residents,'' Brown said. ''The prolonged delays and unresolved issues make continued investment in this project untenable.'' Brown said NZTA will continue to work with the council to explore what options are available. LDR is local body journalism co-funded by RNZ and NZ On Air. Sign up for Ngā Pitopito Kōrero , a daily newsletter curated by our editors and delivered straight to your inbox every weekday.
RNZ News
19 hours ago
- RNZ News
Unmanned military tech: Julia Macdonald
'The Hand Behind Unmanned' by Jacquelyn Schneider and Julia Macdonald. Photo: Supplied Mines, guided missiles, satellites and more recently drones, are just some of the military tech that have been developed over the last few hundred years. A new book 'The Hand Behind Unmanned' explores the factors and beliefs that led to the contemporary American arsenal and asks where it's headed in the future. Julia Macdonald is the co-author of the book, as well as the Director of Research and Engagement at the Asia New Zealand Foundation, and a Research Professor at the University of Denver. She's also held positions at the RAND Corporation, in Aotearoa at the Ministry of Defence, and Department of the Prime Minister and Cabinet where she led development of New Zealand's first National Security Strategy. Julia speaks with Susie Ferguson.
