The higher temperatures came with increased rainfall, marine heatwaves, and sea level rise, says a report from the World Meteorological Organisation.
Many of these changes impacted NZ, which also had below-average amounts of snow on South Island mountains. Last year, the warmest NZ spring on record contributed to the Tongariro National Park wildfires, the report notes.
The SMC asked experts to comment.
Professor Sandra Morrison (Ngāti Rārua; Ngāti Maniapoto; Ngāti Whakaue), Faculty of Māori and Indigenous Studies, University of Waikato, comments:
“The release of the WMO report on the State of the Climate in South-West Pacific 2025 carries sobering messages of the impact of climate change and extreme weather disruption.
“With a region that is a mix of larger, mountainous continental islands and oceanic islands ranging from volcanic peaks to low-lying coral atolls, it is a complex region with its diverse marine and island ecosystems, tropical to temperate climates, and deep ocean circulation patterns that directly influence weather systems like El Niño
and tropical cyclones.
“Three key messages from the report state that first, 2025 was the second-warmest year on record in the South-West Pacific region, at 0.37 °C above the 1991–2020 average. Second, that the average sea-surface temperature for the region was the second highest on record, slightly below the record set in 2024. And third, that sea level continued to rise across the South-West Pacific, affecting coastal communities and low-lying island nations. While these drivers are not new, we know that any increase in temperatures will have devastating impacts on the environment and people alike which this report outlines with significant detailed evidence.
“The purpose of the WMO is not only to report and exchange data but also to help the public understand it. The case studies referenced therefore give real world examples of the drivers of climate change in the South-West Pacific, the impacts on environmental and human systems and a helpful guide of lessons learnt. Such
lessons point to investment in systems that give early warnings to enable planning for predicted weather events, the power of collaboration across stakeholder groups and ensuring good relationships with the users of the data.
“One criticism that I would make would be the need to ensure the inclusion of Indigenous knowledges in a region that has significant Indigenous populations. Indigenous populations are working alongside scientists in creating long term sustainable adaptation strategies which has critical benefits for all populations.”
Conflict of interest statement: “Professor Sandy Morrison is the Coordinating Lead Author, Intergovernmental Panel on Climate Change (Assessment Report 7 WGII Australasia chapter); a member of the Science Committee, WASP (World Adaptation Science programme) and a Steering Group member of the Antarctic Science Platform.”
James Renwick, Professor of Climate Science & Physical Geography, Victoria University of Wellington | Te Herenga Waka, comments:
“The State of the Climate in the Pacific is a very welcome publication from the World Meteorological Organization, as the tropical South-West Pacific is usually poorly-represented in published material about the climate and how it is changing. We see human-induced warming here as we do globally. I am sorry to know the last tropical glacier in the mountains of Papua New Guinea is expected to be gone in the coming year, a permanent change to the landscape. Glacier loss carries on apace here in New Zealand as well, 42% of ice gone between 2005 and 2023, with snow accumulations generally down.
“New Zealand had its warmest spring on record in 2025, contributing strongly to ice loss and to the massive fire in Tongariro National Park. All of the effects of climate change are being felt strongly across the SW Pacific – warming, sea level rise, ocean acidification, intensifying tropical cyclones, marine heatwaves. The only way to combat increases in extremes and the loss of ice & snow is to reduce emissions of greenhouse gases, but there’s little sign of that yet.
“The prolonged La Niña clearly influenced tropical climate across the Pacific last year. This year’s ‘super’ El Niño is bound to bring stresses, dry conditions in the west and much wetter conditions in the central and eastern Pacific, all pumped up by climate change.”
Conflict of interest statement: “I receive funding from the New Zealand government for climate research.”
Associate Professor Daniel Kingston, School of Geography | Te Iho Whenua, University of Otago | Ōtākou Whakaihu Waka, comments:
“The WMO retrospective on climate in the southwest Pacific region for 2025 treads similar ground to previous reports, while also containing some interesting (and alarming) statistics.
“As for the world as a whole, 2025 was the second warmest on record in the southwest Pacific. The world continues to hover around the 1.5 °C warming threshold that has been linked to dangerous climate change impacts.
“What’s notable in this case is that this warmth has occurred despite the presence of a La Niña event – which often acts to reduce overall temperatures in the southwest Pacific. 2025 was actually the warmest year that has occurred in this region without the presence of El Niño conditions – noteworthy in light of the El Niño event this is just beginning to unfold now.
“The report devotes some attention to the impacts of this warmth on snow and ice. The remaining tropical glaciers in this region (in New Guinea) are likely to completely disappear either this year or next, while the report notes that glacier volume in New Zealand has decreased by 42% between 2005 and 2023.
“Details about various marine heatwaves (MHW) are also included. Although 2025 was not a record year for overall MHW extent, recent increases are dramatic: most of the past 10 years have had more than double the coverage of MHW compared to the 1990s and early 2000s.”
Conflict of interest statement: “No conflicts of interest.”
Associate Professor Heather Purdie, School of Earth & Environment, University of Canterbury, comments:
“For those of us who work on snow and ice, the most recent State of the Climate Report for the South West Pacific by the World Meteorological Organisation, sadly, held no surprises.
“I have been monitoring glaciers in the mountains of Aotearoa New Zealand for more than two decades, watching and recording our ice volume shrinking away. We have already lost around 300 glaciers and more will follow, with a reported 42% decrease in glacier volume between 2005 and 2023.
“Glaciers are nourished by snowfall during the colder months, but increasingly we are seeing changes to snowfall patterns. As temperatures continue to rise, snow is arriving later and winter snowpacks are thinning. Even though our mountains generally receive significant snow fall in spring, these late top-ups are not enough to turn the tide on glacier loss.
“However, this year, strong El Niño conditions are developing in the Pacific, and while many eastern areas tend to be drier during El Niño, our glacier regions can experience increased precipitation and lower melt rates. But we will have to wait until the end of this coming summer to see how the glaciers have fared.”
Conflict of interest statement: “No conflicts of interest to declare.”
Professor Karin Bryan, School of Environment and Institute of Marine Science, University of Auckland, comments:
“The State of the Climate report confirms what our local researchers are finding. I think the most concerning of all the indicators they review, is the steady creep upward of the ocean temperature. The viability of organisms and ecosystems is critically linked to temperature, and here we are seeing extremes become more of an everyday phenomenon. Many species are already under threat due to direct anthropogenic effects such as runoff, fishing and habitat change, and do not have the resilience any more to deal with this additional threat.”
Conflict of interest statement: “I have research programmes on the coastal ocean funded by Marsden and MBIE.”