The World Meteorological Organisation has confirmed 2025 as the second or third hottest year on record, and 2015-2025 as the hottest 11 years.
Their annual climate report also points out plummeting glacier and sea ice, rising sea levels, and increasing ocean heat and acidity.
The Science Media Centre asked experts to comment.
Associate Professor Daniel Kingston, School of Geography|Te Iho Whenua, University of Otago|Ōtākou Whakaihu Waka, comments:
“A report that further confirms that global temperatures have increased is not particularly surprising. Climate scientists have been giving similar messages about global warming for decades now. However, these messages get more and more stark each time, and records continue to be broken.
“Some of the more startling details of global climate in 2025 include:
- The past 11 years are the 11 hottest years in the instrumental record.
- 2025 was the second or third warmest year on record (depending on data set used) – despite the occurrence of a La Niña event, which typically depresses global temperatures.
- Energy is accumulating in the Earth system. Although the atmosphere is clearly warming, only 1% of this excess energy is stored in the atmosphere. Over 90% has been absorbed by the planet’s oceans – and they are warming accordingly. Because oceans respond much slower to energy input compared to the atmosphere, these changes will persist for hundreds (and maybe thousands) of years, even in the case of emission reductions.
“Although this report is not written to provide policy advice, the evidence is clear that human action is increasingly destabilizing our climate. With each year that passes without more concerted action on emission reductions, we add to the problems that future generations will face. With the timing of this report coinciding with the ongoing troubles in the Middle East and rapid rises in oil prices, how much more evidence do we need to push individuals, communities and governments to accelerate our transition away from fossil fuels?”
Conflict of interest statement: “No conflicts of interest.”
Dr Lauren Vargo, climate scientist & glaciologist, Victoria University of Wellington, comments:
“This report continues to confirm what climate scientists have been warning about for decades: as greenhouse gases build up in the atmosphere, the planet is warming. While slightly warmer weather might sound pleasant to some of us in New Zealand, the overall costs and risks hugely outweigh any benefits.
“Warmer ocean temperatures together with melting ice is driving sea level rise, now at a rate of almost 5 mm per year (global average). But what concerns me the most is the increase in frequency and intensity of extreme weather and climate events (e.g. flooding, heatwaves, wildfires). These events destroy ecosystems and infrastructure, and impact human health and livelihoods, making them costly both financially and to society.
“One of the report’s indicators is glacier mass balance (the gain or loss of ice each year). Data show that eight of the ten largest mass loss years have occurred since 2016. These measurements come from ~170 glaciers worldwide, including two here in New Zealand. Glaciers are more than just climate indicators. The nearly 3,000 glaciers in Aotearoa are important taonga and are important for tourism, and their melt may impact freshwater resources and increase hazard risks.”
Conflict of interest statement: “No conflict of interest.”
James Renwick, Professor of Climate Science, Victoria University of Wellington, comments:
““Every key climate indicator is flashing red” said the U.N. Secretary General António Guterres. Exactly. The warmest years on record are the ones we’re in right now, all aspects of the climate system are warming, and all the cold bits are melting. This is all because an increase in atmospheric greenhouse gases is changing the earth’s energy budget, we now have more energy coming in than going out. Increased warming goes with increased extreme events, that have consequences for communities everywhere. As is documented in the latest WMO State of the Climate report, the global community is collectively eating away at our life support system.
“The science of climate change has been well understood for a century or more and we know what we have to do to stop it. Stop burning fossil fuels. Policymakers have been advised on this for decades, yet emissions of carbon dioxide and other greenhouse gases keep increasing. I hope this latest report moves the dial with the policymaking community and encourages action to reduce emissions. The costs of inaction are already astronomical, lets not make them overwhelming.”
Conflict of interest statement: No declaration received.
Drew Bingham, Principal Science Advisor, Department of Conservation, comments:
“The WMO Global Climate Report highlights the pressing need to do what we can to prepare our species and ecosystems, visitor experiences, and cultural heritage sites for the impacts they’re already facing from climate change. The report’s finding that the past 11 years were the warmest 11 years in the 176-year record underlines the urgency to build resilience now and plan for increased impacts down the line as climate change continues to intensify.
“More than 4000 of Aotearoa New Zealand’s native species are threatened with extinction or are at risk of becoming threatened. Climate change impacts – the increasingly frequent severe storms and floods, droughts, and increased fire risk – are putting many of our taonga species under even more pressure. DOC’s visitor infrastructure is already being affected and more than 400 archaeological sites and 300 of DOC’s coastal assets including campgrounds and bridges are at risk from rising sea levels and coastal flooding.
“At DOC we’re taking action, for example, by building shelters for tarapirohe/black-fronted tern chicks at risk from extreme temperatures. These low-cost shelters have successfully protected fledgling chicks from temperatures over 40 degrees at their Canterbury braided river habitat. New bridges on the Heaphy Track (to replace ones that were damaged by floods) were designed to be resilient to future climate change-driven floods.
“As the record-hot climate documented in the WMO report becomes increasingly normal, DOC’s climate change adaption action plan will help to prepare for climate change risks. The report reinforces the urgency to build on our adaptation work, and highlights that adaptation is no longer optional or nice-to-have.”
Conflict of interest statement: No declaration received.