Ocean life, coastal homes, and kaimoana around our island nation are being impacted by the changing climate, a new report shows.
Our Marine Environment 2025, produced by The Ministry for the Environment and Stats NZ, highlights how climate change and human activity are putting increasing pressure on our coasts and the ocean.
The Science Media Centre asked experts to comment.
Dr Craig Stevens, Professor of Physics, University of Auckland & Earth Sciences New Zealand, comments:
“This report makes for challenging reading. Being an island nation, we need to take a very strong interest in how the oceans around us are changing with the climate.
“The report does a good job at synthesizing the latest regional ocean data and science and contextualises it in a wider community setting. This won’t have been easy as there are many information channels, and these are not particularly coordinated. The MfE team have done well to collate and structure some key messages from this spread of sources. In a sense, though, the summary is only scratching the surface. This is because we have very little ocean observing infrastructure and have to rely on satellite data and deep ocean buoys or sporadic sampling activity. This leaves major gaps in what and how we measure – and clearly, we can’t assume these global data products will always be available in the future.
“Thinking about our future moana, I can’t help but look to the west. I grew up in South Australia and it is currently struggling with a major harmful algal bloom driven in part by warming oceans – but also likely due to excessive nutrients coming off the land plus some large-scale ocean effects. This is rapidly demonstrating the wider value of the oceans beyond the intrinsic environmental values. Not only aquaculture and fisheries are affected, but entire coastal economies are in jeopardy. The science and decision-making teams there have been able to understand and recommend responses to the situation relatively quickly thanks to long term monitoring and reasonable research capacity.
“There are challenges though. The MfE team need to be better resourced to develop stronger infographics for decision makers. Of course, this requires consistent data. Talking about streamlined, efficient, strategic, connected and inclusive evidence reporting processes is correct – but this requires actual data. The reality is our ocean environmental observing systems and capabilities have never been in great shape – as repeatedly identified by the Parliamentary Commissioner for the Environment. Recent ocean-focused Endeavour funding on topics like impacts of a warming ocean, marine carbon and seafloor disturbance will help, but these will only be in the form of individual surveys and not ongoing monitoring of our changing ocean. An island nation needs more than this.”
Conflict of interest statement: “I was on the interim CE science advisory panel (2022-25) for the MfE and was also an independent reviewer for the document. I am also involved in the Te Moana Mahana project. These comments are my personal views.”
Dr Kathryn Stokes, senior materials scientist at BRANZ (Building Research Association of New Zealand), comments:
“This report shows a marked increase in the number of homes at risk of sea-level rise – from about 49,700 in 2022 to over 219,000 homes today. This highlights the increasing risks coming with climate change.
“Kiwis love houses with views or close to the ocean – but if you’re thinking about buying or building in areas of sea-level rise, it’s worth taking time to consider what the future might look like. A home is a major investment, and in high-risk areas, insurance could become harder to get. Maintenance costs can also rise – things like corrosion for some materials or needing retaining walls to protect against erosion.
“BRANZ’s Climate Resilience – Building Back Better researchers are now working with our collaborators to publish evidence-based, practical guidance – to help New Zealanders better prepare for and recover from flooding and other natural hazards. Our goal is to help New Zealand build smarter and reduce the risks to our homes.”
No conflict of interest.
Dr Pete Wilson, Principal Consultant – Ecology & Marine Science, SLR Consulting, comments:
“This is my second year advising on the Our Marine Environment report, and this year’s focus is a little different. Instead of looking broadly at the impacts from human activities, the 2025 report focuses on the impacts of climate change.
“Human activities at sea and on land still affect our marine environment, but climate change amplifies these pressures. Rising temperatures, ocean acidification, and sea-level rise are compounding existing challenges for ecosystems and coastal communities.
“The report highlights the critical role of coastal habitats. Wetlands, mangroves, dunes and estuaries don’t just support biodiversity, they act as natural buffers against flooding and erosion, helping protect communities as climate risks grow.
“We know a lot about our marine environment, but it’s incredibly complex. This report concludes with identifying key knowledge gaps where better data and monitoring could make the biggest difference for decisions and outcomes. This includes understanding how multiple pressures affect our environment, understanding and valuing our key coastal habitats, and ensuring we’re monitoring the right things and gathering information from the right places – integrating knowledge from multiple sources.”
Conflict of interest statement: “I was engaged as a Senior Science Advisor during the preparation of Our Marine Environment 2025.”
Dr Carolyn Lundquist, Principal Scientist, Marine Ecology, Earth Sciences New Zealand (formerly NIWA); and Associate Professor, School of Environment, The University of Auckland, comments:
“The 3 yearly update on the state of the marine environment highlights the benefits of ongoing investment in long-term monitoring and environmental research in marine ecosystems to document current trends in environmental and climate indicators, and their impacts on biodiversity and ecosystems. Monitoring data also allows evaluation of whether our actions are working to successfully reduce degradation of our marine ecosystems. The report also highlights the importance of mātauranga Māori and tikanga Māori in marine monitoring to inform a more inclusive understanding of changes in our marine ecosystems.
“Recent national datasets highlight that Aotearoa is not tracking with global averages; for example, temperature and heatwaves are increasing at a much higher rate here. The report provides strategic priorities for ensuring Aotearoa’s monitoring and reporting is robust and can prepare us for future change.
“The report also highlights that negative impacts on ocean health affect not just our native biodiversity, but also our economy, and our health and wellbeing. Healthy marine ecosystems are needed to support social, cultural and economic resilience.”
Conflict of interest statement: “I was engaged as a science advisor of the Our Marine Environment report.”
Dr Shane Geange, Principal Advisor Marine, Te Papa Atawhai Department of Conservation, comments:
“This report gives us the most up-to-date look at how climate change and human activities are affecting New Zealand’s oceans and coastlines. The main points from this report are important—not just for managing sea life and habitats, but for our terrestrial ecosystems and all New Zealanders.
“Our Marine Environment 2025 highlights that climate change is making existing problems in our oceans even worse. For example, global warming has made New Zealand’s sea temperatures rise much faster than the worldwide average. This means we’re seeing more frequent and severe marine heatwaves. Sea level is rising more quickly, and our oceans are becoming more acidic and losing oxygen. These changes, combined with other pressures like sedimentation from land activities, pollution, overfishing, and invasive species, are causing bigger problems than any single pressure by itself and reshaping our marine environments.
“Because of these findings, how we manage New Zealand’s marine environment needs to change. We can’t just focus on managing one species at a time or small, isolated areas. Instead, we need to consider climate change and all the different pressures our marine environment is facing at once, for example through ecosystem-based management approaches. We now have enough evidence to take action, and delaying risks further harm to our marine ecosystems.”
Conflict of interest statement: “I am employed by the Department of Conservation and was engaged as a senior science advisor for the Our Marine Environment 2025 report.”