Strained infrastructure identified as NZ’s earliest climate threat
Thursday, 7 May 2026
The earliest, “extreme” effect New Zealand experiences from climate change is likely to be damage to already strained water infrastructure, the Climate Change Commission has warned in a report it is required to produce every six years on climate risks.
The commission also cautioned it was keeping a closer watch on threats to horticulture, and agricultural production more generally, in addition to more obvious risks such as damage to houses and roads from floods and rising sea levels.
The National Climate Change Risk Assessment, which looks out as far as 2090, forecast the risk of damage to drinking and wastewater infrastructure would become extreme within 25 years, if that wasn’t addressed.
That could mean “more service interruptions, boil water notices, or burst pipes, with flow-on risks to rivers and beaches, lost productivity for businesses and communities, and public health implications”, it said.
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“Some communities could even face the eventual withdrawal of services.”
Drinking water pipes were exposed to river and surface flooding, and drinking water supplies face increasing stress from drought, declining water quality, and higher temperatures, it said.
“Rising seas, coastal flooding and more frequent and intense rainfall events threaten wastewater and stormwater networks.”
The report did not directly refer to the risk the Atlantic Meridional Overturning Circulation (AMOC) ocean current system — which includes the Gulf Stream — could weaken to the point of collapse within the forecast period.
Recent academic studies have heightened that fear, with some asserting a collapse is now likely.
Studies suggest an AMOC collapse would result in rapid, catastrophic changes to the climate and society of Europe — driven by a 5 to 15 degree temperature drop — with lesser but still significant knock-on effects potentially reaching New Zealand in the form of additional warming and a further sea-level rise.
Research by Victoria University in 2024 concluded that past changes in AMOC had a significant impact on temperatures in New Zealand and across the southern hemisphere.
The commission did, however, refer to the risk of “tipping points” in the natural environment.
“There are thresholds when change can reach a level where a species, or a whole ecosystem, cannot manage further change, when it is no longer resilient,” the commission said.
“From around the middle of the century, under a high climate impact scenario, the combined effects of pests, damaged habitats, and climate change could push some ecosystems past a point where they can no longer recover.”
While it was “clear climate change increases the likelihood of passing tipping points where ecosystems collapse”, where that point lay was not always clear, it added.
The report said the entire country would be at risk of more extreme rainfall.
About 556,000 buildings that would cost $235 billion to replace and about a quarter of roads and more than a third of rail lines were already at risk of flooding, it said.
But it also warned that between 40% and 87% of farmland would become “markedly drier” by 2050, depending on the extent of global warming.
“Exposure to coastal inundation is projected to rise to 51,700 people by 2050 in a high-climate impact scenario and then is projected to nearly double to 94,300 people in 2090.”
Most buildings in New Zealand were not designed with high temperatures in mind and could become at times “unliveable, posing acute health risks”, it said.
The chief executive of the commission, Jo Hendy, said the country faced “serious and far-reaching climate risks that affect every part of our lives – our homes and infrastructure, our economy, our environment, our health, and our communities”.
The current policy response to almost all climate risks either had significant gaps or was simply insufficient, the commission reported.
Despite that, commission chairperson Dame Patsy Reddy struck an optimistic note in a foreword to the report, saying that with clear, evidence-based advice, New Zealand could “move from reacting to events to planning and adapting with confidence”.
“If we act deliberately now, we can leave a more resilient, more stable future,” she said.
Climate Change Minister Simon Watts said the Government would carefully consider the commission’s findings as it developed New Zealand’s next National Adaptation Plan over the next two years.
Otago University Professor Ross Thompson, an expert in freshwater science, said the emphasis the commission had put on water infrastructure was sensible.
“More extreme climatic events are just exceeding the design thresholds of our stormwater infrastructure.”
People might assume from recent failures, such as the Wellington sewage leak, that was already compromised and they might therefore be complacent about added risks from climate change, he agreed.
“The risk of climate change is increased-frequency events. The worst case scenario is that we get properties that become uninsurable.
The infrastructure problem was fixable, he said. “The concern for me is the report highlights that we're not making adequate progress even though we’re aware of the risks, so I think it is a bit of a call to arms.”
Thompson said there was genuine reason to be concerned about “global scale phenomena” such as the potential collapse of the AMOC system.
“The reality for New Zealand is it’s very difficult for us to do anything in the short to intermediate term around managing that risk, so I think the report has rightly focused on manageable risk.”