New Zealand could experience an increase in landslides – its most deadly natural hazard – as global warming triggers more intense and frequent storms, experts have warned in the wake of two landslide tragedies in the North Island.
New Zealand’s landscapes are scarred with the evidence of landslides – they are responsible for more than 1,800 deaths since written records began – more than earthquakes and volcanoes combined.
In January, a series of tropical storms swept through the North Island, bringing torrential rain and causing two fatal landslides. On Thursday morning, a landslide crashed into a holiday park, in Mount Maunganui in the eastern city of Tauranga, burying six people. Authorities have confirmed they are unlikely to be alive. Earlier that morning, another landslide tore through a house south of the city, killing two.
On Wednesday, Tauranga city council evacuated 150 people from 30 homes in to assess a new slip posing a “risk to life”.
As it grapples with the tragedies, questions have emerged over how the country can better protect itself from landslides and the increasingly extreme weather that can trigger them.
New Zealand sits on a tectonic boundary, which pushes up land and creates slopes, and has a maritime climate with high rainfall – factors, which combined, make it prone to landslides.
Humans are also responsible for reshaping the landscape including through deforestation, and cutting into slopes for transport and housing, says Martin Brook, professor of applied geology at the University of Auckland.
“Land use change has been so profound, that we just aren’t resilient,” he said, adding that while mapping landslide susceptibility in regions had increased, the next step would be using that data to better inform planning decisions.
Global warming, meanwhile, is already intensifying tropical storms that can set off landslides, said Dr Thomas Robinson, senior lecturer in disaster risk and resilience, specialising in landslides, at the University of Canterbury.
“The more we have intense storms, the more frequently they occur, the more landslides we’re going to have, and then the more impacts we’re going to experience,” he said.
Storms in recent years have wreaked havoc across New Zealand. In 2023, roughly 800,000 landslides were caused by Cyclone Gabrielle, making it one of the most extreme landslide-triggering events ever recorded globally, according to Earth Sciences New Zealand.
“The losses and the impacts are increasing,” Robinson said. “We need to have a really serious conversation nationally and internationally about how we’re going to manage the risks we’re faced with.”
Professor of climate science at Victoria University of Wellington, James Renwick, said, increasingly, storms were causing “devastation and misery” to the country.
“To stop such events becoming worse, to stop them overwhelming our abilities to adapt, we must stop adding carbon dioxide and other greenhouse gases to the air,” he said, adding government and business leaders had to find ways to decarbonise the economy as soon as possible.
Politicians have traded accusations in recent days over the coalition government’s climate change policy, which includes slashing targets for reducing emissions, and its decision to scrap a Labour government-era NZ$6bn resilience fund for communities, set up in the aftermath of Cyclone Gabrielle.
The government had “dragged their heels on issues around climate change”, Labour leader Chris Hipkins told media on Tuesday.
“Almost every major action New Zealand was taking to really tackle the challenge of climate change has been wound back under [the government’s] leadership.”
Finance minister, Nicola Willis accused Hipkins of politicising the tragedy and said the government had made “significant allocations of funding towards infrastructure, flood resilience [and] roading repair … needed to respond to the effects of climate change”.
Hipkins responded that the broader debate around climate change was “legitimate”.
Meanwhile, the Tauranga city council has ordered a local inquiry into the Mount Maunganui event, while prime minister Christopher Luxon is seeking advice on a government inquiry, after questions emerged over whether local authorities could have done more to prevent the deaths.
Members of the public say they alerted emergency services to the potential threat before the landslide occurred, while others have pointed out the mountain’s history of landslides.
Despite the dangers landslides pose, they “don’t stick in our psyche” in the same way earthquakes might, said Robinson. The latest tragedies may go some way to shifting that mindset, he said.
“If anything good can come out of this, then having a better and broader understanding of landslide risk and how to prepare for them is a positive.”
