Increasing landslide susceptibility and intensity under climate change for Aotearoa New Zealand

Extreme weather events like tropical cyclones can trigger large numbers of landslides across vast areas due to extreme rainfall. Cyclone Gabrielle in February 2023 triggered ~ 800,000 landslides across the North Island of New Zealand and is one of the most extreme landslide-triggering storms recorded to date. While climate change is expected to increase the intensity of future tropical cyclones, whether this translates into increased landslide numbers from extratropical cyclonic movement towards the New Zealand landmass remains contentious. Here we show that under a + 2 °C warming scenario, a Cyclone Gabrielle-like storm could trigger up to ~ 90,000 more landslides than the 2023 event, while the area experiencing extreme landslide densities might increase by up to 34%. Our findings suggest significant increases in landslide hazards due to climate change, providing an essential evidence base for land-use planning and targeted mitigation efforts in locations where landslide hazards are projected to intensify.