Experts warn of deadly damage for coastal properties if climate change is not mitigated

  • 21/02/2023

Experts are warning of further damage to coastal properties if climate change is not mitigated.

Professor of Geology at Wellington University, James Renwick says the recent Muriwai disaster was a 'climate change wake-up call.'

Muriwai was one of many regions in New Zealand to be hit by Cyclone Gabrielle. Around 200 people were evacuated from the coastal community after a huge slip was caused by the torrential rain. 

Firefighters Dave van Zwanenberg and Craig Stevens died after being crushed by the slip while attending a flooded house. Renwick said the country has had a 'clear wake-up call' about climate change.

He said that extreme events, especially extreme high rainfall and coastal inundation, will only become more intense in future as the climate continues to warm.

"If people build back on sites that were damaged this week, they expose themselves to increasing risk," he warned.

Renwick said conversations need to happen across the country about exposure to hazards and decisions on who is prepared to pay when disaster strikes again.

"We need to do this, as rapidly as possible, before the effects of climate change become unmanageable," he said.

Renwick reiterated there is only one way to manage climate change.

"Stop burning fossil fuels and stop emitting greenhouse gases, especially carbon dioxide," he said.

Renwick said humanity is driving the problem, and has the choice to stop it.

"We just need to find ways to move away from fossil fuels - as fast as possible," he said.

Renwick said to protect one another, people need to adapt to climate changes that have already happened.

"The effects of flooding, of coastal erosion, of droughts and heatwaves, but crucially, we also need to mitigate - to reduce emissions of greenhouse gases to zero," he said.

And climate change isn't the only concern, questions are being raised on why people are building in areas with a history of deadly slips.

University of Auckland geology Professor Martin Brook told Newshub it was not the first time Muriwai has been affected.  

"It's tragic, particularly given the rainfall-triggered landslide deaths there in 1965," he said, where Isobel Crane and 18-year-old daughter Margaret Crane were both killed in a fatal slip.

Brook said there are two main reasons people continue to live in hazardous areas, "people who think 'it will never happen to me', and others who may not have full knowledge of site issues."

He said to prevent houses being built on damaged land, people need to reflect on what has happened and apply a range of passive and active controls.


  • Using landslide mapping and utilizing it to inform future planning.

  • Slope monitoring approaches such as a satellite radar to monitor slope movement.

  • Applying adequate setback distances above and below slopes, to remove houses from high-risk areas.


  • Understand what type of landslides are likely to occur and in what materials (solid and/or rock).

  • Removing weak material from slopes above houses.

  • Catch fences or deflection walls to channelise landslide debris away from houses.

Dr Judy Lawrence from the Climate Change Research Institute warned of further tragedy happening for coastal properties before 2050.

"Such as low-lying coastal locations at risk from sea-level rise," said Dr Lawrence.

Dr Lawrence said it's not just the heavy rainfall that is the issue - "what makes it worse is the ground material and the landforms combined with where houses are located," she said.

She said fixing the legislation now to strengthen what councils are empowered to do will help to avoid hazardous places.

"It will make climate change risk a primary factor in planning, consenting and housing people," she said.

She said the consequences of building in hazardous locations are too high.

"We simply cannot afford to have more houses located in dumb places," she stressed.