Many of New Zealand's coastal homes could have unaffordable insurance within 15 years, a new report predicts.
Victoria University examined the risk posed by rising sea levels and intense storms on about 10,000 homes in Auckland, Wellington, Christchurch, and Dunedin for the Deep South National Science Challenge.
While Christchurch will be hit the hardest, Wellington will be faced with the issue first, the report found.
"The analysis shows that homes in Wellington and Christchurch which currently have a 1 percent probability of coastal inundation are expected to face a partial insurance retreat from 2030, with homes in similarly exposed locations in Auckland and Dunedin following only a few years later," the report says.
"In these four cities, full insurance retreat is likely to occur for at least 10,000 properties by 2050.
"This rapid development is increasing our exposure to escalating hazards under climate change."
The report says many of the country's coastal areas face "unprecedented disasters" due to man-made climate change.
It says compared to the rest of the world, New Zealand has reasonably small tidal changes.
"This means only a very modest amount of sea-level rise is sufficient to change the probability of a storm surge overtopping previous high-water marks.
"Further, while climate change is changing our hazards, we are also increasing our exposure to those hazards."
But the report doesn't analyse the potential risk to inland properties.
"Our prediction is that homeowners currently facing a 1 percent probability of coastal inundation will begin to experience partial insurance retreat within the next fifteen years.
"By 2050 most homes in these locations are likely to have experienced full insurance retreat."
The report says this will affect about 10,230 properties.
"A common response to this increased risk is to 'harden the coasts' to defend property from inundation. However, engineering solutions like sea walls, stop banks and levees will only delay damage at best and might even be counterproductive, as they can encourage intensification in hazardous locations.
"Responses to sea level rise insurance retreat should attempt to eliminate the underlying risk by moving homes out of harm's way."
Last week, Prime Minister Jacinda Ardern announced she would declare a climate emergency in Parliament on Wednesday. She told The AM Show on Monday now was the right time to act.
"We don't want to see the ongoing impacts of climate on coastal erosion, the impact on people's homes, [and] on Government assets. We do need to keep taking action to fulfill our responsibilities."
