Supplied / Donna Drinkwater

AUS - 'Sobering': sea level rise data increases urgency of councils' planning

Wellington mayor Andy Foster says actions are already being taken to reduce the number of properties affected by sea level rise.

The data shows the sea level is rising twice as fast as previously thought in some parts of Aotearoa, massively reducing the amount of time authorities have to respond.

Globally the sea level is expected to rise about half a metre by 2100 - but for large parts of New Zealand it could more than double that because of land subsidence.

The projections show infrastructure and homes in Auckland, Wellington and many other places risk inundation decades earlier than expected. In the capital, some areas will have a sea level rise of 30cm by 2040.

Foster said each area would need to be assessed.

"If we take it as the big picture, the options basically are we defend, or we retreat or we modify and the answer to that is going to be different for different places."

Some areas would be protected to the extent that they can be such as with sea walls, but in other areas that would not be economic.

Wellington's new district plan will notify people of natural hazards including sea level rise.

Anyone wanting to build in a "high risk" area would need to get a special non-complying consent and they were very hard to obtain, Foster said.

"But also the government's recent three houses per property would not apply in those areas and that's the areas that are subject to inundation so you wouldn't be able to intensify in those areas."

Someone could replace an existing house in those areas but would not be allowed to build a new one, Foster said.

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