NZ - Sea level rise: 'NZ cannot afford to protect everything we have built'
New Zealand cannot afford to put back everything that will be damaged by rising sea levels, the Climate Change Commissioner says, as new data shows an earlier risk of inundation than expected.
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.
Climate Change Commissioner Rod Carr said the science had been understood for decades.
"What is new here is the granularity of the science which shows what will happen where and when.
"We've known, now we need to act.
"We do have to make sure that every decision we make about where we build and where we restore infrastructure is seen through a climate change lens.
"We need to understand that New Zealand cannot afford to protect everything we have built and we cannot afford to put back everything that will be damaged."
The government had put out a draft national adaptation plan and Parliament had some years ago put in place the architecture to help New Zealanders understand what needed to be done, he said.
"We need leaders who can lead and we need to support them in making hard decisions about where does the science tell us we need to spend our investment dollars.
In parts of the country defences such as sea walls would be cost effective and appropriate and in others they will "create false hope and wasted resources".
This was a "massive challenge" but the hope was independent scientific evidence can be used to make good choices.
He believed there would be lower-lying communities where people would have to leave their homes within the next 30 years, and the challenge was to use the science and engineering to anticipate what will happen and act in advance.
Managed retreat 'not first port of call ' - Ardern
Prime Minister Jacinda Ardern said the report gave detailed information of the impact of projected sea level rise on coastal parts of New Zealand.
"The reason that's really important for us, is to ensure that alongside local government, planning for the future, we are ensuring that infrastructure or decisions that are being made are taking into account the adaptation that will need be needed in in parts of New Zealand.
"The first port of call isn't necessarily the idea of managed retreat because there are a range of options that can be used."
She said the first steps over the next few months would be working on the national adaptation plan "and making sure that we are working alongside local government and insurers as we work through who bears the cost of some of these."
"We also should not accept that sea level rises going forward into the future are an inevitability, for instance, beyond those that have already been projected in the near term. We should be also making sure that we are doing our bit to do as much as we can to reduce the impacts of climate change."
Retreat a 'traumatic experience'
Local Government New Zealand president Stuart Crosby said retreating from sea level rise should be a last resort.