Kiwis can now see how sea-level rise will affect them
The maps - developed for communities and planners - show how much and how fast the sea level will rise along their stretch of coast.
The entire coastline has been mapped down to a 2km spacing.
It allows people to see how their home could be affected, enabling them to assess the risk from erosion and floods.
Local and international experts from Victoria University of Wellington, Otago University, GNS Science, NIWA and the Antarctic Science Platform are part of the five-year research programme NZ SeaRise.
Their aim is to improve projections of sea-level rise in New Zealand and new data they released on Monday shows sea levels are rising twice as fast as previously thought in some parts of the country.
The new data combines data about where land is sinking with the latest international sea-level rise projections.
The country's two largest cities - Auckland and Wellington - risk inundation decades earlier than expected.
Some areas in the cities are sinking 3mm or 4mm a year - about the annual rate at which the sea is rising.
In just 18 years parts of the capital will see 30cm of sea-level rise, causing once-in-a-century flood damage every year.
Many parts of Auckland will see the sea-level rise 30-50% faster than what was previously thought.
Previously, councils and other authorities had not expected to reach this threshold until 2060 - halving the time to plan for mitigation or retreat.
Globally, sea levels are 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.
ARC's Professor and NZ SeaRise programme co-leader Tim Naish told Breakfast they were "surprised" to see the country's two largest cities are both sinking at rates similar to sea-level rise.
He remarked it was "quite a big shock" and said the cities were going to see sea-level rise ahead of the global average as their coasts were sinking.
Climate Change Minister James Shaw said the new data and maps underscore the climate emergency.
"The first line of defence has to be that we stop putting pollution into the atmosphere that causes global warming in the first place," he remarked.
"We know that the temperature has already increased by about a degree over the last century. We've already had some sea-level rise, we're already seeing droughts and storms the like of which we haven't seen before and in a frequency we haven't seen before. So we do have to adapt to the effects of climate change that have been caused by the pollution we've already put into the atmosphere."
Shaw said he hoped the sea rise tool developed will bring climate change "literally home for people".
"We'll be able to look at what the effects are within our lifetime to properties, to infrastructure and roads, airports, railways," he said.
"I think it's true - for a long time New Zealanders have thought about climate change as a problem that's happening at some point in the future to someone else, somewhere else in the world. What we're now discovering is that it's happening to us, it's happening here and it's happening right now."
He reminded Breakfast viewers the Government had declared a climate emergency in 2020.
"It is a crisis, it is an emergency and we need to treat it as such."
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