Whareroa Marae environment spokesman Joel Ngatuere, pictured earlier this year. Photo / NZME
The people who call one of Tauranga's oldest and most precious sites home are considering retreating from their whenua as they face the threat of climate change.
And there are fears future generations could miss out on their cultural identity due to rising sea levels.
Whareroa Marae is tucked on the Mount Maunganui side of Tauranga Harbour and is the primary marae for Ngāi Tukairangi and Ngāti Kuku hapū of Ngāi Te Rangi iwi.
But a scientific study released this week has identified Whareroa as being at significant risk of inundation from rising sea levels much sooner than anyone expected. The Niwa study predicts coastal flooding events usually tipped to happen once every 100 years will hit once every five years in the Bay of Plenty - within just three decades.
Awhina Ngatuere, chairwoman of hapū Ngāti Kuku, has completed a masters degree in climate change focused on her people's relationship with the moana. But it did not make the reality of their plight any easier to digest.
"When I think about Whareroa and climate change and inundation, what I feel is pain and sorrow," she said.
"We are already in a vulnerable situation by being pegged into the corner [by industry]. We have had a lot of ancestral land that was stripped for sale and of the remaining land that we do have, as descendants, the risk around coastal inundation is only getting worse and worse.
"That's painful to confront. We are still in a state of survival as a people."
Awhina said there was fear of the impact of climate change on future generations.
"We won't have a kainga, we won't have a marae. That really puts our cultural identity at risk.
"We do need to look at where we will retreat to for survival," she said.
"We will never give away our land. It will always be Whareroa. But we have to put plans in place. We are looking at all of those options at the moment.
"It was a difficult one for me and my family to confront but if we look at what our ancestors did, they did do these sorts of things. They have, in time, retreated upwards. It's not a natural thing for us. It is still a difficult thing for us.
"In looking at the future for our children to come and their children, we have to see what that looks like ... retreating to ancestral lands.
"We as Māori have adapted for many generations to survive. This is something again we are going to have to look at doing."
Her husband, marae environment spokesman Joel Ngatuere, said the marae was one of Tauranga's longest-standing structures and to see it become encroached by industry and rising sea levels was heartbreaking.
"It's about adaptation. We know climate change is coming, not just for us but for the world.
"Our marae, just like Maungatapu and Matakana, we are all going to be impacted by rising sea levels. We all have to adapt to change. Can it be mitigated? Possibly but it's about thinking about and talking about it now as opposed to waiting for the waves to come crashing in."
The Niwa findings were the result of a joint study, with environmental consultants from Tonkin and Taylor, into the future risk of local coastal flooding, inundation and erosion within and around Tauranga Harbour. They were commissioned by the Tauranga City Council, the Western Bay of Plenty Council and the Bay of Plenty Regional Council.
The team studied the effects of incremental relative sea-level rise on exposed land areas and found coastal flooding now surpassed erosion as the biggest threat to coastal areas. Low-lying areas at Whareroa, Bethlehem, Welcome Bay, Mangatawa, Windermere, and even the Mataphiti railway bridge were likely to be affected sooner than expected.
Dr Scott Stephens, the chief scientist for coasts and estuaries for Niwa, said the findings were "compelling" and people would need to swiftly adapt.
Stephens said there were broadly three responses to help reduce the impact of rising seas. These were to "protect" by building seawalls, "accommodate" by putting houses on piles and letting the water wash underneath, or to "retreat" by moving away.
"What we do now controls how the future unfolds, so these are important but difficult decisions to make, and there is no one-size-fits-all solution."
Planning to reduce the impact of sea-level rise "needs to start now and will need to be implemented over the next two to three decades".
Stephens said there were many Tauranga properties built high on coastal cliffs and erosion was traditionally the biggest concern.
"But far more properties are built in places that currently experience coastal flooding, or soon will."
A Niwa coastal inundation map of the city's inner harbour, published on the Tauranga City Council website, shows areas already at risk of flooding with more than 1m of water in the event of a one-in-100-year storm.
By 2070/2080, Tauranga's vulnerable areas could include Mirrielees Rd, Bay Central Shopping Centre, Mount Maunganui's Commons Ave and Grace Ave, Tauranga Airport, and the Matua shoreline.
Without any storm event, areas at Mangatawa, Welcome Bay, and Bethlehem were still predicted to be inundated with at least half a metre of rising seas in this time.
New Zealand Insurance Council chief executive Tim Grafton said as weather events became more frequent and damaging, increases in insurance excesses and premiums were expected and it would become much harder for someone living in an at-risk area to obtain.
"We want insurance to remain affordable and accessible to people.
"A lot of people go to live in Tauranga and because it's close to the sea and you've got a good climate there ... But it's important to also acknowledge the environment that you live in ... there are some low-lying areas, flood-prone."
Grafton said climate change impacts were expected to affect hundreds of thousands of New Zealanders and cost billions in the next 30 years or so.
Proposed changes to the Resource Management Act were expected to give local councils more power to respond to climate change, "which, at the extreme, would include 'retreat' from areas where properties will just get hit far more frequently by climate change".
"If we can start looking at thinking about adaptation today, then we will be a lot more effective in dealing with these changes as they arrive. The sooner we start, the less expensive it will be, the less sudden and harsh decisions made will be."
Grafton referred to mortgages - many conditional on insurance. With insurance becoming increasingly harder to obtain for some, house prices were expected to decline "and decline sharply" as demand for homes in at-risk areas reduced, he said.
"It's absolutely critical that people do take a keen interest in this."
Tauranga City Council general manager of strategy and growth Christine Jones said the data that formed the inundation map was released in 2019 to property owners likely to be affected and the information was placed on Land Information Memoranda and used in building consent.
Jones said the council would add the updated information into the City Plan and use this in future city development "within these inundation areas".
The findings helped the council better understand the potential effects of future sea-level rise, she said.
Bay of Plenty Regional Council policy and planning manager Julie Bevan said local councils had been using the information to improve climate change resilience through the resource consent process for new development.
Western Bay council resource management manager Phillip Martelli said it had already used Niwa's findings to release new coastal erosion and flooding maps for Waihī Beach, Tauranga Harbour and Pukehina.
All three councils said the new data aligned with their projections of coastal risks.
Police have instructed holidaymakers to stay out of the water.