Commissioner for the Environment warns more homes in NZ lie less than 50cm above the spring tide level, than those red zoned after the Canterbury quakes

Commissioner for the Environment warns more homes in NZ lie less than 50cm above the spring tide level, than those red zoned after the Canterbury quakes

The Commissioner for the Environment is calling for an “overhaul” of the way we prepare for rising sea levels, identifying at least 9,000 homes that lie within only a half a metre of spring tide levels.

Dr Jan Wright warns this is a larger number of homes than were red zoned after the Canterbury earthquakes.

In her report released today, ‘Preparing New Zealand for rising seas: Certainty and Uncertainty’, Wright provides maps showing elevation levels above spring tide levels, of coastal parts of New Zealand.

While low lying areas can’t be identified as “hazardous”, as they don’t take into account local characteristics like exposure to large waves or protection from a sand dune, they provide a starting point for assessing the risk of rising sea levels.

Wright pinpoints Dunedin as being the town or city with the largest number of homes (2,683) in areas less than 50 centimetres above spring tide levels, followed by Napier (1,321), Christchurch (901) and Whakatane (276).

She identifies 108 Auckland homes in these very low-lying areas, 103 in Wellington and 77 in Tauranga.

There are also 116 Dunedin businesses less than 50 centimetres above spring tide levels and 35 to 40 kilometres of roads within this zone in Dunedin, Christchurch and Napier.

Pushing the boundary out, Wright says there are nearly 10,000 homes 0-150 centimetres above spring tide levels in Christchurch, nearly 8,000 in Napier and around 5,000 in Wellington.

The Insurance Council of New Zealand puts the replacement cost of assets located between 50 and 150 centimetres from average high tide levels between $3 billion and $20 billion. 

Wright accordingly says, "Rising sea levels will have major impacts in many places. In time, some coastal land will become uninhabitable.

“We must plan for sea level rise, but there is time to do it carefully. There are a few cases where action is required soon, but in most cases it is more important to do it well than to rush.”

Properties and roads close to spring high tide marks
  0-50cm above spring high tide mark Total 0-150cm above spring high tide mark
Homes  Businesses  Roads (km)  Homes  Businesses  Roads (km)
Auckland 108 4 9 1,360 60 56
Wellington  103 1 2 5,008 160 58
Christchurch  901 5 40 9,957 193 201
Dunedin 2,683 116 35 3,604 185 72
Napier 1,321 12 37 7,973 76 145
Tauranga  77 4 3 1,231 107 35
Whakatane 276 4 9 1,309 106 38
Nelson 64 4 6 1,043 117 41
Motueka 45 0 4 1,053 3 19

How much are sea levels rising by?

Wright says sea levels in New Zealand have largely been rising in line with the global average of 20 centimetres since around 1900.

While the rate at which levels will continue to rise is unknown, it’s been projected they’ll increase by 30 centimetres between now and 2065.

For this to happen, a “one in 100 year” coastal flooding event would be expected to occur about every four years at the port of Auckland, every year at the Wellington and Christchurch ports, and every two years at the port of Dunedin.

Wright explains the rate of rise will depend on a number of factors including whether land is rising or falling – something that can occur slowly or quickly in an earthquake.

Wright's recommendations 

Referring to the graph above, Wright says, “There is a period of time for each location before exceedances become common. But after this ‘grace period’, exceedances rise very rapidly.”

She says authorities have time to develop good policy and planning for sea level rises, yet stresses there are aspects of planning that should be done with some urgency.

“One is concerned with the granting of consents for greenfields development. New suburbs and the expensive infrastructure they require should be viewed as long-term investments,” Wright says.

“We now see building new suburbs on land prone to liquefaction in much of the country as foolish. We should see allowing new subdivisions on vulnerable coastal land as equally foolish.

“Another is the need to establish much more extensive monitoring systems. This is required before we can develop better models of shoreline erosion and accretion.

“It is not too soon to begin to consider the fiscal implications of sea level rise. Both central and local government will face increasing pleas for financial assistance – whether it be for building a seawall, maintaining an eroding coastal road, or, as will eventually happen, moving entire communities further inland.”

Wright says the highest costs will come from “large scale managed retreat”.

“Both the 2008 Ministry for the Environment Guidance Manual and the 2010 New Zealand Coastal Policy Statement encourage managed retreat – moving homes and infrastructure to higher ground away from the coast – in preference to building bigger and bigger hard defences.

“However, little thinking has been done on how to implement a managed retreat strategy. The critical factor is scale – with scale will come the uprooting of entire communities and the associated financial cost. But the alternative to managing an inevitable retreat will be leaving people living in homes that become uninsurable and then uninhabitable.

“New Zealanders have an expectation that central government will provide financial assistance for those affected by natural disasters. Local Government New Zealand has suggested that a financial mechanism similar to the Earthquake Commission fund could be created to assist with managed retreat.”

Wright says including the forward liability of rising sea levels into the government’s planning and investment decisions will require input from local government, coastal residents and landowners, the insurance and banking industries, and infrastructure providers.

She recognises local and regional councils, which have largely taken responsibility for planning for the effects of a rising sea, have often clashed heads with those affected.

Therefore she says there needs to be better direction and guidance when it comes to scientific assessments of the hazards caused by rising seas, the process of engaging with the community, and the planning and management decisions that follow.

In her report Wright makes seven recommendations to the Minister for the Environment and one to the Minister of Finance, around these issues.

How are different parts of New Zealand being affected?

Wright has identified low-lying areas throughout the country, but warns they do not represent coastal hazard zones, so are not suitable for including in Land Information Memoranda (LIMs).


Wright says a relatively small proportion of Auckland is low-lying, with the majorly low-lying areas not having been densely built on – the Devonport golf course, the Onepoto Domain in Northcote and farmland in Mangere.

“There are pockets of low-lying land in the city, including parts of the Central Business District, Mission Bay, Kohimarama, St Heliers, Onehunga, Mangere Bridge, and Devonport. About half of the low-lying homes in Auckland are situated along the coast in the north of the city,” she says.

The Northern Motorway north of the Harbour Bridge, the causeway on the Northwestern Mortorway at Waterview, Tamaki Drive and the western end of Auckland Airport also sit on low-lying or reclaimed land.


“Most low-lying areas in Wellington are on the floodplain of the Hutt River – in Petone, Seaview, and Waiwhetū. The more pressing issue for this area is river and stream flooding. However, rising sea level will exacerbate such river floods by reducing the fall to the sea,” says Wright.

“There are also small pockets of low-lying land in the Wellington Central Business District, Kilbirnie, Eastbourne, and around Porirua Harbour. Some of these areas have been reclaimed from the sea, so are generally more vulnerable to sea level rise.”

Parts of State Highway 1 near Porirua Harbour, Cobham Drive and Marine Drive have also been identified as low-lying.

The rail line that runs around the top of the harbour is two to three metres above the spring high tide mark, but has been damaged by high seas in the past (ie June 2013). Wellington’s airport has been built on reclaimed land that is more than three metres above the spring high tide mark.


With the quakes causing land to sink by as much as a metre in certain parts of Christchurch – particularly along the low reaches of the Avon River – Wright says the area’s become particularly prone to flooding.

She says a considerable number of low-lying homes are in the Residential Red Zone, which has been largely cleared of buildings. These homes haven’t been included in the tally of homes in low lying areas in the table above.

Main Road to Sumner and the New Brighton coastline have been identified as particularly low-lying, but are protected by a seawall and sand dunes respectively.

Other low-lying parts of Christchurch in Burwood and Travis Wetland aren’t built up.


Having been built on land reclaimed from a coastal wetland, South Dunedin is prone to flooding after heavy rain, particularly when tides are high.

Wright says the seawall protecting the St Clair esplanade has required considerable maintenance in the wake of heavy seas over the last two years.

“Beyond South Dunedin, some areas of the waterfront and Central Business District are low-lying. These include sections of State Highway 1 and Portsmouth Drive,” she says.

The roads that run along either side of the harbour also have low-lying sections, as does the rail line to Port Chalmers and the Dunedin Airport.

Napier, Whakatane, Tauranga, Nelson

With much of Napier having been built on land that rose out of the sea during the 1931 earthquake, or has been reclaimed since that time, it has some very low lying areas, protected by the gravel banks on Marine Parade.

“Nearly 8,000 homes are less than 150 centimetres above the spring high tide mark, and a considerable area of the city, including the airport, is less than 50 centimetres above the spring high tide mark,” says Wright.

She identifies Whakatane as being increasing vulnerable to river flooding as sea levels rise, despite much of the area being protected by stopbanks.

Mount Maunganui and the Tauranga suburbs of Matua and Otumoetai have been recognised as low-lying, even though the harbour provides some protection from the full force of the sea.

About a third of homes in Motueka lie less than 150 centimetres above the spring tide mark, with a sandbar protecting the town from big waves.

As for Nelson, the industrial area around the port, the airport and some suburbs are low-lying, with waves sometimes crashing over the seawall along Rocks Road.

We welcome your help to improve our coverage of this issue. Any examples or experiences to relate? Any links to other news, data or research to shed more light on this? Any insight or views on what might happen next or what should happen next? Any errors to correct?

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I wish these clowns would bring on that global warming that they keep harping on about...I've got three layers on and I'm still cold and there was a frost this morning. Also, Antarctica has more ice than anytime in the last 20-30yrs. Excuses, excuses... sadly, it makes a mockery of the science profession and is destroying its credibility all for the sake of more govt (taxpayer) money to fund more studies so that govt can justify hitting us all with more tax, What an absolute joke.

.....go back to bed with a hotty and your denialism. Get up when you are ready to accept reality.

No body denies climate change but whether it was primary caused by human activities still needs huge amount of scientific proof, which is NOT equivalent to consensus from scientific communities.

Once upon a time, every scientists agreed that the Earth was the center of universe but that did not make it a scientific truth.

Anthropogenic Global Warming was first coined then transitioned to Climate Change for obvious and well documented reason -- there has not been any warming since ....

I will start at the bottom, warming has continued provided you are mathematically competent, ie understand trends and how to ignore anomalies that are explained, ie El ninos. and btw its looking like 2105/6 will beat 97/98 due to by the looks of it a record breaking el nino.

Medieval mumbo jumbo mostly controlled by the catholic church and not actual scientists who were suppressed if they tried to question.

Climate change needs no such proof now, that is what the consensus means, its only a case of how bad which is what is being debated.

Lets see supporters of climate change theory use common language terms which describe the natural weather to bumfuzzle the populace........copycat techniques to flummox the institutionalised indoctrinated.........WHY would any thinking person abandon PROOF? Where does one stop accepting proof in other areas like the courts etc?

Scientific, mathematical proof and evidence is there in abundance, but then I dont class you as a thinking person but an acolyte.

You keep whining on about all this damn evidence BUT you never put it up.....You cherry pick all the time....and then jump all over the top of any one else who has a different opinion...Perhaps you are a paid troll.....why all the name calling and other nasty crap and put downs? Who are you trying to impress and convince?

You fear the size of the worlds population, you fear CO2, you fear climate change, you fear the end of oil, you fear capitalism.........and that is just off the top of my head.......your response is not proof of anything and you know it!!

Correction those who follow a religion rather than reality

Oh dear, you are just not the same quality as profile, go ask him for some lessons on denial and good cherry picking.

The article points to clear sea level rise and it appears to be accelerating no matter if Antarctica has a bit more ice or not.

The article just like the articles 10 years ago telling us we would be growing oranges in Canterbury by now.

Uh....making things up or do you have some proof on "growing oranges in Canterbury" otherwise basing a claim of no global warming as it has not been severe/fast enough isnt exactly sound.

I grow oranges in Canterbury.
Both Navel and Valencia - Ready now -beautiful.


Actually Antarctica has more ice on the surface but LESS under the surface..
(More snow precipitations, less cold)

I wonder how much extra water there is now sloshing around due to continuing deforestation? Not just what the trees held but also the soils underneath.

Go down to the beach at the next super high tide...last one in Westhaven the boat was level with the carpark, very convenient.

2015 will be the warmest year in recorded history by a considerable margin. The October temperature anomaly was the highest ever for any month and year beating the previous record which was September 2015.

Reading that link not every where recorded warmest October.

and so?

Yeah if you choose to ignore the satellite record where it is just another boring year of year of inter glacial warming.

Satellites don't measure temperature, they measure radiance. It is a proxy that has to be calibrated. The estimates often seem to lag significant ENSO events like the current El Niño.

This from back when 2014 was going to be the hottest year ever - and wasn't...

"Satellite microwave radiometers, however, are equipped with laboratory-calibrated platinum resistance thermometers, which have demonstrated stability to thousandths of a degree over many years, and which are used to continuously calibrate the satellite instruments once every 8 seconds. The satellite measurements still have residual calibration effects that must be adjusted for, but these are usually on the order of hundredths of a degree, rather than tenths or whole degrees in the case of ground-based thermometers."

"The temperature measurements from space are verified by two direct and independent methods. The first involves actual in-situ measurements of the lower atmosphere made by balloon-borne observations around the world. The second uses intercalibration and comparison among identical experiments on different orbiting platforms. The result is that the satellite temperature measurements are accurate to within three one-hundredths of a degree Centigrade (0.03 C) when compared to ground-launched balloons taking measurements of the same region of the atmosphere at the same time."

Why is people buying/building in low lying areas my problem via central and local government. You want a beach house or harbour view, great go get it. But irrespective of global climate change BS the dampness that may eventually invade your property is NOT MY PROBLEM ( unless of course I stupidly purchase said property).

Sadly no. Except the new house owners will sue the council for not warning them, or the old ones will sue the council if they try to warn. The result is the rate payer ie you will be paying.

Why is people buying/building near known fault lines my problem via central and local government. You want a house or view, great go get it. But irrespective of global climate change BS the shakiness that may eventually invade your property is NOT MY PROBLEM ( unless of course I stupidly purchase said property).

I agree....but isn't the problem the one where the Government guarantees the Title?

Exactly, and yet we get lumbered with $1b plus of exAMI problems to the detriment of both the tax payer and policy holder. I live on a flood plain a couple of metres above sea level and can almost see one active volcano and a number of extinct/dormant ones, that's my problem not yours.

It sends a clear message to buy up land that has a high potential for some event that destructs the title!

Buy in hamilton and palmy, the two biggest non-sea-side cities in NZ. Even if your house is safe you'll be paying very high rates in any of these sea side towns, especially the smaller ones with smaller rate paying population base to absorb costs of sea walls etc

I've had the report for coupla days now (was embargoed till this afternoon) and have actually read it all through.

Thoroughly. More than once.

Disclosure: I'm a founder member of one of the organisations directly referred to in the report.

As a Finance-related site, Interest has surprisingly managed to miss the two key issues and one Recommendation which turn upon the simple sentence (report, P 10):

Perhaps the most difficult aspect is the impact on people's homes, which for many are not just their homes, but also their financial security.

The two key issues are:

  • What balance is to be struck between mitigation (hard and soft defences) and adaptation (retreat or abandonment)? Wright argues that this is an intensely localised decision: a one-size-fits-all approach won't work.
  • Who pays, over what time frame, via what mechanisms?

The latter segues to the Recommendation to the Minister of Finance, which while expressed as a short sentence, is going to be at least as significant in terms of fiscal impact, as earthquake levies became after Napier 1931:

Establish a working group to assess and prepare for the economic and fiscal implications of sea level rise

In Christchurch alone, the effect of the Christchurch City Councils bungled attempt to shoehorn a Coastal Strategy into the accelerated timeframe of a District Scheme Review (six months soup to nuts, no appeals) involved some $9 billion of property value, distributed across about a third of the city. Wright has some wise words (P78) about the need to involve communities from the very start, and in ways which include 'openness to considering a range of options'.

I can foresee an extension of, or addition to, existing earthquake insurance to cater for the costs involved in some mitigations, some adaptation, and some smoothing of the way for immediate cases.

Wright also draws attention to the difference between projections/models, and observations. This is a crucial point, because localised effects are numerous. E.g. some open-beach areas in Christchurch have popped up 40cm, some have gone down 30cm solely due to the earthquake sequences. Clearly, there is about a century's worth of worst-case SLR between these two cases, yet they are only a few km apart. So localised policies are needed.

All in all, a balanced report with its emphasis on observation and measurement (P74), differential planning horizons (P76) and use of probabilities/uncertainty bars rather than absolutes (P77).

The sky is falling! The sky is falling!

Truly, we are doomed! I want to burn all the non believing "deniers' of my latest religion at the stake. But this will cause more global warming! - sorry 'climate change'. So what to do??? AT least I will be able to sell my J'ville house, (2200M above sea level), as beachfront property to an Auckland refugee.

I gather you mean 200m above sea level :o)

Golly that sea level rise really has come on fast !!!

"Global Warming vs. Climate Change

Both of the terms in question are used frequently in the scientific literature, because they refer to two different physical phenomena."

Nothing like googling....

"And a Google Scholar search reveals that the term 'climate change' was in use before the term 'global warming', and has always been the more commonly-used term in scientific literature:"

Oh and Jville is more like 200~400m. With the CBD at sea level (hutt?) of course there would be few wanting to buy a house around what little of Wellington would be left, there would be no jobs.

Around 25% of Holland is below sea level and they cope fine by building dikes. Just build 1m high dikes and sea walls when the sea levels are getting close to that 50cm level. That should keep the water out for another 200 years.

No need to panic now.

Except that is just one issue,

but lets go with it,

Any idea of the cost and who will pay? do a Trump and get the mexicans to pay?

Say $5000 per linear metre? the amount of concrete and steel needed would of course be huge and they are some of the worst CO2 emitters.

Then there is the collapsing agricultural system, Syria is the first clear example of mass migration. As a result the developed world will need many km of barbed wire fences as well as the sea walls to keep them out, but of course we have to go to them to get the oil we need.

Then there are the record breaking storms, torrential rains causing floods and then heat waves.

Kind of adding up dont you think?

We have a bit more coastline than the Dutch.
Also, they've been at dike building for the past 50 years.
We just still pile a whole bunch of boulders on the beach and call it a solution.
I'm not panicking about houses, by the way, humans can always move.
What I'm worried about is underground fresh water supplies, aquifers, getting contaminated by sea water....

And most of NZ is more than 1m above sea level too...

I find the denial amusing LOL. As if modern humans are benign creatures who never harmed anything, ever. Like we can just burn most of the worlds forests, and as much fossilised carbon as we can extract, and if we just pretend, that wont have any effect on the planet at all.

Anyone with eyes to see, can look at the beaches where they misspent their youth, and how much they have changed today because of sea level rise. There is an abundance of evidence, which would be enough if people were rational.......

I think now most ppl do see it. Last poll I saw I think the number of americans who accepted CC was something like 75%. The evidence is really overwelming, what we see in here is the noisy nutty fringe.

I really wonder if some of them are paid trolls. I wouldn't put it past people like the Koch brothers and their ilk to pay trolls by the post.

Na, many of the "trolls" I think have a genuine/fanatical belief in the free market and strongly libertarian in view point. Both aspects seem to negate any hope of the science persuading them because accepting the science means the Govn has to interfere and that is utterly un-accpetable to them..

Where was this poll ?

Well here are three, all roughly around 75%,

"Three-quarters of Americans now accept the scientific consensus on climate change, the highest level in four years of surveys conducted by the University of Texas at Austin. The biggest shocker is what's happening inside the GOP. In a remarkable turnabout, 59 percent of Republicans now say climate change is happening, up from 47 percent just six months ago. "

"The poll found that 83 percent of Americans, including 61 percent of Republicans and 86 percent of independents, say that if nothing is done to reduce emissions, global warming will be a very or somewhat serious problem in the future."

"Some 61 percent of U.S. adults polled this month said they supported the pontiff’s call to climate, which was the subject of a July encyclical which was the first major writing of any pope focused on the environment. Just 26 percent of the 1,832 adults polled Sept. 17-21 said they disagreed with Francis’ call.

Support was higher among respondents who said they had no religion, with 74 percent supportive, than among Catholics, where 67 percent were supportive."

Sanity prevails. "The NSW government will today unveil sweeping changes to how the state’s coastline is managed, building on its insistence that local councils look at the science and evidence of individual beaches rather than blindly adopting UN predictions of climate change.

In an interview with The Australian, Mr Stokes said he would be announcing “a much more scientific and evidence-based ­approach … it reflects recognition that what is happening on the coast is a product of what is happening to the sand off the coast,” he said.

“We will be integrating coastal management and planning with what is happening in the adjacent seabed.

The initiatives mark the second phase of the Coalition government’s demolition of the previous Labor government’s policy, which among other things directed local councils on the coast to enforce the climate change and sea level rise predictions of the UN Intergovernmental Panel on Climate Change.

Under that regime, councils in some cases included sea-level rise warnings on the planning certificates of some seaside properties based not on what was happening on the beaches concerned — including one that is acquiring sand naturally and pushing back the sea — but on IPCC predictions.

Many owners found that under this policy, their properties became almost unsaleable."

"unsaleable" not un-expected. Of course they can use strong arm on a council, but just how the insurance industry will take that will be interesting. So what we see here is councils being directed to ignore climate effects over the longer term in effect, hardly scientific.

I suspect that the panic will set in and coastal property values will plummet long before they are affected by rising sea levels. People only have to believe that it will be affected in future and they, or a future owner may be faced with the future prospect of a worthless property. Suddenly people are only going to want to pay what ever it is worth to them on the basis that it will be worthless at the end of their ownership, or what somebody would pay for it on a similar basis.
Arguing about whether the sea will rise half or one meter by the end of the century is missing the point a bit. We need to worry about what happens when all or most of the ice melts because I get the feeling that the temperature rise is on a runaway trajectory with all recent projections being revised upwards at an alarming rate. Look at this

"The Australasian region has four very long, continuous tide gauge records, at Fremantle (1897), Auckland (1903), Fort Denison (1914), and Newcastle (1925), which are invaluable for considering whether there is evidence that the rise in mean sea level is accelerating over the longer term at these locations in line with various global average sea level time-series reconstructions. These long records have been converted to relative 20-year moving average water level time series and fitted to second-order polynomial functions to consider trends of acceleration in mean sea level over time. The analysis reveals a consistent trend of weak deceleration at each of these gauge sites throughout Australasia over the period from 1940 to 2000. Short period trends of acceleration in mean sea level after 1990 are evident at each site, although these are not abnormal or higher than other short-term rates measured throughout the historical record."

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