A ‘best case’ scenario of an average 0.5 metre sea level rise, with far more frequent extreme coastal water levels, would caause a lot of problems. A ‘worst case’ scenario is an average 2 metre rise, equivalent to ‘100 year floods’ every day. If scientists are wrong it could be less – or more.
Noted: The impact rising sea levels will have on New Zealand
Under present projections, the sea level around New Zealand is expected to rise between 30cm and 1m this century as warming ocean waters expand, mountain glaciers retreat and polar ice sheets in Greenland and Antarctica shrink. Even if global emissions were to stop today, more warming over the next few decades is inevitable, bringing a trail of storms, ocean surges, flooding and erosion.
The Ministry for the Environment says extreme coastal water levels, currently expected to be reached or exceeded once every 100 years, will, by 2050-2070, occur on average at least once a year.
Evidence is already piling up. Waihi Beach in the Bay of Plenty, Beach Road south of Ōamaru, and small seaside towns in Taranaki and the West Coast all bear the signs of coastal erosion. Low-lying areas in Napier, Whakatane, Tauranga, Motueka, Nelson, parts of Auckland and Wellington have all been inundated by storms.
Just before Christmas, the Whakatane District Council declared 34 properties in Matata in the Bay of Plenty “unliveable” due to severe flooding risk.
“We are a coastal nation so we are going to get whacked by sea-level rise,” says GNS climate scientist Tim Naish, head of a new Government-funded programme set up to assess the magnitude and rate of sea-level rise. “We’re talking places we will not be able to live in because a so-called one-in-100-year flooding event becomes a daily event.”
Worst-case scenario, he says, is an average 2m sea-level rise by the end of the century. Best-case scenario, if we achieve the goals of the Paris climate agreement and keep temperature rise well below 2°C, is 50cm of sea-level rise.
A 2 metre rise would cause major problems for a large part of Dunedin, the reclaimed South Dunedin area. It would also stuff the Portobello road, parts of the road to Port Chalmers (which links the city and Otago province to the port) and also the road to Aramoana.
Stuff: Coastal hazards report warns sea-level rises a ‘slowly unfolding red-zone’
The threat of rising sea levels has been likened to a “slowly unfolding red-zone” as a major Parliamentary report warns thousands of homes could become uninhabitable.
Environment Commissioner Dr Jan Wright released her national report on coastal hazards on Thursday, recommending a major overhaul of the way New Zealand prepared for coastal erosion and rising sea-levels.
She found Christchurch and Dunedin would be the cities most affected by future sea-level rises, resulting in potential damage costing billions of dollars.
In Christchurch, nearly 10,000 homes and 200 kilometres of road were less than 1.5 metres above the spring high tide mark, more than Auckland and Wellington combined.
Dunedin mayor Dave Cull said the report showed the city would likely be the “most extensively affected” by coastal hazards.
“We have an exceptionally large number of homes at risk, as well as infrastructure.”
The report found nearly 2700 homes, mostly in South Dunedin, were less than 50cm above the spring high tide mark.
This already impacts on many property values. Anything like a 2 metre average rise would also impact significantly on Mosgiel and the Taieri Plain, where floods are already common. The Momona airport runway would go under.
But we always have the option of arguing that nothing adverse will happen and doing nothing is fine.
Your NZ 
Gerrit
/ 23rd October 2018Surely then time to look and learn from the Dutch and start building dykes.
Alan Wilkinson
/ 23rd October 20180.5-2m sea level rise by when?
Current global rate is 3mm/yr which would take 170 years to reach 0.5m and 670 years to reach 2m.
Has simple common sense become entirely obsolete?
Griff.
/ 23rd October 2018Yess Alan
Of course rather than your opinion we have actual published science to inform us.
http://www.pnas.org/content/early/2018/02/06/1717312115
Climate-change–driven accelerated sea-level rise detected in the altimeter era
We can also look at what is being measured at the poles .
Your ignorance is not common sense it is denial. You reject reality because it gets in the way of your ideology .
Gerrit
/ 23rd October 2018As soon as one reads
Alan Wilkinson
/ 23rd October 2018No, Griff, I’m just expecting officialdom to use elementary common sense towards the issue.
Supposing your acceleration is accurate and persists then by your own estimate it will take some 80 years to reach the lower level of the range PG is posting about.
That is ample time to adapt supposing counter measures have not become available and been taken. Let’s hear it for common sense.
Griff.
/ 23rd October 2018No Alan
You dont have common sense as pointed out by debunking your liner growth and ignoring of the acceleration in the trend.
You dont want to do anything because it might cost you.
Your greed is not common sense its naked self interest.
Alan Wilkinson
/ 23rd October 2018The acceleration is still speculative because of the short timespan of the available data as shown by the large estimate of the uncertainty (which is almost certainly underestimated).
Even so, the predicted rate of sea level rise is moderate and not alarming. We have time to adapt and respond.
Griff.
/ 23rd October 2018Alan in case you did not notice i not only posted the present rise and projected acceleration I included the fuckin melt from the Antarctic
That is also accelerating at significant rate .
That sea level rise is happening at an accelerating pace is certain Because melting ice and warming oceans are being measured .
We will be facing this problem for the next millennium.
Plenty of time to adapt I am sure because the alternative is called drowning .
But meantime building infrastructure with a fifty year life span must included the projection of rise to a reasonable level of risk .
That means 1 meter of rise minimum over fifty years.
At that level You can kiss goodbye to a hell of a lot of coastal development including parts of Auckland’s motorway system and some very exclusive coastal property . It is not just sea level it is also storm serge and flooding from extreme rainfall both of which are also expected to increase.
We need to start looking at what is at risk and how we minimize that risk going forward or we will end up paying more in the long run.
Because you can bet your last dollar if we dont people like you will be demanding that ratepayers pick up the tab.
Maggy Wassilieff
/ 23rd October 2018Around NZ we seem to have much lower rates of sea-level rise than 3mm/yr.
http://archive.stats.govt.nz/browse_for_stats/environment/environmental-reporting-series/environmental-indicators/Home/Marine/coastal-sea-level-rise.aspx
Griff.
/ 23rd October 2018Oh dear
They tell me you tutor math Maggy.
Do tell us why you think the liner trend over 120 years shows that sea level rise has not accelerated recently?
For someone with a PhD you do post some really dumb shite .
Maggy Wassilieff
/ 23rd October 2018They tell me you tutor math Maggy.
Do they?
Griff.
/ 23rd October 2018you gotta laugh .
If you link to a linear trend it says nothing about if the rate is accelerating .
It is by definition the average rate of rise over the entire record.
Church and white tidal gauge to 2014 linear trend.
modified lowess smooth:
Actual rate of change
from
https://tamino.wordpress.com/2017/07/25/sea-level-rise-has-accelerated/
You accuse me of not understanding but its you who cant even get basic math concepts .
Maggy Wassilieff
/ 23rd October 2018I assume you can interpret v/t graphs. Have a look at what that last graph is doing around 2000 and thereafter.
Acceleration is given by the slope of a v/t graph…The slope is decreasing after 2000 – looks like the rate of sea-level rise is decelerating after 2000.
Wonder what caused the acceleration in sea-level rise from 1922-1938?
Practically the same as 1985 – 2000.
The Consultant
/ 23rd October 2018https://i1.wp.com/redd-monitor.org/wp-content/uploads/2018/10/2018-10-10-153523_987x1040_scrot.png?resize=567%2C512
Let’s do this.
Zedd
/ 23rd October 2018Im guessing those who live on property above 2 meters (above current high tide levels) are not concerned or are just C-C deniers.
Ice free arctic (sea ice).. coming soon
loss of glaciers… happening NOW
diminishing ice shelves in antarctica… happening NOW
BUT.. where is the ‘evidence’ folks ?
The TRUTH is out there folks.. if you actually look, rather than just ignore 😦
btw; I heard recently that one of the biggest financial sponsors of ‘C-C denial research’ is.. wait for it.. EXXON !
Alan Wilkinson
/ 23rd October 2018You’ve taken a long time to tap into your alarmist echo chamber, Zedd? They’ve been claiming that for a decade or two.
Zedd
/ 23rd October 2018‘You’ve taken a long time to tap into your alarmist echo chamber, Zedd?’ sez AW
Ive been writing it on YNZ.. since I first came here. There maybe ‘extremist views’ on both sides, but ignoring or denying ‘the reality’ of the issue, (hoping it will just go away) is just like.. “CRAZY MAN !”
Alan Wilkinson
/ 23rd October 2018Have you been saying since you first came here that you heard recently that EXXON is sponsoring climate denial?
The Consultant
/ 23rd October 2018From a pragmatic perspective there’s no difference between “not concerned” and “C-C deniers”. Either way it’s more than a guess but is likely quite true that most of those who will be hurt by $5 or $10/litre (or higher) petrol costs and other increased fossil fuel costs needed to reduce their use to zero, are indeed people who don’t have lovely homes on the coast, like South Aucklanders.
For the likes of South Dunedin – also solid Labour voters – it will be an interesting scenario: pay vastly more for fossil fuels and still get flooded out because we’re at the mercy of China, India and other developing countries. Even by the IPCC/Paris agreement standards I don’t think that works as an insurance policy, which may be why people are tuning this out when they vote – although they will vote on $10/litre petrol. 🙂
What’s really frightening is that Exxon and others have such incredible control over so many countries, including many communist countries, that have contributed to the increase in annual global CO2 emission tonnage since the mid-70’s. Must be all those oil burning power stations as I don’t think Big Oil owns any coal mines.
The good news is that all the countries who signed up to the Paris Agreement have pledged that their emissions will reduce after they’ve reached peak emissions!!!!! And apparently meeting the targets they’ve agreed to will limit the 2100 temp increase to 2.8C. Apparently there’s a lot of bad news about even a 2C increase so I guess the IPCC is also realising that we’re stuck between a rock and a rising tide.
Griff.
/ 23rd October 2018That such nonsense gets up ticked shows how disconnected from reality some on here are.
.
Burning 1 L of gasoline produces approximately 2.3 kg of CO2.
To have a price component from the ETS of five dollars a liter in petrol would mean paying over $2100 a tonne For CO2 emissions
The highest I have ever seen suggested is $100 a tonne…. its presently $25 .
Even by the IPCC/Paris agreement standards I don’t think that works as an insurance policy,
The IPCC is the organization that gives our best understanding the science behind climate change
It has nothing to do with the negotiation of goverment policy’s like the Paris agreement that is the UNFCCC.
Your opinion is devoid of any actual knowledge about what you are talking about .
The Consultant
/ 23rd October 2018In that case fossil fuels will continue to be burned, which means the zero emission target will remain beyond reach for a period far beyond the supposed drop-dead dates.
A distinction without a difference. No IPCC. No Kyoto, Copenhagen, or Paris treaties or “agreements”, all of which take their guidelines on negotiating CO2 emission reductions from the various emission production scenarios produced as part of each IPCC report. Not to mention national screamfests from individual political parties which demand policies like increased fossil fuel taxes, “green” energy subsidies, market manipulations and a host of other stuff on the basis of …..
…. the IPCC science forecasts.
In any case, the truest of True Believers in Thermogeddon understand exactly what’s required, which is why they leaped all over the latest report screaming about how capitalism needed to be finished off for good or Humanity Will Be Destroyed – or something, something. Long may they scream!
Fortunately the vast majority just ignore this and keep on keeping on – admittedly with ever higher costs that don’t achieve anything, but that’s still a better scenario than the anti-capitalists fondest hopes.
Griff.
/ 23rd October 2018You are gibbering my friend.
Have you thought about seeking some professional help for your delusions?
The Consultant
/ 23rd October 2018Shorter Griff: I’ve run out of arguments
To be fair, looking at the global CO2 emissions graph I linked to earlier, it seems the AGW movement has too. One of the basic questions it raises is whether that steady increase would have looked any different had we not had Kyoto and all the rest, not to mention all the hundreds of billions that have been pissed away on “reducing AGW”.
And the all the screaming about “deniers”.
It all could never have happened – and that graph would look exactly the same.
Griff.
/ 23rd October 2018You can not argue with someone who lives insides a fantersy world
Who are these true believers and what is a Thermogeddon ?
The only ones i have ever seen post such nonsense is nutters like you
Its in your head mate.
Get help.
The Consultant
/ 23rd October 2018… Griff / Gruffydd / Griffith!
The entire body of relevant scientific organizations in the world are telling us climate change is real. Sooner or later civilization is fucked.
Give it ten years and if co2 emissions havent significantly changed its curtains for human civilisation as we know it.
twenty [years]
Impacts of AGW become more and more expensive stifling developement and starting the collapse of capitalism and our civilization.
This one’s a bit more specific…
https://www.kiwiblog.co.nz/2017/09/general_debate_6_september_2017.html/comment-page-1#comment-2014567
The Consultant
/ 23rd October 2018Just in case people don’t want to click, that last one is a doozy:
Sensible.
Sober.
Scientific.
Not unhinged at all! 🙂
Maggy Wassilieff
/ 23rd October 2018Looks like these chaps aren’t too bothered about sea-level rise in the vicinity of Auckland Harbour
https://www.stuff.co.nz/auckland/107941275/plans-for-18-billion-auckland-waterfront-stadium-unveiled
chrism56
/ 23rd October 2018This post is about sea level rise in New Zealand. There are three ports in the records that have long term sea level data and have 2016 records. They are Dunedin, Port Taranaki and Wellington . Here is Dunedin’s https://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?id=690-032
Despite all the assertions of Griff and the satellite altimetry, the tide data shows NO acceleration, just a linear trend going back about 100 years. The same trend is there for ports around the world (Freemantle, New York) , except where there is localized subsidence from ground water pumping, like Houston. This discrepancy between satellite and tidal records is glossed in the literature. If the concern is flooding, then it is the tidal data that is the critical one.
All indications are that there will be about a 20cm rise in the sea level at Dunedin by 2100.
The rainfall data for NZ also shows no overall trends. https://statisticsnz.shinyapps.io/seasonal_rainfall/
Even places that have changed, the scatter is greater than the trend.
It is scare tactics without the data (not some model’s output) to back it up.
chrism56
/ 23rd October 2018And here are the trends for rainfall intensity
https://statisticsnz.shinyapps.io/rainfall_intensity/
Note the summary
For the majority of locations around New Zealand, there is no clear evidence that intense rainfall events changed between 1960 and 2016. However, intense rainfall increased at some sites and decreased at others.
Between 1960 and 2016 at the 95 percent confidence level:
The proportion of annual rainfall occurring in intense events (in the 95th percentile) decreased at 4 of 30 sites (Auckland, New Plymouth, Rotorua and Taupō) and increased at two (Napier and Timaru).
Annual maximum one-day rainfall amounts decreased at 4 of 30 sites (Auckland, Hamilton, New Plymouth and Taupō) and increased at two (Dunedin and Timaru).
Decreasing trends in both measures of intense rainfall have been found at sites located in the northern and central North Island.
So rainfall is not getting worse (As they are doing LMS, the data for Dunedin is skewed by one heavy rain in 2015 – the one in 1980 doesn’t tilt the line).
Another alarmist myth
Griff.
/ 23rd October 2018hello chrism56
Did you actually do anything beside look at the liner trend over the entire record ?
no ….
Sorry mate linking to a linear trend over the entire record shows nothing but that you dont understand acceleration.
lets see what the sea level experts say.
The increasing rate of global mean sea-level rise during 1993–2014
chrism56
/ 23rd October 2018As usual Griff, you do the usual irrelevant rubbish. We are discussing New Zealand. The tide data has shown no acceleration. The rainfall has shown no increase in amount or intensity. That is what the post was about. Discuss the actual data, not what you can google in modelling papers which we know you don’t read and can’t understand..
And as usual and others have pointed out, you get abusive when your arguments are rubbish. That is why you get banned.
Griff.
/ 23rd October 2018you gotta laugh .
If you link to a linear trend it says nothing about if the rate is accelerating .
It is by definition the average rate of rise over the entire record.
You accuse me of not understanding but its you who cant even get basic math concepts .
Hello.
You are arguing with Parliamentary Commissioner for the Environment Jan Wright, World sea level experts John Church and Niel White among many others not “Griff” some dude on the internet.
Hence this post .
No one pays loons like you any notice out in the real world.
Keep making an arse of your self .
Its funny in a look a loon sort of way and you nuts in denial dont count anyway .
Pink David
/ 23rd October 2018“No one pays loons like you any notice out in the real world.”
I would suggest to you, given all the evidence, that the real world is paying far more attention to Chris than yourself. The world continues to use resources it always has, and any changes for the sake of climate change are marginal at the very most.
Griff.
/ 23rd October 2018Yeah whatever pinky
Don’t come moaning on here about carbon tax, oil and gas drilling bans, the shift from dairy to forestry. coal mining bans or the fact you will soon be pinged for driving a gas car then boy.
Or the cost of withdrawing from coastal land you will soon see.
Carbon free 2050 if right wing coal fired Luddites like it or not .
chrism56
/ 24th October 2018If Griff tries to describe maths, you have to laugh. “If you link to a linear trend it says nothing about if the rate is accelerating . It is by definition the average rate of rise over the entire record.” You only went to school cert maths to eat your lunch, didn’t you.
Then the trend is about linear- i.e. there is no acceleration. That is why they show the confidence limits And the NOAA data also shows the velocity of change, which shows the 70s were higher than now. So there has been no acceleration in the tidal sea level rises around New Zealand, There has been no intensification or increase in rain. This is all from the actual data. Things might change in the future – we don’t know – but we also might be destroyed by an asteroid strike. However, all the alarmist predictions so far have been wrong, so their track record is worse than astrologers.
Griff.
/ 24th October 2018ROFL
You are disputing ever major scientific body on the planet.
http://www.realclimate.org/index.php/climate-model-projections-compared-to-observations/
Sea level vrs IPCC
Hensen et al 1988 1988 vrs temperature.
IPCC CMIP3 (circa 2004)vrs temperature.
IPCC sea ice projection vrs reality