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Sea Change Rise Re-asessment Now!

I have been prompted to take a more active role in promoting  greater awareness of what is likely to happen around this Peninsula in the years ahead with the current knowledge of likely sea-change rise. 

This followed an exchange further down the blog with a commenter ('Lets') who I think considers that I take a rather too flippant view of something that is far more serious than this current Council has recognised when I rather ridiculed the 3m in 30 years promoted by the T3 Group. 

Our commenter clearly considers current councillors to be heavily weighted towards climate deniers - probably because their age maks it impossible for them to seriously prioritise real action to deal with it. I think that our commenter lives in hope that the new Council will contain some fresh new members who take the possibility of a rise rather more seriously than that which has been anticipated to date. I hope he/she is correct in that assessment, but don't hold out great hope in that regard. 

In the meantime, I commend to your attention the NIWA report on Coastal Adaptation to "Climate Change -Pathways to Change" dated November 2011. This probably requires regular updating, but it does contain the base information on sea- level rise that we should all be aware of - and adjust our thinking on the subject accordingly. 

I totally concur with Act's viewpoint - my only concern is when people use extremes, such as the T3 example during the Election campaign - that simply turns people off, and is counter-productive when attempting to get concerted action. That is not to gainsay the claim that if anything, estimates have surely increased since 2011 - keep that firmly in mind! I welcome comments that draw attention to more recent and better researched information - either way!

Here is the relevant page from the NIWA document in which our own Jim Dahm had a hand:

The MfE (2008a)guidance manual Coastal hazards and climate change recommends for planning and decision timeframes out to the 2090’s (2090 -2099):

1. a base value sea- level rise of 0.5 m relative to the 1980 –1999 average should be used, along with

2. an assessment of potential consequences from a range of possible higher sea
- level rises (particularly where impacts are likely to have high consequence or where additional future
adaptation options are limited) . At the very least, all assessments should consider the consequences of a mean sea - level rise of at least 0.8 m relative to the 1980–1999 average. Guidance is provided in Table 2.2 (of the guidance manual ) to assist this assessment.

Note: Table 2.2 in the MfE (2008a) guidance manual covers a range of sea-level riseprojections by 2100 with upper bounds from 0.8 m from IPCC (2007b ) to 1.0 –1.4 m (based on three empirical studies from 2007 and 2008 described in the Table 2.2), to which values from more recent studies outlined in a Royal Society of New Zealand Emerging Issues paper could also be considered within the risk -based assessment. (Royal Society of New Zealand, 2010)

For longer planning and decision timeframes where, as a result of the particular decision, future adaptation options will be limited, an allow ance for sea -level rise of 10 mm per year beyond 2100 is recommended (in addition to the above recommendation).

Commentary on the sea-level guidance:

The risk assessment should be based on a broad consideration of the potential consequenc es (direct impacts, loss of assets and amenity) from different sea-level rise magnitudes on a specific decision, objective or issue. The particular sea-level rise adopted in each case should be based on the acceptability of the potential consequences and l ikelihood of that sea-level rise (=risk) and the potential future adaptation costs that may be incurred, especially if sea-level rise is higher than anticipated. Each risk assessment should also take into account the physical shore -type context (e.g.,gravel, sandy or cliffedcoasts ) and the adjacent land-uses. In particular, upgrading existing development should be treated differently from new developments (‘greenfields’), where risk avoidance and aprecautionary approach are paramount (e.g., Policies 3(2) and 25(b) of the New Zealand CoastalPolicy Statement (NZCPS), DoC2010; see Appendix 1) along with the need to recognise the permanency of such developments and that sea level s will continue to rise for possibly several centuries. Therefore in undertaking a risk assessment and appraising future adaptation for greenfield developments, sea-level rises well over 0.8 m should be considered. The MfE guidance (MfE, 2008a) , as it stands, recommends assessing a range of sea levels, starting any appraisal with a 0.5 m rise (by 2090s) and with the “at least 0.8 m” as a minimum higher sea-level rise to consider when assessing future consequences. Using this set of two benchmark values is therefore a minimum to consider, but assessments should not to be limited to those values.

Hence the risk assessment process, as recommended in the MfE guidance manual (MfE, 2008a), is an
enduring approach, although it will need updating periodically in terms of planning timeframes. For example, the 2010 NZCPS requires assessments of hazards for “at least 100 years” (Policies 10(2)(a),24, 25). So already the range of sea-level rises that should be considered needs to take into account the presently recommended extension of 10 mm per year beyond 2100 e.g., the equivalent benchmarks by 2115 (nominally the next 100 years relative to the 1980 –1999 average) would be for an assessment starting at a base value of 0.7 m (equivalent to 0.5 m rise by 2090s) and considering a range of possible higher values including at least a 1.0 m rise (was a 0.8 m rise by 2090s). Both these 2115 values have been rounded to the nearest 10 centimetres, taking into account the present guidance is for the 2090s decade with mid-point at 2095.

The matter is serious. It is time it was taken seriously. It is unrelated to the question of liability related to East Coast erosion that we are facing right now - that was unfortunately the 'hanger' for Act's comments on the post.
I agree with Lets - it is time for our Council to begin making preparations for a sea-level rise that will has a devastating effect on infrastructure - both private and public, and on vulnerable housing. The first thing that could be done is to adopt without delay the 'set-back' lines that have been recommended, for the District Plan, and reject the appeals of those who are unhappy regarding the effect on property valuations. 
The time for action is now!

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Reader Comments (9)

Hi Bill,
We went to the Auckland on Water Boat Show yesterday, there was a big display for Hoppers "Waterfront living at its best". $800,000.00 for a section which is a great deal of money for the temporary use of a bit of land. Council's position must be very clear when approving developments like this that future losses are the purchaser/owners problem not something that they can come back at the approving authority for. Maybe we should put Matthew 7:24-27 into the LTP?

September 30, 2016 | Unregistered CommenterClancy Nixon

Congratulations Bill for taking up this challenge. So where to start? How about with indisputable visual data you can generate for yourself on the Waikato Regional Council website and its coastal inundation tool –

There you can zoom in on any coastal community on the Peninsula and visualise the effect of sea level rise between 0 and 5 meters. As an example – for Thames a 3 meter rise would see all of Moanatairi and Tararu, Northern Grahamstown, Goldfields shopping centre, and much of Shortland under water, and the northern part of Pollen Street would be the new foreshore. A 5 meter sea level rise takes the foreshore to the base of the foothills – Rolleston Street, Heale Street and Parawai Road.

As Bill points out, the guidelines for sea level rise quoted in the 2011 coastal adaption plan are now significantly out of date. For example the latest peer-reviewed report from eminent climate scientist James Hansen (the grandfather of climate science) concludes that even with 2° of warming there will be a multi meter sea level rise this century – perhaps as early as 2065, and accelerating rises into the next century and beyond. See -

Also that well-known greenie lefty institution? – the World Bank has in a recent report 'Turn Down the Heat' - said the world is barreling down a path to heat up by 4 degrees at the end of the century if the global community fails to act on climate change -

So Hansen's warning of a multi-meter rise, perhaps within 50 years and based on just 2° of warming is maybe not as "extreme" as some might imagine.

The time is well overdue for both of our mayoral candidates to stop paying lip service when asked about climate change at recent election meetings by implying that installing a charger for electric vehicles is somehow an answer. No it's time to get real with a serious climate change adaption plan. The one referenced by Bill sets out in detail how the council could go about it

lets ( not "Act" - uuugh)

September 30, 2016 | Unregistered Commenterlets

Hell - sorry - where on earth did the Act come from? - I knew it was wrong even as I wrote it! Must have been a Freudian slip!
And as for Tararu - I took the ruler out and found that 3m comes to the base of my deck from whence I plan to install a bollard for my 'tinny.' Jokes aside - it a mind boggling!

September 30, 2016 | Registered CommenterBill Barclay

Not sure about North end of Pollen Street becoming the new foreshore. Check out very early maps--where A&G Prices are now was virtually the foreshore. Dam should never have sold my house, would have been a beach front house in years to come

September 30, 2016 | Unregistered CommenterSea Urchin

Another area where TCDC lags many years behind some other Councils is warnings on LIMs about sea level rise.

Christchurch City Council has done the coastal hazard study (Tonkin and Taylor) had it peer reviewed and will retain the warnings despite opposition from some affected property owners.

"the council did not have a choice about whether to remove the warnings from the LIM (Land Information Memorandum) reports altogether.

"We have a statutory obligation under the Local Government Act that if we hold information then we need to share that on the LIMs and appropriately.

"So it's important for people who are going to invest or develop or purchase a property that they're made aware of any particular hazards."

Come on TCDC - get your act together - Prospective buyers of coastal property are just as entitled to be told about sea level rise hazards as they are about river flooding hazards

September 30, 2016 | Unregistered Commenterlets

Hi Bill,
Thank you for bringing this important issue to the pages of your Blog. It raises several points.

First is the concern about the possibility. In reality, none of know when or whether the sea will begin lapping around your deck, and i sincerely hope it isn't a problem for our lifetimes. However, those who reject the science may be choosing a path of denial, and those who see it as someone else's problem are not only leaving a mess for children to clear up, but adding cost and challenge to the accumulating problem. So we must begin to consider the conversation.

Next, what data sets too use? NIWA is out-of date, it seems - but comfortably so. Hansen and others, as referred to by your correspondent LETS, may be taking an extreme view. However, perhaps it is only when the information is given in neon lighting that it cuts through the interminable grey of our media's apathy that is the popular defence against inconvenient evidence. T3, whom you suggest may be causing inertia through resistance, was using data from a recent international insurance conference, thinking that the shrinking of policies and the rise in premiums may cause distress sooner than the shrinking ice caps and sea level rise. i notice your correspondent (LETS) uses similar data: perhaps it is not as extreme as you have suggested.

Next, what to do. The rash of significant recent signings of the Paris Accord has pushed the agreement very close to the tipping point of becoming an international treaty. Sufficient nations are already signed up, and the emissions target will soon be achieved, making the agreement to act binding, even though targets remain too little and too loose. However, New Zealand will have to start some sort of process, and communities where the conversation is underway, and steps are in place, will be positioned to apply for whatever resources are available.

It is generally noted that when "elephant in the room" issues are finally named, the initial response is one of dismissal, or even ridicule. However, there is also relief, and after the shock has passed, people are willing to engage. As Schopenhauer noted: Truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident. The climate change truth is midway between stages 2 and 3.

Thank you for making space in your Blog for this issue. It is the defining issue of our age and, unless we begin the conversation and grasp the possibilities this tragedy does offer, our children will inherit a world for which they are ill-prepared and under-resourced.



October 2, 2016 | Unregistered CommenterMark Skelding

When NZ Insurance companies start getting nervous about their bottom line and begin taking sea level rise seriously

you know its time for Councils to get with the program too

October 3, 2016 | Unregistered Commenterlets

Then there is this just published ...

"Planet at its hottest in 115,000 years thanks to climate change, experts say"

"A new paper submitted by James Hansen, a former senior Nasa climate scientist, and 11 other experts states that the 2016 temperature is likely to be 1.25C above pre-industrial times, following a warming trend where the world has heated up at a rate of 0.18C per decade over the past 45 years.

This rate of warming is bringing Earth in line with temperatures last seen in the Eemian period, an interglacial era ending 115,000 years ago when there was much less ice and the sea level was 6-9 meters (20-30ft) higher than today."

Multi meter sea level rise this century ? "Extreme" ?

October 4, 2016 | Unregistered Commenterlets

Yes, it appears that Hansen is well respected, and peer reviewed etc.etc.
I can only say that you Lets keep us 'in the loop.'
In fact, I would invite you to prepare a post on the subject covering all angles known at this point.
I would really welcome the opportunity to put it up, but I do really need a name.
Is that possible, or can we negotiate a alternative?

October 4, 2016 | Registered CommenterBill Barclay

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