Postcards from La La Land: the Cnut conundrum

New Zealand’s merry little band of climate deniers are turning out to be a right bunch of Cnuts. Sea level rise and its implications for Christchurch and the wider world have been making news in recent weeks — as have new projections of rapid sea level rise over the remainder of this century. So what does a good climate denier do? To stay faithful to their core belief — that climate change isn’t happening, or isn’t going to be bad — they have to argue against policies designed to deal with its impacts, as well as those intended to cut carbon emissions. Sea level rise? Like Cnut, they line themselves up against the waves.

I’ve blogged many times on the challenge sea level rise poses for post-quake Christchurch. The 2011 quakes caused large parts of the city to drop by up to half a metre — effectively delivering decades of sea level rise in a matter of minutes. For some areas of the city tidal and run-off flooding are now commonplace.

The current debate on sea level issues has been prompted by the city council’s long term planning process — which recommends1 that development should be restricted in areas where future sea level rise is expected to cause problems. Not surprisingly, this has some owners of coastal properties concerned that they will lose out. The council has also looked at the idea of building a tidal barrier across the Avon-Heathcote estuary to protect the city.

Local politics and property owner self-interest is bumping into the harsh realities of climate change, leading to a wide variety of responses — including “it isn’t happening”.

Let’s begin by looking at that bastion of mild-mannered, soft-voiced and charmingly polite2 climate denial, Richard Treadgold’s Climate Conversation. In a post titled Expert opinion against exponential sea level rise, Treadgold attempts to debunk fears of rapid sea level rise by bowing to the wisdom of experts. Unfortunately, his “expert” is nothing of the sort, because it is none other than Dr Willem de Lange3. de Lange, regular readers may recall, lists his work for the Heartland Institute’s Not The IPCC report as an academic publication — work that involved plagiarising earlier Heartland propaganda, right down to making the astonishing claim that “the Arctic regions have been cooling for the last half century”.

Treadgold produces a chart that de Lange supplied him five years ago that suggests that there is zero percent chance of one metre of sea level rise over the next century, and goes on to comment:

There’s little chance that in only five years since then these probabilities have altered to any meaningful degree. Prof de Lange is among the foremost ocean scientists in New Zealand. Solid evidence is required to contradict his opinion. I’ll look up the IPCC projections for sea level rise in AR5, but I seem to recall it sits at about 450mm by 2100.

Unpacking all the untruths in just this one paragraph would be the work of another, longer, article, but the short version is that de Lange was dramatically wrong five years ago, that our understanding of the issue has advanced a great deal in the interim, and that to call de Lange “among the foremost ocean scientists in NZ” is to do a grave disservice to the oceanographic community in this country. Harmless gilding of the lily, or slapping lipstick on a pig? You decide.

Just what do we know about current sea level rise, and how it might change in the future? The physical science part of the IPCC’s 5th report is now two years old, and based on papers published up to a year or two earlier than that. A lot of work has been done since, and we are learning a lot — not much of it good news — about the way that the ice sheets of Greenland and Antarctica are responding to current warming. There’s a very good summary of the (very conservative) IPCC report at Real Climate here. Even with deep emissions cuts, a rise of 28-61cm is modelled for the end of the century — with the behaviour of the ice sheets a nasty wildcard in waiting.

And those ice sheets are not waiting. Recent evidence from West Antarctica suggests that large parts of that ice sheet may have passed the point of no return, and are now committed to melt. How long will it take? That’s the really interesting question4

If we want to know where we’re heading, we can use paleoclimate (climate history) data to help. The last time CO2 was at current levels, 400 ppm, was the Pliocene — a period 4 million years ago when sea level was around 20 metres (plus or minus a few) higher than today. In other words, as long as atmospheric CO2 is at current levels, we can be reasonably certain that we are committing the planet to very substantial long term sea level rise. We just don’t know how long it will take to get there. We could be lucky, and the ice sheets could melt slowly, giving us a few hundreds to thousands of years to adapt. Or we could be unlucky, and see multi-metre sea level rise over the next century.

James Hansen’s latest paper is relevant here, because it is the first to attempt to model what would happen in the event of ice sheet collapse in the near future. Hansen et al point to the rapid increases in ice mass loss on Greenland and Antarctica over the last couple of decades to justify their modelling, and suggest that the impact of collapse would be to cool large areas around Antarctica and Greenland, leading to an intensification in extra-tropical storms as cold oceans rub up against rapidly warming tropics. This is controversial stuff, and far from being a consensus view — but Hansen’s co-authors include many senior researchers in relevant areas, so their conclusions can’t be lightly dismissed.

In recent decades the rate of sea level rise has increased from the 20th century average of under 2 mm a year to 3.3 mm per year, and I am not alone in thinking that there are tantalising hints of an acceleration in the last few years of satellite data:


The policy relevant question, therefore, and the one that should be exercising the unlucky people who own coastal properties and the councils who administer their services, is not how much sea level rise there is going to be, because we know there is going to be a lot — but how soon it will make seaside life uncomfortable. That involves making some kind of estimate of risk — and that means staying in touch with what’s happening at the poles, not donning rose-tinted spectacles and pretending that nothing will happen.

For the people of Christchurch this is very much a live question, as can be seen by the council’s consideration of a mini-Thames Barrier to prevent flooding around the estuary, and on the other end of the spectrum in the efforts to demand that the Tonkin & Taylor report be “peer reviewed”. The bad news is that the T&T report would probably now be judged to be optimistic about future rises.

Later this year the Parliamentary Commissioner for the Environment — who reviewed the science of sea levels in a report released last year — will release a second report looking at potential impacts on New Zealand coasts. We can also expect the Ministry for the Environment to release updated guidelines for local authorities on climate change, based on the IPCC’s 5th report. These will feed into local authority planning around the country, and set the scene for what promises to be a series of local battles as those with coastal properties seek to limit their long term (inevitable) losses.

There will be a temptation for coastal landowners to choose their climate information from those who would tell them there is no real problem. The bland science and physics denial that infests the pages of Treadgold’s climate echo chamber might be reassuring for the ill-informed, but if they follow the inexpert advice of the likes of Willem de Lange they will end up paying a steep price.

In Christchurch, the city council and the planners committed to rebuilding the quake-damaged city need to face up to the long term problem of sea level rise. It may not do much harm — or cost much money — to allow people to continue to live in coastal hazard zones, as long as there is no new major development or the construction of infrastructure with a likely service life of more than a few decades. But they also need to think about the location of the city itself. Rebuilding the central city at its current location could turn out to be extremely shortsighted.

  1. Based on a revised report (pdf) developed from consultants Tonkin & Taylor’s 2014 work. []
  2. Treadgold’s most recent infelicity is to call James Hansen a “loony“. []
  3. Treadgold affects to address him as “professor” de Lange throughout his piece, but he is nothing of the sort according to his Waikato University web page — he’s a senior lecturer. []
  4. It’s worth reading this very good overview on the question by Andrew Glikson at The Conversation. []

34 thoughts on “Postcards from La La Land: the Cnut conundrum”

  1. At last Christchurch is getting to grips with sea level rise. If Brownlee was not a denier and had stopped to think a bit and get some advice the new CBD would have been on higher ground and New Zealand would have a better attitude towards climate change. Instead of spending thousands on a sea level report they could have just read my blog.

    1. Thanks for this blog, Bob. On Waiheke Island, where coastal properties are at a premium, this conversation has not even begun. And Council continues to issue building permits for properties ridiculously close to the ocean. At some point there will be a very painful awakening.

    2. Bob, check your data of the ALK airport. The touchdown zone on RWY 05 (coming in over the harbour) is at 15ft or 4.5m and at RWY 23 (coming in from Manukau) is at 23ft or 7m.
      I would thus hope to think that the airport is safe for another century or more, longer than age of flying from the Wright Bros to now. Storm surges might have a growing affect but they are still events that recede. But of cause if Hansen’s worst predictions should come to pass, things will look very different. The airport will then probably one of our least problems to deal with as planes could use an extended Hamilton airport or Whenuapai for example.
      Flying as such will need a significant overhaul obviously if we want to move away from carbon based aviation fuels. Perhaps NH3 fuels will be the future.

      1. It still surprises me that folk still think of SLR in the context of AK airport or ChCh eastern suburbs, forgetting that it will hit all of our coast simultaneously. Ports, cities, SH1 & Main trunk railway etc etc. At a time when flooding insurance will be unobtainable.

        1. The reason that the Christchurch district plan is focused on the eastern suburbs is because the government want to get rid of them, and their residents, to avoid or limit their liabilities due to Earthquake damage.

          “Climate change” provides a useful hammer to hit the people with.

          This is the view of people here, anyway.

          1. Wonderful conspiracist ideation on display there, Andy. You’ve clearly been spending too much time listening to the wrong sort of “climate conversations”.

            1. Of cause, denial and conspiracy theories are a well known defense mechanism for people under stress…..
              The tough edge of climate change is showing its relentless advance. It is time we start to get used to the fallout and learn to deal with it.

            2. of course people are stressed out about 1.7mm of sea level rise per year.

              It has nothing to do with 10,000 earthquakes, and years of battling EQC and insurance companies.

              They are in denial, all of them.

            3. Here is an illuminating expose of AGW denier “Steve Goddard”, who Andy Scrase appears to emulate:

              You should know that I’m pretty much a nobody in the climate debate. I’m laughed at by all climatologists. I’m not even taken seriously by true climate skeptics. I don’t have a degree in climatology. I haven’t written a single academic paper about climate change and I don’t have a job related to climatology or the weather. What I do have is a blog and a Twitter account. But as it turns out, that’s pretty much all you need to be a somebody in the climate debate…

              Sometimes people try to engage with me as if I were looking for honest dialogue. Well, they’re idiots. There’s nothing honest about me, so good luck trying to have a debate with me. I believe I’m engaged in a war against climate terrorists who are looking to destroy our way of life.



  2. We have three regular deniers via the ODT. Dr. Jock Allison, Peter Foster Bsc and Calvin Oaten. The first two obviously know the facts but out of solidarity toward the farming lobby will not admit there’s a problem and if there is it is not anthropogenic. This takes methane out of the discussion (they hope). The other chap who is a bit of a number whizz, looks for mathematical discrepancies. All focus on minutiae whilest the beaches erode, the seas advance, the glaciers retreat and our climate creeps toward draught and flood.
    Their current focus following obediently on from Wattsupwithat and Jonova is the missing stratospheric hot spot (no longer missing) and the water vapour mysteriously increasing by “God knows what”. Poorly maintained tide guages in NZ ports affords opportunities as well.

  3. Clearly who-ever proposed a barrage hasn’t actually thought about what they are suggesting. ANY sort of barrier across the mouth of the estuary would encourage the sea water to pass under or through the fragile South Shore spit.
    I was surprised when an engineer discussing SLR glibly proposed that if need be, they would build a barrier from Scarborough to Waipara, with extensions up the rivers as required. He looked stunned when I pointed out the porosity of alluvial gravels and the likelihood of some spectacular salt-water springs appearing inland of said dyke.
    Plus such a solution would be required at a time when every coastal community and city would be struggling with their own similar problems.
    It would appear that our political leaders are hoping for the best and planning for the best.
    If I owned a property anywhere east of the CBD I’d be quietly relocating before even the deniers start wondering why their feet are wet.

    1. Up here (Waipara), I regularly cycle along what I take to be an Eemian beach – where the sea would have been during the high stand (+3-6m) of the last interglacial. It’s a pretty substantial terrace (Hursley Terrace, in fact) that runs from Leithfield to the north, parallel to and about a kilometre inland of Amberley Beach.

      Down at the beach, the road to the golf course is getting washed out with every storm as waves eat away at the shingle bank it’s built on. Along the shore, there are some nice exposed tree root systems. I get to see ocean incursion every time we take the truffle hound for a walk there.

      My guess is that 4-6m of sea level rise is already “baked in”, and we need to be aggressively reducing atmospheric carbon ASAP in order to avoid much more. I wouldn’t be building anything much more complex than beach huts on the coast.

  4. Goodness, I had a walk over to the “dark side“.
    Oh what a complete load of tosh and more tosh. The total hubris of Treadgold is really hard to beat. “The IPCC [collective voice of the world’s climate science community] get it wrong because they don’t know what determines temperature.”…
    Perhaps the man can get away with pleading insanity. But then again he stills owes us for his lost quixotic law case. Perhaps “insanity” would be too cheap a solution for the man….
    Oh and Andy, its so nice to see you in action over there, bathing in the nonsense too and splashing about some of your own: “So the relationship between “global surface warming” and SLR seems to be weak.” (One of Andy’s ‘highlights’ on the Climate Conversation)…
    And “We don’t need to get bogged down in Greenhouse physics when there is no empirical evidence that anything unusual is happening to sea level at all.” (One more of Andy’s ‘highlights’ on the Climate Conversation)…
    Don’t you sometimes cringe at the complete nonsense you subscribe to and fabricate yourself over there?

    1. No I don’t cringe because there is no empirical evidence that SLR is accelerating and some that suggests the converse

      Nevertheless, whatever “the science” tells us, there are several thousand property owners who are affected by the proposed district plan. This will, for example, potentially prevent people building a conservatory on their coastal property based on a projection of what might happen in 100 years.

      As far as I’m concerned, the councils and government can make their own decisions on infrastructure, but people need to be able to manage their own risks, as indeed the thousands of people in Christchurch did when they built properties that were marked as liquefaction prone prior to the earthquakes

      I can assure you that there is plenty happening behind the scenes in Christchurch – mainly without my assistance – that will give you plenty to blog about in the months ahead

      1. Andy, sorry, you said that ‘the relationship between “global surface warming” and SLR seems to be weak’.
        It would seem that the only weakness around is your ability to distill truth from wishful thinking:

        As to the empirical evidence of SLR acceleration:
        Obviously the rate of SLR has increased over the last century.

        And I am sorry, but cringing and whinging will not help those owning affected properties. What will slowly happen is that insurers and banks will not want to be sitting on or insuring assets that have a use by date unlike real estate on higher ground. It is only fair that potential buyers should be notified of that fact. It is also fair I would think that society does not want to collectively pay for (that is what insurance is doing) those who wish to cash out by means of a tax on the rest of us when the water taketh away their assets.
        Society might decide to build defenses to hold back the inevitable for a few decades longer…. but the smart money is on moving to higher ground I would think.

        And the laughable tosh you guys slosh about at Climate Conservation is certainly not going to do a “Moses” for you….

        1. Your SkS doesn’t provide any link between global surface warming” and SLR. In fact, most of the SLR is due to ocean heat accumulation.

          Secondly, you claim that “Obviously the rate of SLR has increased over the last century”

          According to the Ministry for Environment

          There is less certainty yet whether an acceleration in global mean sea-level rise has begun.
          Using reconstructed global mean sea levels from 1870 to 2004, a small acceleration of sealevel
          rise of 0.013 ± 0.006 mm per year over the 20th century has been observed.

          (Page 11)

          Also, from the V1 Tonkin and Taylor report

          Historic sea level recorded at the Lyttelton Port has risen at a rate of 1.9 ± 0.1 mm/year between 1925 and 2010 (Hannah & Bell, 2012), which is in line with the global record.
          Therefore, we consider it is reasonable to imply that global projections of sea level rise can be applied to obtain future projections of sea level rise for Christchurch. Note, there is variance within the long term trend of sea level rise and the latest data from New Zealand port tide gauges shows the mean sea level has remained relatively constant for the last
          decade (Hannah & Bell, 2012).

          As for “whinging”, no one is doing any whinging. There is a democratic submission process which is being adhered to

          1. Andy says “Your SkS doesn’t provide any link between global surface warming” and SLR. In fact, most of the SLR is due to ocean heat accumulation.”

            But obviously ocean heat energy comes from the surface warming of the planet. Sea level rise is being driven by global warming one way or the other, either through thermal expansion or melting ice.

            There is a change in rate of sea level rise since about the 1970s. Have a look at the links in Thomas’s post. There is also a steeper trend since 2010. It will be interesting to see how that develops.

            The Tonkin and Taylor report looks rather conservative, in light of more recent evidence on sea level rise.

            Regarding building in low lying areas. In my opinion if people want to add a room to a house that should be their affair. Mitigation / adaptation rules have to be practical. However it doesn’t make much sense building new subdivisions in susceptible areas.

          2. Its Andy at his best: “Playing stupid”:

            Your SkS doesn’t provide any link between global surface warming” and SLR. In fact, most of the SLR is due to ocean heat accumulation. (Andy S)

            Err, does this imply that Andy S finally accepts the evidence of ocean heat accumulation due to AGW?

    2. It gets better, Thomas, as site moderator Richard Treadgold works on what I can only assume is a stand-up comedy routine:

      As a member of the NZ Climate Science Coalition, I am frequently privy to learned conversations.

  5. The T&T report linked in this post is the V1 report, there is now a V2 report

    It was “peer reviewed” (rewritten?) by Terry Hume of Hume Consulting (formerly NIWA, 22 years or so)

    Link here:

    PDF link here (12Mb)

    As you can see,, the V2 report is much more detailed on the geotech side.

    The SLR projections are based on AR5 and use the more recent RCP terminology which was absent in the V1 T&T report

  6. Indeed there have been a few efforts to alert the Christchurch Rebuild Gang about the silliness of spending much money anywhere within Christchurch’s present urban area… Like:-

    Regardless of the outcome of the political or engineering processes, those with most money to loose from foolish investments on land that soon will be sea will determine what happens. The insurance actuaries are quietly doing their sums. First they will ramp up the rates if there is a risk which contains at least some chance of the bad thing not happening (not every house burns down – so Fire Insurance works for them). But where the risk becomes a certainty (and enough sea level rise to drown Christchurch and every other property within 75 metres of present day sea level is a certainty) then they will simply refuse to take that risk at any cost. No insurance, thus no finance,thus no building, and the land lies fallow awaiting its inevitable fate as beach and eventually as seabed.

    I understand that it is illegal to issue a building permit for a development which cannot prove a viable 50-year life. Year 2065 – I would imagine that the high tide mark for that year will tidy up quite a few properties around the nation.

    And of course critical infrastructure like sewage treatment and disposal plants will be drowned very early on, then salt water intrusion into water supply wells adds another minor complication. These issues could make large parts of the city uninhabitable long before denialists sitting glued to their silly little screens watching the latest edition of NZ Had Talent notice that the surf is swirling around the legs of the dining room table.

    Building barriers is, of course, a nonsense. The scale of the civil engineering works is far beyond the economic or construction resources available; the barrier will have to be continually raised at exponentially increased cost for each increment, while the land ‘protected’ by the barrier becomes ever more susceptible to catastrophic failure. We simply cannot afford it. Better to retreat gracefully and spend resources on adapting to the inevitable rather than pursuing futile Canutist quick-fixes which solve nothing and fool nobody.

    Interesting times.

    1. I understand that it is illegal to issue a building permit for a development which cannot prove a viable 50-year life.

      There are many new houses being built on Marine Parade in Christchurch, and also on the Southshore Spit.
      These are all insurance rebuilds, paid for by the insurance companies

      1. Fascinating isn’t it!

        I imagine that the rebuild is an obligation of the ‘contract’ twix the insured and the insurer. The insurer cannot avoid the payout including conditions in the insurance agreement that provide for a rebuild.

        It will THEN be very interesting to see if that same insurer, or any other insurer are prepared to take on the risk of continued cover for those properties.

        Those are questions the present owner will need to consider come policy renewal time, and any prospective owner will need to consider if (for some unimaginable reason) they want to buy such a property.

        1. The insurers can review their policy at any time. They can also exclude inundation events, which they have already done for central Christchurch in Flockton basin

          In many ways, the central basins are more vulnerable than the coastal zones, since the water has nowhere to go when you combine a high tide with heavy rainfall in an area that is a natural pool.

          However, it is only the coastal zones that have building restrictions put on them.

  7. Here’s another angle to coastal living with climate change.
    increased health risk

    “Drawing on a decade’s worth of health and weather data, scientists with the University of Maryland and the state Department of Health and Mental Hygiene found that the risks of getting a salmonella infection increased when temperatures soared far above normal, or when torrential downpours occurred. What’s more, they found the risks even greater in coastal areas than inland.”

  8. Which is another good reason, in addition to accelerating SLR, that Andy sold up in South Brighton and moved inland.

    Just another example of “Do as I Say, not as I Do”, Andy?

  9. No, Andy, you were, in your own words up-post, just “managing your own risks” by moving well away from the coast.

    I suspect that your new home is not on a flood-plain, nor in the middle of a pine forest, either.

    You may be a professional AGW denier, Andy, but you are not a fool, and you know full well what is coming.

    1. I dont think he is a professional AGW denier – no evidence of professional standards and who would pay for this. Perhaps also not a fool, but most certainly a twit.

  10. Andy, your actual words were “people need to be able to manage their own risks”.

    Which, you are clearly doing, clever chap that you are, by quitting your South Brighton property to move inland and upwards.

    Much of humanity will soon be doing the same. Problem is, how will they feed themselves, with the river flats and coastal plains suffering salt intrusion and inundation?

    1. In retrospect, we made the right decision not to rebuild in ChCh and take the insurance payout, now that the City Council plan to make coastal development very difficult and destroy millions of dollars in equity through their proposed district plan

      This wasn’t the motivation in the first place, though ..

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