Commentary, Climate, Owen McShane

NIWA has applied the scary scenarios generated by the latest run of IPCC computer models to New Zealand. Having failed to predict the weather over Easter they now play safe by forecasting so far out none of us will be around to check them out. We need to be aware of NIWA’s conflict of interest. They not only advise the government on climate policy, as a commercial operation they offer their services on coping with global warming to local bodies and other agencies. So alarmism is in their interest.

The real headline grabber is that our coastal baches and homes are at risk from rising sea levels and more frequent storms.

Of course, all the New Puritans among us are thrilled to bits. They just hate the way we have so much fun on the beach. That’s why they love mangroves which turn sandy beaches into mud. Now, climate change gives them another excuse to keep us away from the coast “for our own good”.

Many local bodies love to protect our “built heritage” of old buildings. But they couldn’t care less about our heritage of enjoying the bach on the beach.

Now, with the endorsement of the IPCC and NIWA they can declare the coastal area a future “no-go” zone on the grounds that ratepayers should not have to pay for future damage – which would leave them with less money to pay for councils’ other follies.

The news media are full of stories and cartoons about beach properties being washed out to sea while inland properties become millionaire real estate. Some councillors enthuse about prohibiting all development near the coast.

It seems that some insurance companies will now refuse to insure coastal properties, and hence we may not be able to mortgage the seaside bach, let alone the coastal McMansion – which serves us right, of course.

These insurers seem to be over-reacting.

We have to remember, however, that insurance companies make their money out of the difference between “perceived risk” and “real risk” – which is why they frequently sell Life Insurance policies in airports. We should not be surprised if a “climate change” premium on your coastal property is an attractive proposition for an insurer.

Before we put our beach houses on the market we should ask “How big is the difference between perceived risk and real risk for the average property owner on the coast?”

The IPCC report estimates that sea levels around New Zealand could rise by half a metre over the next hundred years. Sea levels have been rising slowly in the South Pacific since the end of the Little Ice Age in 1850 – at a rate of about one to two mm per year – or four to eight inches in one hundred years. There has been no sign of any overall increase in this rate in recent decades. But for its own reasons the IPCC estimates that the rate will increase about threefold during the next century. It is easy to“cherry pick” your start and end dates to get data which provide higher rates of increase or equally high rates of decrease. The Pacific Ocean is a volatile place. That’s why some people tell you Tuvalu is sinking below the waves while others tell you the Tuvalu seas are retreating. Both are true, depending on the date range of the data.

But let’s accept the IPCC’s estimate that sea levels will rise about one quarter of half a metre over the next 25 years – which is about 125 mm, or six inches.

Many of us who own these coastal properties have a life expectancy of about 25 years. And most residential mortgages have a 25 year life as well.

So why should we should worry about events more that 25 years in the future? After 25 years many of us will be six feet under. The younger folk will have paid off their mortgage – at which point the insurance companies lose interest.

The end result is that the vast majority of people have little interest in events more than 25 years out, which coincides with what economists’ standard “discounting” of costs and benefits would tell us anyhow.

Furthermore, the IPCC’s estimated sea level rises twenty five years out are no greater than those we have already experienced in our lifetimes to date.

When did you last hear from someone complaining about how rising seas have inundated their properties?

So why should the next 25 years pose any greater threats than we have experienced in the past?

The real risk of catastrophic coastal inundation comes from Tsunami. These events can come out of the blue, at any time, and be of any size. If we are concerned about Tsunami risk we should ensure the Earthquake and War Damages Fund provides sufficient cover because Tsunami are caused by earthquakes anyhow – in spite of the large number of people who believe they are a symptom of global warming. The Earthquake Commissions covers “earthquake, natural landslip, volcanic eruption, hydrothermal activity or tsunami”.

Unlike Tsunami, sea levels rise very slowly. We can measure the trends and take appropriate responses. Any problem we face in New Zealand is trivial compared to what the Dutch have to cope with. We get richer all the time and people in twenty five years time will surely be able to afford to raise their houses a few inches or take other actions. They will have plenty of warning.

Before local bodies rush to “zone out” developments on the coast they should look at appropriate mitigation and adaptation measures.

For example:

•Local bodies might warn people, on their LIM reports, that over the next twenty five years sea level MIGHT rise by 150 mm, or six inches. The resulting panic should be manageable.

•However, they should also point out that when seas rise slowly they erode headlands and cause accretion in the bays – so in many situations, such as our typical bays, it will be self-correcting anyway.

•They should also point out that in many parts of the country – such as the Bay of Plenty – the tectonic plate movement is raising the land faster than the sea is rising. The net result is the sea level is falling.

•Councils can also require that those who chose to ignore these “dire warnings” can sign a contract which indemnifies councils, and hence ratepayers, against any liability or responsibility for any inundation resulting from rising sea levels, or storm surges or whatever. After all, if people are prepared to take the risk, why should other ratepayers be liable? People continue to live beneath Mt Vesuvius.

People can also take other measures to mitigate rising seas on their own account. The Dutch are now building houses which float in the event of flooding. The floor plate of the house is made of buoyant concrete slabs which are “moored” to foundation piles by steel collars. When floods occur the house simply rises, until the flood waters recede, and then settles down again. Connections to sewage and water lines must be flexible, but that is no problem.

This solution can cope with floods of any kind. In New Zealand most flooding will continue to be the result of severe rainstorms. If you have a sea view the water will come through the back door.

Finally, in spite of all the panic responses to the IPCC’s latest exercise in alarmism, I have yet to read of anyone suggesting we should reconsider putting the extension to the Victoria Park motorway in a tunnel below sea level immediately adjoining the water front. Wouldn’t it be sensible to put it up on pylons and continue to give motorists the view – and safe passage over any Tsunami that might strike Auckland one day?

Watch out for bargain properties on the coast. Sometimes fools and their money should be parted.

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