Risky business in planning for rising sea levels
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Last weekend, the Australian government released the latest in a series of reports documenting the possible impacts of climate-change-induced sea-level rises (SLRs) on Australia. It found a “worst-case scenario sea level rise of 1.1 metres” within 90 years would have a devastating impact, with as much as $266 billion worth of potential damage and loss to buildings and infrastructure. This upper bound of 1.1 metres is used consistently by government. Inundation maps use three simple sea-level rise scenarios for the period about the year 2100: low (0.5m), medium (0.8m) and high (1.1m). The big problem is that 1.1 metres is the wrong figure by a wide margin, with serious implications for the efficacy of the risk management and planning such research should underpin. In releasing an earlier report, Senator Penny Wong told ABC Insiders on November 19, 2009 that “1.1 metres … is about the upper end of the risk”. But the report said:
So a mid-range projection from the government’s own report in 2009, based on the peer-reviewed science, transmuted into a peculiar creature, a “plausible value”, and now two years later “is about the upper end of the risk”, which the Department of Climate Change knows to be wrong, as the literature also demonstrates.
As Ross Garnaut has noted, climate science projections have sometimes been reticent when compared to observations. The 2007 IPCC report excluded the impact of melting ice-caps from its now-obsolete sea-level figures, and recent satellite data shows Antarctica and Greenland losing ice mass at an increasing (and possibly exponential) rate. Dr David Carlson, director of the International Polar Year Program, says a “very plausible outcome” is a metre or more of sea level rise in this century from Greenland alone. And the West Antarctic glaciers also appear particularly vulnerable. So what difference would a metre make? A huge amount. The damage to buildings and infrastructure impacted by a 2-metre rise and associated storm surges is likely to be more than double the $266 billion figure established in the recent report, and it seems extremely foolish to neither recognise that possibility nor plan accordingly. Sensible risk management requires an assessment of the full range of possible outcomes, their impacts and consequences; not the average. By not doing so, the government is failing in its fiduciary duty. Communities and business, infrastructure authorities and local government planners are relying on the government’s assessment of sea-level rise risk to plan their future and make contingency plans. By simply ignoring the available science and failing to assess the risk associated with the full range of possibilities, the government may leave itself open to huge litigation should reality turn out to be closer to the scientists’ upper bound that the government’s “plausible value”. Or perhaps we can leave it all to Senator Ron Boswell, who told an estimates hearing in February: “Being someone who has spent his life in boats, since I was a kid, I haven’t seen any sea level change.” |
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16 Comments
Ah yes Ron Boswell … the drinking man’s Barnaby Joyce.
I spent a bit of time this week looking at what a 1.1 meter rise would do to the world’s largest coal port - Newcastle NSW - where we are busily doubling the port’s capacity with another coal loader built on the very flat, very swampy Kooragang Island. The short answer is: Kiss it all goodbye. And the rail link, the town centre, much of the suburbs around it … the lot…
Maybe the threat to harbourfront property will spur the masses into action… talk about an assault on Our Way of Life. But I doubt it.
Not that I think a piddly little carbon price is going to do much in the global scheme of things either to be honest. I’m afraid I’m most pessimistic about all this.
How does any national government tackle a global problem that a significant part of the population either doesn’t understand or just wants to pretend away?
Still at least a carbon tax gives us the idea we’re doing something when really we don’t want to do anything at all. Its main selling point seems to be how little impact it will have. Far too little, Far too late.
Cheer me up someone.
Given that the sea will rise steadily across several years — even in the event of an ice cap surge — we do have the option of continuous adaption.
Vulnerable buildings and infrastructure could be built demountable, rather than monolithic. Then, as time runs out for each locality, infrastructure, industrial areas and suburbs would be able to gradually migrate uphill.
Entrepreneurs could note that demountable structures are transportable and often mass producible. There must be big bucks in it when the potential market is so global.
Yairs Roger. Was that meant to cheer me up?
A sort of caravan park future? Grey nomads all.
Possible, probably even inevitable but not pleasant.
And we haven’t even mentioned the obscene amount of tax revenue we’ll be devoting to razor wire just to clad our crumbling coastline and keep out those Bangladeshis, Kiwis and other queue-jumping landless illegal foothold seekers who’ll be treading water out there whining for our hospitality…
Forget the prefabs. Learn from history. Razor wire, Roger, that’s where the big money will be. If we get in early we could make a killing.
How hard would it be to return Port Phillip Bay to its original state? Ie, an area not connected to the oceans? Surely its possible to extend Point Nepean across to Queenscliff and hey presto - no flooding problems in Melbourne.
How hard would it be to build accross the Sydney Heads? Or build around Moreton Bay to protect Brisbane? Or across the mouth of the Swan to prevent Perth being flooded? There are actually several work arounds for Australian cities that should dispel horror stories about Brighton and St. Kilda being underwater for instance!
Its just never going to happen.
Port Phillip Heads - 3km. Sydney Heads - 2km. Botany Bay Heads - 2km. Gold Coast - South Stradbroke Island. South Stradbroke Island - North Stradbroke Island. North Stradbroke Island - Moreton Island & the real feat of engineering - Moreton Island - Bribie Island. (About 15-16km).
If we can’t do that over a century I would have to say I’m very disappointed with our skills and abilities as a country.
Peter,
Don’t know the topography of Melbourne or Brisbane well, but Sydney poses a few engineering issues for the Kanute Project you envisage.
Manly - which was the original harbour mouth is a flat sand spit… that would need fixing. Same with Narrabeen to the North. Botany Bay and all that flat stuff down south would need a bit of fixing up too. And you can’t trust the cliffs - they’re crumbly and already recede by up to 0.5m per year. One of the fastest rates of cliff erosion on earth actually.
That’s part of the problem of course, cliffs and structures that look really solid and sea-rise proof aren’t. Not once tides and waves start hitting them 24/7.
For a decent look at this stuff check out http://www.ozcoasts.org.au/
Must admit I admire your can-do positive approach. Just the pluck and spirit that got us where we are.
I must remember there is nothing that can’t be fixed with enough cement.
A 1.1 meter rise will just about give me a beach-front property. Pity I won’t live to see it.
And for those who say the sea levels aren’t rising I can point to nearby areas where I live where there used to be beaches all year round that are now permanently under water. The land banks are now stopped up with boulders to prevent more erosion. This has happened over the last 30 years that I have personally witnessed. Another nearby beach had a ski-lane marker around 20 metres behind the sand-dunes. It has now fallen into the water. I despair over what we have left for our grand children.
@Peter Johnson envisages dykes to protect Brisbane from flooding by the rising sea.
However the water that flooded Brisbane came down the river. Although it might be logical to lower the sea level so the floods will drain as quickly away as they do now, a rather more practical alternative would be to move the city upwards, to higher ground.
A climate which is angry enough to surge ice sheets into the sea is also likely to raise storms of increasing ferocity. That can include higher waves on top of higher storm surges at the same time as record floods coming down the river seeking somewhere to go. Dyking up the old cities would be just delaying eventual disaster.
For that matter, perhaps every coastal city might plan to absolesce the “old city” near the river in favour of the “new city” on higher ground. A city of demountables on leased land could creep towards the new city as buildings leapfrogged across the built-up area to slightly higher ground for few more dry years.
Trouble is, Ron, the boats keep floating higher as the sea rises. Actually, maybe he’s onto something. All we have to do is move the entire country into a big Ark thumb our noses at the pesky climate.
Roger, you’re starting to scare me now with your leap-frogging demountables heading for the hills …
Given that a purported 1% drop in house prices in Sydney is regarded as The End of Civilisation As We Know It… how do you think we’re going to handle this terminal rising damp problem? Will the property owners of the CBD’s be holding out their hand for taxpayer compo? What about people who have literally lost everything they’ve worked for? You bet they will.
I don’t suppose any skeptics out there would like to chime in with some of that reassuring pshaw phooey sort of science in which I could seek solace.
Why, Peter, of course the sea-threatened landowners are going to react just the same as our greenhouse-threatened hydrocarbon producers do. They are going to bombard us with a ceaseless stream of the familiar “reassuring pshaw phooey sort of [anti] science in which [trusting souls] find solace”, a spin designed to stupefy their buyers and the taxpayers whom they hope to fall back on if the inevitable happens while they’re still there.
It is no wonder that the government is trying to play down the estimates of sea level rise. If they don’t warn the public that the rate of sea level rise is accelerating, they lay open the public purse to everybody who can claim you-didn’t-warn-us and it’s-an-act-of-God and it’s-a-1-in-10,000-year-event.
However, they can’t lay out all the warnings, because all of those over-mortgaged and over-charged land owners constitute a pretty hefty voting block, who don’t want their prospective buyers heading for the hills.
If we havent suffered confusion from voices of denial before, we’re gonna be spinning soon.
Here pete I’ll try cheering you up
I think we are going to get to that 1.1 metres well before the end of the century
Ok I’ll have another go check out graeme connors : I’m going to get a beach house in the blue mountains
funny song and a relief for us planatery worriers
Thanks buckets Jeremy, I’m whistling a bit of mozart now.
I agree with you actually regarding 1.1 being a rather optimistic number. I reckon I’ll be seeing that.
I’ve been wading through some recently translated Russian stuff mostly about Arctic ice but also on the methane under the tundra. Once that stuff gets moving I think all bets are off. Mr Spratt knows a bit about this stuff but the numbers are looking much worse of late.
I live in a little cattle town out in the bush. I’ve already got an idea where to put my jetty. Must get the DA in.
hear that song ? Its a classic and it gives me relief
yeah hansen talks about past climate change and how when a significant shift is on there can be dramatic changes in decades due to all the feedback loops you allude to
Yep. I reckon once the planet’s had enough of you it’s pretty immune to skepticism and denialist arguments. I wonder if there were skeptical dinosaurs? Highly likely.
While I have increasing doubts about the rates of climate and sea level change, the one thing I am increasingly certain of is that we will be reacting in the customary fashion… lots of wars, lots of razor wire. Nature might be unpredictable. We’re certainly not.