Just about everyone in the world must know that the Maldives government decided to hold a cabinet meeting under water. (Scroll down for video of the president’s message.) Strangely none of the news items carried an image of the meeting that I saw, but here’s one:
(The image was from Tumblr but the link doesn’t work any more.)
The problem, of course, is that the place is barely above sea level. As Wikipedia says:
The Maldives holds the record for being the lowest country in the world, with a maximum natural ground level of only 2.3 metres (7 ft 7 in), with the average being only 1.5 metres (4 ft 11 in) above sea level, although in areas where construction exists, this has been increased to several metres.
Not a lot of leeway in the context of new concerns about sea level rise.
Roger Jones recently told us that:
the last time the Earth was at 387 ppm CO2 for a sustained period, sea level was 25 m higher plus or minus 5 m.
That was during the Middle Pliocene epoch (3.0–3.5 Myr ago) according to this study (behind the paywall) which Roger regards as pretty robust. Good enough for me.
We don’t know how long sea levels would take to reach such levels. The recently published UNEP Compendium tells us:
Some scientists are now warning that sea levels could rise by up to two metres by 2100 and five to ten times that over following centuries.
Al Gore told us that if either West Antarctica or Greenland melted there would be water where the Twin Towers were and I believe 2 metres would see the basement of the House of Commons flooded. So I thought I’d take a little look at how the Chinese would get on. Not too well as it turns out.
This handy gizmo will give you flood maps up to 14 metres right down to street level. This is the area around Shanghai at 14 metres:
There is intrusion with one metre, particularly to the north. It gets progressively soggier from there. Shanghai is pretty much gone with 6 metres.
For some reason the image doesn’t work all that well with Japan, but you can get an idea from this site:
That’s 6 metres. The red inlet on the right is Tokyo, then moving west you have Nagoya and Osaka with nice splashes of red.
The 2009 UNEP Yearbook showed the following Asian cities as at risk from sea level rise, though at what metres isn’t clear from the text. Considerably less than 25, I’d suggest.
I do have an image that shows what 25m would do to major centres. It comes from Hansen’s Iowa Testimony, slide 46 – pdf):
Notice the large chunk it takes out of China and what it does to the river deltas on the subcontinent.
None of this should be a big surprise when you consider the consistent relationship between CO2, temperature and sea levels, which have moved together over millions of years. The rough relationship between temperature and sea level from the last ice age to an ice free world in represented in this graph:
That comes from Rahmstorf from Archer, 2006, via Climate Code Red with the 2007 IPCC projection added.
The image provides a powerful ‘back of the envelope’ check on the overall situation. If we’ve gained 120m of sea level with about a 6C rise from the last ice age it’s reasonable to think that a further 4-6C will make a mess of the remaining ice sheets.
Secondly, you’ll note that the 25m rise in the Pliocene is not new. Remember the fossil birch tree discovered in the Transatlantic Mountains in the 1990s, about 500km from the South Pole, dating from the Pliocene. What’s changed is the error bar. It used to be plus or minus 10m, now it’s plus or minus 5.
Finally, the actual sea level 40mya is moot and probably irrelevant. The continents were in a different place and the shape of the ocean basins would have been different. My rough maths makes the diameter of the earth about 3,500 times the average ocean depth, so a bit of flexing of the shell as the continents move around would be the order of the day. The point is that right now if you melt the remaining ice sheets the waters will rise about 75 metres eventually.
Hansen reckoned this would happen with 425ppm, plus or minus 75. I reckon that’s a bit low, simply because there is an almighty and very stable lump of ice that’s built up at the bottom of the world which would take a bit extra to burn off.
But to sum up, our gift to posterity at current CO2 levels is a 25m lift in sea levels. From the images above you can see that’s not pretty.
Rudd and Wong’s ’science’ gives us 450ppm if you’re lucky. More realistically it will be 550ppm or even 650. The gang meeting at Copenhagen are not much better, and if China and India are at all aware of the real situation, they’ve shown no sign as yet.
My mother always told me to put things back where I found them, which is why I’ve always been in favour of 280ppm. Let the planet and it’s natural variations work it out from there.
In case you’re thinking that all the problems are well into the future, remember what Barry Brook told us last year:
a rise in average sea level of just 30 cm (at the low end of projections and likely to occur within decades) would cause a ‘once-in-a-century storm’ to reoccur every 3 years. Thus major hazards for coastal infrastructure arise long before complete inundation
And indeed, our people are on the job. Quite fortuitously (I wrote most of this yesterday) we woke this morning to stories of hundreds of thousands of buildings in peril, 250,000 in the Sunshine State (blog post here).
But it’s a bit like looking at our toes, not noticing the train coming full speed down the track.
Brian,
A little while ago I saw one TV image of a Maldives Cabinet member in scuba gear about to go underwater. But no other TV coverage.
I live on a hill.
No.
I’m impressed that all the members of the Maldives Cabinet are qualified divers.
Or maybe not.
“But what are we going to do about the Minister for Tourism, Arts, Sports and Sewerage Works? He weighs 300 pounds and can’t swim.”
“Oh, slap some extra weight belts on him and keep his air hose out of shot. If that doesn’t work out, well we’re due for a Cabinet reshuffle anyway.”
Haven’t we some way to go in the reduction stakes to ‘catch’ up to India and China, given their relatively low emissions per capita?
As I understand it, the Chinese at least are taking significant steps in technological research.
Great minds, Nabakov
I wonder if they were more or less productive than normal? Maybe our pollies should get certified…
The Howard ministry once conducted a cabinet meeting whose only means of communication was by dog whistles.
But did anyone listen? No.
(Except for the dogs of Canberra, that is. They were driven mad.)
Here they are. They look in pretty good shape to me and apparently had a lot of fun practising.
I see Germany (-17%), and the UK (-14%) were able to reduce their emissions from 1990 levels by 2004, and further beyond. Whats exactly is wrong with the rest of us?
So much for the ‘impossibility’ argument.
Brian, the UNEP Compendium leaves a litle to be desired in how it translates the original science (done in too much of a hurry with insufficient fact checking). I recently reviewed a document that drew from it and had to go back to all the original sources. However, the graphics are very well done.
Roger, thanks for the tip. For everyone, the main site is here. It is intended to provide a summary of 400 important papers published since the IPCC AR4 and looks a magnificent resource. But if it’s unreliable that disappointing because it becomes pretty useless for people like me.
Lefty E, generally the Brits and the Germans are amongst the most serious and the most successful. BUT, the Germans have an advantage in counting the rust bucket industries of the East, which have since collapsed, in their starting point. Also a slightly declining population helps.
The Brits, I’ve seen it contended, would have their gains wiped out if they counted just air travel and the manufacturing that they’ve outsourced to other countries during that time. That is the emissions content of what they are consuming hasn’t gone down when taken together with stuff that’s not counted. Soils is another issue.
We still have a way to go before we know what’s going on.
wpd @ 5, I’ve got another post I’m working on which gives some information about China. Three comments.
First, as far as I can see they are expanding everything, including their use of coal.
Second, in the (not too) long run, we’ll all have to get down to net zero. 387ppm is clearly too much. I think the Indian and Chinese are pretending not too notice the whole 350ppm movement, or hoping they can keep sinning for a while before they become good.
Third, the Chinese seem to think that in the natural order of things everything should be made in China and seem to be gaming the situation to make this happen.
So in sum, I’m buggered if I know what their real position is, assuming that there is a coherent, unified position in there somewhere, which there may not be.
Brian: “This handy gizmo will give you flood maps up to 14 metres right down to street level.”
Incidentally, Brian, did you read the attached notes for Flood Maps, which say IIRC that:
(a) this is mean sea level, so you will get greater inundations for high tides, and especially king tides
(b) for every 1 m rise in level, the shoreline can move inland up to 100 m due to shoreline erosion (more if it is unconsolidated sand, less if it is solid rock).
As such, a 1-2 m sea level rise would virtually wipe out the WA seachange towns of Busselton and Dunsborough – entire town 2m or less above sea level.
All built on sand – easily eroded.
It would also decimate coastal suburbs of towns on the Gold Coast, Sunshine Coast and Coral Coast in Queensland. Some coastal suburbs of Adelaide (eg Glenelg) are probably vulnerable too?
I agree with you Brian
280 ppmv sounds like the best target.
Sadly, of the extra heat the world has absorbed the vast bulk of it is in the oceans (just 3% of it is in the atmosphere, 7% melting ice sheets), and that hasn’t all dissipated, but rather been absorbed. Even if we could have 280ppmv tomorrow that accumulated ocean heat will take some time to dissipate.
Reducing growth in CO2e means easing off the throttle (but still accelerating). Lowering concentrations means easing off the throttle even more and so accelerating more slowly still, at least until we reach the equilibrium point — possibly, as you suggest, as low as 280ppmv.
Agree Brian – there’s loads of problem with accounting, but that said – ALL Kyoto countries have been measured on the same basis, with International aviation and shipping excluded across the board.
Germany did benefit from the the East (reductions in Eastern Europe were even greater – but there not good comaprators, for the reasons you note) but even so – I gather 75% of the EU reduction by 2012 will come from Germany.
France has shut down its last coal mine – and oh look, the economy didnt collapse.
Just pointing out the massive increases in the rest of the West are pretty near unjusitifiable.
Love the ad for wet carpet & flood repair in the map of flooded China.
Joe @16, now there was a good idea for a huge future market!
What about instant house stilts, and a 1-2 m jack-up service, Queenslander-style?
How about outrigger floaties for your car at high tide, and a mooring post so it doesn’t float off during the night?
Rudd is right – there are loads of business opportunities out there from climate change.
Elise @ 13, Thebarton (inner western suburb of Adelaide) would become beachfront with modest sea level rise, as the CBD of Adelaide is only about 20m above MSL.
I know a bloke who lives in the city who’s planning on mooring a gondola in his
carportboathouse. Ah, Adelaide! Venice of the South!David @18: “Ah, Adelaide! Venice of the South!”
Could that bloke send a few gondolas westward too? We have a lot of future canal estates coming up…
Ah Perth! Venice of the West!
Yet another business opportunity – city gondolas! How cool is that?!!
There’s no end to the future business potential of climate change.
Brian #12,
the Chinese are running a big integrated model with all their energy sectors and the scientist involved believe China can peak and decline within three decades. The policy makers are yet to be convinced.
But if they are – game on. Nor will the Chinese sign onto anything until they know that it is achievable – but may agree to voluntary measures while all this is worked out. They play hardball in negotiations – have seen them in action.
If everything is made in China, and their comparative advantage becomes zero emissions goods, how hard is the rest of the world, and their suppliers of raw materials, going to have to run to keep up? This is a serious proposition for Australia if we design our policy to preserve the old industrial order.
Forgive me for a stupid question but qiven the quote:
“Roger Jones recently told us that:
the last time the Earth was at 387 ppm CO2 for a sustained period, sea level was 25 m higher plus or minus 5 m.”
and considering we are at 387 ppm CO2 now, and the sea levels are not 25m higher, doesn’t that tend to imply that CO2 is not driving temperature?
Either way it tends to raise questions on the arguments put forward.
If CO2 was the driver sea levels should be higher (to match historical observations? Since we don’t match historical observations it tends to imply other factors at play?
Flats, the crucial term here is “sustained period”.
Let us say that your car is capable of a speed of 200kmph if you push the pedal to the floor.
Let us say that you do push your pedal to the floor and note after a time that you are travelling at only 180kmph. You complain about this. however, your wiser passenger points out that you have not given you car sufficient time to achieve its maximum speed, and that you should learn patience.
The world’s foot is on the gas but the rate of increase in CO2 has been so rapid that its effects have not yet manifested themselves in things like sea level that have powerful inertial effects, much like the weight of your car.
Flats, CO2 levels haven’t been at 387 ppm for a sustained period yet. Wait for a hundred years or so, then see where sea levels are.
Oh, and educate yourself on the science while you’re waiting. There are plenty of excellent resources that others have linked to.
I’ve been working on managing the impacts on climate change on coastal development since 2001. There is little doubt that the the popular discussion of climate change has increased now that potential impacts can be modelled. It’s like a morbid viewing of Australia’s funniest home videos, ‘Come on kids lets see what happens to Asia when the sea level rises.’ ‘What happens to red necked yanks when the dam wall breaks?’
From a land use perspective, the impacts of climate change will be catacylsmic. From an environmental perspective they will be cataclysmic. There are vulnerable people in vulnerable communities already feeling the impacts now and no amount of modelling is going to improve the situation. We are deluding ourselves if we believe reducing carbon emmissions will have any effect. The debate about ETS or Cap and Trade or what ever system is economically acceptable sounds like a barn door closing. The world missed an opportunity with Kyoto. It is no longer a game of who produces less carbon (because the simple answer is those who use nuclear energy or those who live in mud huts and herd goats.)
In 2001 the State Coastal Management Plan – Queensland’s Coastal Policy included a statement concerning climate change and sea level rise and it was one of the few positions articulated by any Australian government, federal state or local. It states,
Planning for the coast must address the potential impacts of climate change through the following heirarchy of approaches:
avoid – focus on locating new development in areas not vulnerable to the impacts of climate change;
planned retreat – focus on systemic abandoment of land, ecosystems and structures in vulnerable areas;
accomodate – focus on continued occupation of near coastal areas but with adjustments such as altered building designl and
protect – focus on the defence of vulnerable areas, populaton centres, economic activities and coastal resources.
It is now 2009 nearing 2010 and we are yet to seriously discuss what the future of our society over the next 20-30 years. In fact I doubt the above statement has influenced any major land use decisions over the past 6 years.
We are failing to realise that greatest impact of climate change will be on the ability of a highly urbanised society to rapidly adapt to a changing environment.
Earlier this year the CSIRO developed software that credibly models the impact of sea level rise scenarios in local areas. It was presented to members of the Sydney Coastal Councils network. I attended the presentation and thought the model was excellent, however, land use planners at the State and local level will be unable to utilise the tool because of the polarised and often hysterical debate wrought by doomsday hand wringing discussions that politicians focus on.
Clearly the capacity lies with the Federal government. Forget Sydney’s Councils or the NSW Government who still debating the merits of light rail public transport systems and improved walkable environments. If you want to do something about climate change start thinking about where and how you and your children are going to live over the next 20 years. What will you eat, where will your water come from. How will you move, where will your energy come from. Then get on the email and start asking your local federal member the same goddamned questions.
The only thing worse than standing on the train line looking at our toes and waiting for the train, is knowing that all we have to do is step to one side and choosing not to do so because nobody else is.
Adios
Flats,
think thousands of years. The atmosphere takes decades to warm. The ocean takes decades to centuries. Ice sheets grounded below sea level are vulnerable to warming oceans – they are relatively unstable, melting up to 1-2 m per century (these are estimated rates from previous warm periods). Ice sheets above sea level take even longer to respond. So to get a response on the scale of the Pliocene (about 3 million years ago), would take thousands of years.
Or we could warm the Earth much faster and speed things up. No one has a reliable estimate of how fast ice sheets could melt under greater rates of warming (rapid rise greater than 2 degrees) above interglacial levels because we have discovered no geological precedent that is measurable. The models are being improved but aren’t there yet. The process is really hard to reverse, because there is a delay coming back down as well.
Flats @ 21, the notion that temperature and sea level are linked is surely a no brainer. Here are two graphs that relate temperature and CO2, which can drive each other.
Here you have three graphs (more actually) that include sea level change.
When the climate forcing is coming mainly from GHGs, mostly CO2, as now, the effects follow through, with feedbacks, over a period of more than a century. The subsequent impact on sea level plays out over an even longer period, probably more than a millenium. Which is all pretty instantaneous in terms of geological time.
Thankyou for all the responses.
It’s sometimes hard to figure out the lay of the land when there is such a huge variance in future projections, from the ridiculous (Gore) to the more credible. It’s interesting that you are talking in hundreds or thousands of years because much of the information out there talks as if it’s all going to happen tomorrow.
The whole debate is murkied as much by AGW proponents who are more alarmist than scientific, as any of the so called ‘deniers’.
As far as I can determine the current ocean level is rising at about 20cm per century. The IPCC project a rise of 40cm this century. Gore stated 6m by the end of the century. Is there anywhere that the actual changes can be viewed? Being 10 years in is there any sign of faster rising oceans?
Flats,
to give credit to Gore, I think almost all of what he says can be backed up scientifically. I’ve heard him speak a number of times and am impressed. The timing of sea level question is really difficult but there’s more certainty that these large changes are bein “locked in”. So how much is a little easier than how fast.
The IPCC numbers accounted for thermal expansion (warming), some steric expansion (freshening) and glaciers and ice caps. The ice sheet components (Greenland, Antarctica) were not quantified. Frankly, this was a mistake, as it has been misread by many, including yourself.
The science since has upgraded the risk from ice sheets, and also from glaciers. Much of this is from past climate evidence. Estimates of up to 2 m per century rates of rise exist in the literature, though this is controversial. I suspect this number will be confirmed but needs more data points.
There is now a pretty wide body of scientific opinion that unchecked emissions could deliver > 1 m rise by 2100. Sea level rise is accelerating but it’s also really variable on short time scales. For the past decade, thermal expansion has been slower, but melt from ice has increased. The former is more variable than the latter over decadal time periods, so this is a worry.
Roger @28, could you please explain something about the graphs that Brian linked to @26? I am genuinely curious:
There seem to have been 4 separate periods when both CO2 and temperature increased to the 2-4′C range, that we are currently debating ahead of Copenhagen.
They are PEAKS, rather than plateaus. Why are they so peaky? Why did they fall away almost equally as “fast” as they occurred?
Probably this is not a question that can be answered in 3 paragraphs or less, but I am hoping that you will attempt the challenge?!
Elise,
the temps are Vostok, so represent a part of Antarctica. The last interglacial, where it was 1-2 degrees warmer globally for a few? thousand years, sea levels were 4-6 m higher with contributions from Antarctica and Greenland. The previous interglacials are pretty hard to spot in the geological record and I’m not up with the latest in global estimates, but the farther one goes back in time, the harder it is to find globally relevant proxies, whereas the point (regional) estimates from the ice are pretty good. Note that CO2 does not exceed 300 and it is globally mixed.
This interglacial is unusual in that it is long and sustained. There is some assertion that the combination of different orbital forcings is changing (a phase thing rather than a physical change to the orbits). That’s the best I can do off the top of my head.
Word, Pradesh.
Roger @30, thanks Roger, but I am none the wiser!
Why did the temperature and CO2 levels fall away so steeply? What was the physical mechanism?
What was the earth doing to “correct its condition”, given that us humans weren’t up to much at that stage? Where did the CO2 go, at such short notice?
Was there a massive growth of vegetation due to high CO2 levels, that got suddenly buried under piles of mud, taking the carbon with it (thus making coal and oil for us to squander this millenium)?
Or was there a big wobble in the third moon of Saturn, which sucked off the CO2?
Dreaded sunspots that leached CO2 from our atmosphere?
A visitation by space monsters that live on CO2?
Or something else entirely…?
And the UK achieved its emission cuts by, you guessed it: switching from coal power plants to natural gas.
Another example of COALFAIL.
Sorry to say,you have all typed some amazing crap that isn’t worth reading.Can you really assert a premise about how this ocean level will inundate in the same way across disimilar geographical locations,especially the consistently troubled Pacific Rim!? The word Tsunami wasn’t invented for AGW proponents,the Gulf Stream has been around before even the inventor of its presence had lifted his leg into any form of the equivalent of a nappy!I have read here,with some joy,I might add,that Humans no more about outer space than the World’s oceans,even the C.S.I.R.O has said similar.Then all matters like that are forgotten when it comes to AGW.Recently ,and now possibly endangered by oils pill, new reefs were discovered off the coastline.Spare me please from being insulting,are you tell in g me you can measure effectively with precision the movement of water,as either mass or volume with there being a distinction in the descriptions, without discovering even within the mass or volume,wether all physico-chemical formulaes behave in whatever are the equivalents in Laboratories and in nature elsewhere!?Earthquakes underwater have not been considered the phenomena they are today without a development in the understanding of their occurrences being subject to technical improvement.I doubt any claim based on a potential hazard to a countries shoreline determined by mathematical modelling will account for the geophysical reality a shoreline is.Only the longer history has substantiated access where,say corral deposits can be found in near or in mountainous ranges.Sand deposits go deep close to mountain ranges and even around mountain ranges.There is enough sand around to swallow all this CO2,by combining piping seasonal matters like dropping temperatures and micro organisms.
Elise, let me try (hope I’m right). As Roger said the graph was Vostock. I don’t know what zero was but probably a global average value, maybe 1950-1980, or preindustrial or whatever. With Vostock the highs would be higher than the global average and the lows lower. There is an interesting graph here if you scroll down to “The last 1.35 million years”. It’s the Western Equatorial Pacific SST, with some nice lines across to get a good comparison.
With the peaks, you have to explode out the x axis and they don’t look so pointy. Here’s one of the Eemiam vs the Holocene, I think from Vostok.
The driving factor in the past few million years has been the Malankovich cycles, with the 41ky cycle first dominating, then more recently (800kya?) the 100ky cycle. When the three cycles conspire to switch the thing into an ice age, then it happens. It is some comfort to me that we have had repeated partial meltings of Greenland and Antarctica which were turned around by the Malankovich cycles, which is a fairly weak form of climate forcing. Because it’s weak it’s being totally swamped by AGW.
As to where the CO2 goes, it presumably doesn’t blow off into space, so most will end up in the sea through a mixing process where the air meets the ocean, whence plankton and other little critters use it for shells, kark it, fall to the bottom and become limestone. There are other carbon sinks, including methane in permafrost, peat bogs and methane clathrates via the guts of little bugs chewing up vegetation.
I believe as a rule of thumb if you emit a bunch of CO2 about 20% lasts past 100 years and is virtually permanent, at least in net terms as balance is achieved in the carbon cycle. If you google “carbon cycle images” the most common one is this one which I think is actually a few decades old.
Elise,
during glacial/interglacial periods the two main drivers of the Earth’s response to orbital changes (which affect the net radiation hitting the Earth, where it is concentrated most – north or southern hemisphere and variations in that due to the shape of the orbit) are albedo changes and greenhouse gases. Albedo changes are thought to be the main trigger and greenhouse gases amplify that. The radiation changes are smooth – the Earth’s response is not. Because the Earth is a complex system, there is not a 1 to 1 correlation of CO2 and temperature on short time scales (a few centuries or less) unless one puts large amounts of greenhouse gases into the atmosphere. Much of the time, internal variability is the driver of these short term fluctuations.
When it’s cold there is lots of ice reflecting energy into space and lots of CO2 in the ocean (also in permafrost). The cold ocean high in CO2 is like beer or soda, which loses CO2 as it warms. When climate is warm there is more CO2 in the atmosphere. Albedo is the trigger most of the time and CO2 follows, although CO2 emissions from the Southern Ocean may have initiated some warming at the end of the last ice age. Methane follows CO2 in the atmosphere, because a warm Earth has more fire and wetlands (rotting organic matter in saturated conditons produces methane) as dos nitrous oxide, two more greenhouse gases.
So these changes are not all CO2. Melt a big ice sheet quickly (like the Laurentian ice sheet of the northern hemisphere at the end of the last ice age) and the radiation absorbed by the Earth will rise quickly, warming the planet. The oceans give up CO2, forests grow and absorb it, but there is still plenty left over for a positive feedback in the atmospheric response. That’s one reason why there is a worry about melting more ice at the poles – darker surfaces will absorb more energy perhaps accelrating warming in those regions. If humans were 100 times as long lived as we are, we might think the climate is as variable as people think the weather is in our much shorter lives.
By forcing climate with greenhouse gases, the chance of us triggering off one of these abrupt change mechanisms increases greatly, but no-one can say by how much.
TheDeshMan @ 24, good to hear from someone in the front line, though the news is not good. A reality check.
LE @ 33, yes and not with any contribution from an ETS. Or Germany, I think.
Brian @35 and Roger @36, thanks guys!
By the way, a clarification regarding this bit: “The cold ocean high in CO2 is like beer or soda, which loses CO2 as it warms.”
Presumably we are heading towards a potential double whammy, because our oceanic beer/soda is getting warm at the same time as we are putting more CO2 into the atmosphere?
We might start to lose the buffer of a big watery sponge to soak up our excesses, so to say, causing the climate to go ever more rapidly pear-shaped?
Maybe that was a metaphor too far…?
Elise, there was a report a couple of years ago about failing sinks. Down about 10% from memory. Roger will know.
And the more of our CO2 the ocean soaks up the more acidic (or less alkaline) it becomes.
Meanwhile at Climate Progress, Greenland and western Antarctica are shrinking faster than scientists thought and in some places are already in runaway melt mode:
BTW we’ve got an electrician fixing our power tomorrow, which will be off for most of the day, so no more bad news from me for at least 18 hours!
phillip sez, you have all typed some amazing crap that isn’t worth reading.
Coming from the person with some of the most unreadable nonsense in the Aus blogosphere, that’s rich. You’ve been told a thousand times to use the space after punctuation, and to use paragraphs. Why wont you?
Back on topic, VicUrban, a quasi-Government authority that does more for sustainable suburban design than most, has a remarkable blind spot regarding sea level rises and one of its centre-piece developments, Docklands. They’re planning for at most 18-59 cm of rises, the hyper-conservative figure taken I believe from TAR. I tried to ask them once what they were doing or thinking about this issue, they were distinctly uninterested. City of Melbourne is worried, it’s going to become their liability.
Using the “handy gizmo” above, Kingsford Smith Airport appears to start having problems at around the one metre mark. Given that no one has been able to come up with an new Sydney airport site for the last 50 years it could be interesting to see if rising sea levels could speed up the decision making process…. Not that KSA is the only piece of infrastructure under threat….
greg, not sure how much flying will be done in a world of 1 – 2 metre sea level rises. Sanity may have kicked in by then.
Sadly Elise@38, you are quite right. The past performance of our CO2 sinks is no predictor of future performance. The rate at which CO2 can be taken up will progressively decline, and of coruse if warmer conditions on the land also subvert the viability of forests. soils and the biota there (and in the oceans/large bodies of water too) then err … not good …
And then there’s that decomposing Arctic permafrost with its massive stores of CH4 just to kick matters along. Unless we hold onto that, savings at Copenhagen will be lost in the wash. That’s why savings NOW are better than savings between 2030 and 2100. We get paid with interest on those we make today, because we foreclose permafrost decomposition, extend the period when ocean sinks keep working as they have in the past, avoid albedo loss in the Arctic etc …
This article was in today’s Age, which is relevant: http://www.theage.com.au/national/against-the-tide-20091027-hj28.html
Wiful @ 40, the numbers you quote are from AR4 not from TAR. The latter had an upper bound of 88cm, I forget the lower bound. When AR4 came out with a midpoint of about 40cm there was much crowing from the galleries. The full story was something less than a Nobel Prize effort on the part of the IPCC. I went into this in some detail in June last year. I’ve just re-read it and was quite impressed!
Here’s the guts of it:
Stefan Rahmstorf then did a calculation
Rahmstorf’s numbers have themselves been quite influential and taken as more solid than he intended. He said:
Not to mention what would happen if ice sheet decay goes nonlinear.
In this regard the Climate Progress link I gave @ 39 is a worry. People have been a bit relaxed over Antarctica, but it’s the real wild card, especially since the Andrill Project showed that the WAIS has substantially collapsed and regrown over the last 5 million years.
Nevertheless it won’t all happen in the twinkling of an eye and Hansen’s guestimate of two metres by 2100 is still relevant. Which would be one helluva problem.
Greg @41, not just Sydney’s Kingsford Smith airport!
Take a gander at Brisbane’s Eagle Farm airport – swamp @ 1m sealevel rise.
That’s MEAN sea level, not including high tides or king tides or storm surges.
Aussies had better gear up for serious dike building and waterproofing, in the next couple of decades…
Oh, and by the way, the Dutch have already worked out that this is only economic for a meter or so below mean sea level. They did a big study that showed the water pressure for larger differences would force water through the ground under the dikes faster than you could economically pump it out. If we are headed for more than a meter of rises, then dikes will not be a silver bullet.
By the way, as a matter of risk assessment, one should have a worst case scenario of the FASTEST sea level rise we can reasonably expect. That is, how much higher in 2020, 2030, 2050, etc, if we include the highest physically feasible rate of melting of the Arctic, Greenland and Antarctica?
The IPCC has been anxious to be internationally credible and it appears that they have NOT given us the all-in worst case. Rather, they appear to have worked on a set of cases EXCLUDING any variables or feedback loops they can’t agree on.
This is not a good position for risk management – whether households are buying their retirement home, councils are approving land development, or governments are planning infrastructure.
We really must have a reasonable estimate of the worst case. Otherwise we have ill-informed people looking in the rearview mirror, and proclaiming that it only rose x% in the last decade (i.e. before the tipping point), so there is nothing to worry about….
Does anyone know if an all-in, maximum rate has been attempted?
Brian @45, oops I must have been typing at the same time.
You have partly answered the question, except for the non-linearity answer which is pending further study.
i love how antarctica is portrayed as melting even though it has had a positive increase in ice since 1978. i think it is very misleading to talk about melting in west antarctica without reference to increases in east antarctica that offset the change.
Elise, the last link I gave is the only attempt I’ve seen, which focusses on the saucer-like topography of Greenland under the ice and hence the need for the melting ice to exit through gateways. I think perhaps it neglects West Antarctica a bit where a lot of the ice is below sea level.
Hansen has been fond of reminding us that during the Meltwater pulse 1A event about 14.500 years ago the sea level rose an average of a metre every 20 years for 500 years. I think he overcooks that a bit. After all there was an awful lot of ice around at latitudes lower than now when that happened.
But, yes, the worst possible scenario is something that should exercise our minds.
I understand that somewhere early in the process you could lose all your lovely beaches, which require a bit of stability to build up and maintain shape.
Denier talking point 57a … Antarctica: It’s Growing!!
No it isn’t. West Antarctica is shrinking and East Antarctica either is too or is stable. Some snow deposition in East Antarctica makes it appear to be growing, but this is misleading because it really doesn’t affect the overall ice mass balance.
Here of course, the filth merchant troll quotes West Antarctica but ignore the specification to talk of Antarctica as a whole.
my understanding is the change in mass in antarctica has had a negative effect on the sea level. i think you have your talking points slightly wrong
the correct response is the increase in east antarctica is caused by an increase in precipitation which won’t continute forever.
drscroogemcduck,
Rignot et al. Nature Geoscience, 2008
Brian @49: “But, yes, the worst possible scenario is something that should exercise our minds.”
There’s an interesting set of classifications that could be made for risk management:
(a) Decisions where you can assign probabilities to the alternative outcomes (due to a lot of events which have provided historical data)
(b) Decisions where you have no real idea of the probabilities of alternative outcomes (because it has only happened a few times, or never happened before)
(c) Decisions where the outcomes from your decisions are affected by other’s decisions.
A lot of decision analysis and risk management theory has been developed for case (a), with the use of decision trees and monte carlo simulations and EMVs (Expected Monetary Value) weighting the outcomes according to their probabilities.
That’s all very nice and good. The bugger of it all, is that climate change is most likely case (b) with case (c) thrown in for good measure.
In short case (c) is the province of game theory – you know, zero sum games, prisoners dilemmas, tragedy of the commons, etc. This is the problem for Copenhagen – how to get everyone to participate and play fair.
The interesting thing here, is how do you assess case (b) for risk management?
The proposal is that you draw up a table, which identifies a set of choices/actions (rows), and a set of scenarios (columns) for High, Medium and Low conditions. Then you populate the table with your outcomes. You can’t assign probabilities reliably, but you can make an estimate of the cost of different outcomes.
Looking at your table, you can discuss what “decision rule” will apply:
1. maximax (maximise upside) – risk seeking
2. maximin (minimise downside) – risk aversion
3. minimax regret (minimise opportunity cost) – minimise the cost of backing the wrong horse.
For example, in the case of investment in late 2007 we were headed for a possible major calamity, or then again maybe a “stronger for longer, supercycle” depending on which set of economists you believed. Given the inability to predict and assign probabilities, we could have decided the leadup to the GFC was a case (b).
We could have made a simplistic decision table with 3 rows (all in stocks, 50-50 stocks and cash, all cash), and 3 columns (boom, plateau, bust).
Obviously you get the best answer for decision rule 1 with all stocks-boom, and rule 2 is all cash-bust. The classic optimist-pessimist contrast.
This is where Isaac Newton went wrong with investing in the South Sea bubble – first optimisism (huge stock holdings), then pessimism (sold out), then regretting (bought in again), then crash! Oh bugger…! He should have used Rule 3.
Rule 3 (minimax regret) is the interesting one – we could have acknowledged a priori that we would regret shifting to all cash (8% interest or so) if the 2007 boom continued, and more seriously regret all stocks if a 2008 bust occurred. Minimising your regret, or “minimising your opportunity costs” if you prefer that expression, leads to a 50-50 choice in this simplistic example.
So what has GFC to do with climate change? Not much except that CC is another, more difficult case (b). We will all be the wiser in retrospect, with our 20-20 hindsight. But we have to make investment decisions today (no action on CC is a form of defacto investment decision).
Can we Aussies, let alone the G20 countries, even agree on a range of outcomes and the relative costs in each case?
Which decision rule are we arguing for?
Some who are strongly convinced of worst case scenarios (e.g the Greens?) would probably argue for Rule 2 immediate strong action? Those who aren’t yet convinced of climate change (e.g. Barnaby Joyce and more than half of the Liberals and Nationals) may argue for Rule 1? There is little common ground here.
In between, could we have the ALP and the enlightened Liberals with some sort of Rule 3, hedging our bets or minimising the opportunity costs from a wrong decision?
Would it help break the deadlock on this upcoming debate, if the Aussie electorate and pollies were clear and agreed on what decision rule we are applying?
Elise,
this stuff is precisely what I work on, so interesting post. All the tools you mention can be used in various contexts. It gets even hairier than you describe – there are multiple framings of risk – you won’t get a coherent description of the decision rules from policy makers. Those that do have a good grasp on it don’t want to telegraph what they have done to manage the political risks because that detracts from the other risks! One of my responses to these multiple framings and debates held at cross purposes is to get more deeply into cultural theory and the psychology of risk perception. As researchers, one of the thing we have to do is to hold a mirror up to these multiple views, so that people can gain a broader perspective.
Subjective probabilities in uncertain science can be tested for what impact they may have on decisions – this tells you whether the uncertainty matters or not. This technique has been under-utilised.
The incompletely quantified sea level projections by the IPCC in AR4 were an error of judgement. The climate modellers still think in forecasting terms – they also need to get a better grounding in managing uncertainty and risk using a combination of Bayesian methods and techniques used by the social sciences.
Can I just mention that if people say, as some do, that losing all the ice sheets would take 3000 years, that is still an average sea level rise of about 2.5m per century, which would be extremely difficult to cope with even if it happened in a nice smooth linear fashion.
If people want to think more about Antarctica I did a fairly detailed post on the Wilkins ice bridge collapse which tried to put it in some context of what was happening overall.
There is an interesting post by Rahmstorf and Vermeer at RealClimate. What’s going to happen in the 21st century? Too hard.
Stefan Rahmstorf’s comment at comment 33 is a worry:
We are pushing the climate harder than it’s been pushed probably since 65mya.
Roger @54: “Subjective probabilities in uncertain science can be tested for what impact they may have on decisions – this tells you whether the uncertainty matters or not. This technique has been under-utilised.”
I’m not sure if this is the same as a decision tree technique, where you draw up the tree with the various decision nodes and costs, but you leave the probabilities flexible. First you set your best guess at all the probabilities, and see which set of decisions gives the best outcome.
Then you say, “What would the probability have to be, in order to tip the balance and make another set of decisions preferable?” So you start progressively changing the probabilities and see how far you have to go before your decision changes.
For a practical example, we could consider peak oil and buying a new family car. This makes an interesting tree.
The first decision node might be “Buy now, or wait a few years and keep driving the old gas guzzler?” If you wait a few years, then you put in a set of average petrol costs (e.g. $1/litre, $3/litre, $5/litre) and thus running costs for the old banger, plus higher maintenance costs for the aging car.
If you decide to buy now, then you put in the sale price on your old banger and go straight into another decision node “Buy small petrol, Buy diesel, Buy hybrid?”. For each alternative, you put a purchase price, and a set of running costs based on average petrol costs.
Then in say 5 years, plug-in electric and fully electric vehicles are available, so you have another decision node “Sell the old banger now, or continue running it into the ground for another 5 years?”. If you sell, then you put a sale price and a decision node for the different types of new vehicle.
For the other branches (where you bought a new car 5 years ago), you could also have a decision node for “Trade-in on a plug-in hybrid or fully electric?”
Meanwhile peak oil may have hit big time, so fuel prices may have skyrocketted and old bangers are only worth scrap metal.
Anyway, the upshot is that you can fiddle with the probabilities of different oil prices, and see at what point the decision flips from one best outcome to another.
To put it simply, if we have say 90% probability of today’s fuel prices continuing, then keeping the old banger is probably going to be the best financial decision. If we have a 90% probability of $5/litre oil, then the decision will probably be at least diesel, and possibly hybrid depending on purchase cost and maintenance costs.
Perhaps it tips over from old banger to diesel/hybrid at 50% probability of high prices? If this seems easily achievable (subjective assessment of probability) given the way things are going, then it tells you what to do, even though you don’t know the exact probabilities.
This would be how you can justify the subjective decision process on reasonable financial grounds.
But of course cars are not a purely financial decision. As better half has explained to me, they are also an emotional/image/performance decision for most men, which is why Top Gear is so popular…
Thye BBC has a neat summary of the Managing Our Coastal Zone in a Changing Climate report.
Elise @ 53 and 56, Roger @ 54, that is one of the most fascinating little interchanges endless threads of commentary have thrown up. Thanks
Brian @58, glad to have contributed something you find interesting.
I must say that your information has been likewise fascinating to me!
Thanks in return
It’s also a bit disheartening when people think (maybe correclty) that substantial sea level rises are a ways off into the future, so we just don’t have to worry about them, we only have to concern ourselves with 1 – 2 metres this century.
Discounting the future is all well and good, but basically accepting that people in two centuries will have to deal with ten metres and that’s not our problem is deeply immoral.
@ 48: the media has no scruples as it just makes money!
Hey Hey Australia: Tesla Roadster Breaks EV World Record: 313 Miles on Single Charge (501 KM) The 10th Annual Global Green Challenge
The Global Green Challenge (a kind of spin off from the World Solar Challenge) in Australia…