Guest Post by Willis Eschenbach
There’s an old con game that has been played on the suckers for hundreds and hundreds of years. It is done in various forms, with various objects, under various names—three card monty, the shell game, Thimblerig, bottle caps, cups and ball, the game is the same in every one. The essence is, the con man puts a pea under a shell, then switches the shells around and asks which shell is hiding the pea.
Figure 1. The Conjuror, by Hieronymus Bosch, painted 1475-1480. The type of tricks the conjuror is doing are thought to be among the origins of the shell game.
I bring this up because our favorite conjuror, James Hansen, is up to his old tricks again. He has a new paper out, Paleoclimate Implications for Human-Made Climate Change, And as always, you have to figure out which shell is hiding the pea.
Here is his money graph, the one that is getting lots of play around the blogosphere. The main observation I’ve seen people making is that having been bitten by previous failed prognostications, Hansen is taking the well-tested Nostradamus route now, and is predicting sea level rise for when he’ll be 137 years old or so …
Figure 2. Hansen’s Figure 7: ORIGINAL CAPTION: “Five-meter sea level change in 21st century under assumption of linear change and exponential change (Hansen, 2007), the latter with a 10-year doubling time.”
Folks are saying that the bad news is, it looks like we won’t be able to tell until 2040 or so if Hansen’s claim is true. But that’s not the case at all. Those folks are not keeping close enough watch on the pea.
In the paper Hansen says:
Sea level change estimates for 21st century.
IPCC (2007) projected sea level rise by the end of this century of about 29 cm (midrange 20-43 cm, full range 18-59 cm). These projections did not include contributions from ice sheet dynamics, on the grounds that ice sheet physics is not understood well enough.
Rahmstorf (2007) made an important contribution to the sea level discussion by pointing out that even a linear relation between global temperature and the rate of sea level rise, calibrated with 20th century data, implies a 21st [century] sea level rise of about a meter, given expected global warming for BAU greenhouse gas emissions. …
… Hansen (2005, 2007) argues that amplifying feedbacks make ice sheet disintegration necessarily highly non-linear, and that IPCC’s BAU forcing is so huge that it is difficult to see how ice shelves would survive. As warming increases, the number of ice streams contributing to mass loss will increase, contributing to a nonlinear response that should be approximated better by an exponential than by a linear fit. Hansen (2007) suggested that a 10-year doubling time was plausible, and pointed out that such a doubling time, from a 1 mm per year ice sheet contribution to sea level in the decade 2005-2015, would lead to a cumulative 5 m sea level rise by 2095.
The short version of that is:
• The IPCC predicts sea level rise of about a foot (30 cm), but they don’t take ice into account.
• Rahmstorf says a linear projection gives about a metre (3.3 feet) of sea level rise.
• Hansen 2007 says there’s a missing exponential term in Rahmstorf’s work, because the ice will be melting faster and faster every year.
OK, so Hansen 2011 rests on the claims made in Hansen (2007), which turns out to be Scientific reticence and sea level rise. At the end of Section 4 Hansen says that Rahmstorf estimates a 1-metre sea level rise, but that a non-linear ice melting term should be added to the Rahmstorf rise.
Under BAU [“Business As Usual”] forcing in the 21st century, the sea level rise surely will be dominated by a third term: (3) ice sheet disintegration. This third term was small until the past few years, but it is has at least doubled in the past decade and is now close to 1 mm/year, based on the gravity satellite measurements discussed above. … As a quantitative example, let us say that the ice sheet contribution is 1 cm for the decade 2005–15 and that it doubles each decade until the West Antarctic ice sheet is largely depleted. That time constant yields a sea level rise of the order of 5 m this century.
So to get the final Hansen projection, we need to see what is happening in Rahmstorf, A Semi-Empirical Approach to Projecting Future Sea-Level Rise, paywalled, where we find the following graph of projected sea level rise.
Figure 3. The Rahmstorf estimate of sea level rise, to which Hansen says an exponentially growing ice term should be added.
ORIGINAL CAPTION: Past sea level and sea-level projections from 1990 to 2100 based on global mean temperature projections of the IPCC TAR. The gray uncertainty range spans the range of temperature rise of 1.4° to 5.8° C, having been combined with the best statistical fit shown in Fig. 2. The dashed gray lines show the added uncertainty due to the statistical error of the fit of Fig. 2. Colored dashed lines are the individual scenarios as shown in (1) [Ref. 1 is the IPCC TAR Bible, no page given]; the light blue line is the A1FI scenario, and the yellow line is the B1 scenario.
(In passing, let me again protest the use of the entire IPCC Third Annual Report, thousands of pages, as a reference without giving us chapter and verse in the way of page numbers. My high school science teacher would have slapped my hand for that, it’s a joke.)
The upper blue line is the one that gives us about a meter of sea level rise. So I took that as Rahmstorf’s 1 metre rise. To that I added, as Hansen claims we should, an amount that starts at 0.5 cm in 2000 and doubles every ten years. This is following Hansen’s claim that the non-linear ice disintegration is a separate term that starts small but will “come to dominate” the sea level rise over the century. The result is shown in Figure 4.
Figure 4. Rahmstorfs predicted rise (blue), Hansen’s projected additional rise from “non-linear ice disintegration” (dark red), and total sea level rise (green) predicted in H2011. I have included the last century’s rise of 16 cm, as calculated by Rahmstorf, in the lower right corner for comparison purposes. IMAGE SOURCE
OK, so what Hansen is actually predicting is the green line. However, his real forecast is actually much worse than that. Hansen again, emphasis mine:
The eventual sea level rise due to expected global warming under BAU GHG [greenhouse gas] scenarios is several tens of meters, as discussed at the beginning of this section.
I’m going with “several tens” to mean more than two, so he’s predicting a 30 metre sea level rise!!! … I guess he figured nobody paid any attention when Al Gore threatened us with a 20 metre sea level rise, so he’d better pull out all the stops and give us a real scare, something to make us shake in our panties.
There is a bit of good news, however. Both the Rahmstorf and the Hansen projections are already way above the reality. Since 1993, when the satellites started measuring sea level, we’ve gone up about 4.6 cm (1993-2011). Rahmstorf’s projection is 6.4 cm for that time period, about 40% too high already. Hansen’s larger projection is 7.2 centimetres rise over that time, or 55% too high.
The annual rise is also entertaining. According to the satellites, the trend 1993-2011 was 3.2 mm/yr, and has been declining recently. The change 2009-2010 was under a mm, at 0.9 mm/yr. And 2010-2011 was just about flat.
In 2010-2011, Rahmstorf’s projected rise is already 4.5 mm/yr, about fifty percent larger than the actual rate of the last 18 years. And Hansen’s annual rise is even worse, at 5.3 mm per year.
So both in terms of 1993-2011 rise, as well as current annual rise, both Rahmstorf and Hansen are already way above observations. But wait, there’s more.
Hansen’s rate of sea level rise is supposed to be accelerating, as is Rahmstorf’s rate. By 2020 Hansen says it should be rising at 6.3 mm per year, and everlastingly upwards after that. But in fact we’re already way under their supposed rates of annual increase, and the observed rate of rise is declining …
How does Hansen get these nonsensical numbers? Well, he noticed something in the observations.
This third term [melting ice] was small until the past few years, but it is has at least doubled in the past decade …
My high school science teacher, Mrs. Henniger, bless her, thought extending a linear trend into the future was a crime against nature, and I would hesitate to express her opinion on Hansen blithely extending a ~ 7% annual increase for a hundred years. That kind of compound interest turns a centimeter (3/8″) into 5 metres (16 feet). If Dr. Hansen had submitted this nonsense to her, you would not have been able to read it when it came back for the red pencil scribbles.
You can’t do that, folks. You can’t just observe that something has doubled in the last decade, and then extend that exponential growth out for a century. That’s beyond wishful thinking. That’s magical thinking.
Two final points. First, the pea under the walnut shells. Note carefully what Hansen has done. He has claimed that the sea level rise will be “several tens of metres”. This is at least thirty metres, or a hundred feet, of sea level rise.
He seems to be at least somewhat supporting this claim with his Figure 7 (my figure 2). But if you look at the caption, this is not a forecast, a projection, or a scenario of any kind. Instead, this is merely an “approximation” of what a linear sea level rise might look like and what an exponential rise might look like. You know, in case you didn’t understand “linear” and “exponential”. His actual forecast is under another walnut shell somewhere. We know his “Approximation” can’t be a real projection because it shows almost no rise occurring currently, or for some years.
Second, even this doesn’t begin to unravel the errors, deceptions, alarmism, and con games in Hansen’s work. Do you see the guy in the dark vest and the white pants and shirt at the left of Hieronymus’s painting at the top? See what he has in his hand while he’s looking all innocent at the sky? See who it’s chained to? Hansen’s not really the shell game conjurer, that guy’s a piker, he’s not making much money on the game.
Hansen’s the guy in the dark vest with his hand on your pocketbook …
w.
[UPDATE]
Joel Shore observed correctly that Hansen was basing his estimate of a huge sea level rise on paleoclimate date. Joel is right that Hansen claimed the paleoclimate data shows a rise of 20 metres for every 1°C temperature rise. Because of this, Hansen says that a 2°C future temperature rise will give a 40 metre sea level rise.
Let’s take a bit calmer look at what we know. We know that when there is an ice age, a lot of the water in the ocean behaves badly. It goes up on the land as mainly northern hemisphere ice and snow and glaciers. As a result, the sea level drops by a hundred metres or so. The glaciers stay there until the ice age ends, at which point they melt, and the sea level rises again. Since we’re in an interglacial, right now the glaciers are mostly melted.
So I would certainly not expect further warming to have much effect on melting or sea level. The easy ice is all melted, the giant miles-thick Northern Hemisphere glaciers are almost all melted back into the ocean. The rest are hiding mostly on north slopes in northern climes. So where is the meltwater going to come from?
And curiously, what I found out from Joel’s question is that if you know where to look, we can see that the graphs in Hansen’s own paper bear me out. They say the oceans won’t rise. I don’t particularly believe Hansen’s results, but presuming that they are correct for the sake of discussion, then let’s look at his graphs.
Look first at the sea level during the past four interglacial periods. I stuck a ruler on it so you can see what I mean.
As you can see, at the level of detail of their graph the sea level has never been higher than it than it is now.
Now look at their temperature observations and reconstruction:
According to Hansen, temperatures have been as much as 2.5°C higher than at present … but the sea level hasn’t ever been higher than at present.
If Hansen’s claim were true, that a 1°C temperature rise leads to a 20 m sea level rise, we should see sea levels forty metres or more above present levels in Hansen’s graph (b). Look at the scale on the left of graph (b), that’s off the top of the chart.
Instead, we see nothing of the sort. We see much warmer periods in the past, but the sea levels are indistinguishable from present levels. Hansen’s own graphs show that he is wrong. So it appears that Hansen is doing the same thing, he’s extrapolating a linear trend out well beyond the end.
He’s noticed that when warming temperatures were melting the huge glaciers over Chicago, the sea level rose quickly. Unfortunately, he has then extended that trend well past the time when there are no glaciers in Chicago left to melt …
w.
@Willis Eschenbach
Thanks for the post (http://wattsupwiththat.com/2012/01/29/hansens-sea-shell-game/#comment-879219) however to me you illustrate my problem, not a solution.
“Consider a one inch cube. It has a volume of one cubic inch, and a surface of six square inches.
Consider a two inch cube. It has a volume of 8 cubic inches, and a surface area of 24 square inches.”
To me melting only occurs at the point of contact between the ice and the medium which is warming it, not throughout the whole cube, hence my original “silly” question. Your reply seems to treat the cube as an object which will conduct the heat throughout itself which is against my understanding. My understanding is that melting transports the heat away before it can be conducted into the object. for example a cube of ice on a hot plate melts at the point of contact where water and later steam acts as a barrier to more melting by transporting the heat away from the cube. Surely glaciers would act more like that?
It referred to 40 years from then, which works out to 2030. Yes, we’re halfway there.
This is off on a tangent, but fascinating – bbc program clip of apparently the only place on earth where you can go under sea ice to exposed sea floor. Incredible footage of a regular tidal drop of over 12 meters (~40 ft) leaving what was floating sea ice unsupported above the sea floor. Natives chip thru the surface, and go under the ice to retrieve mussels!!! Apparently they’ve only got about 30 minutes before the tide comes back in and they have to scramble out again.
http://www.youtube.com/watch_popup?v=Z0qGvC3vqaA
I honestly think that the man is going insane.
Hansen’s prediction reminds me of another famous linear projection. Mark Twain, extrapolating from the decreasing length of the Lwr Mississippi River from 1722 when a loop was cut off to its present length in 1875, remarked that ‘Anyone who is not blind or idiotic can see that 742 years from now the Lwr Mississippi will be one and three quarters of a mile long.’
Joel Shore says:
January 29, 2012 at 7:40 pm
“…One might be able to quibble about whether it is really 20 m per 1 C…but I think the general conclusion from the paleoclimate data that the sensitivity of sea level to temperature is very strong seems to be correct. Then the question becomes how fast that sea level rise can be realized…”
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Joel
That is only half the picture. The question is twofold: “…the question becomes how fast that sea level rise can be realized” AND for how long can that realisation be maintained.’
The paleo record deals with the rate of ice melt predominantly from mid latitudes, as this becomes all exhausted the rate of sea level change slows since it is more difficult to melt ice from high latitudes even if global temperatures are by then somewhat warmer tha they were when the mid latituted ice began melting. .
http://www.usatoday.com/weather/resources/askjack/2004-11-21-melting-polar-ice_x.htm
Hmmmmmmmmmmmmmmm………………………………
It is issues like this raised by Willis which demonstrate the weakness of peer review.
The point raised by Willis is a basic point, and is an obvious weakness in the Hansen paper. That being the case why was it not raised in the course of peer review? and thus why does the Hansen paper not address this issue and if there is a good argumnent, against the point raised by Willis, set that argument out?
How can one have faith in peer reviewed literature when in practice it is often so weak?
“Mrs. Henniger, bless her, thought extending a linear trend into the future was a crime against nature, and I would hesitate to express her opinion on Hansen”
Why hesitate ?
If temperatures do rise about 3.0C, the Greenland glaciers will melt out but it will take 5,000 to 10,000 years.
The best example we have is the interglacial 400,000 years ago (see Willis’ chart) which was a long interglacial of over 20,000 years. This is like the current one which is expected to be the longest interglacial yet and it will be the longest interglacial yet if temperatures rise 3.0C.
In the interglacial 400,000 years ago, the southern third of Greenland melted out and small trees even grew in the southern interior. But temperatures were not especially warm in that interglacial, it was just long. Greenland is too far south to have glaciers in the southern half. They are only there because of the ice ages and the fact that the interglacials are not long enough to break the back of 2 km high glaciers building down from northern Greenland.
So we were already going to get sea level rise as Greenland slowly melts down as the interglacial continues.
Antarctica? 3.0C of warming will certainly melt back lots of Antarctica but, again, it will take thousands and thousands of years.
So Hansen has taken something which takes 20,000 years (or least it has in the past when temperatures were close to the 3.0C temperature rise) and shrunk that timeline down to 100 years.
You know, Hansen would be right if we were warming out of an ice age and going into the next warm period. Of course that is not what he is saying. I wonder what will happen when we go to the next prolonged (100ky) warm period, will there be people at the onset claiming that the loss of the mile thick continental glaciers will be the death of the world? Will we have built up cities along the tropical shorelines 30 meters or more below the current shore and have to evacuate? Will people find a way to blame themselves for their sins against the natural deity and give up all their worldly goods to assuage their sins?
As far as I can tell, no one is opining that we are leaving this ice age any time soon, and most seem to be saying that we are in for at least one more glaciation period before the next prolonged warm period. I wish the Gaea worshipers would quit attempting to assuage their guilt with my money and job!
It is right to ask the question where is the 30m of sea water going to come from?
Whilst it is true that there is much ice in Antartica, the question becomes how easy is it to melt that ice, how much energy is required?
Much of the ice in Antartica is on land (it is only land ice that will raise sea levels and hence we are only interested in that ice). Hence, a warming ocean will do little to melt this ice. The high latitude of Antartica will always result in short summers and weak solar irradiance. The temperature of Antartica will always be cold. Given these basic facts how long will it take to melt a significant proportion of land based Antartican ice? The answer is that 100 years will make little impression. We are taling 1000s of years if not 10,000s of years.
It is the same issue as the Himalayan glaciers (but on an even more extreme scale). Given the volume and the high altitude and resultant temperatures due to dry adiabatic lapse rate the Himalayan glaciers can’t me melted in 30 years or even in 300 years.
It is simply impossible that any substantial volume of land based Antartica ice could be melted in 100 years. Any scientist who does not recognise this has no understanding or feel for the huge numbers and the huge amount of energy that would be involved in such task.
DEEBEE says:
January 30, 2012 at 2:56 am
If these guys were real sceintists — without superhuman agendas — the interesting question to ask would be why such a small temperature rise in the latest cycle has resulted in a historically maximal sea level change. BUt seems focussing on that would have to explain unprecedented higher sea levels. IMO that is the pea that is being hidden.
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Deebee, no one know what you are writing about. What “small temperature rise in the latest cycle has resulted in a historically maximal sea level change” Show your work please.
Rational Debate says:
January 30, 2012 at 3:52 am
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Very col video. Forthe last third I was convinced Hansen was right!
It seems to me that the main arbiter of where sea level decides to stay (and why it levels off at roughly where we are now) is the continental land mass of Antarctica. We have been sitting at a level because we have warmed to where the southern sea ice reaches its minimum. The land of Antarctica prevents further melting.
Looking at the Southern Sea Ice images we can watch this happening year after year. The temperature rises to a level where the summer maximum shrinks the ice back to roughly the size of the Antarctic land mass. There it stops. Until there is a temperature rise that can clear large amounts of ice from the Antarctic land mass during the southern summer there will be no visible increase in sea level.
If I am wrong in this please let me know.
But as I see it – to get his sea level rise Hansen would need to either get rid of Antarctica or hugely increase the warming mechanism (a mechanism I have yet to see proven in any form).
I am impressed that he moved away from just linear projections. This is truly progress. However, how does he know that it’s not a sigmoidal function with a fairly low asymptote? Since there is only so much water and ice on the planet one knows that it’s definitely a sigmoidal function. The asymptote will depend on the equilibrium amount of high and water….it doesn’t really matter the slope of getting there…what matters is the physics that drive the steady state equilibrium amount of ocean water. So sadly even though he has made progress beyond the simple linear projection, it’s still a giant fail in understanding.
Two final points. First, the pea under the walnut shells. Note carefully what Hansen has done. He has claimed that the sea level rise will be “several tens of metres”. This is at least thirty metres, or a hundred feet, of sea level rise.
What does he really believe? Check the length of the lease on the New York offices to find out.
On the bright side, if he’s right, it will be much easier to deliver coal to power plants by using barges. That’ll get rid of the “death trains.”
richard verney says:
January 30, 2012 at 4:08 am
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Richard, Willis gave that answer in detail, but the “educated” Joel,, in troll like fashion, ignored it entirely, then tried to chastise Willis for not reporting that Hansen hedged his own silly assumptions.
Hansen shouts “the world is ending, the theater is on fire”, and then, after everyone panics, giving him a dime for saving their lives, on the way out, he says, well it could be on fire someday.
Willis, I’ve recently posted the specific references that you have requested here WUWT, and I think many folks here know them. For latecomers, here are some excerpts (a Google search readily finds all the referenced articles freely available):
With specific regard to the BEST hockey stick, please let me point to the striking similarity of Hansen’s Figure 6 and 7 (from the 1981 Science article, to the 2011 findings of the BEST Project’s “Decadal Variations in the Global Atmospheric Land Temperatures” (see BEST Figure 1). Both Hansen’s 1981 predictions, and the 2011 BEST confirmations, are temperature-change “hockey-sticks” plain and simple.
Willis, I thank you sincerely for asking these fine questions, to which the literature clear and publicly verifiable answers. This is what solid science and rational skepticism are all about.
Elevator Answer to Willis Eschenbach’s Questions: The Northwest Passage has opened and the BEST temperatures have “hockey-sticked”, and both findings are in excellent accord with the specific predictions that James Hansen and his colleagues made in their 1981 Science article titled “Climate Impact of Increasing Atmospheric Carbon Dioxide”.
This article is just plain wrong..Last interglacial features RSL at ~4 m above present with temperatures~2 degrees warmer than present. No doubt sea levels will rise by metres.. IF warming continues.
http://www.youtube.com/embed/nj6DK_WX7Yc
‘a physicist’ says:
“the BEST temperatures have “hockey-sticked”…”
Wrong! Wrong, Wrong, WRONG.
Muller’s BEST analysis has been thoroughly DEBUNKED.
‘A physicist’ has been wrong about every one of his assertions. That’s what happens when your beliefs are based on religios faith, instead of honest science.
“Look, again a hockey-stick graph! So it must be true! We’re all doomed!”
Ahem –
Yeah, sure, we’re all doomed to die one way or another some day – but certainly not by rising sea-levels for sure.
What a raccoon…
A physicist says: Before the 21st century, I believe there is no record of any wooden ship ever making the Northwest passage without over-wintering in the ice at least one year, sometimes two years, or (sadly frequently) never returning at all.
Keith W. says: Sorry, Physicist, but you lose. The St. Roch, a RCMP schooner made of Douglas Fir and Eucalyptus sailed through the Northwest Passage from Halifax, NS to Vancouver, BC in 86 days in 1944, using a previously uncharted route. Keith W., please let publicly acknowledge that my assertion was wrong, and that your outstanding post is 100% right-on-the-facts!
And please let me thank you too, for alerting everyone to the wonderful voyages of the brave Arctic ship St. Roch and her gallant crew!
Henceforth I shall say: “Before the 21st century, there is precisely one record of any wooden ship ever making the Northwest passage without over-wintering.” It is sobering to reflect, that with the Northwest Passage melting wide-open every summer, these brave Arctic sea-adventures very likely can never happen again.
“With specific regard to the BEST hockey stick, please let me point to the striking similarity of Hansen’s Figure 6 and 7 (from the 1981 Science article, to the 2011 findings of the BEST Project’s “Decadal Variations in the Global Atmospheric Land Temperatures” (see BEST Figure 1). Both Hansen’s 1981 predictions, and the 2011 BEST confirmations, are temperature-change “hockey-sticks” plain and simple.”
So you’re proposing an ‘eyeball’ comparison as validation of a prediction? I’ve looked at both and they don’t appear to be similar much at all. I don’t see how a scientist could claim validation based on this.