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.
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Gneiss:
“Will, what’s your source for these 5-6 sea ice mass records since 2007?”
My source is: Arctic Climate Research at the University of Illinois. If you want to debate these issues this is fine, but I think you should first be familiar with the basic data sources…
See here:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.antarctic.png
Gneiss:
No, it’s not. For example, Rignot et al. (2011) found good agreement between two methods of estimating Greenland and Antarctic mass balance. They conclude:
“Using the two-decade long MBM observation record, we determine that ice sheet loss is accelerating by 36.3 ± 2 Gt/yr2, or 3 times larger than from mountain glaciers and ice caps (GIC). The magnitude of the acceleration suggests that ice sheets will be the dominant contributors to sea level rise in forthcoming decades, and will likely exceed the IPCC projections for the contribution of ice sheets to sea level rise in the 21st century”
Me:
This is what the IPCC states:
Thermal expansion is the largest component, contributing 70 to 75% of the central estimate in these projections for all scenarios. Glaciers, ice caps and the Greenland Ice Sheet are also projected to contribute positively to sea level. General Circulation Models indicate that the Antarctic Ice Sheet will receive increased snowfall without experiencing substantial surface melting, thus gaining mass and contributing negatively to sea level.
See here:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-es-8-sea-level.html
Now it is worth noting that the West Antarctic ice streams have increased in recent years. However it’s remise to cite a paper that discusses this issue without noting increases in ice extent in the southern high latitudes and so forth. The ‘rapid’ warming in one region and the ‘rapid’ cooling in other regions are possibly related to complex patterns of atmospheric circulation change. Anyway, the point here is try to avoid making sweeping generalisations if possible.
Joel wrote,
“Not really…You need to read the discussion that Hansen has about the ice core data vs the deep ocean data. Hansen does not believe that the ice core data gives as reliable an indication of global temperatures as the deep ocean data, which suggests that the global temperature was in fact not that much higher than today in previous interglacials.”
There is a vast amount of data on the temperature of past interglacials, particularly the last (Eemian/Sangamonian/MIS 5e). There is absolutely no doubt that it was considerably warmer than the present essentially everywhere. Just a few random paleontological examples:
Capybaras in South Carolina
Hippopotami in Yorkshire
Monkeys in Bavaria
Water buffaloes on the Rhine
Cory’s Shearwaters breeding in Wales
Birch forests in northeastern Greenland
Larch forests on the coast of North-east Siberia
Sea level was about 20 metres higher about 2.5 million years ago, before the ice ages really started. So Antarctica and Greenland accumulated more ice around this time.
If you go back 95 million years ago, sea level was 250 metres higher and 20% of the continents were flooded by shallow ocean. It was warm enough that there was, essentially, no ice but the main reason was that the Atlantic Ocean had just formed and its average depth was less than half of today. Less average global ocean depth, the water comes up onto land.
———————
I wouldn’t use any of Hansen’s paleoclimate prognostications. I have all the data he has used and there is no way to process it into the numbers he quotes. It is simply distortion. This is very common with the very pro-AGW climate scientists in terms of the paleodata. They actually think noone will doublecheck their numbers and the other climate scientists obviously don’t. That mean we have to.
And now for something completely different.
How high’s the water momma?
[youtube=http://www.youtube.com/watch?v=kqOOuEImTQY&w=640&h=360]
JJ says:
January 30, 2012 at 7:54 pm
CAGW is on the way down, and some of the folks who have been pushing it must realize that they might be held culpable for their actions.
It would appear that Hansen is laying the groundwork for an insanity defense.
==========================
JJ, the curious part is watching Joel and “aphyscistnot” cling to Hansen;s insanity more tightly then any “cling to their guns and religion.”
Will Nitschke says:
I’ll let you read what he says in his paper.
But, he is not rejecting the data. He is merely saying that the general rule-of-thumb that the temperature change determined at these high latitudes is double the change in average temperature may not be very accurate for those interglacial temperatures. It is clear from the data that there is some breakdown in the correlation between the deep ocean temperatures and those ice cores temperatures, since one implies average global temperatures in previous interglacials that were considerably higher than the current interglacial whereas the other implies average global temperatures being about the same as in those previous interglacials.
OK, I see that the salon.com reporter is now covering for Hansen. In her 2001 story she wrote this.
But now she is claiming that she asked him about 40 years despite the fact that she put her question in quotes.
She pathetically ruined the credibility of all her future quotes merely to cover for his stupid prediction.
Willis says:
I am not arguing this…Hansen is. I don’t know enough about the data to have a strong opinion.
Note, by the way, that the claim is not that it was not any warmer in the Eemian…but just that it was not as much warmer as the ice core record would imply. It is clear that the ice core record and the deep ocean record disagree on this point of how much warmer it was, so they can’t both be right. Hence, the question becomes which data is closer to being correct and Hansen argues that the deep ocean data is more reliable.
Yeah…It doesn’t look like quite 5m from that plot. That claim may come from higher-resolution data…I’m not sure. Wikipedia talks of the sea level during the Eemian as being 5-7 m higher than today. ( http://en.wikipedia.org/wiki/Eemian_sea )
Willis Eschenbach says:
January 30, 2012 at 12:02 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.
Let’s be fair here. I always like having Joel comment on my posts. Why? Because his science-fu is strong. In this instance, he pointed out (quite correctly) that Hansen’s claims were based on the paleo stuff.”
Willis, I appreciate your intention to be fair sports with Joel. It might be that at the change from ice-age to interglacial the sea level varies with a certain amount of meters per 1°C. My point was that we are not in such a period.
We are in an interglacial already.
According to Mann’s temperature chart we have seen an unprecedented heating of the world of over 1°C lately. According to Hansen’s and Joel’s logic this should have brought us 20 m sea level rise.
To say the next 1°C will bring something so spectacular that the last degree did not, one should have very good reasons to say this, not only showing at what happened when the ice age ended and ignore the fresh history. The prediction based on paleoclimate is very much to question by the recent history.
When one looks at the tide gauge measurements as posted by Tokyoboy and compares with these projections one really ask himself what’s up here?
Prediction based on paleoclimate should have a validity check based on recent history and on what is really possible as done by tty above. I expect at least these 2 points before crying wolf. And yes it did not even pass the paleoclimate check as you pointed out.
Willis say: ” The IPCC predicts sea level rise of about a foot (30 cm), but they don’t take ice into account.”
This is certainly not right. The estimated contribution from ice caps and thermal expansion is shown here: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-5-21.html
What they do not take into account is the new and controversial theory that the fluid melting water will change the dynamics of the ice.
Lars P. says:
First of all, it is Hansen’s logic, not mine. I am just trying to explain his logic…I am not convinced that it is correct. (I think the truth lies somewhere in between Hansen’s extreme and the extreme that there is going to be no worrisome sea level rise.)
Second of all, everybody agrees that the sea levels do not respond instantaneously. So, nobody would claim that we should see all the rise right away (or even most of it). The question becomes how fast the sea level rise can occur…Most people have thought it takes many hundreds to thousands of years for the sea level to equilibrate to the current temperature…but Hansen is arguing that it can be faster. But, still nothing close to instantaneous!
Joel Shore says;
Wikipedia talks of the sea level during the Eemian as being 5-7 m higher than today. ( http://en.wikipedia.org/wiki/Eemian_sea )
Appealing to the authority of Wikipedia now, are we Joel?
Markus Fitzhenry.
Aside from all this projecting sea level changes using carnival side-show techniques, has anyone EVER addressed the world’s Mass Balance of ice inventory and correlated this MB with sea level change? After all, aside from volume increases of ocean warming causing rising sea levels,from where can sea level rise come from but melting of ice. Since the alarmists never talk about MB, I can only conclude that it is constant or increasing. If MB was decreasing, we would never here the end of it!
Jan Kjetil Andersen says:
January 31, 2012 at 12:47 pm
I love a man who is certain, especially when he is as wrong as you are. I am talking about the IPCC predictions of future sea level rise. What you have shown is an IPCC estimate of the current mass balance of the oceans.
When you have figured out the difference, perhaps you will not be so certain. And in a scientist, not being certain is a good thing.
Certainly, my statement was not as detailed as it might have been. It was merely an attempt to explain the differences between the IPCC (30 cm rise), Rahmstorf (1 m rise), and Hansen (40 m rise). Were I asked for details about my claim in a polite manner, I would have said, here’s how the IPCC actually describes their estimates:
All the best,
w.
Willis say: “I am talking about the IPCC predictions of future sea level rise.”
Yes, and IPCC have a taken ice melting into account for that. You find the exact prediction on future sea level rise in table 10.33 on page 821 in the IPCC fourth report here:
http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter10.pdf