Guest Post by Willis Eschenbach
Much has been made in AGW circles of the sea level forecast of Vermeer and Rahmstorf, in “Global sea level linked to global temperature” (V&R2009). Their estimate of forecast sea level rise was much larger than that of the IPCC Fourth Assessment Report (FAR). Their results have been hyped at places like RealClimate as being much more realistic than the IPCC estimates.
So I figured I’d see how Vermeer and Rahmstorf are faring to date. Their results for each of the IPCC “scenarios” are archived here, and the first thirty years of their estimates are presented along with nearly twenty years of actual observations in Figure 1.
Figure 1. Satellite-based sea level observations (blue line), along with the V&R2009 sea level estimates corresponding to the various IPCC future scenarios. Sea level observations from the University of Colorado. PHOTO SOURCE
So … how are the V&R2009 predictions holding up?
Well, … or to be accurate, not well. As you can see, the observations showed an actual sea level rise that is below the lowest of the V&R2009 estimates from the lowest of the IPCC scenarios.
At present, assuming that the distance between their “best” estimate and their “lower” estimate is two standard deviations, the data is now more than four standard deviations below the “best” V&R2009 estimate.
So in answer to how their forecasts are faring, the answer is … very poorly. Abysmally, in fact. Actual observations are lower by four standard deviations than the V&R2000 “best” estimate, and are two standard deviations lower than their “lower” estimate.
w.
Technote 1 – The Colorado folks have recently included a 0.3mm/year increase in sea levels in their results. They say (possibly correctly) that this is necessary to adjust for the sinking of the ocean floor with the increasing weight of sea water from the melting at the end of the last ice age. However, since neither the IPCC nor the V&R2009 figures include that adjustment, I have not included it in this analysis so that we can compare apples to apples.
Technote 2 – I have aligned the Colorado observational results so that their trend line is zero in 1990, in order that they can be compared directly with the V&R2009 results, which have 1990=0 as their starting point. This also aligns the starting observations with the V&R2009 “best” estimate.
Technote 3 – some folks felt that my last post, “Yes, Virginia, there is an FOIA” was short on science content and long on passion … hey, what can I say, I’m a passionate guy. I trust this post will redress the balance in their estimation.
[UPDATE] Steven Mosher has graciously pointed me to a stunning disassembly of V&R2009, at the blog Climate Sanity. Makes my effort above look simplistic by comparison. He shows, among other things, that the V&R formula for sea level leads to ridiculous results when it is fed with actual data rather than IPCC scenarios … quite lethal to their claims. Well done, that man. – w.
Is there a set of data to chart in parallel that shows the decrease in land ice, expansion of sea through warming and any gap between the three ie Lost land ice + expansion – seabed sinkage – land rise(post ice) = sea level rise. And how does it all relate to Trenberth’s travesty of lost energy. Does it all add up in the models? If not then surprise, surprise, they are wrong (being the polite phrase).
Re the Colorado adjustment. Such “adjustments” cannot cause flooding. The sole point of the adjustment is to cause panic.
I was watching “Run Silent Run Deep” last night and thinking about how the models just didn’t look right in the ocean scenes. Too bad Hollywood isn’t the only ones faking it.
I’m a little confused and this may be a dumb question but…
If this study was published in 2009 then weren’t all their projections known to be wrong at the time of publishing?
Bryan A says:
July 3, 2011 at 2:04 pm
You mean this sort of thing?
http://www.flickr.com/photos/hughrocks/1968256557/
Sea levels are dropping, faster than previously unimagined.
Imaginations ran wild with a perceived endless trend, which is why there is now a 4 sigma deviation from reality.
All that has to happen for sea levels to drop rapidly is for the extra-cold winters ice to mix with the remaining anomalously warm waters that upwelled in the last El Nino.
I think that 0.3mm/year adjustment is the most illogical thing they could put forward. I’m disappointed that I haven’t seen more discussion of its merits, or lack of.
The number is a suspiciously round number. Are they sure its not 0.25mm/year, or 0.325mm/year. It just seems like a really stupid proposition to have put forward, and indefensible on the face of it.
I say measure what’s happening always. With there system in place, in 20 years time and the cold starts hitting hard, how on earth are they going to manage a varying adjustment to account for more ice forming. It becomes unmanageable, and surely unprovable.
There were so many problems with Vermeer and Rahmstorfs model that it made my head spin.
It results in bizarre consequences, which by themselves disqualify it. For example, see the test cases here…
http://climatesanity.wordpress.com/2010/04/03/rahmstorf-2009-off-the-mark-again-part-3/
and here…
http://climatesanity.wordpress.com/2010/04/12/rahmstorf-2009-off-the-mark-again-part-4-parallel-universes/
and here…
http://climatesanity.wordpress.com/2010/04/14/rahmstorf-2009-off-the-mark-again-part-5-variation-of-gamma/
and here…
http://climatesanity.wordpress.com/2010/09/07/rahmstorf-2009-off-the-mark-again-part-7-constant-sea-level-rise-rate/
The second term of their model (b dT/dt) forces a nonsensical temperature scenario for the last decade and half to reproduce the observed satellite data and nearly impossible temperatures for the coming decade to maintain 3mm rise per year. See here…
http://climatesanity.wordpress.com/2010/05/27/rahmstorf-2009-off-the-mark-again-part-6-satellite-data/
for more math details see here…
http://climatesanity.wordpress.com/2010/06/11/rahmstorf-2009-off-the-mark-again-part-6-and-a-half-gory-details/
They used sea level data that had been already been superseded by the sea level data’s authors. Had they used the updated data with a correction for groundwater depletion, their model predicts sea level rise for the 21st century that is half of what they published. See here…
http://climatesanity.wordpress.com/2010/11/28/rahmstorf-2009-off-the-mark-again-part-10-sea-level-projections-exaggerated-by-factor-of-2/
The code for their model, which was archived by the National Academy of Sciences has at least one laughably bad error. See here…
http://climatesanity.wordpress.com/2011/02/13/rahmstorf-2009-off-the-mark-again-part-12-a-mathematical-comedy/
“Technote 1 – The Colorado folks have recently included a 0.3mm/year increase in sea levels in their results. They say (possibly correctly) that this is necessary to adjust for the sinking of the ocean floor with the increasing weight of sea water from the melting at the end of the last ice age.”
I have found this a red herring for a few reasons that need further investigating. Ignious rock from volcanoes cooling from lava under the ocean very likely have a larger affect than just the weight of the water. This rock displaces water and reduces the ocean volume and is significant contribution towards the rising of ongoing sea levels. Why we know this is because not just of the rock cycle, but periods of recent glaciation (1950’s to 1970’s) and stable global temperatures have made very little difference to the rate. (based on traditional methods) Increasing weight of sea water from the melting at the end of the ice age is not the only factor. In this case displacing the volume doesn’t increase the weight of sea water, increases sea levels proportional to rising ocean beds.
Thanks Willis
With Vermeer and Rahmstorf’s mid projection of 9 vs reality of 5.5, shall we say that is a ‘bit high”?
If we compare V&M’s rapid rate of rise in Fig. 3, vs actual recent decline it appears even the short term direction is off. It would be very helpful if you could also show the rate of change.
One ongoing evaluation is on the “skill” of IPCC’s Global warming models to forecast future temperatures. Lucia Liljegren at The Blackboard is statistically testing this “skill” and finds it increasing wanting. See her category “data comparisons”. e.g. May T Anomalies: Cooler than April. 29 June, 2011 (12:10) e.g. 25 month smoothed observations HadCrut shows 0.02 C/decade NOAA/NCDC 0.06 C/decade and GISTtemp 0.12 C/decade, compared to IPCC’s multi model mean of 0.205 C/decade.
It would be very helpful for some statistician to apply Lucia’s evaluation method to sea level data.
Al Gored,
Thanks for the link re: lowered sea floor adds .3mm/year in sea level. Oddly, I was just chatting with my husband and used a kiddy pool on loose dirt and soft grass to illustrate my skepticism about this adjustment. While the oceans may contain more water, the issue (I thought) was the peril of putting Manhatten Island and 2000 other islands, some inhabited, under water (to the surprise of the people who drowned because they didn’t get the memo).
Willis, can you elaborate on the University of Colorado adjustment and their reasoning? Please remember, IANAS. Thanks in advance.
Tom Rude, “In addition, Yin explained, if floating ice along the coastal areas melts it will allow the flow of glaciers to accelerate, bringing more ice into the seas.”
Yin is saying that floating ice holds back glacier flow? I was under the impression that a 10′ deep reinforced concrete wall wouldn’t slow a glacier flow. I don’t understand. Any idea how Yin comes to this conclusion? Thanks in advance.
Typo on previous post.
Should be igneous rock.
This is an interesting example of alarmist science at it’s best. Yes, we definitely have to make sure that the enivronment is maintained, but we should not be giving out doomsday advice like it is popsicles.
Hoser said: “Looks like the models all assume exponential increases.”
This has been an underemphasized criticism of the AGW models. They are positive feedback models and therefore, are likely to produce exponential increases. The early growth of exponential models is very linear. So if you are fitting to the early part of an exponential increase to reality, projections to the very non-linear later portion of the curve are not valid as a description of that same reality.
@Bob Johnson: There you go again sticking reality into the argument. Don’t you know reality does not matter when you have models?
Wouldn’t you know it? All my life I cannot yet tell by looking at the coast to see if the sea level has risen, and now it’s dropping. No reason to get excited.
Bob Johnston says:
July 3, 2011 at 2:43 pm
You are quite correct, but you neglected to take into account that this was published in the vanity press laughingly known as the “Proceedings of the National Academy of Science”. They are famous for pal review, which is no review at all. In this case, Rahmstorf is a member of the inner circle of AGW supporters that roost at RealClimate, so (as clearly happened in this case) his writings will be given only the most cursory of peer reviews.
w.
OK,lets look at reality. Sea level has risen 0,00001 percent in the last 100 years. How the f*ck is that any kind of problem?
SandyInDerby says:
July 3, 2011 at 2:47 pm
An interesting picture, as the house gives it scale. A rough estimate puts the house foundation 8 house-heights above the high-tide mark, which means a rebound of something like 30 metres over 10000 years, or 3mm per year. Over and above the sea level rise of something like 3mm/yr, therefore this part of Scotland’s coastline has risen 6mm/yr.
As for the alleged drop in seabed of 0.3mm/yr, doesn’t erosion and sedimentation have any contrary effect?
Willis I thought there were some interesting numbers in the 2010 BAMS State of the Climate Report (Oceans Sections/ Sea Level Variation).
http://www.ncdc.noaa.gov/bams-state-of-the-climate/2010.php
“Over this brief time period and in areas more than 200 km from the nearest coast where comparisons can be made with Argo and GRACE, the mean rate of total sea level rise is 1.5 ± 0.9 mm yr–1 (note that the uncertainties from here to the end of this section are 95% confidence levels). This rate cannot be compared with the global average over the entire altimeter time period cited above since at least 10 years of data are required to determine a reliable rate (Nerem et al. 1999). This rate is, however, in agreement (Fig. 3.29) with the sum (1.6 ± 0.6 mm yr–1) of the rates of the upper (depths < 700 m) ocean steric (0.5 ± 0.5 mm yr–1) and ocean mass components (1.1 ± 0.6 mm yr–1)."
But best to ignore the numbers though.
Yeah – you would’ve thought bright guys like that woulda noticed their model was already 30mm out at the time of publication! Sheesh! Did they think nobody would notice?
I have aligned the Colorado observational results so that their trend line is zero in 1990, in order that they can be compared directly with the V&R2009 results.
Why not just zero everything in 1992, the first year both datasets have in common? An easy process as the model numbers are in whole cm. The observations are available from 1992, with a trend of c3.1mm / year. So an offset of 6-7mm might be expected back to 1990, the graph here looks to have been shifted more like 10mm. Please explain.
As you can see, the observations showed an actual sea level rise that is below the lowest of the V&R2009 estimates from the lowest of the IPCC scenarios.
Here are the model numbers for A1F1 best and lowest in cm change since 1990:
1992 1 1
1993 1 1
1994 1 1
1995 2 1
1996 2 1
1997 2 2
1998 2 2
1999 3 2
2000 3 3
2001 4 3
2002 4 3
2003 5 4
2004 5 4
2005 6 5
2006 6 5
2007 7 5
2008 7 6
2009 8 6
2010 8 7
That is, a rise of 70mm or 60mm over 18 years. Or crudely, 3.9 or 3.3mm / year. The middle estimate is high, however the lower estimate is actually consistent with the UoC figure of 3.1 +- 0.4cm (itself the lowest-trending of the main indices), is it not?
Speaking of ‘science content’, the sea level metric cited by V&R is from GRACE, (their ref 16). As they say,
Another semiindependent test is provided by the satellite
sea-level record updated from ref. 16 that started in 1993 and
now provides 16 years of data (up including 2008), with a linear
trend of 3.4 mm/year (after postglacial rebound adjustment).
When the reservoir correction is applied it yields 3.6 mm/year,
and the extra point is shown as an open circle in Fig. 4.
Might be interesting to grab the GRACE data and graph that, as we are interested in apples v apples, no?
Now with closed tag…
Yeah – you would’ve thought bright guys like that woulda noticed their model was already 30mm out at the time of publication! Sheesh! Did they think nobody would notice?
I have aligned the Colorado observational results so that their trend line is zero in 1990, in order that they can be compared directly with the V&R2009 results.
Why not just zero everything in 1992, the first year both datasets have in common? An easy process as the model numbers are in whole cm. The observations are available from 1992, with a trend of c3.1mm / year. So an offset of 6-7mm might be expected back to 1990, the graph here looks to have been shifted more like 10mm. Please explain.
As you can see, the observations showed an actual sea level rise that is below the lowest of the V&R2009 estimates from the lowest of the IPCC scenarios.
Here are the model numbers for A1F1 best and lowest in cm change since 1990:
1992 1 1
1993 1 1
1994 1 1
1995 2 1
1996 2 1
1997 2 2
1998 2 2
1999 3 2
2000 3 3
2001 4 3
2002 4 3
2003 5 4
2004 5 4
2005 6 5
2006 6 5
2007 7 5
2008 7 6
2009 8 6
2010 8 7
That is, a rise of 70mm or 60mm over 18 years. Or crudely, 3.9 or 3.3mm / year. The middle estimate is high, however the lower estimate is actually consistent with the UoC figure of 3.1 +- 0.4cm (itself the lowest-trending of the main indices), is it not?
Speaking of ‘science content’, the sea level metric cited by V&R is from GRACE, (their ref 16). As they say,
Another semiindependent test is provided by the satellite
sea-level record updated from ref. 16 that started in 1993 and
now provides 16 years of data (up including 2008), with a linear
trend of 3.4 mm/year (after postglacial rebound adjustment).
When the reservoir correction is applied it yields 3.6 mm/year,
and the extra point is shown as an open circle in Fig. 4.
Might be interesting to grab the GRACE data and graph that, as we are interested in apples v apples, no?
Now with closed bold tag…
Yeah – you would’ve thought bright guys like that woulda noticed their model was already 30mm out at the time of publication! Sheesh! Did they think nobody would notice?
I have aligned the Colorado observational results so that their trend line is zero in 1990, in order that they can be compared directly with the V&R2009 results.
Why not just zero everything in 1992, the first year both datasets have in common? An easy process as the model numbers are in whole cm. The observations are available from 1992, with a trend of c3.1mm / year. So an offset of 6-7mm might be expected back to 1990, the graph here looks to have been shifted more like 10mm. Please explain.
As you can see, the observations showed an actual sea level rise that is below the lowest of the V&R2009 estimates from the lowest of the IPCC scenarios.
Here are the model numbers for A1F1 best and lowest in cm change since 1990:
1992 1 1
1993 1 1
1994 1 1
1995 2 1
1996 2 1
1997 2 2
1998 2 2
1999 3 2
2000 3 3
2001 4 3
2002 4 3
2003 5 4
2004 5 4
2005 6 5
2006 6 5
2007 7 5
2008 7 6
2009 8 6
2010 8 7
That is, a rise of 70mm or 60mm over 18 years. Or crudely, 3.9 or 3.3mm / year. The middle estimate is high, however the lower estimate is actually consistent with the UoC figure of 3.1 +- 0.4cm (itself the lowest-trending of the main indices), is it not?
Speaking of ‘science content’, the sea level metric cited by V&R is from GRACE, (their ref 16). As they say,
Another semiindependent test is provided by the satellite
sea-level record updated from ref. 16 that started in 1993 and
now provides 16 years of data (up including 2008), with a linear
trend of 3.4 mm/year (after postglacial rebound adjustment).
When the reservoir correction is applied it yields 3.6 mm/year,
and the extra point is shown as an open circle in Fig. 4.
Might be interesting to grab the GRACE data and graph that, as we are interested in apples v apples, no?
1DandyTroll sarcs:
July 3, 2011 at 2:33 pm
So, essentially, when the ocean floor sinks the sea rises even more. I can really visualize it: Mann and his schtick rising to even greater heights by the second in a pool of quicksand.
———-
The sarcasm obscures your meaning but you do understand don’t you that if the sea floor falls the continents rise and vice versa .
Ric Werne quoted Vermeer:
=============================================
… sea level rise would also contain a term proportional to the time derivative of temperature, dT/dt. In other words, global sea level would be a good global thermometer …
=============================================
He must have been reading Shaviv’s blog! He’s been there, done that:
http://www.sciencebits.com/calorimeter
Ah, there’s no better flattery than imitation.