WUWT readers may recall yesterday where Dr. Mann was so eager to list this paper on his resume/CV, he broke the embargo set for 15:00 EST June 20th, today, at which time this blog post appears.
As much as this is an editorial target rich environment, I’m going to publish this press release and paper sans any editorial comment. There’s plenty of time for that later. Let’s all just take it in first. Below, figure 2 from the Kemp et al 2011 paper. It should look familiar. Note the reference in Figure 2 to GIA (Glacial Isostatic Adjustment) adjusted sea level data, which has recently been the subject of controversy, it was first noted here on WUWT.
First the press release:
Contact: Evan Lerner
215-573-6604
Penn researchers link fastest sea-level rise in 2 millennia to increasing temperatures
PHILADELPHIA — An international research team including University of Pennsylvania scientists has shown that the rate of sea-level rise along the U.S. Atlantic coast is greater now than at any time in the past 2,000 years and that there is a consistent link between changes in global mean surface temperature and sea level.
The research was conducted by members of the Department of Earth and Environmental Science in Penn’s School of Arts and Science: Benjamin Horton, associate professor and director of the Sea Level Research Laboratory, and postdoctoral fellow Andrew Kemp, now at Yale University’s Climate and Energy Institute.
Their work will be published in the journal Proceedings of the National Academy of Sciences on June 20.
“Sea-level rise is a potentially disastrous outcome of climate change, as rising temperatures melt land-based ice and warm ocean waters,” Horton said.
“Scenarios of future rise are dependent upon understanding the response of sea level to climate changes. Accurate estimates of past sea-level variability provide a context for such projections,” Kemp said.
In the new study, researchers provided the first continuous sea-level reconstruction for the past 2,000 years and compared variations in global temperature to changes in sea level during this time period.
The team found that sea level was relatively stable from 200 B.C. to 1,000 A.D. During a warm climate period beginning in the 11th century known as the Medieval Climate Anomaly, sea level rose by about half a millimeter per year for 400 years. There was then a second period of stable sea level associated with a cooler period, known as the Little Ice Age, which persisted until the late 19th century. Since the late 19th century, however, sea level has risen by more than 2 millimeters per year on average, which is the steepest rate for more than 2,100 years.
To reconstruct sea level, the research team used microfossils called foraminifera preserved in sediment cores from coastal salt marshes in North Carolina. The age of these cores was estimated using radiocarbon dating and several complementary techniques.
To ensure the validity of their approach, the team members confirmed their reconstructions against tide-gauge measurements from North Carolina for the past 80 years and global tide-gauge records for the past 300 years. A second reconstruction from Massachusetts confirmed their findings. The records were also corrected for contributions to sea-level rise made by vertical land movements.
The team’s research shows that the reconstructed changes in sea level during the past millennium are consistent with past global temperatures and can be described using a model relating the rate of sea-level rise to global temperature.
“The data from the past help to calibrate our model and will improve sea-level rise projections under scenarios of future temperature rise,” research team member Stefan Rahmstorf said.
In addition to Horton and Kemp, the research was conducted by Jeffrey Donnelly of the Woods Hole Oceanographic Institution, Michael Mann of Pennsylvania State University, Martin Vermeer of Finland’s Aalto University School of Engineering in Finland and Rahmstorf of Germany’s Potsdam Institute for Climate Impact Research.
Support for this research was provided by the National Science Foundation, the National Oceanic and Atmospheric Administration, United States Geological Survey, the Academy of Finland, the European Science Foundation through European Cooperation in Science and Technology and the University of Pennsylvania.
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Here’s the abstract:
Climate related sea-level variations over the past two millennia
Andrew C. Kempa,b, Benjamin P. Hortona,1, Jeffrey P. Donnellyc, Michael E. Mannd,
Martin Vermeere, and Stefan Rahmstorff
We present new sea-level reconstructions for the past 2100 y based on salt-marsh sedimentary sequences from the US Atlantic coast. The data from North Carolina reveal four phases of persistent sea-level change after correction for glacial isostatic adjustment.
Sea level was stable from at least BC 100 until AD 950. Sea level then increased for 400 y at a rate of 0.6 mm/y, followed by a further period of stable, or slightly falling, sea level that persisted until the late 19th century. Since then, sea level has risen at an average rate of 2.1 mm/y, representing the steepest century-scale increase of the past two millennia. This rate was initiated between AD 1865 and 1892. Using an extended semiempirical modeling approach, we show that these sea-level changes are consistent with global
temperature for at least the past millennium.
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Figure 1: Two points in salt Marshes in North Carolina are used as the basis for the study:
Materials and Methods
Sea level in North Carolina was reconstructed using transfer functions relating the distribution of salt-marsh foraminifera to tidal elevation (7, 12). Application of transfer functions to samples from two cores (at sites 120 km apart) of salt-marsh sediment provided estimates of PME with uncertainties of <0.1 m. For each core a probabilistic age-depth model (10) was developed from composite chronological results and allowed the age of any sample to be estimated with 95% confidence. In Massachusetts, plant macrofossils preserved in salt-marsh sediment overlying a glacial erratic, were dated using AMS 14C and pollen and pollution chronohorizons (Fig. S1). The modern distribution of common salt-marsh plants was used to estimate PME. Sea level was reconstructed by subtracting estimated PME from measured sample altitude. Corrections for GIA were estimated from local (13) and US Atlantic coast (15) databases of late Holocene sea-level index points. Detailed methods are presented in SI Text.
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They compare data at points around the world to the new SL hockey stick (in pink in the background):
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Conclusions
We have presented a unique, high-resolution sea-level reconstruction developed using salt-marsh sediments for the last 2100 y from the US Atlantic coast. Post-AD 1000, these sea-level reconstructions are compatible with reconstructions of global temperature, assuming a linear relation between temperature and the rate of sea-level rise. This consistency mutually reinforces the credibility of the temperature and sea-level reconstructions. According to our analysis, North Carolina sea level was stable
from BC 100 to AD 950. Sea level rose at a rate of 0.6 mm/y from about AD 950 to 1400 as a consequence of Medieval warmth, although there is a difference in timing when compared to other proxy sea-level records. North Carolina and other records show
sea level was stable from AD 1400 until the end of the 19th century due to cooler temperatures associated with the Little Ice Age. A second increase in the rate of sea-level rise occurred around AD 1880–1920; in North Carolina the mean rate of rise was 2.1 mm/y in response to 20th century warming. This historical rate of rise was greater than any other persistent, century-scale trend during the past 2100 y.
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The full paper is available here: PNAS_Kemp-etal_2011_Sea_level_rise
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tallbloke says:
June 20, 2011 at 12:53 pm
According to Manns new sea level curve, the Romans built inland ports in southern England.
WUWT?
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Obviously, the Romanns were well ahead of their time.
PME, Paleo Marsh Elevation (above local mean sealevel) is between 0.07 and 0.25 meters throughout the entire 2000 year history of the location. We are to believe that any collection of 3 or 4 nanofossils can have a AVERAGE mean sea level value with a precision of 1 or 2 cm when superimposed upon by tides, hurricanes, local river meanders, and reworking of sediment?
I also note that the nanofossils chosen are different at the two locations, at least as depicted in Fig 1. So what did they do? Use a different transfer function for each location?
Mann and Penn State have apparently forgotten the Scientific Method. It matters not if you can find 1, 2 or a dozen examples where sea level is accelerating.
If there is a single example that sea level is not accelerating, then according to the scientific method, unless you can find a cause why it is not accelerating, it is not accelerating. Period, end of story.
Anything can be “proven” by looking for examples of where it is true. A broken watch gives you the right time more than 700 times a year. This is not proof that it is keeping time. The proof that the watch is not keeping time is whether you can find examples where it is not true.
There are plenty of examples showing that sea level rise is not accelerating. Look at the WWII waterfront facilities built in the Pacific. Look at the records from even earlier.
http://www.john-daly.com/ges/msl-rept.htm
The level of sea level rise is so small that they have had to add .3mm per year “correction” to allow for the rise that is not taking place because of rebound since the ice ages. Why? The rise is not taking place, but still we have to add it in, as though it was.
Why not add a correction for evaporation? Like rebound after the ice ages, the oceans would be rising a lot more if it wasn’t for evaporation.
Bioturbation warning on this one among other warnings.
Benthic foraminifera in a lagoon environment present in a core sample have probably been through the gullet of some animal or displaced by some burrowing organism multiple times. To be crude, lagoonal sediment like this have been best described as worm sh*t. The forams did not die and lay undisturbed on the bottom.
When you look at relative abundance of the different foraminifera species, are you looking at preservation issues (some foraminifera shells are delicate). Are human influences considered (i.e. pesticide runoff killing the little critturs). What about, temperature, salinity and lets not forget the occasional hurricane coming through and giving everything a good mixing. Sea level IS NOT the only environmental factor in benthic micro faunas.
In fairness to Mann, he didn’t design this study, conduct the research or write the paper. His contribution was data analysis. Of course, he is the go-to guy for magical correlations and hockey sticks.
Use of Mann’s 2008 temperature reconstruction seemed rather weak (if not entirely foolish). The statistical analysis seems a bit hinky to me, but I do not possess the expertise to challenge it. Perhaps Willis Eschenbach or Steve McIntyre will take a stab at it. Most of my doubts concern the use of this particular proxy for sea level and, of course, where they chose to sample.
I’d offer a comment – but I’d likely be hauled through the courts and banned for life from WUWT !
Seriously though – semiempirical this and reconstruction that? and THIS is modern science?
Measuring sea levels with salt-marsh foraminifera micro fossils is quite a sensitive and valid method to measure the depth of the sea bottom in the past. We should not, therefore suspect fraud in the data. However, this technique does not measure sea level, but marsh bottom instead. It is well known that marshes have been in-filling in modern times due to sedimentation from accelerated land erosion. What this report in essence measures, is the rate of land erosion, which has very little to do with sea level rise. That this fact is omitted from the paper may be called fraud.
This is typical Mann cherry-picking of proxies. The same kind of cherry-picking he did in MBH98 and Mann08, where he used the corrupted Tiljander proxy, even though he had been informed beforehand that the Tiljander sediments had been overturned due to road work. He used the proxy anyway because it provided the hockey stick shape that shows up in all of his papers.
What is Mann’s motivation for producing his BS [bad science]?
Money, and lots of it:
Michael Mann grants, 1996 – 2005:
Total: $6,232,700
This is an incomplete list. For example, there was also the post-Climategate
payolagrant of $1.8 million to study mosquito vectors. Mann is not an epidemiologist or a biologist. Draw your own conclusions.You know, I’m a bit disappointed with this. I was looking forward to dissecting the paper and having a great contentious discussion about it………. it doesn’t seem to rise above the level of a derisive snort. Medieval Climate Anomaly?? lol, it was never known as that. People, other than history revisionist typically call it the Medieval Warm Period, but whatever……. all from N. Carolina……wow. Based on, in part
fictionalhighly contentious temp reconstructions. Yep, that just about seals it for me!! I’m going to Wallyworld right after work and buy me some floatys!!!A quick internet search shows, as others have already attested, that isostatic rebound and tectonic subsidence can exceed the measured rise attributed to temperature change by an order of magnitude, and even groundwater pumping can match the magnitude. The paper states that “all records from the Atlantic coast of North America, Gulf of Mexico, and New Zealand (23) show stable or falling sea level between AD 1400 and 1900…” Reference 23 is from New Zealand. Meanwhile, there are pages and pages of botanical references to a steadily rising relative sea level on the Atlantic coast of the US in the form of buried stumps and roots. This paper is just a thin veneer of empirical data swabbed over a modeling approach that uses Mann’s hockey stick as input.
suyts says:
June 20, 2011 at 1:35 pm
tallbloke says:
June 20, 2011 at 12:53 pm
According to Manns new sea level curve, the Romans built inland ports in southern England.
WUWT?
=====================================================
Obviously, the Romanns were well ahead of their time.
They actually did, which means that sea level was higher than at present:
http://www.dailymail.co.uk/sciencetech/article-1066712/Uncovered-lost-beach-Romans-got-toehold-Britain.html
RHS says:
June 20, 2011 at 12:05 pm
How difficult would it have been for Mann to include recent data points? Is there a good reason (besides the ones I want to see) why he stopped data collection/recreation ten years ago?
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John B says:
June 20, 2011 at 1:03 pm
That would be because it is a paleo-reconstruction of a 2000+ year period. Proxies generally don’t exist right up until yesterday. And even if he could and did go the extra 10 years, it would only add 0.05% to the length of the x-axis. Welcome to non-cherry-picked science.
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John, I know it’s a press release, but it says “any time in the past 2,000 years”.
That would include the past 10 years.
In their conclusions they say “salt-marsh sediments for the last 2100 “, which also includes now.
Even their title implies now “over the past two millennia”
Biggest problem is, they used Mann’s reconstruction that does include measured data. Then turned around and picked a time frame for their sediment paleo that didn’t include the measured data of the past decade.
Yes, they could have included the last decade.
They’ve done it before.
They cherry picked……
I wouldn’t regard listing a forthcoming paper on one’s vita as breaking an embargo, so long as the paper itself was not released and no press-release-length discussions of the paper were issued.
Wow, I never knew that Bristlecone’s could be used to track sea levels.
Note #1
Footnotes 1 and 2 indicate the basic premise of the paper rests on the foundation
of Mike Mann’s old hockey stick reconstructions and GISS temperature calculations
(with the database “revised”) along with the UEA-Met temp revisions controlled by
Jones, et., all endorsed by the ever accurate IPCC reports… written by the “Team”
and their associates.
This is not an auspicious opening paragraph for “new” scientific information.
It sounds more like recycling of old, questionable studies.
I’ll read on an submit notes as possible.
This comment box from wordpress.com still cut and paste.
The best counterpoints in the above comments are enough to discredit this paper, but what if it were right, that there was a sea level rise of 6-7 inches in the 100 years leading up to 2000? Something similar would be expected in a warming climate, but it doesn’t add a single ounce of weight to the AGW hypothesis. The temperature record isn’t that seriously contested – so far – and on its own is only proof (so far as it’s accurate) that the temperature has risen. Nothing else can be deduced from it. Same applies to this paper – the sea level at one point appears to have risen and that’s all. It’s a pointless exercise from a scientific point of view – except for one little thing . . . . if the supposed rise in sea level can be explained away by, let’s say, reverse glacial rebound (northern Canada is on the rise and therefore there might be an opposite effect at work on the area measured in this paper) then that would cast some doubt on the temperature record! . . Long shot, but not impossible . . .
The reference to the hockey stick model is very apt here as once again they appear to have mislaid the post-Roman cool/wet period when sea levels rose substantially, as Hubert Lamb pointed out many years ago. As Hubert Lamb, the climate scientists responsible for setting up the UEA research unit, wrote about the Medieval Warm Period and the Roman Warm Period his books are just the thing to debunk this latest hoax. See also Basil Cracknell, Outrageous Waves: Global Warming and Coastal Change in Britain over 2000 Years, Philimore of Chichester: 2005 in which he highlights exactly what happened with rising sea levels in the 4th and 5th centuries AD – completely different to what this paper claims. Yes, I think there is more than enough evidence out there to pull this little caper apart
Last time I looked it seemed to me that water tends to run downhill.So even if readings are higher in one place than another equilibration will surely occur,though there may be a time lag as water does take some time to run downhill.So, if rising levels were to be of any significance they would have to rise everywhere, wouldnt they? Localised “rise” will, of course appear to have ocurred where there has been land subsidence.Then the issue becomes subsidence against what set point.Logically the centre of the earth ? But I doubt even the most sophisticated satellite can get a fix on that.Even then if land subsides anywhere must it not bulge elsewhere as the earth is surely not compressible. Trivial(by terrestrial standards) subsidence can of course occur by pumping out ground water etc,but this wouldnt affect ocean level. Enough, my head is beginning to go round.
Given that sea levels vary globally and the generally accepted figure is a global average, it seems very fortunate that the chosen locale for the study reflects exactly what one would expect if the concensus view is correct.
However something I’ve long wondered – sea level rise is claimed to threaten low lying sea fronts, thus practically speaking one MUST notice this change occurring – somewhere. I’d like to see anecdotal evidence from as many people as possible all over the world about what sea level is doing where they live. Anecdotal is not scientific, sure, but if water rises far enough to affect property then it MUST eventually be noticeable, now mustn’t it. Regardless of the statistics involved.
My own observations from a place called Hervey Bay on the coast of Australia. Over the course of 50 years, I have not noticed any significant change at all. If anything, the sea level seems to be less now as king tides in the 70s often caused water to flood onto the esplanade which I don’t think it does now. Now I could be wrong, but anecdotally at least I see no difference at all.
Hey,
I grew up next to the River Mersey estuary in the UK. It had tidal ranges of up to 30 feet and the landing stages for the ferries were floating and sometimes were a level walk and others a quite steep walk.
I’ve always been a bit suspicious since then about people who claim to be able to measure sea level rises in terms of ‘millimetres’.
Sedimentation is inadequately considered here. Important for PME trends.
Same shape (the graphe), so same statistical method? Old wine in a new barrel? A bad and cheap sequel? Trade mark is clear anyway. Mann, you know our names, give us the numbers…
Does this new study signify that Mann has deserted his old ‘team-mates’, Phil and Keef at UEA, for another club?
when did the Medieval Warm Period get renamed the ‘Medieval Climate Anomaly?’
2 mm a year. 1 meter in 500 years.. assuming no reversal, assuming its right, and so we all panic and shut down the very economy that taxes people so these guys can do these studies. What madness