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):
======================================================================
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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Look at the bright side….
We now have enough hockey sticks to field a whole new team.
Bigger, better, stronger, faster — and even scarier.
Did Al Gore check with Mann before his recent Montecito purchase?
I wonder if they compensated for glacial rebound using one of the more modern reconstructions. I seem to recall that in some of the reconstructions by the U of Toronto geophysics crowd, the N. Carolina area is actually in the far field zone of the Laurentian ice sheet, which means that it is currently falling, not rising, due to the viscous relaxation from the removal of N. American continental glaciation. These sorts of corrections are themselves time dependent, so you have to use a mantle viscosity model along with an ice loading model to correct for apparent sea level rise/fall. I would suspect that this sort of study, done properly, would not be for the faint-hearted. I also note that the glacial rebound models have to be calibrated, in turn, by sea level records, so the potential for at least “ellipticity”, if not a certain amount of circularity in the reasoning exists.
http://www.pnas.org/content/suppl/2011/06/14/1015619108.DCSupplemental
Doesnt take long to find the divergences and exclusions
So far, just a few comments:
1. At least 4 times they mentioned ESTIMATED Paleo marsh elevation (PME). So still guessing, are they?
2. “…these sea-level reconstructions are compatible with reconstructions of global temperature, assuming a linear relation between temperature and the rate of sea-level rise…” Still no proof that there is a linear relation, just an assumption that there is.
3. It’s amazing how sea level is “stable” when the temps are cooler, but always rise when warmer. If you assume their linear relation between temps and sea level rise, there should also be noticeable dips during the LIA.
They’re making all this assumption on TWO sites in N Carolina. Just think how much worse it would have appeared if they had used the coast of Louisana.
BTW, Anthony, kudos for your adherence to ethics and protocol regarding announcement of this paper.
Mann? Not so much. It’s fun to read his resume, he’s never had a real job in his life! BS->MS->PhD->faculty.
So typical.
It’s not even worth serious comment!
The boy who cried wolf and got caught out is now crying “shark”!
An important aspect of experimental science is replication. ENVISAT is a European Space Agency satellite which also measures changing sea levels. It finds a trend which is significantly less than TOPEX/JASON/U. of Colorado
In fact, in line with Craig Loehle’s ARGO data assessment and my own calculations on the steric sea level, it shows negligible sea level rise in the last few years on their adjusted data, and a fall on their unadjusted data.
http://tallbloke.files.wordpress.com/2011/06/msl_adjust.gif
http://tallbloke.files.wordpress.com/2011/06/msl_noadjust.gif
When considering sea level that may or may not be changing in quantities measured in mm per year, it is worth bearing in mind that in order to measure them, we have to know where the satellites doing the measuring are extremely accurately. Due to the fluctuation of solar activity, the orbits of the satellites experience varying amounts of drag from the expanding and contacting outer shell of Earth’s atmosphere. It is extraordinarily difficult engineering and computer science stuff, and I wonder whether the error is larger than the signal.
The fact that these two platforms and software systems arrive at trends varying by several hundred percent indicates to me that there is a possibility that human decisions are a factor, and as you know, these are influenced by more than just technical considerations.
Upside down Mann Thinks:
“The European Space Agency people are not on message with their danged ENVISAT”
The people directly involved with these measurement apparently have the same reservations as I do.
http://www.cosis.net/abstracts/EGU04/05276/EGU04-J-05276.pdf
“The currently accepted value is 2.5±0.5 mm/year.
However, every few years we learn about mishaps or drifts in the altimeter instruments, errors in the data processing or instabilities in the ancillary data that result in rates of change that easily exceed the formal error estimate, if not the rate estimate itself.”
And
“It seems that the more missions are added to the melting pot, the more uncertain the altimetric sea level change results become.”
My father’s side of the family lived in Florida for seven generations. I have numerous friends and relations with oceanfront property and not one of them has any concern about rising sea levels. I would really love for Mann to point out any place where Americans have had to abandon property due to sea level increases. Real sea level increases and not subsidence. Much like the elusive proof that climate changes are unnatural, this will also go unanswered.
I’m with David. Sea level rise started its steep incline well before CO2 was even an issue. But the proxies used for the past???? Not sure about that.
As I see it, all this paper shows is the rate of local subsidence at two present day marshy points in NC.
It is loaded with sample bias. Figure 3 screams evaluation attention bias toward the sites that perform as desired.
Once again we see calibrated and measured (recent) data compared to filtered (old) proxy data and amazingly it produces the required hockey stick. I have not read the paper yet, but my spidey senses are telling me that there’s a mannomatic PCA somewhere in the filtering process.
It seems the data points aren’t too far away from New Bern – which according to the
NC Division of Water Resources, http://www.ncwater.org/Permits_and_Registration/Capacity_Use/Central_Coastal_Plain/landsub.php is subsiding:
“It is a pretty good bet that land subsidence in the North Carolina coastal plain is due to heavy pumping of ground water from aquifers referred to in various places in these web pages, namely the Black Creek and Upper Cape Fear aquifers. This last plot has some very interesting testimony to that theory. The rate of subsidence at Cove City increased in the second interval covered in the leveling runs (from 1968 to 1978) from 0.17 to 0.25 inches per year. This can be explained by New Bern bringing their Cove City water supply wells on-line in the late 1960s. Higher rates of land subsidence are associated with higher ground water withdrawal rates.”
By the way, didn’t UpsideDownMann get awarded a couple of million bucks to buzz off and study mosquito vectors in Mongolia or something? Did anyone get anything for the cash? How come he’s back climatebothering us so soon?
LOL!
These so called scientists don’t even take the time to cross check their work with reality.
Here is a picture of Kitty Hawk Beach circa 1950:
http://2.bp.blogspot.com/_fTP7NWs-Lqg/SwWfo9ZnRbI/AAAAAAAACAM/pzLdI317jdg/s1600/1950%27s+Kitty+Hawk.jpg
And here is a modern view looking the opposite way.
http://www.flickr.com/photos/jonesairfoils/20512475/
I don’t detect any significant rise in sea level (not accounting for hi/lo tide, etc). In fact, the idea of using glacial rebound on a barrier island is ludicrous. The barrier island would probably not rebound at all in the modern era.
The Hockey Team is still desperate to find their hockey stick.
So now Mann says there was a MWP ? Its so confusing …
No. quite the opposite.
From the SI
This is another clever obfuscation of reality that of course neglects atmospheric circulation patterns in relation to sea level changes distribution. Even looking at the heterogeneity of the sea level map by Cazenave and co. one can see it is easy to manipulate whatever one wishes to say. The same paper could be made carefully selecting sites of sea level drop. And to boot they still have to adjust… LOL
And guess what it also matches the HadCRUT curve…
Climategate hitting CRU hit at teh heart of the Global Warming fraud.
Mann should be fired with cause.
I bet they used the data upside down… Just kidding. That trick has already been pulled. I can’t wait to see what Steve McIntyre does with this paper. I wonder if they archived the data and code? Has this method of sea level reconstruction ever been used before? I have a hard time believing this approach will be as valid tree rings… and we already know those don’t make good thermometers.
A transfer function? Sounds to me like they used math to determine how far above sea level these samples were created 2000 years ago? Anyone have anything to say about the validity of that assessment of their method?
According to Manns new sea level curve, the Romans built inland ports in southern England.
WUWT?
Bull since the sites are carefully selected. Take a sea level satellite map for Cazenave and see how the distribution of sea level anomalies follow atmospheric circulation patterns. Another Mann made fraudulent claim!
tallbloke tide gauges and several hundred years records where is no proof of reading continuity are better ?
The reality is just like the ‘magic tress’ there a other factors that can affect what is observed here , the default to AGW its not proving, even if you start with the premiss it has to be .
Looks like Mann’s modeling software is good for all kinds of things. Add air you get a hockey stick shaped warming graph, add water and you get a hockey stick shaped sea level rise. I suspect he is selling the idea that if you add enough money you can get a hockey stick shaped stock market graph as well.
A curiousity in the figure showing Mann’s temp record with the sea level rise record:
The temp record peaks (until very recently) just before 1000 AD. Temps then fall.
Meanwhile, sea level starts a 400 year steady rise just about the time that temps peak and start to fall. The sea level rate of increase of about 0.6 millimeters per year starts around 1000 AD and finally levels off about 1400 AD.
Am I wrong, or isn’t sea level rise, if causally correlated with temperature increase, supposed to be reasonably synchronous?
Interesting sea level map here. Shows, once again, how ridiculous it is to cherry pick your reference point:
http://www.agu.org/news/press/pr_archives/2011/2011-17.shtml