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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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?
I am willing to purchase any beachfront property that these scientists may be looking to unload, at a heavy discount, of course.
“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.”
I’m sure there is no chance of any observational errors in a 300 year old record done by 10 generations of tidal gauge “volunteers” … naaahhh … I’m sure they all used GPS coordinates to confirm their locations and “altitude” …
also no chance of sediment accretion or erosion over that 300 or 80 year record … no chance …
Why would anyone believe anything Michael Mann publishes, let alone something that involves proxies and a hockey stick? Madness.
“To reconstruct sea level, the research team used microfossils called foraminifera preserved in sediment cores from coastal salt marshes in North Carolina.”
Bwaaaahaaahaaahaaaaaahaaahaaahaaa!
So now Mann says there was a MWP ? Its so confusing …
Shock horror not only is it worse than we thought it is, gasp, another hockey stick. What a pile. Will now read the paper but fully expect my initial reaction to be correct 🙂
I do not pretend to understand the technical presentations. However, I think I recognize a familiar shape in the graphs. Can I safely conclude that it is worse than we thought?
Why just this region? What about the global sea level rise? Seems like a cherry picking exercise.
Am I reading this correctly?
If my eyes aren’t fooling me… The acceleration in sea level rise occurred between 1865 and 1892… When it jumped from -0.1 mm/yr to 2.1 mm/yr.
Meaning that the acceleration in sea level rise started long before atmospheric CO levels climbed above the low 300’s/
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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Probably because the satellite (Envisat) measurements don’t agree…………..
http://stevengoddard.wordpress.com/2011/06/19/hiding-the-decline-in-sea-level/#more-32692
I like the way the phrase ‘the team’ is used over and over again.
What a crock.
I didn’t see any reference whether or not the land rose, fell, or remained stable during that entire period Mann referred to above. Nor did I see any mention of soil erosion.
Why are the error bars shaped like tilted rectangles in some of the graphs? This implies that uncertainty in dating of a sample has an impact on the implied sea level in a predictable and biased manner. Some error rectangles slope downwards, while others slope upwards. And why does the Iceland data have essentially no significant dating errors, while the others have significant dating errors?
“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.”
My, my. After all the efforts The Team made in trying to remove this period, or to turn it into a local phenonemum.
“assuming a linear relation between temperature and the rate of sea-level rise.”
Any evidence for this?
“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?”
Based on his previous “work” to “hide the decline” no doubt!
If it cast doubt leave it out , seems to Mann’s standard approach to what ever he does , in this case the last ten years when in fact there are more not less accurate data to be had .
“Two points in salt Marshes in North Carolina are used as the basis for the study”
I guess that is better than one tree.
This is really hilarious. Is Mann a masochist?
Meanwhile, will the entire ocean be dead before next week when Manhattan floods? A familiar expert – much adored by WUWT readers – says it is worse than we thought, as usual:
“World’s oceans in ‘shocking’ decline”
“”The rate of change is vastly exceeding what we were expecting even a couple of years ago,” said Ove Hoegh-Guldberg, a coral specialist from the University of Queensland in Australia.”
http://www.bbc.co.uk/news/science-environment-13796479
Shocking, just shocking. The BBC’s Richard Black seems to do nothing but parrot scary UN press releases.
Funny how everything Mann touches turns into a hockeystickish shape. Did he use these fancy half-3D graphics to make it harder to see noncorrelation?
Ye horror!
The skies are falling! The seas are rising! The Earth is warming!
Not.
Oh, my…
I can’t WAIT to see what Willis does with this hanging curve ball.
OMG!!! – another “potentially disastrous outcome…..”
2mm per year.
That’ll be 2 metres in only…………………….. 1000 years.
Better put that beach house on the market tomorrow.
I visit Wrightsville Beach and Fripp Island most every Summer. I love the Outer Banks also and have never noticed any of this man’s alarmist proclamations. Tarheel born and bred(though I despise Carolina). NC State here. A working man’s institution rife with veterinary, scientific, engineering, and architectural glory.
That said, next visit to the old North State, come say hello and we will hold an evening of climate change exchange in friendly confines…….my study. Plus, I make the best Old-Fashioned you will ever bring to your lips Mr. Watts. Have I had one too many already? Thanks for what you do every day……every single day.
Your friend in Charlotte,
Edward Lee
As a resident of North Carolina and a love of the barrier islands (the Outer Banks), I have to cry foul.
Why was the shifting sands of the North Carolina chosen? The barrier islands are formed because of the Gulf Stream current. That means they didn’t exist at one time. The sands are never, ever still and new inlets are being formed all the time. Take a drive on NC highway 12 and see for yourself. There is an inlet called Oregon Inlet which was formed after a hurricane. (It is named after a ship that went through the newly formed inlet.) The sand is so unsteady there that our tax dollars go to keep Oregon Inlet an inlet to save time for commercial ships. The bridge that goes over Oregon Inlet, the Bonner Bridge, is rated a 2 out 10 in the quality of bridges. It is impossible to keep it in good shape because of the constant shifting sand.
My point in all this is simple. Blackbeard the pirate didn’t hide off North Carolina because of the weather. He hid there because the sands are always shifting. North Carolina, like Florida, is a hurricane magnet. Furthermore, North Carolina also gets Nor’easters. Both of these cause tremendous amounts of erosion. The tidal gauge measurements aren’t exactly the most reliable on this earth. I will bet money North Carolina was chosen, and not some other state or provence just because it would deliver the desired results.
I can see some obvious issues here immediately,
Firstly the comment “consistent link between changes in global mean surface temperature and sea level.”
I am not sure how you can have several hundred years of cooling and simultaneously have rising sea levels and call it a “consistant link”!!!
Secondly, no link is actually proven and thirdly, two points on the north carolina coast can not be assumed to be a proxie for a) the entire world b) the entire USA!