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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[snip – over the top – Anthony]
Straight from the horses mouth Mosh!
“An error of this magnitude is not implausible as we used
the global Mann et al. (34) reconstruction”
Lol.
[oops, too much italic – Mod, can you remove my last post, please?]
jack mosevich says:
June 20, 2011 at 12:16 pm
Why just this region? What about the global sea level rise? Seems like a cherry picking exercise.
Not at all! It’s only cherry picking if the intent is to mislead. The paper looks at North Carolina because that is the data they are using. It quite clearly states that, but they also go to the lengths of correcting for GIA.
http://en.wikipedia.org/wiki/Post-glacial_rebound
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?
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.
Jeff Carlson says:
June 20, 2011 at 12:13 pm
So now Mann says there was a MWP ? Its so confusing …
Mann never denied these phenomena, only their extent and amplitude. The data says what it says!
So they took Mann’s hockeystick and used it – even though it had been discredited numerous times.
That alone destroys any credibility this paper might have.
Sea levels were higher during the “roman warm period” and the “mwp”, not lower, at least in Europe, Africa and Asia. “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.” I myself, have a collection of books ranging from Archaeology to History and related subjects, mostly covering the time period 1,500 B.C.E. to Late Antiquity and the Early Middle Ages. The quote above flies in the face of current Archaeological research and Historical knowledge. The microflora that they mention in research are often used by Archaeologists to gauge ancient tsunamis, not permanent high water.
But most people on this forum will probably want websites, and not a list of books:
http://www.politics.ie/environment/127371-sea-levels-were-higher-roman-times.html
http://www.salt.org.il/frame_arch.html
http://www.lundyisleofavalon.co.uk/history/sealevels.htm
http://www.everythingselectric.com/forum/index.php?topic=357.0
The principle reason 300 elite Spartans, 600 Helots, 1,000 Phocians and possibly 2,000 Thebans were able to hold off the Army of Xerxes for three days had as much to do with sea level as it did to the fanatical training of the Spartans.
http://en.wikipedia.org/wiki/Thermopylae
http://www.historynet.com/battle-of-thermopylae-leonidas-the-hero.htm/6
http://heritage-key.com/blogs/owenjarus/reconstructing-thermopylae
The sea levels in the Malian Gulf were much higher than today, allowing the Athenian Navy to support the land forces. The pass at the cliffs of Zastano was probably less than 100 meters wide.
How can Micheal Mann assume that the sedimentary data has not been disturbed by the forces of nature? North Carolina has been hit by legions of hurricanes over the millennia. All it takes is one strong hurricane to strip (or deposit) feet of sediment at a location.
As an example. I was on the island of St. Thomas, US. Virgin Islands during hurricane Hugo. The hotel I was originally staying it lost 50+ feet of sea wall protected shoreline property (meaning the ocean moved the shoreline 50+ feet closer to the hotel.) There was also about a 3 foot depth of sand, gravel, and debris deposited into the parking lot. All that from one storm.
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.
The crucial step to go from local subsidence and relative (to local) sea level to the Global GIA sea level is in the correction factors from these two holocene databases, which are unaffected by the work in this paper.
What is the correction f(t) and what error bars are on their data points?
The corrections result in the diagonal sides of the rombus data points on the GIA graph.
“Note that members of the NAS are permitted to communicate up to 4 papers per year. The members are responsible for obtaining two reviews of their own papers and to report the reviews and their responses to the reviews. Note, as well, that rejection of such contributions by the Board of PNAS is a rare event, involving approximately 2% of all contributions.”
i pulled my head out my kiester just long enough to drop it on the ground
got sand in my eyes now i cant see
good thing the water is close by
i can wash the crap off
good luck
AJStrata says:
June 20, 2011 at 12:47 pm
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.
And you can tell from those two photos that the 4 inch or so rise they are claiming over that period must be phoney? Wow!
Wasn’t this demolished two years ago on WUWT?
http://wattsupwiththat.com/2009/10/29/north-carolina-sea-levels-rising-3mm-a-year-uc-sea-level-data-says-differently/
russ says:
June 20, 2011 at 12:38 pm (Edit)
Did Al Gore check with Mann before his recent Montecito purchase
He didn’t need to. The house is about 180 feet above sea level. The clue is in the name.
Tide gauges on a passive (subsiding tectonically due to slab cooling) margin, and to boot, the isostatic rebound in the northern continental interior results in additional down tilt in the Carolinas.
Hey hockey team: Where is that Ft. Point tide gauge? That one is far more interesting than the ones on the swampy flat Carolina shore.
tallbloke says:
June 20, 2011 at 1:15 pm
russ says:
June 20, 2011 at 12:38 pm (Edit)
Did Al Gore check with Mann before his recent Montecito purchase
He didn’t need to. The house is about 180 feet above sea level. The clue is in the name.
=======================================================
Plus, around there, I have found non fossilized mollusk shells up on top of the mesas. Probably a couple or three mil old, max.
how can you trust anything Mann does?
I’d like to see the emails they had to make this paper?
Salt marshes? Seriously?
Michael Mann with his bucket and spade
Went to Kitty Hawk Beach and played
But the tide it was rising
(Really not so surprising)
And down came the castle he’d made
An error of this magnitude is not implausible as we used
the global Mann et al. (34) reconstruction prior to AD 1100
and not the Northern-Hemisphere-only reconstruction in which
Mann et al. (34) had greater confidence.
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good grief………………..
“Since the late 19th century, however, sea level has risen by more than 2 millimeters per year on average,”
Since the late 19th century, sea level has risen by more than 7 inches, and no one noticed……
….and it’s a travesty they didn’t
Amazing the results you get when all of your conclusions are predetermined and you don’t mess with actual data.
I wonder how much of this study is real data and how much is model generated to fill in the gaps in the data.
Why don’t they take it further back and start the sea level rise graph at end of the Pleistocene? That initial 140 meter sea level rise as the North American and European glaciers melted would make this current sea level rise look like a drop in the bucket. But then, that represented real climate change.
“Penn’s School of Arts and Science…”
Looks more like art than science to me…
the moorings of major ports like Benghazi, Libya, Istanbul etc are in exactly the same sea level place that they were constructed with hundreds of years ago.
the Tower of London – another Medieval construction along the Thames is at the same relation to the river, if you compare a contemporary photograph with artistic expositions of the time of its construction.
Just a few empirical facts there, so I rather suggest that Mann cam to his conclusion first then worked backwards to make the data fit
SteveSadlov says:
June 20, 2011 at 1:18 pm
tallbloke says:
June 20, 2011 at 1:15 pm
russ says:
June 20, 2011 at 12:38 pm (Edit)
Did Al Gore check with Mann before his recent Montecito purchase
He didn’t need to. The house is about 180 feet above sea level. The clue is in the name.
=======================================================
Plus, around there, I have found non fossilized mollusk shells up on top of the mesas. Probably a couple or three mil old, max.
Is that where the seagulls have lunch?
AJStrata has the right idea with photographs. I bet there are hundreds of photos spanning 100+ yrs of various parts of the US coastline. As many have suggested, beach front prices are not falling off the cliff !
Good fun at Bishop- Hill site re. IPPC report – clever people needed to help.