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.
===================================================================
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.
======================================================================
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.
======================================================================
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.
========================================================================
The full paper is available here: PNAS_Kemp-etal_2011_Sea_level_rise
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The Corps of Engineers and University of Florida both said they could find no sea level acceleration,
and actually found de-celeration…………..
http://www.jcronline.org/doi/full/10.2112/JCOASTRES-D-10-00157.1
Whenever Sea-level is up, my thoughts goes to Niels Axel Moerner;
Claim That Sea Level Is Rising Is a Total Fraud;
http://www.climatechangefacts.info/ClimateChangeDocuments/NilsAxelMornerinterview.pdf
R.S.Brown says:
June 20, 2011 at 8:51 pm
“To credit any type of Glacial Isostatic Adjustment (whether it’s a rebound
or a subsidence) t the Atlantic shore regions of North Carolina is superficially
unrealistic or, at worst, deliberately deceptive and misleading.”
I’m not an expert on this, but I infer that any steady change in tide gauge elevation is classified as GIA whether it is related to glaciation or not. The GIA tables accessible from http://www.psmsl.org/train_and_info/geo_signals/gia/ have GIAs for locations like HONOLULU and DAKAR that clearly haven’t had a glaciation problem in the past few million years.
ferd berple says:
June 21, 2011 at 6:52 am
“Charts are marked with datum corrections, such as WGS84. This gives you and adjustment for GPS lat long, as almost always a chart has some lat long correction as they were made before the days of GPS. They don’t redraw the chart. They note the correction factor in the legend. I have never seen a chart marked with a correction for sea level rise. If it was happening it would be marked on the charts.”
In general, sea level changes aren’t usually going to matter much. They are thought to be about the same magnitude as water level changes due to changes in prevailing winds — a few inches a century. Further, almost shoreline feature on the planet is either sinking or rising a few inches a century. Nonetheless, there does seem to be a discrepancy between casually observed sea level change (near zero except where there is lots of subsidence or oil/water is being pumped out from under the shoreline), Eight inches or so a century (tidal gauge data) and Seventeen inches a century from satellites.
Actually, you can. You see beaches are sloped. This makes a triangle between the level of the ocean, vertical plane, and the slope of the beach. Now people have actually classified beach slopes, believe it or not.
Gentle Beach (1:50 slope). Arctan (1/50) = 1.14 deg
Moderate Beach (1:33 slope).Arctan (1/33) = 1.72 deg
Average Beach (1:20 slope).Arctan (1/20) = 2.86 deg
Steep Beach (1:10 slope).Arctan (1/10) = 5.71 deg
So if the ocean rises 4 inches in the vertical plane, you would see:
4″/(1/50) = 200 inches of horizontal change or ~ 16 feet difference when seen from directly above (nearly 5 meters)
4″/(1/33) = 133 inches / ~ 10 Feet (3 Meters)
4″/(1/20) = 80 Inches / ~ 7 Feet (2 Meters)
4″/(1/10) = 40 Inches / ~ 3 feet (1 Meter)
Now that looks like a fairly gentle beach compared to others I’ve seen/been on. I’d wager it’s at least average if not a mildly sloping beach. So yes, images from the same tide level (itself an oxymoron since no tide is equal) can tell you if the shoreline has moved relative to the sea level or vice versa. Why is it so easy to assume that your eyes are lying to you, but a complicated math function applied to 2000 year old fossilized lifeforms is dead-on accurate in determining your doom?
So wait, (and please bear with me i am no expert in this field) michael mann has produced a paper which splices two data sets together (the former being a proxy based on two, yes just two points on the globe) …. and ignores contrary data (evistat) .all sounding familiar so far….to arrive at a conclusion that this agrees with already exposed as deeply flawed earlier data (hockeystick) . I think this says more about peer review process than anything.
Over here in Germany the “findings” of this “research paper” already made it into newspapers – one nationwide, the FAZ, and at least one local paper. Do Rahmsdorf et al use some of their funds to pay for publicity?
The paper itself is a crime against nature, because it uses up valuable resources (energy for computers and travel, paper, etc.) and does nothing at all to improve our understanding of “mother gaias” ways. Just how can it be that a bunch of charlatans masquerading as scientists are still able to get millons of $ / € for useless activities?!? I certainly wouldn´t mind if the debt crisis in the EU (and the USA) had the effect of ending this waste of resources.
Looking at AGW, the casino that once was a working financiel system, the craze about “renewables”, I can only come to one conclusion: Madness took control. Cleaning up this mess will not be an easy task.
Last not least: Looking for evidence, checking theories or models with reality is what makes the difference between science and fiction. The fact alone that admiralty charts which were drawn 200 years ago are still correct down to the details of drying rocks (thanks to ferd berple for this information) should send the “research paper” directly into the bin.
Jeremy says:
June 21, 2011 at 8:09 am
Thanks for the beach slope scale. Now I can quantify my observations.
Those of us who love beaches walk them. In walking them, we are aware that they can change considerably in a matter of 100 feet and they can change dramatically because of nearby storms. But we know them like the backs of our hands. The beach itself is like a beautiful painting that gets more beautiful by the day. So, when I say that the sea level has not risen, it is not like visiting a fresh water lake and saying that the water level is up or down by however many inches. The beach is a manuscript on which the condition of the water is written in fine detail. A change of one inch in sea level would cause dramatic changes in that manuscript.
“Then in the 11th century, sea level rose by about half a millimeter each year for 400 years, linked with a warm climate period known as the Medieval Climate Anomaly.”
“Then there was a second period of stable sea level during a cooler period called the Little Ice Age. It persisted until the late 19th century.”
Umm, I thought Mann’s other work denied the existence of a ‘Medieval Climate Anomaly’ and a ‘Little Ice Age’? Is this a back door retraction of that work?
Latitude says:
June 21, 2011 at 7:30 am
The Corps of Engineers and University of Florida both said they could find no sea level acceleration,
and actually found de-celeration…………..
http://www.jcronline.org/doi/full/10.2112/JCOASTRES-D-10-00157.1
=============
Yes, but did they construct model to validate that claim? If a model doesn’t predict it it’s obviously flawed data (observational data being overrated in any case). 😉
From Don K on June 21, 2011 at 7:53 am:
Here’s the explanation for the adjustment:
http://sealevel.colorado.edu/content/what-glacial-isostatic-adjustment-gia-and-why-do-you-correct-it
Their reasoning goes like this: With the glaciers gone, the “sides” of the “bowl” are rising, increasing the available volume that the water can fill. The adjustment compensates for this apparent deepening of the oceans. Honolulu and Dakar qualify for the adjustment by merely having shorelines. The mean rate of the adjustment is 0.3mm/yr.
So you can watch a particular spot on a shoreline, know for a fact that there has been no change to the sea level for fifty years, but it will be determined from the models the GIA adjustment is 0.3mm/yr, thus there was actually 15mm of rise despite no observed change.
Yes, that is supposed to make sense, incredible as it seems.
Daft question, probably, but I’ll ask it anyway.
I live on the South West coast of Cumbria, in the UK. One thing I know about coastal areas is that there is this little thing called the tide, which is when the sea comes inland for a few hours, and then it withdraws again, repeating the cycle every 12 hours or so. Maximum and minimum high and low tide, in this area at least, can vary by up to two or three meters in a year.
I’m not familiar with the region under investigation, but I’d assume if it is coastal it is also subject to tides. If so, and if tides can vary by meters in a year (heck, even within a few days) then how can they measure the sea level so accurately via these proxies to be able to say that it varies on the order of tenths of millimeters a year?
This isn’t an objection to the study, it’s a request for information, as there’s obviously somethjing I’m missing.
I have no idea if this paper, as an attempt to produce a credible long history of sea level, is specious, foolhardy, cutting edge or a cogent mainstream bit of work. I doubt many here have any idea either. I suspect it would take quite detailed knowledge of the techniques involved in deriving this sort of data from these sorts of sediments to begin to judge the reliability of the work.
But the issue of sea level rise is one of an indicator of increasing heat content of the climate system. It is only a very long-term danger to human infrastructure.
The few inches to a foot that are ‘measured’ over the last ~century have been called into question on the basis of apparent unchanging coastal features. As a previous poster pointed out the ~4 inches that might have been seen in a human lifetime or photos from the past are well within the wind/tide/waves variation.
But there is another error in the sloping beach argument. –
@- Jeremy says:
June 21, 2011 at 8:09 am
“You see beaches are sloped. This makes a triangle between the level of the ocean, vertical plane, and the slope of the beach.
So if the ocean rises 4 inches in the vertical plane, you would see:
4″/(1/50) = 200 inches of horizontal change or ~ 16 feet difference when seen from directly above (nearly 5 meters)
The geometry is correct.
As long as you assume the the slope of the beach is at an absolute fixed height independent of the ocean. But beaches are dynamic changing objects. They are shaped by the water that washes against them. As the tides/waves wash across it sediments are deposited and removed. The slope may remain the same but it is easy to see how the overall level may alter in response to changing ocean depth so that the apparent position of high/low tide points are the same.
Perhaps if you had a hard bedrock slope on a tectonically stable seashore…
But there is a lot of tide-gauge data and more recent satellite data, recent advances in the field have help clarify the problems with GIA and local discrepancies. Looking for postcards, holiday snaps and personal anecdote seems a less than rigorous way to collect data.
There seems to have been rather little sea level change after the big rises as the major ice-sheets melted ~8000 years ago. But the recent rise looks increasing exceptional in the context of the last few millenia.
It is not that anyone is in imminent danger of flooding – any more than they are from storm and subsidence issues. Its that this amount of change in ocean levels is a big indicator of the amount of energy change happening in the climate.
Try-
“In Search of Lost Time: Ancient Eclipses, Roman Fish Tanks and the Enigma of Global Sea Level Rise ”
The reason why the ‘bathtub’ model of ocean levels is wrong, and the implications of the the influence of gravity – falling sea levels in Scotland if all of Greenland’s ice-cap melted!? is well worth waiting for…-grin-
Woops, that was meant to be an embedded link… sorry.
Izen says:
“…the issue of sea level rise is one of an indicator of increasing heat content of the climate system.”
True dat. Matches this.
@Smokey,
Sorry, I apologise, this time it was Richard calling me names.
@Smokey,
1. I didn’t conflate anything. My reference to cherry picking accusations and the photos were originally in separate posts.
2. The reference to the photos did not call on personal knowledge. Read it again: ”
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).”
Pretty sure he is referring to the photos. There is nothing to suggest otherwise.
3. I repeat, it is not cherry picking if you have done it for a reason and you are honest about it. Think about it, if someone else were to do a study using a different method, or a different location, would that be cherry picking? No, it would be a different study. It may or may not show results that agree with this one – that’s science. Anyone else can do a different study, whose results may or may not agree with this one. If you think you can make a serious study from photos, go ahead! OTOH, cherry picking is, for example, showing a graph of the last 10 years temperature, or temperatures from a few chosen locations, and claiming that these “FACTS” debunk AGW (but who would do such a thing)
4. I think the reason for only going up to 2000 has more to do with the kind of data they were using than any wish to “hide the decline”. I think that for two reasons. Firstly, the flattening of the last 10 years would hardly even show up on the results, so why hide it? Secondly, if it had been technically possible to include the last 10 years, I am sure they would have done so to head off the kind of criticisms they are receiving here. I could be wrong. (There’s a quote ripe for mining)
5. I repeat my question: Why don’t you call each other when your buddies post nonsense? Some of you are scientists, I think. You may disagree about the extent and certainty levels of AGW, but you must cringe at some of the satements made here, particularly the “argument from incredulity”, as in “I don’t understand X, so X cannot be true”, where X might be “a trace gas having a measurable effect” or “CO2 being both a feedback and a forcing”. These scientific principles were discovered way before Michael Mann and the IPCC, and the scientists among you know that.
5a. I suppose I have come to realise that the reason you can all get along so well is that you don’t have to actually agree, as long as you all keep bashing the mainstream. After all, it’s not really about the science, is it?
How about showing me your Christmas tree picture again Smokey, that was a real zinger 😉
kadaka (KD Knoebel) says:
June 21, 2011 at 10:02 am
“http://sealevel.colorado.edu/content/what-glacial-isostatic-adjustment-gia-and-why-do-you-correct-it
Their reasoning goes like this: With the glaciers gone, the “sides” of the “bowl” are rising, increasing the available volume that the water can fill. The adjustment compensates for this apparent deepening of the oceans. Honolulu and Dakar qualify for the adjustment by merely having shorelines. The mean rate of the adjustment is 0.3mm/yr.
…
Yes, that is supposed to make sense, incredible as it seems.”
Well yes, it actually does make sense if you believe that the glaciations depressed the poleward continents and squeezed magma out from under them which then flowed under the ocean basins and more equatorward continental areas. Now it is returning — slowly, ever so slowly. That’s plausible, if not overwhelmingly persuasive.
My problem is that the actual GIA corrections available from PSMSL don’t seem to match that description. For example, they actually have Dakar rising a bit. So I infer that in reality, “GIAs” probably include some (all?) tectonic changes whether they are glacier related or not. If so, I think that’s reasonable other than the nomenclature.
John B,
No need to apologize. But I think the stress of trying to prove climate disruption is getting to you. You’re replying to two separate posts that I didn’t make here. Lie down, relax, and repeat after me: “Serenity now…” : -)
John B, it’s a blog. Not a science journal. All sorts of people post here, some make sense some don’t. By and large there’s a lot of silly stuff but there are also gems of wisdom. It’s not necessary for someone to take every post as scientifically sound. It’s discussion.
Re my point about anecdotal evidence, sure that’s not science. But the practical physical effects of science are what the whole AGW case is about. And if sea levels are rising at historically unprecedented rates, then at some point it must become obvious. Now, not at some indeterminate future date.
If it is not obvious, then there is a discrepancy that causes one to wonder, surely?
izen says:
June 21, 2011 at 12:05 pm
You have not spent a lot of time on Florida’s beaches, have you? However, your response is nonsense regardless of your familiarity with beaches. If a person’s experience of a beach is not going to be changed by a rise in sea levels then why should that person care about a rise in sea levels? You say because a rise in sea levels measures changes in the energy in the oceans. But that just invites the same question again: why should a beachcomber care about a rise in the energy in the oceans if it is not going to change the beach? Like all good Warmista, your ploy is to attempt to move away from actual human experience of the environment to some theoretical claim about the environment. You are engaging in a fancy form of Changing The Subject Without Seeming To. Do you have anything to say about human experience of beaches on the East Coast of the USA? That is the topic.
John B says:
June 21, 2011 at 12:29 pm
“2. The reference to the photos did not call on personal knowledge. Read it again: ”
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).”
Pretty sure he is referring to the photos. There is nothing to suggest otherwise.”
I politely clarified that matter for you and explained that such use of photos should be backed by personal experience. It is the personal experience that matters.
@Izen
Thanks for the video link. I just watched the whole thing.
@Everyone else
Try it! The bit about why the sea level in Scotland will go down if and when the Greenland Ie Sheet melts is at about 38 minutes.
It also explains why Alaskan glaciers melting is causing the sea level in Alaska to go down!!! Don’t take my word for it though…
Mr Mann, 150 years of data is not a statistically valid sample set for making judgements on the significance of slight variations in temperature and sea level … sea level has varied hugely since mankind first trod the earth … nothing to see here …
elbapo says: “I think this says more about peer review process than anything.”
This paper, it seems, did not have to be peer reviewed in the normal sense.
http://wattsupwiththat.com/2011/06/20/manns-new-sea-level-hockey-stick-paper/#comment-685050