Below: North Carolina’s Albemarle Sound.
Note marker at 36N -76W.
First the Press Release from the University of Pennsylvania:
North Carolina Sea Levels Rising Three Times Faster Than in Previous 500 Years, Penn Study Says
October 28, 2009
PHILADELPHIA –- An international team of environmental scientists led by the University of Pennsylvania has shown that sea-level rise, at least in North Carolina, is accelerating. Researchers found 20th-century sea-level rise to be three times higher than the rate of sea-level rise during the last 500 years. In addition, this jump appears to occur between 1879 and 1915, a time of industrial change that may provide a direct link to human-induced climate change.
The results appear in the current issue of the journal Geology.
The rate of relative sea-level rise, or RSLR, during the 20th century was 3 to 3.3 millimeters per year, higher than the usual rate of one per year. Furthermore, the acceleration appears consistent with other studies from the Atlantic coast, though the magnitude of the acceleration in North Carolina is larger than at sites farther north along the U.S. and Canadian Atlantic coast and may be indicative of a latitudinal trend related to the melting of the Greenland ice sheet.
Understanding the timing and magnitude of this possible acceleration in the rate of RSLR is critical for testing models of global climate change and for providing a context for 21st-century predictions.
“Tide gauge records are largely inadequate for accurately recognizing the onset of any acceleration of relative sea-level rise occurring before the 18th century, mainly because too few records exist as a comparison,” Andrew Kemp, the paper’s lead author, said. “Accurate estimates of sea-level rise in the pre-satellite era are needed to provide an appropriate context for 21st-century projections and to validate geophysical and climate models.”
The research team studied two North Carolina salt marshes that form continuous accumulations of organic sediment, a natural archive that provides scientists with an accurate way to reconstruct relative sea levels using radiometric isotopes and stratigraphic age markers. The research provided a record of relative sea-level change since the year 1500 at the Sand Point and Tump Point salt marshes in the Albemarle-Pamlico estuarine system of North Carolina. The two marshes provided an ideal setting for producing high-resolution records because thick sequences of high marsh sediment are present and the estuarine system is microtidal, which reduces the vertical uncertainty of
paleosea-level estimates. The study provides for the first time replicated sea-level reconstructions from two nearby sites.
In addition, comparison with 20th-century tide-gauge records validates the use of this approach and suggests that salt-marsh records with decadal and decimeter resolution can supplement tide-gauge records by extending record length and compensating for the strong spatial bias in the global distribution of longer instrumental records.
The study was funded by the National Oceanic and Atmospheric Administration Coastal Ocean Program, North Carolina Coastal Geology Cooperative Program, U.S. Geological Survey and National Science Foundation.
The study was conducted by Kemp and Benjamin P. Horton of the Sea-Level Research Laboratory at Penn, Stephen J. Culver and D. Reide Corbett of the Department of Geological Sciences at East Carolina University, Orson van de Plassche of Vrije Universiteit, W. Roland Gehrels of the University of Plymouth, Bruce C. Douglas of Florida International University and Andrew C. Parnell of University College Dublin.
I was curious, because this seemed a bit “off” to me based on other data that I’ve seen. So I went to the University of Colorado Sea Level data server and entered the coordinates for Albemarle Sound (36N -76W or in their usage 36N 284W).
The graph they serve up looks like this:
It’s low resolution, but does look rather flat. Fortunately they provide the data with the plot. You can read all about the Topex/Poseidon data preparation here.
I took that raw data and plotted it here in an expanded size and did a trend line, shown below:
The result was surprising. A slight negative trend.
I chose a different location to get closer to Pamlico Sound, also cited in the study. Unfortunately the interactive tool at UC is coarse on lat/lon and the closest I could get was 35N -76W, just off the outer banks.
The data from that point is plotted below. The source data for 35N -76W is available here.
Apologies for the slight cosmetic differences in line size between the two graphs. I had a computer reset between sessions and lost some settings.
So, if there is 3mm rise per year recently, since 1992, we certainly can’t see it. I can’t say anything for the other years in the study.
But in the press release they say:
The rate of relative sea-level rise, or RSLR, during the 20th century was 3 to 3.3 millimeters per year, higher than the usual rate of one per year.
If that is true, then the rate appears to have slowed significantly in the late 20th century to present. For 35N, -76W, the 1.12mm/yr rate certainly looks like the “…usual rate of one per year”.
Or, perhaps, to paraphrase the Great Communicator, “A rising number of boats lifts all tides”….
glacial rebound goes both ways. While the Laurentide Ice Sheet was depressing the northern half of north america, it was tilting the whole continent, causing a large drop in sea level in the southern half. While arctic canada sea levels are dropping due to rebound raising the bedrock up again, southern US sea levels would be rising long term for the same reason but in the opposite direction. The “normal” rate should be about 1- 1.5 mm a year due to rebound anyways. A rise to 3 mm a year should be due to the glacial losses of the late 19th and early 20th century as we exited the LIA, releasing the ice weight that was slowing rebound during the LIA.
I have a request. Does anyone have a link to sea surface temperatures, since 1994, in the Gulf of Mexico just offshore Louisiana?
I have a plot of the Topex/Jason-1 satellite sea level from U. Colorado for that area, and it definitely shows a seasonal change in level – lower in winter, higher in summer. The difference, on average, is about 25 cm (roughly 10 inches).
Thanks in advance.
The marshes can cope I hope.
“Rising atmospheric carbon dioxide is largely responsible for recent global warming and the rise in sea levels. However, a team of scientists, including two Smithsonian ecologists, have found that this same increase in CO2 may ironically counterbalance some of its negative effects on one of the planet’s most valuable ecosystems—wetlands.
“The team conducted their study for two years (2006 – 2007), during which they focused on the role that organic matter, both growing and decaying, plays on soil elevation in wetlands and the effect CO2 has on this process.”
“Our findings show that elevated CO2 stimulates plant productivity, particularly below ground, thereby boosting marsh surface elevation,” said Adam Langley, the paper’s lead author. Patrick Megonigal, the paper’s corresponding author, added “We found that by stimulating root growth, thus raising a marsh’s soil elevation, elevated CO2 may also increase the capacity for coastal wetlands to tolerate relative rises in sea level.”
http://www.sciencedaily.com/releases/2009/03/090323212035.htm
I was always taught that water found its own level. Isn’t sea level, sea level? Isn’t this a world wide measurement. As the article says you get local highs/lows, here in Melbourne, Australia the sea level outside Port Phillip bay is higher outside than inside because the tide cant get through the narrow opening quick enough. So shouldn’t sea level be a global measurement?
@colinjely
That was my point in my post about pouring water into a pond. If I pour water into a pond, the pond gets deeper, evenly across the pond and not in one location. To say that the sea level is rising/falling at a faster rate along some section of coast, and not globally at the same rate indicates that something is amiss.
So CO2 also travels back in time, to the 19th century, and accelerates sea level increases before there was enough CO2 to otherwise do it.
What an amazing gas CO2 is.
The study could have been done for probably 50% of the actual grant costs- since the ‘researchers’ already knew the answer before they started the study.
Think of how much money can be saved on ‘research’ if the results are known prior to those troublesome and tedious research projects.
RE: And do we know what is happening with local subsidence?
Well, the entire Atlantic and Gulf coast of the US is a passive margin, so, from a plate tectonics point of view, slow subsidence would be expected.
ehh, Greenland melting? How much? When did it start? Most people have seen this before.
“July 15, 1992, fifty years to the day later, 74-year-old Brad McManus stood on the ice cap surrounded by the recovered pieces of his late friend Harry Smith’s P-38…
How do you get a P-38 out of the ice? Simple…melt the ice! Well, maybe not as simple as that, seeing how it was 268 feet of ice.”
http://p38assn.org/glacier-girl-recovery.htm
So in the 50 years from 42 to 92 that part of the Greenland Ice cap gained 260 odd feet in depth, I wonder what a return visit 18 years later to the same site would find? Probably only take a small seismic or ultrasound unit to get a physical picture of the previous excavation site, including current depth to any remaining bits and pieces. My money is on them being deeper than the 268 feet they were in 92.
Would not be science of course, more like a stunt, but visually it would get across to a large audience.
Pearl and Angie – thanks for direction to Warwick Hughes post giving Aust Gov measurements of actual sea level rise and fall in Australian and South Pacific.
http://www.warwickhughes.com/blog/?p=283
Opposition MP Tony Abbott struck back with “Sea levels had risen along the NSW coast by more than 20 centimetres during the past century. Has anyone noticed it? No, they haven’t,” he told reporters in Canberra today.
http://www.theaustralian.news.com.au/business/story/0,,26268796-5019301,00.html
Where does he get the 20 cm from? Would it be that the BoM chart (see Hughes for 20 yrs only) shows fluctuations (but no trend) plus/minus 20cm?
But how extraordinary that such a powerful (and perhaps erroneous) anti-Alarmist statement is not checked or countered in/by MSM.
I guess it is that if we start arguing on actual data then Alarmism is bound to lose. Perhaps it’s like if the recent pause in catastrophic global warming were blamed on a quiet sun dampening the CO2 effect…As others have observer: more and more the imperative to avoid discussion of the facts. Dare I say that this is one of the signs of peaking of an apocalyptic movement. A December blizzard off the North Sea would certainly help define such a peak. We can only pray.
Loco (08:49:00) :
Set the flamingos FREEEEE!
http://minnesotansforglobalwarming.com/m4gw/videos/
THANK YOU! THANK YOU! THANK YOU! 🙂 🙂 🙂 🙂 🙂 🙂
Cassandra King (01:51:21) :
The ever alarmist BBC has just issued a warning that the coastline of Wales in the UK will have to be evacuated and abandoned
So Global Warming does have some benefits after all! 🙂
It’s been mentioned above but subsidence and particularly the interplay of the subsidence and sedimentation rates are key in this environment. Looking at the greater Mississippi delta area of LA and the changes in ecology (ie fresh to brackish to salt) one would easily conclude it was due to a sea level rise. It is in fact due to lack of cyclical sediment input because the natural process of repeated flooding from main channel break-outs during floods (channel switching or avulsion) are mitigated due to the efforts of the Corps of Engineers and its wish to control flooding and maintain a shipping channel . I’m suggesting that any modification of historical sediment influx due to development (as simple as percent area in pavement, farms, roads, diversion of waterways etc) would probably be bigger than any ongoing, background, natural changes.
So, sea level has been rising for 500 years, and….the coast has been inundated and people had to move inland, as per the dire warnings of Mr. Gore et al! Wait… no, the coast has actually marched outward and added land area onto which people move their fancy “cottages” to wait for the next hurricane! This is a fact that is obvious to any Geology undergrad with half a wit. Shorelines along subsiding continental margins (ie: SE and SW coastal and Gulf of Mexico, USA) are most commonly accretive, ie they accumulate sediment at a rate higher than the rate of subsidence. Eroding shorelines are commonly found along emergent margins, where the wave base cuts into the existing sediment (ie: SE coast of the South Island New Zealand, NW coastal USA).
The reality of shoreline inundation is a balance of sediment supply, energy and accomodation space (subsidence or sea-level rise). The only simple thing about it is the argument proposed by Mr. Gore regarding cause (AGW) and dire consequences.
Roger Dueck, P.Geol.
All this nonsense about preserving the earth as we know it in our tiny fraction of time on earth must have to do with a growing transhumanism. We must believe, like Ray Kurzweil, whether we know it or not, that if we can just stay healthy long enough, we will never die. Technology will solve it.
Most of the rabid eco/green/planet worshipping/maniacs don’t even have children, much less grand children. They have never held a dying parent in their arms. Ashes to ashes, dust to dust.
“Understanding the timing and magnitude of this possible acceleration in the rate of RSLR is critical for …” Hysteria and Copenhagen.
Perhaps someone who knows more about this will explain this to me, but it seems that regardless of what the rate is, it is well within the possible values for the effect of isostatic rebound (previously glaciated crust “rebounds” upwards and adjacent non-glaciated areas are levered down). When you combine that with the uncertainty due consolidation of sediments (surely they’ve heard of that) how do these guys propose to attribute anything to warming.
http://grace.jpl.nasa.gov/data/pgr/
Scroll down to the 3 figures of the globe showing rates at different scales and the uncertainty in blue and red.
It appears that salt marsh sedimentation is a good proxi for local water depth average and nothing else. Qualification for AGW dedicated grant funding may be the “facts” that the study was looking for.
Any geologist can look at the area map and see it is a subsidence area, the only question is how fast.
It must be horrorable to have an expensive Degree and no real job expectations.
I’m glad the world always need ditch diggers.
Well, excuse me. I’ve scrolled up and see others have brought up isostatic rebound and consolidation of sediments. I hope at least that the link adds to the discussion.
I would also like to relay an anecdote about coastal Alabama. In the summer of ’08 storms exposed an old shipwreck on the Fort Morgan Peninsula. Like many other curious folk I went down to see it and saw something that was far more interesting to me.
In the water near the beached wreck were numerous tree stumps, intact with roots, under about a foot of seawater. The area has been beach since the earliest Europeans arrived in the area so there is no way that this inundation could be due to AGW related rising sea levels.
According to my geology professor in college the local crust is actually being levered upward due to the load of Mississippi sediments taking the Miss. Delta down. If this is true then the ongoing rise of sealevel or consolidation of sediments is pretty dadgum large.
I also wonder if the Chesapeake Bay Impact Crater could be having some small effect.
Quote: “Even the courses of the modern rivers in the lower bay region point to the continued influence of differential subsidence over the crater. Most of the rivers, like the Rappahannock, flow southeastward to the Atlantic. But in contrast, the York and James Rivers make sharp turns to the northeast near the outer rim of the crater. We infer that the topographic depression over the crater has been maintained recently enough to have been a significant determinant of the modern courses of these rivers. This continued subsidence also may play a role in the high rate of relative sea-level rise that is well-documented for the Chesapeake Bay region. One of the locations of highest relative sea-level rise is at Hampton Roads (the lower part of the James River), located over the crater rim.”
http://woodshole.er.usgs.gov/epubs/bolide/ground_subsidence.html
OH! by the way, I’ve dug miles of ditches. People with worthless degrees become forklift operators. 🙂
p.g. sharrow n.d.d.
“Tide gauge records are largely inadequate…” So instead of actual measurements they’re going with “Accurate estimates…” Isn’t that a bit of an oxymoron? How do they get this millimeter precision from swamp mud with “…decimeter resolution…”? A decimeter is 100 millimeters. Did they do any accounting for the fact that as erosion from higher land piles sediments onto river deltas and coastal marshes, those areas subside, sluffing and sloughing and generally sinking and sliding… *smacks self for the silly alliteration*
But seriously (*smack* stoppit!) “Did they check the lake for DDT?” to quote Dr. Roy Spencer. That seems to be his catch phrase shorthand (again with the s-words…) for “Did the researchers consider the factors that should be bleedin’ obvious?”.
When examining a mucky coastal zone to look for evidence of sea level change, the researchers should consult geologists with knowledge of the area. If nobody has studied the research area to determine how much or even if there’s subsidence, then that research needs to be done along with the sea level investigation.
P.S. There’s been no reduction in tropical storms in Idaho, ever. 😉
Well, I was curious about long term data, so I went to NOAA’s tides and currents site. The most complete gauge record from North Carolina is Wilmington. Here is what it shows:
http://www.tidesandcurrents.noaa.gov/sltrends/trends/8658120.png
In case you are curious (I was) NONE of the records show a rate of 3 mm a year!!!
Or exaggerating co2’s effects by 2000%…
“”In addition, this jump appears to occur between 1879 and 1915, a time of industrial change that may provide a direct link to human-induced climate change.””
Oh, I almost forgot.
Not only are there solar and lunar sea tides, but there are also solar and lunar land tides. The moon in particular stretches out the Earth like an egg, to the tune of several inches each day.
These may or may not be in phase with the sea tides, depending on whether the sea tides are affected by resonance.
But I am only an egg, so to speak, in these matters.