From the University of Haifa via Eurekalert
The sea level has been rising and falling over the last 2,500 years
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  IMAGE: Rising and falling sea levels over relatively short periods do not indicate long-term trends. An assessment of hundreds and thousands of years shows that what seems an irregular phenomenon today…
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“Rising and falling sea levels over relatively short periods do not indicate long-term trends. An assessment of hundreds and thousands of years shows that what seems an irregular phenomenon today is in fact nothing new,” explains Dr. Dorit Sivan, who supervised the research.*
The sea level in Israel has been rising and falling over the past 2,500 years, with a one-meter difference between the highest and lowest levels, most of the time below the present-day level. This has been shown in a new study supervised by Dr. Dorit Sivan, Head of the Department of Maritime Civilizations at the University of Haifa. “Rises and falls in sea level over relatively short periods do not testify to a long-term trend. It is early yet to conclude from the short-term increases in sea level that this is a set course that will not take a change in direction,” explains Dr. Sivan.
The rising sea level is one of the phenomena that have most influence on humankind: the rising sea not only floods the littoral regions but also causes underground water salinization, flooded effluents, accelerated coastal destruction, and other damage.
According to Dr. Sivan, the changing sea level can be attributed to three main causes: the global cause – the volume of water in the ocean, which mirrors the mass of ice sheets and is related to global warming or cooling; the regional cause – vertical movement of the earth’s surface, which is usually related to the pressure placed on the surface by the ice; and the local cause – vertical tectonic activity. Seeing as Israel is not close to former ice caps and the tectonic activity along the Mediterranean coast is negligible over these periods, it can be concluded that drastic changes in Israel’s sea levels are mainly related to changes in the volume of water.
In the present study, in light of earlier studies, research student Ayelet Toker and Dr. Sivan, set out to examine Israel’s sea level over the past 2,500 years, based on data deduced from many coastal archaeological findings. They made a careful selection of findings that have been reliably and accurately dated, and first focused on findings that were excavated by the Antiquities Authority in Acre of the Crusader period. These revealed that the sea level during the Crusader period – just 800 years ago – was some 50-90 centimeters lower than the present sea level. Findings from the same period at Caesarea and Atlit reinforced this conclusion. When additional sites were examined from periods before and after the Crusader period, it was revealed that there have been significant fluctuations in sea level: During the Hellenistic period, the sea level was about 1.6 meters lower than its present level; during the Roman era the level was almost similar to today’s; the level began to drop again during the ancient Muslim period, and continued dropping to reach the same level as it was during the Crusader period; but within about 500 years it rose again, and reached some 25 centimeters lower than today’s level at the beginning of the 18th century.
“Over the past century, we have witnessed the sea level in Israel fluctuating with almost 19 centimeters between the highest and lowest levels. Over the past 50 years Israel’s mean sea level rise is 5.5 centimeters, but there have also been periods when it rose by 10 centimeters over 10 years. That said, even acute ups and downs over short periods do not testify to long-term trends. An observation of the sea levels over hundreds and thousands of years shows that what seems a phenomenon today is as a matter of fact “nothing new under the sun”, Dr. Sivan concludes.
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Andrew P (00:44:52) :
In case anyone thinks that my grandfather was privy to Hitler’s inner circle, I should maybe add that my grandfather was on Monty’s side, not Rommel’s !
Does the deep sea-bed heave at all?
Most liquid spheres in motion (especially spinning) will have a periodic oscillation in the fluid body (the mantle of the Earth). A reverberation.
If the mantle under the oceans gently heaves by a few meters over a period of centuries, it would certainly have an affect of sea levels.
.
2500 years is a pretty long time. Torah was canonized 2400 years ago, around 400 BC. 😉 Things related to the sea and other issues were going up and down, yet many important things – and even things you would call details – were the same.
For example, the Sea of Galilee was referred to as Lake Galilee in the Bible. It is amazing 209 meters below the sea level but it seems that it used to look the same when the Bible was being written. So even if you live at places that are so anomalously crazily below the sea level, you may continue to do so for millennia. The geometry around matters. And as the Dutchmen know, it is possible to live in a country where 20% of the territory is below the sea level. With a little bit of human work, you may increase the percentage even above that. Landfills are possible, too, although this finding was shocking for me when I learned about it in Boston.
Of course, as the previous WUWT explained, the sea level has only been relatively stable for 6000 years or so, since the disappearance of the last continental ice sheets. The ice that is left can’t make much difference because Greenland and Antarctica would have to heat up a lot to melt. If the Earth warmed up by 10-50 degrees, substantial portions of Greenland and Antarctica ice could melt, but the change in the sea level would still be just a modest fraction of the changes caused by the melting continental ice sheets. On the warm side, there are simply no big changes waiting for us – even if the temperatures change 10 times more than the (already exaggerated) IPCC mean projections.
Cheers, LM
Simon Jenkins
guardian.co.uk, Thursday 4 February 2010 21.00 GMT
and the comments are good as well, no surprise there since the comments are “open”, so no flaming censorship, strange how that works
The Med is a sea with a smallish connection to the ocean proper via the Strait of Gibraltar. Clearly its level will be affected much more by local changes in river discharge/rainfall and evaporation in the region than the worldwide sea level is.
Sea Levels at Harlech Castle in North Wales construction completed Circa 1290
http://www.castlewales.com/harlech.html
The castle’s other remarkable feature is the defended “Way from the sea,” a gated and fortified stairway plunging almost 200 ft down to the foot of the castle rock. Once, this gave access to supplies from the sea, but the tide level has since receded, leaving Harlech somewhat isolated upon its rock. During Madog ap Llywelyn’s uprising of 1294-95, this maritime lifeline proved the savior of the garrison, which was supplied and victualled by ships from Ireland.
tokyoboy (00:05:59):
tokyoboy, no need to be sorry. This is a fascinating graph and it’s the first time I’ve seen it. Are there Japanese temperature records for the same period that we can use for correlation purposes?
Does anyone know whether this was a localized event, or is it confirmed in other places? Without confirmation, I am not ready to extrapolate this to the entire globe, since Israel is on the far side of the Mediterranean, far from the relatively narrow connection with the Atlantic.
Sea Levels at Harlech Castle In North Wales:-
“The castle’s other remarkable feature is the defended “Way from the sea,” a gated and fortified stairway plunging almost 200 ft down to the foot of the castle rock. Once, this gave access to supplies from the sea, but the tide level has since receded, leaving Harlech somewhat isolated upon its rock. During Madog ap Llywelyn’s uprising of 1294-95, this maritime lifeline proved the savior of the garrison, which was supplied and victualled by ships from Ireland. ”
http://www.castlewales.com/harlech.html
The castle was constructed Circa 1290 what does this demonstrate?
Regarding sea level, here is the latest error in IPCC AR4:
http://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch12s12-2-3.html
States “The Netherlands is an example of a country highly susceptible to both sea-level rise and river flooding because 55% of its territory is below sea level where 60% of its population lives and 65% of its Gross National Product (GNP) is produced.”
The real figure for Netherlands territory below sea level is 26%, so AR4 has it more than double. AR4 is looking like a joke a minute!
This guy, Gerald Marsh, says that it isn’t CO2, or the Milankovitch Cycles that cause the Glacials/Interglacials, but Galactic Cosmic Rays.
http://arxiv.org/ftp/arxiv/papers/1002/1002.0597.pdf
During the Roman era the level was almost similar to today’s,
Roman warm period, water expands when warmed maybe, but there probably was no Roman warm period when the Mannian method is used.
This article seems to raise more questions than it answers. Seems to be a very superficial press release. Is there an actual report associated with it? The article mentions “assessment” and “research” but not whether this will result in or has resulted in a published, peer-reviewed paper. Therefore I would largely ignore this press release until more substance is available.
Having said that, I believe that properly presented sea level research is crucial to quieting the alarmist rumblings of doom.
John Silver (01:14:53) :
A friendly correction: The sea ice extent is referencing floating ice. The water level will not change if floating ice melts nor will the level change if the water becomes frozen.
The water’s displacement is already accounted for, liquid or solid. Kind of anti-intuitive.
ScientistForTruth (03:17:30) :
The real figure for Netherlands territory below sea level is 26%, so AR4 has it more than double. AR4 is looking like a joke a minute!
Where did you get that 26% from? The national geographic put it at half:
http://news.nationalgeographic.com/news/2001/08/0829_wiredutch.html
Wikipedia puts it at 20% althought the reference is to a Dutch document so I can’t tell if it’s correct.
Let’s face the facts that if there is a volcano in Antarctica that melts some of the ice, the sea level is bound to go up. And no amount of CO2 sequestration anywhere in the eco-system is going to change that fact.
Stacey (03:02:27) :
Excellent example of glacial rebound in my opinion. It’s the same with many Viking Villages in Norway that are now a long way from the edge of the Ffjord.
Proves the point that you shouldn’t just look at local sea level changes and extrapolate this to a global sea level change.
That the mediteranean sea rises and falls dramatically over time, unconnected to CO2 levels, is without doubt.
Witness, for instance, Alexandria. 1600 years ago, under the water. Cars didn’t cause that.
http://www.underwaterdiscovery.org/Sitemap/Project/Alexandria/Default.aspx
Other cities in the Med. Sea that were built on dry land, and then sunk completely. No doubt that there are hundreds more.
http://www.usatoday.com/news/world/june01/2001-06-28-sunken-cities.htm
Some interesting details about SDO this morning from NASA
SOLAR DYNAMICS OBSERVATORY: THE ‘VARIABLE SUN’ MISSION
http://science.nasa.gov/headlines/y2010/05feb_sdo.htm
including their view of the Solar dynamo
http://www.youtube.com//SDOmission2009#p/u/6/ppGgyc7BjsQ
@SteveE
Thanks for your comment please could you explain glacial rebound?
I’d love to see that sea-level graph plotted alongside the most reliable (i.e. not with the MWP airbrushed out!) long term temperature reconstruction we have. From the sound of it in some places it correlates nicely (Romans and today) and yet in others (1700s) it’s completely out of phase.
It would place a quite significant nail in the warmist alarmism if it became obvious that past changes were not always temperature related.
“Sea Levels at Harlech Castle In North Wales:- “The castle’s other remarkable feature is the defended “Way from the sea,” a gated and fortified stairway plunging almost 200 ft down to the foot of the castle rock. Once, this gave access to supplies from the sea, but the tide level has since receded… The castle was constructed Circa 1290 what does this demonstrate?” – Stacey
Probably that there has been a lot of coastal sedimentation since 1290. It’s not so much that the sea level has lowered as that the coastline has moved outward.
http://en.wikipedia.org/wiki/Cinque_Ports
Cinque Ports originally received their charter circa 1100’s.
New Romsey is 1.5 miles from the sea and Sandwich is 2 miles from the sea?
I don’t think Anthony is ever vituperative although some of our comments may be. I thought that was a mean description when compared to say, Monbiot or Delingpole!
And although I am no geographer I always thought that the Med was quite isolated from the Atlantic by the straits of Gibraltar – the tides in the Med are very, very slight, only a few measly feet – is that related?
I pose a question to readers of this thread.
I read a book by Thor Heyerdahl many years ago. In that book he described his assistance to the Maldives in recovering their pre-Muslim history. Towards the end of the book he described some research he did in India.
He purportedly explored and described an ancient port (ca 5000 years old) which was a stunning 250 feet above the current sea level. Not much was left, but the quays could easily be made out, and there was still evidence of dredging.
Has there been that much continental upthrust in that part of India?
Or did the filling of the Mediterranean really siphon off that much of the ocean?
Just asking, since Prince Philip is so seriously concerned about a purported six inch ocean rise during the last century.