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Friday, May 3, 2013

The Holocene transgression (and global sea level)

During the Holocene climatic optimum there was a time when global sea levels were 2.5 to 4 meters (8 to 13 feet) higher than the twentieth-century average. (source) Temperatures were 1 to 2 degrees warmer than present. (source)

This called the Holocene Transgression. It took place at various times in different areas, but scientific studies of it call it the Holocene transgression. For example
To establish a chronology of the Holocene transgression in Arctic Siberia,
Sea-level highstand recorded in Holocene shoreline deposits on Oahu, Hawaii
Mid to late Holocene sea-level reconstruction of Southeast Vietnam using beachrock and beach-ridge deposits

Google Scholar lists over three thousand papers, including 1,810 that include the term "sea level".

But an article about the Holocene Transgression is not found on Wikipedia. The maximum sea level rise during the Holocene climatic optimum is called the maximum Holocene transgression, an example is shown here
The altimetric correlation between the base of the beach ridge dated at 6055 ± 20 YBP and the inner margin of the corresponding marine terraces allowed us to constrain the maximum Holocene marine transgression to about 3 to 2 m above sea level.
 Here is another example in the following evidence based science paper.
A detailed ecological, micro-structural and skeletal Sr/Ca study of a 3.42 m thick Goniopora reef profile from an emerged Holocene reef terrace at the northern South China Sea reveals at least nine abrupt massive Goniopora stress and mortality events occurred in winter during the 7.0–7.5 thousand calendar years before present (cal. ka BP) (within the Holocene climatic optimum).
 Sea level rose by ∼3.42 m during this period, with present sea-level reached at ∼7.3 ka BP and a sea-level highstand of at least ∼1.8 m occurred at ∼7.0 ka.
Google Scholar has 5,869 papers about it.

It's considered by scientists who study our planet to be a factual thing. In essence it was the highest sea level rise in the last 100,000 years.

 You might not be able to read about it on Wikipedia, (it does appear in the Holocene climatic optimum article). The article on the  Older Peron  was fairly good, and explains the sea level, but since this blog post was edited to remove any hint that there was a higher sea level during the Older Peron .  The article on the Holocene Maximum doesn't mention sea level at all.  Nor does the article on sea level mention the Holocene transgression, or the higher sea level that we know happened.

The sea level change is one of the strongest reasons for knowing the Holocene climatic optimum occurred. Also the remains of trees above the current treeline, lake sediments, ice cores and other evidence support a much warmer period 9,000 to 5,000 years ago, and at some point it was as warm as it would get. There was much less ice and the oceans were higher. You can actually see this high level here in the image

 Like many things not found on Wikipedia, it's fascinating and interesting.  There are raised beaches worldwide that provide irrefutable evidence of the higher sea level, and this has been known for a very long time. (source, Encyclopedia Brittanica, 1956 edition)

But you won't find that fact on Wikipedia either.

Some of the water came from the Hans Tausen Iskappe, which didn't exist during the climactic optimum.   The history of our planet is very interesting. The climate history is very interesting.

While there is an article on Paleoclimatology, it doesn't mention the Holocene transgression, the climactic optimum, or the sea level that occurred because of it.

You won't find an article about the History of Climate or Climate History on Wikipedia, but that is another entry.

The maximum sea level rise at any point is called the Holocene sea-level highstand, That's another term you won't find an article for on Wikipedia.

For example, from the Journal of Sedimentary Research, Section A: Sedimentary Petrology and Processes

Vol. 70 (2000), No. 3. (May), Pages 478-490
Responses of Stable Bay-Margin and Barrier-Island Systems to Holocene Sea-Level Highstands, Western Gulf of Mexico
 Independent evidence from studies of geodynamic, climatic, and glacio-eustatic processes can explain the mid-Holocene highstands and late Holocene lowering of sea level that is observed in tectonically stable coastal regions far from former centers of glaciation.

(edited July 2014) Like all things Wikipedia, the information on Wikipedia can change.  Anytime, by anyone.  Since
this original blog entry the Older Peron was changed to remove relevant data by an account
 that only made two edits to Wikipedia.  Both edits were to gut the Older Peron article.

Meanwhile, back in the world of science

Mid to late Holocene sea-level reconstruction of Southeast Vietnam using beachrock and beach-ridge deposits
Sea level paper

Image of Holocene climatic optimum