Sea level manipulations of data, there is NOT alarming rise
Danilo Anton
Sea level changes have been commonplace along geological history.  It is difficult to pinpoint those changes in older sedimentary rocks because the level of emerged lands also varied considerably..
Many times we don't know how high was the depositional sea level if the marine sediments are found on high elevations which were uplifted milliones of years ago. Obviously the level can be assumed through analysis of the geological context  and correlations. However in most cases these are only assumptions. Similar arguments can be used in relation to marine sediments buried under hundreds of meters of other sediments

Even when sediments were not uplifted o did not sink locally it is very difficcult to know what was the sea level worldwide.
It is somewhat easier to estimate past sea level in more modern sediments, let's say Quaternary or Pliocene sediments. However, even in those cases, the vertical movements of continental masses may introduce modifying factors.
Having said that, when sea level changes in a scale of a few years are studied, other difficulties arise. First, there are always vertical movements en ALL coastal shores. These movements may be a few millimeters per year or even less. However we don't know them with precision and it is very difficult to measure those millimetric changes, because it is not easy to find a reference.
On the other hand, sea levels may vary in different oceans due to increased evaporation, flow from neighboring rivers or melting from ice caps or glaciers. Therefore it is hard to know exactly (to the millimeters scale) what is the worldwide sea level.
With satellite measurements it has become much easier to get data from all oceans and seas. However, often these data require some elaboration and they may be manipulated to demonstrate whatever theory want to be demonstrated.
Nils-Axel Mörner has been studying the subject for several decades and described these uncertainties and manipulations in an article entitled "There Is No Alarming Sea Level Rise!" (see footnote reference).
Economic, academic and egotistic interests are providing non-trustable data and it has become increasingly difficult to believe some ot the official assumptions and particularly the catastrophic forecasts of coastal flooding in many parts of the world.

https://www.21stcenturysciencetech.com/Articles_2011/Winter-2010/Morner.pdf

GREAT SEA-LEVEL HUMBUG
There Is No Alarming Sea Level

Renowned oceanographic expert Nils-Axel Mörner has studied sea level and its effects on coastal areas for some 45 years. Recently retired as director of the Paleogeophysics and Geodynamics Department at Stockholm University, Mörner is past president (1999- 2003) of the INQUA Commission on Sea Level Changes and Coastal Evolution, and leader of the Maldives Sea Level Project. Now he has his own company on Paleogeophysics & Geodynamics in Sweden, and can be reached at morner@pog.nu.

In an interview and paper published in 21st Century in 2007,1 I have shown that global sea level is not in an alarming rising mode, which is the main threat in the International Panel on Climate Change scenario. If sea level is not rising at a high rate, there is no serious threat and no real problem. In subsequent papers, I continued to present new data on sea level stability. In Mörner 2007b, our field observational database from the Maldive Islands was described in detail. A new study in Bangladesh was published in 2010 (Mörner 2010a). 

One of the approximately 1,190 beautiful coral islands that comprise the nation of the Maldives. 

As Mörner shows, the Maldives are not in danger of inundation. short sea level booklet titled “The Greatest Lie EverTold” (Mörner 2007c) was updated in new editions in 2009 and 2010. Here I will investigate the proposed rates of sea level changes by IPCC and others. Figure 1 illustrates the differences between the IPCC models and the observational facts. After 1965, the two curves start to diverge significantly (the area marked with a question mark). This paper will highlight the differences and seek the solution of what data to trust and what to discard.

(To be continued)