At http://malagabay.wordpress.com/2013/07/13/the-inflating-earth-sea-level/ … Tim Cullen takes a look at sea levels in the context of the Inflating Earth hypothesis. What he says is interesting to all geologists and anyone else that might have faith in the science involved. Local mean sea level is defined on the height of the sea with respect to a land benchmark, averaged over a period of time, long enough that fluctuation caused by waves and tides are smoothed out. A period of 19 years is preferred because the Earth, Moon and the Sun's relative positions repeat almost exactly in the Metonic cycle of 19 years ( which is long enought to also include the lunar nodal tidal constituent.
However, other features are not constant as it is known the Earth's surface can rise or fall vertically, the Earth's crust stretches and compresses horizontally, the volume of water entering the oceans can rise or fall as well as the volume of water leaving the oceans (evaporation etc.)
In the long term geological timescale it is difficult to estimate ancient global sea levels. On top of this there is the difficulties associated with dating ancient geological formations – and incomplete inventory of all the world's geological formations. Needless to say, the science of geology has overcome these problems and has produced charts of global sea level fluctuations over millions and millions of years.
These models have come up with some oft quoted information – reliable or otherwise. Sea levels gradually rose in the Cambrian; they were stable in the Ordovician (with a huge drop at the end of that epoch as a result, it is thought, of glaciation; stability in the Silurian; a fall (gradual) in the Devonian – leading to a long term sea level low point; but in the Permian the sea levels go up (and so on). Mainstream is very keen to claim 'Ice Ages' lower sea levels. Geologists who study the position of coastal sediment deposit through time noted dozens of shifts of the shoreline (and recoveries) and it is claimed this results in sedimentary cycles which can be correlated (or modelled on computer screens) around the world – with 'great confidence' (as they are at pains to stress). The confidence involved may arise from the fact only a limited global geology is being looked at – and this is based around sea levels in developed countries. Basically, sea level fluctuation is subject to uniformitarian geochronology. They are closely entwined. The blog author then points out a few chosen problems, by asking i) what is the source of ocean water – and what is the rate of its arrival? He says this is largely ignored in the narrative (as far as the information being fed to the general public) as it is an inconvenience. ii) The uniformitarian model ignores the opening up of the oceans around 200 million years ago as a result of sea floor spreading – and how this might have affected sea levels. The problem here is that prior to the Jurassic (during Pangaea) drainage basins, in some situations, would have been landlocked, and therefore sea levels cannot refer to the huge ocean that existed around Pangaea (so what do the early sea level estimates refer to?) It sounds like a lot of pompous waffle is involved as mainstream can really have no idea when the current ocean basins became connected in order to establish a global sea level (simulated). However, uncannily, he says, mainstream sea level data matches the 'sea floor spreading' pattern which is also part of the uniformitarian model. The blog author then claims that over the last 100 million years the Earth has been losing water into space via photo dissociatin of wate into oxygen and hydrogen (which is I suppose part of the Inflating Earth model). The heavier oxygen remains in the lower atmosphere but the lighter oxygen is lost to space via the exosphere.
Now, the blog author has an axe to grind and the role of the water in climate is worth looking at – it is fundamental, but in spite of any scepticism involving the Inflating Earth model the anomalies produced by the author are tangible and usually glossed over in textbooks and articles on the subject.