Global sea levels are pretty well flat at the moment but a paper in the journal Geology is not at all discouraged by this and assures us one and all that they are set to rise by 40 to 70 feet – see www.physorg.com/print251376839.html. Part of the research was done on a coral atoll in the Pacific and some of it in the seismically active area of New Zealand and soil cores taken from Virginia were also used – but it is unclear if any of this has a bearing on the conclusions. What they were looking at, as geologists, was the Pliocene epoch – and as such they were guilty of a variety of assumptions. Some of these involve the idea co2 levels were about 2 degrees C higher than today. The model, as all these things involve modelling nowadays, whowed that melting of the ice cap in Greenland and the West Antarctic ice shelf would occur – as in the Pliocene it was warmer at the Poles. Much warmer. However, it admits that a constant couple of degrees of warmth would take thousands of years to produce a catastrophic leap in sea levels – but geologists speak in terms of millions and billions of years so a few thousands is almost an instant.
Lots of assumptions form the backbone of this research. First one is the idea co2 will cause a major global warming episode – unproven. Secondly, that the Pliocene world was somewhat like our own and it was co2 that was responsible – not a change in the axis of rotation (not in the frame). Thirdly, it is assumed raised sea levels (in some localities) mean that sea levels world wide were raised – were they? and that raised sea levels automatically mean that ice has melted in order to make the sea levels climb. Why isn't the simple idea of a change in the geoid tackled – but we know why.
See also http://wattsupwiththat.com/2012/03/20/dont-bother-with-the-2c-limit-the-… … and see the first comment. It asks, what was the sea level height in 1700 or 1800 when co2 levels were much lower. The answer of course is that sea levels have not risen greatly since Tudor times. Most commenters seem to think that high temperatures in the Pliocene were due to geological factors – but why didn't these geologists know that? Basically, the Panama sea passage was open and the Drake Passage was closed and it was all to do with ocean circulation of warm tropical water. Various studies have blamed a consistent pattern of El Ninos was in operation during the Pliocene – but is this a convenient explanation without any solid evidence (apart from modelling with restricted input). To get a flavour of the geological view see The Pliocene Paradox by Federos, Ravelo, Dekens, de Menocal, Barriero, Pacanowik and Philander (Yale University, Columbia University and the Geophysical Fluid Dynamics Laboratory). We may note that models are involved also in order to replicate the Pliocene conditions as they see fit – on a global scale. For instance, the models demand sea surface temperatures to rise in the western Pacific tropical surface to above 30 degrees – but observation made from sediment cores show no evidence of this taking place. So, did a pattern of repeated El Ninos occur in the Pliocene – or is that baloney?