Ice Age Sea Levels

3 Dec 2010

At www.physorg.com/print210426748.html we learn that research at Southampton University is looking at the rate of sea level rise at the end of the Ice Age. Presumably computer simulation is being used which is programmed by the idea that sea levels rose as a result of a melting ice sheet rather than through a catastrophic redistribution of ocean waters. Never the less, the change involved a rise of 120m in sea level - but this is assumed to have taken place between 19,000 and 6,000 years ago, providing an average of just 1m per century. Amazingly, this is almost exactly what Hubert Lamb said some 50 or so years ago, a rise of 1cm per annum. However, studies of sea level change at individual locations is marked by abrupt swings in sea level rates. This includes an analysis of the distribution of fossil corals around Barbados and coastal drowning in Indonesia. The article then cites difficulties in the real world such as dating fossils precisely and the scarcity of sea level markers as well as local factors unrelated to global sea levels. They seem to prefer computer simulation to the real facts it would seem - in tandem with the use of statistics. Noble as the latter may be the idea is to create an average trend and is not designed to identify sudden and abrupt shifts in sea level that may have occurred during the Holocene - or at any other time. The result is a slow and gradual rise in sea levels which is actually contradicted by evidence from individual sites and locations. It is also based on a very big assumption, namely there were excess ice sheets that melted when the climate warmed up. If there were no excess in ice sheet formation and the evidence from the Late Glacial Maximum might be of a polar region slightly askew to what it is in the modern world, and then the rise in sea levels would have a completely different origin. Basically, the methodology has smoothed out the wrinkles, somewhat like the hockey stick model as far as temperatures are concerned. It has reduced sharp rises in sea level at the beginning and towards the end of the Mid Holocene Warm Period to minor bumps in the data.