Bursts in sea levels

21 Oct 2017

At https://phys.org/print427601705.html ... scientists have discovered sea levels did not rise slowly after the end of the Ice Age but rose in a series of steep bursts. These abrupt changes fit a catastrophist model but not necessarily a uniformitarian one. The research is published in Nature Communications (Oct 2017) and may cause a rethink on the waters around the UK. Currently, we have a smoothed rise in sea levels, with a leap around 8000 years ago. Since that date sea levels do not seem to have varied greatly - not by any dramatic degree. The research here is said to confine itself to the immediate post-Ice Age period - and therefore we have no input for anything later, in the Holocene proper. The Gradualist smoothed sea level pattern of a rise that was exponential and is related to the melting of the ice sheet. The new findings have also been gelled into this period as it is assumed that meltwater pulses were at play. In the press release we appear to have the obligatory connection to future global warming as a sort of drip feed of doom to the media outlets. They seem to swallow all this guff so I suppose the process has been working. You can just imagine some erstwhile presenter on the telly adopting a serious face profile and informing the viewers it is worse than we thought - by the end of the century sea level would have made a series of jumps, many feet high, as a result of global warming (even though there is not enough ice out there to cause such a dramatic leap). The research took place off the coast of Texas in a region well known for a steep rise in sea levels in the immediate post Ice Age period. In a way it is nothing new. If they had found evidence of sea level rise of the same magnitude in somewhere like South Africa or Argentina it may have been more rivetting.

The research itself took place in 2012 on a voyage that used multibeam echo soundings (sonar) to map ten fossil coral reefs up to 50 miles off the coast of Texas in water as much as 190 feet deep. It was genuine field research and should be applauded. However, the guesstimate of the age of the corals was based on the knowledge that the Caribbean sea levels rose dramatically at the end of the Ice Age - all that meltwater pouring out of the Mississippi river system with an origin in Minnesota and the Great Lakes area. They discovered a series of jumps - or  sea level rise that occurred very quickly, and for the moment this is dated to the warm phase between the end of the Ice Age and the Younger Dryas period - but is this also a guesstimate?

The same story popped up in Scientific American - see www.scientificamerican.com/article/oceans-can-rise-in-sudden-bursts/ ... where the major finding is that sea levels rose very quickly (on several occasions). . It is thought it was driven by several meltwater pulses as a result of collapsing glaciers - which is not unreasonable. Again, the piece focuses on global warming as an important side issue (even though we are thousands of years later than the end of the Ice Age and there are very little left of glaciers that might cause such a dramatic rise this century. One to file away for future reference.