Sea Level Fall

30 Jul 2018

At https://www.nature.com/articles/d41586-018-05760-3 ... (25th July 2018)an analysis of ancient coral from the Great Barrier Reef in Australia reveals that global sea levels 'fell rapidly' at the end of the last glacial period. The Late (or Last) Glacial Maximum, is dated t its maximum extent between 26,500 and 19,000 years ago and is often thought to represent a prolonged period when glaciation was at its greatest extent. Apparently, this is contradicted by coral growth and retraction in eastern Australia (we are told). However, when getting into the 4 page version of the study we find it is founded on reality - the growth and retraction of the coral reef reflecting changes in sea level, but a series of assumptions are built into the modelling exercise as well as a general acceptance of the idea that sea level changes were global (whereas the area of investigation was confined to the Great Barrier Reef) and the other illogical assumption that sea levels go up and down solely as a result of expansion and retraction of ice sheets. The study itself is in Nature journal, and Yokayama et al claim there was rapid growth in global ice because sea levels fell by 17m in just 50 years - in geological time the blink of an eye. This was followed, they say, almost immediately by ice sheet retreat, as sea levels popped up again. We are left reflecting that the LGM was subject to changes that are not yet understood.