Sea level studies: Overview

Abstract

Understanding relative sea-level changes helps explain critical interactions in Earth environmental systems throughout the Quaternary. Relative sea-level changes record transfers of mass between oceans and continents during expansion and contraction of great ice sheets driven by climate change. They record extreme events, including storm surges and tsunamis, as well as predictable daily tides. They also record vertical movements in the Earth's crust over a wide range of timescales, from co-seismic uplift and subsidence during great, Mw > 8, plate-boundary earthquakes, through century- and millennial-scale movements driven by the process of glacial isostatic adjustment, to timescales beyond the Quaternary, as global ocean volumes change as a result of plate-tectonic movements. Vertical changes in relative sea level result in major horizontal shifts in coastal environments. The combination of all these factors means that no single location on Earth records all of these changes. No location can be considered stable and therefore a record of “absolute” sea-level change. Perhaps the most significant advance in studies of Quaternary sea-level change is the recognition that key questions will only be answered by the integration of multi-proxy based reconstructions of sea level with model predictions.