DRIVING MECHANISMS OF PAST AND PRESENT SEA-LEVEL CHANGE TO QUANTIFY PROJECTION UNCERTAINTIES

The limited instrumental and paleo sea-level reconstructions in Singapore and South East Asia hinder the interpretation of sea-level change on global, regional and local scales and limit the possibilities to tune and refine models that predict future changes and their spatial variability. We will develop new records of relative sea-level (RSL) change from mangrove environments and coral microatolls to extend the instrumental records from satellite altimetry and tide gauges. The new regional RSL dataset spanning the last ~2000 years (Common Era) will capture multiple phases of climate and sea-level behaviour for model calibration, provide a pre-anthropogenic baseline for assessing recent trends, and characterize natural variability. To estimate global sea level and the spatio-temporal field of Singapore and South East Asia, the new RSL datasets will be combined with satellite altimetry and tide-gauge measurements in an empirical Bayesian statistical framework. The data and models will be used to test the following research questions: (1) Did sea level in Singapore and South East Asia vary as a consequence of the Medieval Climate Anomaly and the Little Ice Age? (2) Is the rate of sea-level rise since ~1850 CE greater than any other centennial trend during the last 2000 years? (3) Can spatial variability of past and present day sea level be attributed to ocean dynamics and/or vertical land motion? Understanding past and present sea-level changes and their driving mechanisms will provide the foundation for accurately projecting future sea levels for Singapore and South East Asia.