Exploring the drivers of global and regional sea-level change over the 21st century and beyond
Under UKCP18, we have developed methods for providing state-of-the-art global and regional sea-level projections under RCP2.6, RCP4.5 and RCP8.5. This work also includes exploratory sea-level projections extended to 2300 with methods that remain traceable to CMIP5 model simulations. The presentation will explore the application of UKCP18 sea-level projection methods to example tide gauge locations around the world. Adopting the framework of Hawkins & Sutton (2009) we find that local sea-level variability dominates over model and scenario uncertainty for the coming decades, with model uncertainty the largest source of variance in projections by the end of the 21st century. The extended sea-level projections illustrate the large degree of committed sea-level change under all emissions scenarios, with the magnitude (and even sign) of change strongly dependent on geographic location. A breakdown of the model uncertainty shows that the dominant contribution to variance in the projections is a function of location, time-horizon and emissions scenario. The results indicate that there may be different priorities for future sea-level research depending on the locations and time-horizons of interest.