What is causing sea level change?
Several factors cause sea level to rise and fall. These factors act over different time scales. • ‘Eustatic’ changes are caused by long-term variations in ocean volume. For instance when ice sheets and glaciers melt, they add water to the sea and ocean volume increases. • ‘Steric’ change in sea level is due to water density changing. Density varies as water temperature and salinity changes. • Storm surges, river run-off and waves reflecting in bays and harbours can cause very localised, but often quite large changes in sea level. The land surface can move also vertically, causing isostatic sea level change. The British Isles are still adjusting to the removal of the ice sheet which covered most of the land surface about 20,000 years ago. This post-glacial rebound has caused the North and West of Britain to rise, but the South East of England to sink. Isostatic changes therefore add to see level rise in the South and East and work against sea level rise in the North and West. In the Sou
