Ice2sea scientists have investigated trends in the evolution of sea level in the Mediterranean Sea in collaboration with another external programme. Sea levels are determined globally by the volume of water in the world’s oceans as well as its temperature. Regional factors also affect sea levels, however, such as patterns in air pressure and winds and gradual deformation of the Earth’s crust in response to redistribution of mass (Glacial Isostatic Adjustment). Finally, the Mediterranean sees local changes in the elevation of the seabed due to quite frequent earthquakes, which can redistribute sediment across the seabed and cause some vertical crust deformation. Even humans can affect local sea levels directly by extracting ground water – this can cause the ground to subside under the sea.

The multitude of causes of sea-level change and its imminent relevance to humanity means that there is a pressing need to understand what exactly causes it – a huge undertaking given the local nature of many causes and effects! To this end, Mikis Tsimplis and his colleagues use various, sometimes unusual, methods to quantify the uncertainty associated with each of these factors. To reconstruct past sea levels, for example, they use the position of human coastal settlements from the last 10,000 years as well as notches carved into the coastal limestone by erosion.

Ice2sea Work Package: WP6.2

Publication: Tsimplis, M., G. Spada, and M. Marcos (2011), Multi-decadal sea level trends and land movements in the Mediterranean Sea with estimates of factors perturbing tide gauge data and cumulative uncertainties., Global and Planetary Change, 76(1-2), 63-76.