The variations in the relative sea level occur at very different scales both in space and time and reflect the combined variations of the absolute sea and land levels. An effective separation between these and the identification of the single physical processes responsible for the sea level changes observed in a given region and period of time can be achieved through a scale analysis. While the spatial extent of the phenomenon is characterized by comparing statistically the data at local, regional and global scales, the time extent is characterized by studying the different regimes in the series through a nonparametric change-point algorithm. The details of the procedure are presented by an application to the variation of mean sea level in the northern Adriatic sea in the last century. The mean sea level in the region is found to be inhomogeneous both in time and space. The rate of increase in mean sea level is at some sites equal to that of the Mediterranean basin, which in turns equals the change in global mean sea level. At other sites, starting from about year 1950, the rate is one order of magnitude larger. The latter suggests soil compaction due to water draining from the water bearing table for agricultural use as the main active factor. ¿ American Geophysical Union 1996