The indicator measures the increase in the average sea level in Venice, being of fundamental importance for the studies and conservation interventions of the city of Venice, as well as the lagoons and high Adriatic coastal areas at risk of flooding. In Venice, the average sea level has increased since the beginning of the recordings: in the period 1872-2024 the level increases by an average of 2.6 mm / year, with a trend not always constant and uniform over time. In this regard, it is considered appropriate to highlight the rate for the last thirty years (1993-2024), where the average sea level rise is almost doubled (4.8 mm/year).

The weather variables observed in the Venice Lagoon (the average annual atmospheric pressures, the total annual rainfall, the number of rainy days and thermal anomalies) allow to photograph the climate changes taking place. During 2024, in the presence of an average annual pressure of 1,0155.9 mbar (below 0.3 mbar compared to the average of the reference period), 1,127 mm of rain were recorded (+34% compared to the average) over a period of 96 rainy days, while temperatures continue to show themselves in trend and continuous increase.

The indicator shows the number of annual cases of tidal maximums, divided by height classes, detected at the station of Venice - Punta della Salute, representative of the historic city center. Monitoring the trend of the high and medium-high tide classes (above 80 cm compared to the ZMPS reference plane) allows you to control the pressure exerted both on the historic center of Venice (effects on the estate of the banks and buildings), and on the surrounding lagoon (environmental effects on the vegetation of the barenal habitats and on the greater erosion of the natural banks). In the last period, 2019 was an exceptional year as there were 28 cases of “high water”, i.e. exceeds of the threshold 110 cm on the ZMPS, record value of the entire historical series. As of 2020, the entry into operation of mobile barriers against flooding from high tide (model system "Mo.S.E.") has led to a differentiation in the number of cases of high water between the lagoon and the sea. 2024 recorded 12 cases of “high water” at sea and a single pass in Venice (on May 16, first case from 2021), thanks to the drive of the Mo.S.E. which defended the city.