Sea-level rise in Venice: historic and future trends (review article)

• Published in: Natural hazards and earth system sciences Vol. 21; no. 8; pp. 2643 - 2678
• Main Authors: Zanchettin, Davide, Bruni, Sara, Raicich, Fabio, Lionello, Piero, Adloff, Fanny, Androsov, Alexey, Antonioli, Fabrizio, Artale, Vincenzo, Carminati, Eugenio, Ferrarin, Christian, Fofonova, Vera, Nicholls, Robert J., Rubinetti, Sara, Rubino, Angelo, Sannino, Gianmaria, Spada, Giorgio, Thiéblemont, Rémi, Tsimplis, Michael, Umgiesser, Georg, Vignudelli, Stefano, Wöppelmann, Guy, Zerbini, Susanna
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 01.09.2021; Copernicus Publ. / European Geosciences Union; Copernicus Publications
• Subjects: Accuracy; Atmospheric correction; Climate change; Environmental Sciences; Gauges; Global Changes; Human influences; Ice sheets; Lagoons; Literature reviews; Man-induced effects; Removal; Satellite altimetry; Sea level; Sea level changes; Sea level rise; Sea level trends; Sea level variations; Subsidence; Time series; Trends; Variation; Water masses
• ISSN: 1684-9981; 1561-8633; 1684-9981
• DOI: 10.5194/nhess-21-2643-2021

The city of Venice and the surrounding lagoonal ecosystem are highly vulnerable to variations in relative sea level. In the past ∼150 years, this was characterized by an average rate of relative sea-level rise of about 2.5 mm/year resulting from the combined contributions of vertical land movement and sea-level rise. This literature review reassesses and synthesizes the progress achieved in quantification, understanding and prediction of the individual contributions to local relative sea level, with a focus on the most recent studies. Subsidence contributed to about half of the historical relative sea-level rise in Venice. The current best estimate of the average rate of sea-level rise during the observational period from 1872 to 2019 based on tide-gauge data after removal of subsidence effects is 1.23 ± 0.13 mm/year. A higher – but more uncertain – rate of sea-level rise is observed for more recent years. Between 1993 and 2019, an average change of about +2.76 ± 1.75 mm/year is estimated from tide-gauge data after removal of subsidence. Unfortunately, satellite altimetry does not provide reliable sea-level data within the Venice Lagoon. Local sea-level changes in Venice closely depend on sea-level variations in the Adriatic Sea, which in turn are linked to sea-level variations in the Mediterranean Sea. Water mass exchange through the Strait of Gibraltar and its drivers currently constitute a source of substantial uncertainty for estimating future deviations of the Mediterranean mean sea-level trend from the global-mean value. Regional atmospheric and oceanic processes will likely contribute significant interannual and interdecadal future variability in Venetian sea level with a magnitude comparable to that observed in the past. On the basis of regional projections of sea-level rise and an understanding of the local and regional processes affecting relative sea-level trends in Venice, the likely range of atmospherically corrected relative sea-level rise in Venice by 2100 ranges between 32 and 62 cm for the RCP2.6 scenario and between 58 and 110 cm for the RCP8.5 scenario, respectively. A plausible but unlikely high-end scenario linked to strong ice-sheet melting yields about 180 cm of relative sea-level rise in Venice by 2100. Projections of human-induced vertical land motions are currently not available, but historical evidence demonstrates that they have the potential to produce a significant contribution to the relative sea-level rise in Venice, exacerbating the hazard posed by climatically induced sea-level changes.