Venice records surge in high tides

With 15 high tides in just nine days, ten of which exceeded 110 centimetres, the city has reached what the director of the Venice Tides Centre, Alvise Papa, described on Friday as “a record for the period”. Ten of the tides were high enough to trigger the MOSE flood barrier system.

Papa said the spike is closely linked to the steady rise in average sea level, which he attributed to climate change. “Today we are at about 40 centimetres,” he told ANSA, referring to the baseline sea level, “while in the early 2000s it was around 21 to 23 centimetres.”

As a result, much weaker weather systems are now capable of producing dangerously high tides. “In the past, very strong winds were needed to raise the tide by 80 centimetres,” Papa said. “Now much weaker ones are enough to reach one metre.”

The figures mark a sharp increase compared with recent years. During the same period last year, only one high tide was recorded. In the past 15 years, the number reached double figures only once, in 2014, when 11 high tides were logged.

Recent weather conditions exacerbate the problem

Papa noted that recent weather conditions have not been particularly severe, making the data more striking. Sea levels remained above one metre for a record 42 hours, compared with just four hours during the same period last year. In 2024, the figure stood at 13 hours, while in 2023 it was 16.

The trend is expected to worsen, Papa warned. If the average sea level continues to rise, increasingly modest disturbances will be enough to flood large parts of the city. “This is where the MOSE system comes in,” he said, stressing that keeping water levels below one metre is now essential to protect Venice.

The MOSE system

The MOSE system — an acronym for Modulo Sperimentale Elettromeccanico — was conceived after devastating floods in 1966, when Venice was submerged under nearly two metres of water. Planning began in the 1980s, but construction did not start until 2003, following decades of political debate, environmental objections and legal disputes.