By 2035, Venice may say goodbye to high water

Dec 11, 2022 414

Sea levels in Venice may temporarily stabilize in the coming years, thanks to the achievement of a delicate balance of processes involving the North Atlantic Ocean. Described in the journal Earth and Space Science, this hypothesis was formulated by scientists at Ca' Foscari University of Venice, who examined relative sea level fluctuations in the Venice Lagoon.

The team, led by Davide Zanchettin, evaluated situational data collected over the past 150 years, comparing information on the surface temperatures of the North Atlantic Ocean and the rise of water in the lagoon. Changes in the surface temperature of the Atlantic Ocean indeed appear to be related to sea height in Venice, and as the North Atlantic may go through a colder phase in the coming years, a slowdown in the rise of water levels in the Mediterranean is expected.

The research team found that water rise may be related to the Atlantic Multidecadal Oscillation (AMO), a natural variation in sea surface temperature in the North Atlantic that occurs with a time period of 60 to 80 years.

Historically, during the coldest phases of the fluctuation, water rise in Venice appears to slow down, in contrast to what is observed during more temperate times. By the end of the century, current estimates indicate that the iconic Italian city could experience an additional relative sea level rise of between 30 and 120 centimeters.

In the most pessimistic scenarios, Venice could still face serious problems, scholars explain. However, in the short to medium term, factors such as the AMO could lead to even very significant deviations from the curve drawn by climate projections that links the present with the end of the century.

"The scientific literature suggests that we are about to witness a cold AMO phase," Zanchettin notes, "our models indicate that in this case the sea level in Venice could stabilize by 2035.

"These results," adds Francisco Mir Calafat, a researcher at the National Oceanography Centre in Liverpool, "could explain the interruption in water level rise observed throughout the Mediterranean between 1960 and 1989 and the recovery in the 1990s. However, there are many factors at play to consider, such as melting ice caps and thermal expansion of water due to global warming." A better understanding of these dynamics, the authors conclude, could facilitate the planning and development of infrastructure appropriate to local needs.

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