The sea level in Venice could temporarily stabilise within the next few years, thanks to a delicate balance of processes involving the North Atlantic Ocean.

Described in the journal Earth and Space Science, this hypothesis was formulated by scientists from the Ca' Foscari University of Venice, who examined fluctuations in relative sea level in the Venice Lagoon.

The team, led by Davide Zanchettin evaluated 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 appear to be linked 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 the rise in water levels may be related to the Atlantic Multidecadal Oscillation (AMO), a natural variation in sea surface temperature in the North Atlantic that occurs over a 60 to 80 year period.

Historically, during the coldest phases of the fluctuation, the rise of the waters in Venice seems 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 a further rise in relative sea level of between 30 and 120 centimetres.

In the most pessimistic of 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 linking the present with the end of the century.

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

"These results 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 the melting of the ice caps and the thermal expansion of water due to global warming," adds Francisco Mir Calafat, a researcher at the National Oceanography Centre in Liverpool.

A better understanding of these dynamics, the authors conclude, could facilitate the planning and development of appropriate infrastructure.