Is Venice Sinking? The Science Behind the City's Future

The short answer is yes, Venice is sinking, but the full picture involves several interacting processes that together determine how much higher the water stands relative to the city each decade. Scientists refer to the key measure as relative sea level: the combination of eustatic sea level rise (the global increase in ocean volume due to thermal expansion and ice melt) and local land subsidence (the downward settling of the ground beneath Venice). Both contribute to the water creeping higher against the city's foundations, and separating the two is essential for understanding what has happened, what is happening now, and what lies ahead. Over the past 150 years, relative sea level in Venice has risen at an average rate of approximately 2.5 mm per year (Lionello et al., 2021). That may sound small, but compounded over a century and a half, it has already raised the effective water level by roughly 35 cm relative to the city's pavements and building thresholds. The consequences are visible: flooding events that were once rare have become routine, and the lowest points of the city, particularly Piazza San Marco, now flood at tide levels that would have passed harmlessly a century ago. The most alarming period of land subsidence occurred between 1950 and 1970, when industrial groundwater extraction from the aquifers beneath the lagoon caused the ground to compact significantly. The city sank measurably during those two decades, and the effects were severe enough to prompt a ban on further groundwater pumping. That intervention worked: the rate of anthropogenic subsidence slowed dramatically. Natural subsidence from tectonic settling continues at a much lower rate, but it is the eustatic component, driven by global climate change, that now dominates the equation. Recent observational data paints a sobering trajectory. A 30-year analysis of tide gauge and temperature records in the Venice Lagoon found that relative sea level rise has accelerated to 4.9 mm per year (Ferrarin et al., 2024). Over the same period, air temperatures above the lagoon have increased by 1.8 degrees Celsius and sea surface temperatures by 1.1 degrees Celsius. These are local manifestations of global trends, but the enclosed, shallow lagoon amplifies their effects. Projections for 2100 vary depending on emission scenarios, but the range is stark: between 30 cm and 110 cm of additional sea level rise on top of current levels (Lionello et al., 2021). At the lower end, the MOSE flood barrier system, operational since 2020, should be able to manage the increased tidal threats with more frequent activations. At the upper end, the barriers could need to remain closed for months at a time, fundamentally altering the lagoon's ecology and the city's relationship with the tides that have shaped it for over a thousand years. For visitors, the practical implications depend on timescale. In the near term, Venice is well-equipped: MOSE prevents the worst flooding, elevated walkways handle moderate acqua alta, and the city functions through its tidal cycles as it always has. Over the coming decades, the conversation shifts from tourism logistics to existential questions about adaptation, investment, and what it means to preserve a city whose identity is inseparable from the water surrounding it.