Overview
- An international team led by Piero Lionello reports that Venice’s mobile MOSE gates will reach functional limits with higher seas, as more frequent closures strain navigation, water quality and the machinery.
- The study maps four paths for the city: reinforce the existing barriers, build ring dikes to encircle the historic center, close the lagoon permanently, or retreat from the lowest areas.
- Researchers estimate costs ranging from about €500 million to €4.5 billion for ring dikes to more than €30 billion for a closed lagoon, with relocating buildings potentially costing up to €100 billion.
- Projected sea-level rise by 2100 is roughly 0.42 to 0.81 meters under common scenarios, with extremes up to about 1.8 meters, and the city continues to sink by about 1 to 2 millimeters each year.
- The authors identify a critical window between about 0.75 and 1.75 meters of rise that would demand a strategic pivot, which could arrive as early as the 2070s under higher-emission pathways.