Without adaptation, potential economic damages between 7 and 17 billion EUR have been estimated for the next 50 years . Additionally, the ecosystem is vulnerable to warming  and SLR . The duration of the closure of the lagoon inlets is expected to increase from 2 to 3 weeks yr-1 for RMSL rises of 30 cm, to 2 months yr-1 for 50 cm and 6 months yr-1 for 75 cm , resulting in disconnection from the sea for most of the time for RMSL rise exceeding 75 cm. Frequent closures of the inlets would prevent ship traffic and in/outflow of water. For Venice, adaptation pathways considering the full range of plausible RMSL  levels are not available, indicating a long-term adaptation gap. As planning and implementation of adaptation of this extent can take several decades , this increases the risk that the city will not be prepared in case of rapid SLR.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report