Venice at Sea-Level Crossroads: Four Engineering Bets to Save the City

European researchers compared four protection strategies for Venice against rising seas—open-lagoon closure with movable barriers, ring dikes, fully enclosing the lagoon by raising barrier islands, or relocating residents and monuments. Their projections show the open-lagoon approach becomes unreliable by around 2300 under even low-emission futures; ring dikes could work but would disrupt lagoon ecosystems and cost €0.5–4.5B; enclosing the lagoon could guard against up to 10 meters of rise but costs €30B+, sacrifices the lagoon ecosystem and port function; relocation is the costliest at about €100B and ends Venice's role as a functioning port. Large-scale projects could take up to 50 years to implement, underscoring the need for early planning.