Attributing Venice Acqua Alta events to a changing climate and evaluating the efficacy of MoSE adaptation strategy

We use analogues of atmospheric patterns to investigate changes in the three most devastating Acqua Alta (flooding) events in the lagoon of Venice associated with intense Mediterranean cyclones occurred in 1966, 2018 and 2019. Our results provide evidence that changes in atmospheric circulation, although not necessarily anthropogenically driven only, are linked to the severity of these events. We also evaluate the cost and benefit of the MoSE system, which was designed to protect against flooding. Our analysis shows that the MoSE has already provided protection against analogues of the most extreme events, which occurred in 1966, while for 2018 and 2019 events our analysis is non-conclusive because of the lack of analogues situations of those events.  These findings have significant implications for the future of Venice and other coastal cities facing similar challenges from rising sea levels due to extreme events. Our study represents one of the first examples that goes beyond identifying the circulation drivers of extreme events to quantifying the changes and their impacts. The framework we presented is general and can be applied to other case studies. However, our study also has limitations, including the limited database of sea-level for the past, the limited analogues used, and the fact that we did not use climate models. Despite these limitations, our study provides important insights into the attribution and impacts of extreme events, which are crucial for developing effective mitigation and adaptation strategies. We hope that our work will inspire future research and inform policymakers in their efforts to reduce the risks associated with extreme events.