The city of Venice and its lagoon represent great historic, ecologic, and economic interest. The most known and debated symptom of the frailty of the Venetian lagoon system are the periodic flooding events that afflict Venice, locally referred to as “acqua alta”. An increased impact of storm surges on Venice has been observed in recent decades, and the future rise of sea level as a consequence of global warming may lead to dramatic impacts on both the historical centre and the surrounding ecosystem. Local changes such as subsidence must also be considered. A large amount of scientific literature has been devoted at understanding the dynamics leading to the flooding of Venice, predicting the timing and intensity of the events and describing changes in their frequency and intensity under future global warming scenarios.

This special issue aims to critically discuss the current understanding of the Venice flooding phenomenon. It is structured with a focus on “its meteorological and climatic precursors, its prediction, and its historical and expected future variations under a globally changing climate”. The synthesis is oriented toward clarifying consolidated knowledge, highlighting gaps of knowledge as well as identifying major opportunities for progress. This special issue is composed of three review papers, addressing three different and complementary aspects of the hazards causing the flood of Venice. Review paper 1 describes the tools that have been developed and are currently used for the prediction of the sea level events, which are used for warning the population and will be needed for managing the movable barriers to prevent future floods. Review paper 2 describes the factors leading to extreme events, their past evolution, and expected future levels under a climate change perspective. Review paper 3 considers the evolution of the mean relative sea level, whose past increase and future expected positive rate are the major causes of the increasing flood hazard level. The editorial provides an introduction to the three reviews, where the critical issues posed by the floods of Venice are summarized and the basic meteorological and oceanographic processes and factors involved (that are common to the three reviews) are introduced.