Can the Mose project still save Venice from the “acqua alta”?

Francesca Venturi

Over the centuries, the city of Venice has adapted to natural phenomena, starting with the increase of the level of the lagoon on which it was built over 1,000 years ago. However, today as the number of extreme natural events tends to increase, the city's ability to adapt is put under strain. Climate expert Carlo Giupponi, professor of environmental economics at the Venice University of Ca' Foscari and dean of the Venice International University of San Servolo, argues that the 20-year old, 6-billion-euro Mose project of barriers and locks won't be able to protect the city from high tides.

Already 350 years ago, scientist and mathematician Benedetto Castelli (1578-1643) was called upon by the city's doges to study the lagoon's tides to better protect the city. At the time, he had to surrender to the strength of nature, as he wrote in his book On the Measurement of Running Water (1628).

On Nov 12 the tide reached the level of 187 centimeters, close to the historical record hit in 1966. Was it an exceptional occurrence?

 “Extreme events are increasingly frequent. The current situation in Venice is similar to the one of last year, caused by the storm Vaia (which at the end of October 2018 caused a trail of destructions especially in the Veneto region). It is characterized by heavy rain and a strong Sirocco South-East wind. Historically, this phenomenon occurs a couple of times over a period of 1,000 years. It is very telling that it occurred twice, in two consecutive years”.

As he answers questions in his Venetian home, Carlo Giupponi indicates the picture of the main door of a medieval palace. The lagoon's water covers the entrance steps and the water level has increased by at least 10 centimeters compared to when the building was built.

What does this tell us?

“Clearly, it shows the city's ability to adapt to a strong increase of water levels, especially if one goes beyond the collection of current data and compares today's situation to the scene in antique paintings. However, this said, the water level increases on average by 5.6 millimeters per year. In addition to the global phenomenon of the sea level rise, Venice must face specific issues, linked to the lagoon or to the human presence, like for example the excavation of canals and the exploitation of the water table. Until recently, the city managed to deal with these changes, but its ability to adapt has hit limits. It could easily not manage to cope with the increased frequency of these extreme occurrences.

What is the difference between the aqua granda of these recent days and the one that took place 53 years ago?

The 1966 flood was caused by the overlap of two tides, associated with the Sirocco wind. It was a very rare event at the time. Nowadays, the combined presence of various factors occurs increasingly often, putting Venice under strain in facing emergency situations.

Do you think that the long-awaited launch of the Mose project could help resolve the situation?

The Mose project is a rigid one, conceived in a different historical phase. It's difficult to adapt it to the current times. In particular, it doesn't take into account the wind factor, which played a key role in increasing the consequences of natural events in the most recent occasions. Moreover, the works carried out for the building of the Mose have in turn caused natural changes, in particular to the tides affecting the Lido. Now the tides are more frequent, they rise fast, and the currents are stronger. Therefore, it's more challenging than before to make forecasts which the city needs to get ready and run for cover".

Why are many Venetians skeptical about the Mose project?

“They criticize the project because it exhausted most of the funds used normally to clean up canals and equip the city to face high tides. For the past 20 years, ordinary maintenance -- which was originally paid for by the resources diverted to finance the emergency law passed right after the November 1966 flood -- is no longer done”.

As an expert of climate changes, do you think that one can still be optimistic about the future?

"Over recent decades, graphs show an acceleration of economic, social and even natural phenomena. What was valid in the past, in terms of forecasts, is no longer valid today. In this context, if you want to be pessimistic, you have all the reasons to be so. But if you want to be optimistic, you must focus on the definition of our geological era, Anthropocene.

What do you mean exactly?

The human being is one of the main factors behind the current geological evolution and our ability to control problems is greater than in the past. We are responsible for the problems we face. At the same time, we are no longer at their mercy. Therefore, we need more awareness and responsibility. We all can do our part. On the one hand, scientists ring alarm bells, which normally the political class ignores as the time horizon of scientists is much too long in the eyes of politicians who tend to focus on upcoming elections. On the other hand, citizens can greatly influence politicians, given that they vote for them. There is a direct link between voters and elected representatives. This is why the role of social movements such as the Fridays for Future and the much-criticized Greta Thunberg is important".