After Venice’s November 2019 flood, it was hit with four additional extraordinary tides in six weeks. This shocked Venetians as well as raising concerns about climate change’s increasing impact.
This summer, the repeated infiltration of brackish lagoon waters into St. Mark’s Basilica is a quiet reminder of how serious the threat remains.
“I can only tell you that we had tides exceeding a meter five more times in August than usual, which is unusual. “I am referring to the month of August when we are quiet,” Carlo Alberto Tesserin (St. Mark’s chief caregiver) told The Associated Press.
Venice’s unique topography is vulnerable to climate change because it was built on log piles and canals. Rising sea levels are increasing the frequency and severity of high tides that flood the 1,600-year old Italian lagoon city. This is also slowly sinking.
Climate scientists and global leaders will be thinking about the fate of Venice’s coastal cities at the U.N. climate conference in Glasgow, Scotland that starts Oct. 31.
According to a new study by the European Geosciences Union, Venice’s worst-case scenario for sea rise by the end century is 120 cm (3 feet, 11 inches). This is 50% more than the worst-case global sea-rise average at 80 centimeters (2ft, 7 1/2 inches), forecasted by the U.N. science panels.
Its unique combination of architecture and canals, as well as its natural habitat and human ingenuity has earned it UNESCO World Heritage status for its exceptional universal value. This designation was put at risk by the effects of over-tourism, cruise ship traffic, and other factors. Although it was saved from the endangered list by Italy banning cruise ships from passing through St. Mark’s Basin in Italy, alarm bells continue to ring.
St. Mark’s Basilica, which is situated at Venice’s lowest point, offers an exceptional position to observe the effects of rising seas. The piazza outside floods around 80 centimeters (30 inches), and water flows into the church at 88 cm (34.5 inches). This is an increase from the previous 65 centimeters (25.5 in)
“The conditions are worsening since November 2019’s flooding. It is now a regular occurrence that flooding occurs in these months. It is an everyday occurrence,” stated Tesserin, whose honorific, First Prcurator of St. Mark’s dates back to the ninth-century.
According to city data, almost as many Venice inundations over 1.1m have occurred in the past 20 years as in the previous 100 years. These inundations were caused by tides winds and lunar cycles.
Floods exceeding 140 cm (4 feet, 7 inches), are also accelerating. Since 1872, when Venice began keeping records of floods, this mark has been crossed 25 times. The last 20 years have seen two-thirds of these records, and five, or one fifth, of them, were registered between Nov. 12 and Dec. 23 2019.
Jane Da Mosto (executive director of We Are Here Venice) stated that “What’s happening now is on a continuum for Venetians who have always experienced periodic flooding.” “We live with flooding that is becoming more frequent. My concern is that people don’t realize that we are facing a climate crisis.” It is already happening now. It’s not about making plans for the future. It is important to have solutions in place for today.
Venice’s defense was given to the Moses system for moveable underwater barriers. This project, which cost around 6 billion euro (nearly $7billion), has now officially entered the testing phase.
The Rome government placed the project under ministry control after the devastating 2019 floods. Last year, they activated the barriers when floods of 1.3 metres (4 feet, 3 inches), are likely.
Since October 2020, the barriers have been raised 20 more times. This has prevented the city from flooding during a season that is becoming more frequent.
Elisabetta SPITZ, the extraordinary commissioner, is standing by the integrity of the undersea walls, despite the concerns of scientists and experts that they may lose their utility in the coming decades due to climate change. The project was delayed once more, and will be completed in 2023. Spitz stated that additional 500 million euros ($580 millions) of spending is required to improve its efficiency over the long-term.
Spitz stated that “we can say that the Moses’ effective life is 100 years” after taking into consideration the maintenance and interventions that will need to be made.”
Paolo Vielmo is an engineer who wrote expert reports on the project. He points out that the sea-level rise was predicted at 22 centimeters (8 1/2 in) when the Moses was first proposed over 30 years ago. This is far less than the U.N. scientists’ worst-case scenario of 80 cm.
He said, “That puts the Moses outside of contention.”
The current plans state that the Moses barriers will not be raised for floods exceeding 1.1m (3ft, 7in) until final approval is granted. St. Mark’s is now exposed.
Tesserin oversees work to protect Basilica’s base by installing a glass barrier. This will prevent marshy lagoon water, which can seep inside, from entering. Salt deposits in the walls, wall cladding, and stone mosaics, making it difficult for Tesserin to supervise. High tides continue to disrupt the project. It was meant to be completed by Christmas. Tesserin now says that they will be able to complete it by Easter.
Venetians are used to carrying rubber boots everywhere they need. Tourists love the sight of St. Mark’s golden mosaics and domes reflecting in rising water. Businesses along St. Mark’s Square see themselves as ground zero for the climate crisis.
We must help this city. It was a beacon for the world. But now, it needs to be understood by the entire world,” Annapaola said. She spoke from behind metal barriers that prevented water reaching 1.05m (3ft, 5in) from entering her cafe, which is marble-floored.
“The acqua alta is becoming worse and it completely blocks businesses. Venice is a city that thrives because of its artisans and tourism. She explained that Venice will die if there is no tourism. “We have a huge responsibility to save it, but we are still suffering a lot.”