Severe flooding in Venice, which has flooded much of the Italian city, is a direct result of climate change, says the mayor.
The highest water level in the region for more than 50 years leaves "lasting traces" tweeted the mayor of Venice, Luigi Brugnaro.
"Now the government has to listen," he added. "These are the effects of climate change … the costs will be high."
The waters of Venice reached a peak of 1.87 m, according to the tidal monitoring center. Only once since official records began in 1923 was the tide higher, reaching 1.94 meters in 1966.
The pictures showed popular tourist attractions that were completely flooded and people wading through the streets when Venice was hit by a storm.
St. Mark's Square – one of the lowest parts of the city – was one of the worst hit areas.
St. Mark's Basilica was flooded for the sixth time in 1200 years, according to church records. Mr Brugnaro said the famous landmark had suffered "severe damage". The crypt was completely flooded and there are fears that the columns of the basilica will be structurally damaged.
Pierpaolo Campostrini, member of the St. Mark's Council, said four of these floods have occurred within the last 20 years.
The city of Venice is made up of more than 100 islands in a lagoon off the northeastern coast of Italy.
Two people died on the island of Pellestrina, a thin strip of land separating the lagoon from the Adriatic Sea. One man was electrocuted while attempting to pump in his house, and a second person was found dead.
Mr. Brugnaro said the damage was "tremendous" and that he would declare a disaster and warns that a project to help the Venetian Protecting the lagoon from devastating floods "must be completed soon."
"The situation is dramatic. We ask the government to help us, "he said on Twitter, adding that the schools would remain closed until the water level drops.
He urged local businesses to share photos and video footage of the devastation by the government.
People across the city waded through the floodwaters.
A number of businesses were affected, with chairs and desks floating in front of cafes and restaurants.
In stores, workers tried to remove their supplies from the water to prevent further damage.
A shopkeeper, who was not named, told the Italian public service broadcaster Rai: "The city is on its knees."
Three water buses sank Venice, but the tourists continued their visits as best they could.
A French couple told AFP that they had "effectively swum" after some of the wooden platforms had been set up in flood-prone areas around the city.
Wednesday morning, some boats were stranded.
Since 2003, a project to protect the city from flooding has been underway, but has been plagued by rising costs, scandals and delays.
The so-called Mose Project – a series of large barriers or locks that would be lifted from the seafloor to the sea Lagoon at rising sea level and Winter storms shut off – was successfully tested in 2013 for the first time.
- Attention: Venice flood barrages pass first test
The project has already cost billions in investment. According to the Italian Ministry of Infrastructure, the flood barriers will be handed over to the city council of Venice after the "final phase" of the tests in late 2021.
Italy was hit hard by heavy rain on Tuesday and bad weather was forecast again in the coming days. Venice is hit by flooding every year.
Is climate change behind the floods in Venice?
By BBC meteorologist Nikki Berry
The recent flooding in Venice was triggered by a combination of floods and a meteorological storm. Strong sirocco winds blow northeast across the Adriatic. When these two events come together, we get what is known as the Acqua Alta (flood).
This recent appearance of Acqua Alta in Venice is the second highest tide in recorded history. However, if we look at the top 10 tides, there have been five in the last 20 years and the last was last year.
While we should try to prevent a single event from being attributed to climate change, the increased frequency of these exceptional tides is obviously a big problem. In our changing climate, sea levels are rising and a city like Venice, which is also sinking, is particularly susceptible to such changes.
The weather patterns that caused the storm surge on the Adriatic were driven by a strong meridional (sweeping) jet across the northern hemisphere feeding a conveyor belt of low-pressure systems into the central Mediterranean.
One possible effect of a changing climate is that the jetstream becomes more frequent meridional and such blocked weather patterns become more frequent. In this case, it is more likely that these events will be accompanied by astronomical spring tides, increasing the likelihood of flooding in Venice.
In addition, the meridional jet stream can be attributed to stronger typhoons in the Northwest Pacific, leading to more frequent coldouts in North America, and a troubled Mediterranean is another downstream effect.
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