Art charts how low Venice has sunk
ROME - Scientists looking for clues as to how much the city of Venice has sunk in the last few hundred years didn't use complicated calculations or theories. Instead, they turned to Canaletto, an 18th-century Venetian landscape artist.

A detail of the Venetian artist Canaletto's 1723 painting "Rio dei Mendicanti" is seen in this reproduction.

IN HIS STUDY presented in November, Dario Camuffo, a climate expert, said he and his team looked at the paintings and compared them with the same places in present-day Venice. By doing that, the scientists found that the city has sunk more than 2 feet since 1727.
"I thought the city's descent might be a relatively recent phenomenon" until Canaletto's works were analyzed, Camuffo said.
Camuffo decided the city has been steadily sinking at the rate of about 8 inches a century for at least 300 years.
The scientists decided to use eight of Canaletto's paintings for the study because exact measurements of Venice's sea level only go back as far as 1872. The artist's works go back further.
Camuffo said Canaletto was so precise in his detail that he even painted the dark algae stains on the buildings along the canal banks.
"Suddenly I realized we could use this detail to determine the sea level at the time," Camuffo said from his office at the Institute of Atmosphere and Climate Sciences and Climate, in Padua, a day before the study was presented in nearby Venice.
"Nobody knows how high the tide was when Canaletto was working, but we do know the algae on the buildings always occupy the average level reached by high tide, where dry and wet spells alternate."
After studying the paintings, the experts are hopeful about one thing. It seems Venice has been sinking more slowly in the last few years, but no one is exactly sure why.

Climate expert Dario Camuffo stands in front of the St. Mark's Basin in Venice on Thursday.