快猫短视频s have discovered that Canaletto鈥檚 highly accurate paintings of 18th century Venice record sea levels a century and a half before sophisticated measuring began. They hope it will help them to save Venice and its rich cultural heritage from crumbling beneath the waves.
Venice is built on a lagoon in the Adriatic Sea, making it highly vulnerable to changing sea levels brought on by global warming, a problem made worse by the fact that the city itself is subsiding.
Last century, channels were blasted to allow big ships to enter the port. Unfortunately, this also meant that high tides and sea surges brought on by Sirocco wind storms could flood the lagoon and the city. As well as causing problems for residents, the sea water seeped into the porous limestone buildings and began to rot them away.
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Instruments were first used to measure sea levels in 1872, and scientists have been looking for ways to find out what happened before then, to help them predict what might happen in future. Now, Dario Camuffo of the Institute of Atmospheric Science and Climate in Padua and his team have discovered that Canaletto鈥檚 paintings can be used to reconstruct the past.
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Canaletto needed a quick and easy way to sketch his paintings to keep the money coming in. So he used a kind of pinhole camera, a camera obscura, to trace the outlines of the buildings he painted onto canvas. This makes his paintings almost as accurate as a photograph, says Camuffo. 鈥淐analetto is absolutely reliable,鈥� he says.
These 鈥減hotographic鈥� paintings depict a brown-green line of algae growing on buildings that marks the average high-tide level at the time. So Camuffo and his team compared the position of the line in the paintings with the modern-day level. They found that the relative sea level in Venice has risen by up to 0.8 metres since Canaletto鈥檚 time, or by 2.7 millimetres per year.
The information will be invaluable in helping decide how best to protect Venice and its heritage from the rising tides, says Camuffo.