Canaletto's paintings open a new window on the relative sea-level rise in Venice

The paintings by Canaletto (1697-1768), made with the help of a camera obscura, are just like real photographs, documenting as they do the Venice of the XVIII century with an accurate reproduction of all the details. The brown-green front left by the Laminaria, an alga living between the high and low tide, constitutes a precise biological indication of the average level of the high tide. By comparing the level of this front at Canaletto's time with the present level, we can calculate/discover the relative sea level rise which has occurred in the last two and a half centuries. (C) 2001 Editions scientifiques et medicales Elsevier SAS