Venice at risk

Physics Today : The Italian city of Venice is under threat of frequent flooding under the latest climate change scenarios, say Laura Carbognin at the Institute of Marine Sciences in Venice and colleagues in Climate Dynamics , and new expensive flood barriers may be unable to protect it.Since the early part of the 20th century Venice has suffered a number of damaging floods, particularly in the 1960s. About four times a year St Mark’s Square, the center point of the city, floods during a particularly high tide (about 110 cm according to the research paper).The new €3 billion controversial flood barriers called Mo.S.E. is due to be completed by 2014. It will protect Venice from these high tides by sealing the city’s lagoon off from the surrounding inlets.The study calculates the tides that will effect Venice by combining land subsidence data from the city—Venice was built on a marsh, and the buildings have been sinking at 0.05 cm per year for sometime—and the latest forecasts on global sea-level rise from the Intergovernmental Panel on Climate Change .Carbognin’s team predict that by 2100, the tide will rise above 110 cm between 30 and 250 times a year, under the most conservative estimates, and that alternatives to Mo.S.E. will have to be considered to save the city. “The temporary closure of inlets alone could not be suitable to efficiently protect Venice from flooding,” says the report.One of the simplest suggestions is to refill the underground aquifers to “float” up the city from its surrounding area. A modeling study has offered “encouraging results,” says Carbognin’s team, that could rise the city by 30 cm over a 10-year period. Related Link Global change and relative sea level rise at Venice: what impact in term of flooding Can Venice be raised by pumping water underground? A pilot project to help decide