Rising sea levels are an obvious problem for the canal-laden city of Venice, Italy, which is threatened with increased flooding as climate change pushes the waterline farther and farther up. And now, scientists have found that the flooding problems are being exacerbated by the entire city's gradual sinking.
The city is actually sinking into the water at a rate of about 2 millimeters per year, according to researchers at the Scripps Institution of Oceanography at the University of California, San Diego. Two millimeters might not seem like a lot – that's only a drop of 1 centimeter every five years – but couple it with the 2 millimeters per year that sea levels are rising, and the problem starts to get at least a little concerning.
It's bad enough in Venice, but it's even worse in neighboring islands. Of the 117 patches of land in the Venice lagoon, those on the southern side have been observed to be sinking at a rate of 3 to 4 millimeters per year, according to the research, to be published later this month in the journal Geochemistry, Geophysics, Geosystems. The researchers also found that the entire area is also tilting to the east, going down like a very slow Titanic.
This subsidence is familiar for Venetians, who discovered a few decades ago that pumping groundwater from beneath the city was essentially eating away at the stability of its foundations. The city stopped that pumping, and research from the last decade showed that the subsidence had stopped. These new results indicate that the groundwater pumping was only making an already occurring subsidence even worse. Unfortunately for the city's roughly 270,000 residents (and an estimated 60,000 tourists a day), the sinking of Venice is a natural process and doesn’t seem to be stopping.
But hope for the city's future is not completely lost. A multi-billion dollar project is currently underway to create a system of floodgates around the city to prevent the sort of flooding that now occurs a handful of times a year – a phenomenon only expected to increase.
Photo credit: Reuters