RARELY was a city so aptly named. By the end of this century, Italy鈥檚 City of Water could be facing dangerously high tides almost every day, and costly flood barriers now being built might not be able to protect it.
A study by Laura Carbognin at the Institute of Marine Sciences in Venice and colleagues provides the best estimate yet of how the city will cope with the effects of climate change. The team took forecasts of global sea-level rise from the Intergovernmental Panel on Climate Change (IPCC) and factored in the impact of local land subsidence. With the help of this localised sea-level forecast, they then calculated the city鈥檚 tides.
The team found that by the end of the century, Venice鈥檚 tides could exceed 110 centimetres 鈥� the so-called acqua alta (鈥渉igh water鈥�) level 鈥� between 30 and 250 times a year (Journal of Climate Dynamics, ). Each time, the city would be forced to raise its system of flood barriers, named and due for completion in 2014. The impact on the local environment would be considerable, with pollution and untreated sewage trapped inside Venice鈥檚 lagoon.
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Carbognin鈥檚 estimates are conservative and the reality could be much worse, says NASA climatologist Vivien Gornitz. Sea levels are already rising faster than forecast by the IPCC. Even MOSE may be insufficient to save the city, she says.