Can CO2 help save Venice from the sea?

On 14 May this year, Italian Prime Minister Silvio Berlusconi cut the ribbon on a multibillion-dollar project named MOSE that is aimed at solving the problem of “acqua alta,” the increasingly frequent floods that jeopardize the survival of Venice.Cost is estimated (a few say conservatively) at 3 billion euros and construction time (a few say optimistically) at 8 years. MOSE involves building mobile barriers at the Venice Lagoon inlets to prevent severe Adriatic Sea storms from flooding the city. Although the Italian government and the local administrations have given their final approval, MOSE still has several opponents who believe it will cause severe threats to the lagoon ecosystem,and will soon become obsolete because of the expected sea level rise due to global warming. This article presents a complementary solution which has none of the environmental consequences charged to MOSE, and extends its life in circumstances of global climate change,but nevertheless is not as expensive: injection of anthropogenic carbon dioxide (CO2), or sea water,in a brackish,sandy aquifer lying 600–800 m below the lagoon. Based on new hydrogeological and geo-mechanical data, preliminary simulations show that fluid injection into this deep formation can uniformly raise Venice up to 30 cm in 10 years, thus neutralizing almost all of the high tides.The results suggest that fluid injection might represent a helpful complement to the MOSE project,with no measurable environmental impact.