Low-lying coastal cities are at risk due to projected sea-level rise over the next century. One particularly vulnerable city is Venice, Italy, which already suffers from periodic flooding due to severe storms in the Adriatic Sea. A combination of land subsidence due to past fresh water extraction (a 23 cm drop in the last 100 years) and future sea-level rise have prompted the Italian government to implement a solution. A 3 billion Euro, 8 year project to protect the city from the sea has been launched, but Comerlati et al. (2003) suggest a more environmentally friendly and less costly measure would be to raise the city by injecting CO2 underneath.
Reference
Comerlati, A., M. Ferronato, G. Gambolati, M. Putti, and P. Teatini, 2003: Can CO2 help save Venice from the sea? EOS, 84, 546.