By Jessica Burgoyne

Italy is a very low-lying area, threatened by rising sea levels throughout the Venetian Lagoon. In the past, methods of dealing with flood waters included the demolition of buildings that were becoming engulfed by sea water and rebuilding on taller, stone foundations on higher ground. However, with sea levels rising at an accelerated pace, this is not an applicable or effective method of coping with the problem. Destroying the historical infrastructure of the city also makes this an outdated technique. Venice is experiencing more frequent instances of aqua alta (high water), a problem which many scientists believe is being enhanced by the ongoing burning of fossil fuels and the consequential rise of the sea. The following link will provide a virtual example of just how threatened Italy (Venice in particular) is by various increases in sea level rise. http://geology.com/sea-level-rise/venice.shtml. In addition to SLR, the sediments underlying the city (which is essentially built a top a lagoon), are continuing to settle while, fresh water is being extracted on a regular basis from a large aquifer which also underlies the city. The settling of sediment and the removal of water from the underlying aquifer are two major factors that promote rapid subsidence of the historical city.

Some Facts
Up until 1900, extreme high tides flooded St. Mark’s Square about 7 times a year
Since 1989, these tides occurred no less than 40 times a year
Tides get so high that boats cannot navigate through the canals because they can not pass under bridges.

Rising tides are damaging to the buildings of the city. The tall foundations are built from very resistant marble but above the foundation, brick is used. In the past, sea levels never rose above the marble but now it is occurring on a regular basis. The salty water from the Adriatic Sea soaks into the more porous brick and leeches into the interior of the ancient buildings destroying historical structures bit by bit. The result of the intrusive salt waters is the inevitable crumbling of the building. Replacing the old disintegrating bricks with newer waterproof bricks is and option however these renovations would take away the great historical value of the buildings and the city and therefore is an unlikely solution to the problem. Many raised wooden foot bridges have been built and put in place when the tides are come up too high to walk through. This has been done for sometime, but another more effective solution must be explored.

There have been many proposed solutions, two of which I wish to discuss.
In Rome a group of engineers have suggested that the inevitable situation of Italy sinking could possibly be solved by pumping seawater beneath the city. Twelve holes, being one meter in diameter would be drilled 700m deep within a six mile area surrounding the city. Sea water would then be pumped into these holes. Ideally, the seawater would expand the settling soils and in combination with the clays, should push up the soil. This process would hopefully raise the entire city by one foot rescuing it from the tides.

At this time, Venice is supported by millions of wooden piles which are driven into the soggy ground. Despite this support, Venice has continued to sink. As a result, another project has been developed to try to combat the constant subsidence of the city. The projects name is Moses and it involves a series of moveable dams. 79 individual dams, with 300 ton flaps will be constructed and hinged to the seabed. They will rise up and block incoming water from entering the lagoon, in times of aqua alta. Although Moses is complete, after 10 years of construction, it is currently parked by the city’s arsenal. Project implementation has been delayed for a year by the minister of environment. One representative wants to halt the project as he believes its implementation will cause more damage to the lagoon than it will resolve.

Some Facts
· Venice has sunk approximately 7cm a century for the past 1000 years.
· In the past 100 years it has subsided 24cm.
· The new project, Moses, will near $4 billion

To conclude, we can say that increases in pollution emitted by the combustion of fossil fuels, is a main factor in the growing issue of climate change. Climate change is causing some areas of the world to warm, resulting in global sea level rise due to the melt of marine glaciers and ice caps. Low lying areas are particularly vulnerable to flooding as temperatures continue to rise, ice caps continue to melt and sea level continues to rise. To address the exact question asked, “Is Italy sinking because of climate change?” we can say that yes Italy is sinking but not solely as a result of climate change. As you read previously, Italy has been subsiding for various reasons over the past 1000 years or more. Because of increased levels of anthropogenic pollution and emissions, the process of climate change is being amplified. Emission of carbon dioxide is the main contributing factor to rising temperatures and the consequential melting of polar ice caps. As a result, already low lying areas are prone to flooding as tides become more drastic with SLR. Therefore, the combination of Italy being constructed a top a lagoon and its vulnerability to frequent aqua alta causes it to be a place which is very susceptible to extreme flooding.





References

http://geology.com/sea-level-rise/venice.shtml

http://www.msnbc.msn.com/id/10143146/

http://www.pbs.org/wgbh/nova/venice/solutions.html

http://www.spiked-online.com/Articles/00000000543C.htm