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Tuesday, June 24, 2008

Florida circa 2100: Global warming's toll

Published June 23, 2008
Most of Florida pumps its drinking water from deep, underground pockets of fresh water in the Floridan Aquifer. The aquifer, however, sits in limestone, which is naturally porous. Along the coastline, there are breaks in the limestone, where the fresh water mixes with the sea.

Seawater is actually heavier and denser than fresh water because of the amount of salt and sediment in seawater. However, a large enough column of fresh water can equalize the pressure from the sea.

As long as the pressure remains constant, that zone where the fresh water and salty sea mix won't move. But that zone can shift depending on how the water pressure changes.

Rising seas will exacerbate that problem. The expanding ocean and the additional meltwater will increase the pressure of the sea as it pushes against the freshwater pockets. Eventually, it would overwhelm the fresh water and infiltrate inland wells.

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