Debra Perrone, Assistant Professor UC Santa Barbara, discusses the dwindling groundwater supply affecting 12 million US wells caused by global warming and over-consumption. The world relies on groundwater, which is getting harder and harder to find.  With groundwater close to the surface vanishing, well-drillers are forced to turn to deep drilling for corporate, agricultural, and domestic water needs. But going deep this way is far more expensive and increasingly yields contaminated water.