World could have 40 percent water shortfall by 2030

The world could suffer a 40 percent shortfall in water in just 15 years unless countries dramatically change their use of the resource, a UN report warned on Friday.

Many underground water reserves are already running low, while rainfall patterns are predicted to become more erratic with climate change.

As the world's population grows to an expected 9 billion by 2050, more groundwater will be needed for farming, industry and personal consumption.