Precipitation - Our Only Continuous Water Source

Nature's Water Cycle makes water available in a number of steps that makeup the continuous cycle. We obtain most of our water from two sources: (1) Existing moving bodies of water (e.g. river), and relatively stagnant bodies of water (like lakes and water from underground aquifers) and (2) Precipitation i.e. rainfall. 

Precipitation's role

 

Rainfall
Source - sites.google.com

Precipitation from the atmosphere, in the form of snow/sleet/hail and rain, is the only source that replenishes liquid water available from all other sources. 

Any increase in river flows, any rise in the water level of lakes and seas, and any rise in the water table is the direct result of precipitation. 

State of Worldwide Water

The majority of water (70%+) is used in agriculture. Starting with the Green Revolution in the late 1950s, humans have tapped existing water bodies to the extent that many are over depleted and increasingly scarce. 

Under normal circumstances, rainfall would have any depletion. However, as our extraction rate continues to be much greater than that which can be madeup by rain, many of the historical water bodies are no longer available as dependable sources of water.

The obvious solution is to increase precipitation and/or reduce water withdrawals i.e figure out how to get more rain and/or make agriculture more water efficient!