Water has historically been a source of tension and a factor in conflicts that start for other reasons. Recent humanitarian catastrophes, such as the Rwandan genocide or the war in Sudanese Darfur, have been linked back to water conflicts.

Fresh water is a renewable resource, yet the world’s supply of groundwater is steadily decreasing, with depletion occurring most prominently in Asia, South America and North America. 97% of the water on the Earth is salt water and only 3% is fresh water; slightly over two thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air.

Conflicts occur mostly over freshwater; because freshwater resources are necessary, yet scarce, they are the center of water disputes arising out of need for potable water, irrigation and energy generation. The lack of cost-effective water supply options in areas like the Central Asia, among other elements of water crises can put severe pressures on all water users, whether corporate, government, or individual, leading to tension, and possibly aggression.