In March, a report from the office of the US Director of National Intelligence said the risk of conflict would grow as water demand is set to outstrip sustainable current supplies by 40 per cent by 2030.
"These threats are real and they do raise serious national security concerns," Hillary Clinton, the US secretary of state, said after the report's release.
Internationally, 780 million people lack access to safe drinking water, according to the United Nations. By 2030, 47 per cent of the world’s population will be living in areas of high water stress, according to the Organisation for Economic Co-operation and Development's Environmental Outlook to 2030 report.
Some analysts worry that wars of the future will be fought over blue gold, as thirsty people, opportunistic politicians and powerful corporations battle for dwindling resources.
Dangerous warnings
Governments and military planners around the world are aware of the impending problem; with the US senate issuing reports with names like Avoiding Water Wars: Water Scarcity and Central Asia’s growing Importance for Stability in Afghanistan and Pakistan.
With rapid population growth, and increased industrial demand, water withdrawls have tripled over the last 50 years, according to UN figures.
"Water scarcity is an issue exacerbated by demographic pressures, climate change and pollution," said Ignacio Saiz, director of Centre for Economic and Social Rights, a social justice group. "The world's water supplies should guarantee every member of the population to cover their personal and domestic needs."
"Fundamentally, these are issues of poverty and inequality, man-made problems," he told Al Jazeera.
Of all the water on earth, 97 per cent is salt water and the remaining three per cent is fresh, with less than one per cent of the planet's drinkable water readily accessible for direct human uses. Scarcity is defined as each person in an area having access to less than 1,000 cubic meters of water a year.
The areas where water scarcity is the biggest problem are some of the same places where political conflicts are rife, leading to potentially explosive situations.
Some experts believe the only documented case of a "water war" happened about 4,500 years ago, when the city-states of Lagash and Umma went to war in the Tigris-Euphrates basin.
But Adel Darwish, a journalist and co-author of Water Wars: Coming Conflicts in the Middle East, says modern history has already seen at least two water wars.
"I have [former Israeli prime minister] Ariel Sharon speaking on record saying the reason for going to war [against Arab armies] in 1967 was for water," Darwish told Al Jazeera.
Some analysts believe Israel continues to occupy the Golan heights, seized from Syria in 1967, due to issues of water control, while others think the occupation is about maintaining high ground in case of future conflicts.
Senegal and Mauritania also fought a war starting in 1989 over grazing rights on the River Senegal. And Syria and Iraq have fought minor skirmishes over the Euphrates River.
Middle East hit hard
UN studies project that 30 nations will be water scarce in 2025, up from 20 in 1990. Eighteen of them are in the Middle East and North Africa, including Egypt, Israel, Somalia, Libya and Yemen.
Darwish bets that a battle between south and north Yemen will probably be the scene of the next water conflict, with other countries in the region following suit if the situation is not improved."Water too often is treated as a commodity, as an instrument with which one population group can suppress another" -Ignacio Saiz, Centre for Economic and Social Rights
Water shortages could cost the unstable country 750,000 jobs, slashing incomes in the poorest Arab country by as much as 25 per cent over the next decade, according to a report from the consulting firm McKinsey and Company produced for the Yemeni government in 2010. More