Time for a world water wake-up call
About a third of the world’s population lives in areas where fresh water is scarce or hard to get because of poor infrastructure. And the problem is rapidly getting worse for lack of the political will and concerted effort needed to achieve sustainable management of the world’s finite water supplies. Climate change will aggravate the looming water crisis, as rising temperatures and more erratic rainfall in many regions drive up demand for irrigation.

Together, water scarcity and climate change will pose great hardship for many people in many ways. But most catastrophic of all are the expected impacts on global capacity to produce enough food. Within 40 years, the world will have another 2.5 billion people to feed, most of them in developing countries. Given that one liter of water is used to produce one calorie of food, it will take up to 6,000 cubic kilometers of additional water annually—nearly twice the amount used for food production today—to feed those people 2,500 calories daily.

No one has any idea where that additional water will come from. Agriculture is already the global economy's thirstiest sector, accounting for 70% to 80% of total water use. Yet, by 2050, its share will have declined to about 60% or 70%, as a result of competing demands for water from urban expansion and industrial development.

The only solution is to make agricultural use of water far more productive and efficient than it is today. Two ways of doing this are, first, to refurbish old and neglected irrigation systems and, second, improve rainfed agriculture through better soil management and expanded use of water harvesting and supplemental irrigation. New higher yielding crop varieties that tolerate extreme conditions, like drought and flooding, can also help.