Water is key to food security - FAO report

Everybody understands that water is crucial for growing food - but often in an abstract way. Can you give more details on how water helps feed the world? First of all, it's important to make the distinction between rainfed agriculture - farming that depends on natural rainfall - and irrigated agriculture. Irrigating land changes everything - it concentrates inputs and forces changes in agronomy and marketing. While many people in the Horn of Africa are pastoralists, not crop farmers, the current situation there makes it painfully clear the risks and vulnerability associated with rainfed food production systems, especially as the impacts of a changing climate are now making themselves felt. It's not that rainfed agriculture is a problem per se, but it is more vulnerable, and tends to be less productive. As regards irrigation, one can't understate the contribution it has made to feeding the world. Over the last 50 years, the Earth's population doubled and the global food system responded remarkably to the increase in food demand. This was done through just a modest increase in total cropland -- not more than 12 percent. The achievement occurred mainly through intensification of agricultural production, i.e. an increase in yield and cropping intensity, which in turn would not have been possible without irrigation. Irrigated land has increased proportionally much faster than land under rainfed agriculture. In fact, while the world's cultivated area has grown only by 12% over the last fifty years, irrigated area has doubled over the same period, accounting for most of the net increase in cultivated land. Meanwhile, agricultural production has grown between 2.5 and 3 times, thanks to significant increase in the yield of major crops.