A huge amount of water goes into the food we eat, much more than most people think. Indeed, it takes a thousand times more water to feed the human population than it does to satisfy its thirst.

This remarkable relationship between water and food security is exactly what the United Nations Food and Agriculture Organization wants us all to contemplate today, World Water Day 2012.

Since the first of these annual campaigns, in 1993, World Water Day has been organized around a theme. The focus last year was “Water for Cities.” In 1995, it was “Women and Water.” This year, organizers are reminding us all that water conservation is one good reason to eat lower on the food chain:

It takes about 1,500 liters of water to produce 1 kilogram of wheat; producing the same amount of beef takes15,000 liters.

The FAO warns that feeding the 9 billion people expected to populate the planet by 2050 simply won’t be possible unless we figure out how to grow more food with less water. Already 70 percent of fresh water collected for human consumption is put toward irrigation. If more of those irrigated crops fed people rather than cattle, we would be headed in a step in the right direction. But it’s going to take smarter application of water as well.

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Just in case you need yet another example of how tightly our food and water security are intertwined, recall that drought is still the No. 1 cause of severe food shortages in developing countries. Climate change is no doubt going to exacerbate that problem in at least some parts of the world.

“Severe reductions in river runoff and aquifer recharge are expected in the Mediterranean Basin and in the semi-arid areas of the Americas, Australia, and Southern Africa, affecting water availability and quality in already stressed regions,” the FAO reports.

Not all the news on this World Water Day is gloom and doom. A report released earlier this month revealed that more than 2 billion people gained access to improved drinking-water sources between 1990 and 2010.

Credit: José Manual Suárez via Wikimedia Commons.