Why Wasted Food Means Wasted Water

May 19, 2008 -- The wasting of food is wasting water -- a lot of it -- and there isn't much to spare.

A report released this week by the Stockholm International Water Institute says that as much as 50 percent of the calories grown globally don't make it to the table. Given that crop production uses about 1,800 trillion gallons (1,700 cubic miles) of water a year, almost 40 percent of which comes from irrigation rather than rainwater, that loss represents a lot of water.

In the United States, up to 30 percent of food is tossed out each year, the report says, worth about $48.8 billion and equivalent to flushing 10 trillion gallons of water down the drain.

"There's a very low awareness about the size of these figures," said report lead author Jan Lundqvist. "I think most people don't realize that the loss and the wastage is at that level."

"It's not possible to reduce wastage and losses altogether, but we think a realistic target is to reduce losses and wastage by 50 percent by 2025," he added.

"The situation looks quite different in different parts of the world," Lundqvist said. "In the tropics, they have quite a big loss in the field from rodents, pests, mold. The farmers have poor storage, and the transport system is insufficient. But in our part of the world, we have comparatively much larger wastage at the end of the food chain."

These losses together make up more than half of the total. The remaining losses come from crops grown for animal feed that don't end up as calories in animals because of animals' inefficiencies in converting food into body mass, the report shows.

The authors wrote the report to highlight what they felt was an overlooked strategy for confronting increasing global pressures on the water supply from rising populations, increasing affluence, biofuels and climate change, Lunqvist said.