September 3rd, 2008

You Just Ate A Swimming Pool

Posted by Jason Pelletier, Low Impact Living

This year has brought ample evidence that something’s amiss in our global food supply: prices have shot through the roof on everything from hamburgers to orange juice, Costcos and other big box retailers in the US have experienced runs on certain types of rice, and food riots have erupted in developing countries around the world. There are many factors at play here - weather, crop use for biofuels, high energy costs — but there’s another one that hasn’t garnered all that much attention lately: waste.

Andrew Revkin (in his Dot Earth blog at the New York Times) just highlighted a report released last week that shows just how much food is wasted. The report, titled “Saving Water: From Field to Fork” (published by the Stockholm International Water Institute), is filled with statistics that show the extent of waste in our food supply. One good example: between field and fork, about 50% of the energy contained in food never makes it to our tummies. It is wasted in the fields, in storage, in distribution, and in the feeding of livestock. Another interesting stat: the energy contained in livestock feed is over 3x the amount of energy contained in the end dairy and meat products, meaning that 70% of it is entirely wasted.

That’s not where the real waste comes in, though. As the title of the paper suggests, the waste of water in the food chain is even greater. With many parts of the world (including my home state of California) facing water shortages that are only going to get worse, this is a somewhat hidden but incredibly important problem. According to the study, the food that the average US citizen eats per day takes over 1,500 gallons of water to produce! That is over 10x the average per capita household fresh water use.

That’s a pretty grim number, and there are a number of things that we can do about it. The first is to buy and use the right amounts of food. The study states that US households throw away about $43.3 billion worth of food each year, equating to about 112 pounds per person per month (from a great article by Andrew Martin, New York Times). Farmers and food suppliers also have a major opportunity to reduce the waste: even in the US, with our sophisticated and modern agriculture, anywhere from 10-35% of food output (and associated water) is lost on the farm to pests and spoilage.

Another option, though, has to do with the kinds of food we eat. Our diet is high in animal and processed food products compared to many parts of the world, and these two categories of food use huge amounts of water to produce. Here are some stats to produce a pound of various US foods (based on this study from the University of Twente and UNESCO, both in the Netherlands):

• Tomatoes: 30 gallons of water
• Bananas: 60 gallons of water
• Almonds: 600 gallons of water
• Chicken: 300 gallons of water
• Cheese: 500 gallons of water
• Beef: 2,000 gallons of water
• A typical Thanksgiving dinner for six: 30,000 gallons of water!

Now, changing our diets alone isn’t going to solve this problem. But, it’s at least a lever we can control today until water efficiency improves all the way down the food chain. So the next time you have a hankering for half-pound burger slathered in cheese, remember this: you’ll be eating the equivalent of over 1,000 gallons of water.