Water and food

Some of the startling statistics about water in When the Rivers Run Dry, written by Fred Pearce:

  • 25 gallons to produce a portion of rice

  • 40 gallons for the bread in a sandwich

  • 130 gallons for a two-egg omelet or mixed salad

  • 265 gallons for a glass of milk

  • 400 gallons for ice cream

  • 530 gallons for a pork chop

  • 800 gallons for a hamburger

  • 320 gallons for a small steak

  • 50 cups for a teaspoon of sugar

  • 37 gallons for a cup of coffee

  • 66 gallons for a glass of wine/beer

  • 530 gallons for a brandy

  • 1200 gallons (assuming 50 gallons/bathtub) to grow 9 ounces of cotton

Pearce talks about the relative water consumption of various human activities:

  • drinking: 265 gallons (1 ton)/year

  • home use: 50-100 tons/year

  • food and clothing: 1500-2000 tons/year

That makes clear that the bottleneck is clearly food and clothing, and that becoming vegetarian might actually be the best way to conserve water.

While I was walking home last night, I came to the minor realization that if we treat the human-earth relationship as a complex system, then some resource will always be the bottleneck. Pearce's book implies that it as water; the more obvious candidate (from a public perspective) has been energy (oil).

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