We don’t realize it as we sit down to a meal, but most crops require huge volumes of water to grow: 65 gallons to grow a pound of potatoes; 650 gallons for a pound of rice.
Often, food supplies are only maintained at the expense of literally emptying some of the world’s great rivers, such as the Indus in Pakistan, the Yellow River in China and the Nile in Egypt. Elsewhere, underground reserves are being pumped dry.
But increasingly, countries are giving up on trying to feed their populations from their own resources and are switching to food imports. That means they are also importing the water embodied in the crops, or virtual water. Every ton of wheat arriving at a dockside carries with it, in virtual form, the thousand tons of water needed to grow it.
And if you're looking at meat, it's much higher -- about 2,500 gallons per pound of beef.
Similarly, it's not that you're going to get zapped by electricity when touching aluminum, but the amount of electricity required to extract that aluminum is vast.
Maybe you should have actually read my comment: I was explicitly excluding cases where river or fossil water is being used.
And the "65 gallons of water per pound of potatoes" is utter bullshit. Whether rain falls on untouched grass land or on potato plants does not matter to the water ecosystem.
The point isn't how much water is physically in food exported, but how much was required to create it. From this Forbes article:
http://www.forbes.com/2008/06/19/water-food-trade-tech-water...
We don’t realize it as we sit down to a meal, but most crops require huge volumes of water to grow: 65 gallons to grow a pound of potatoes; 650 gallons for a pound of rice.
Often, food supplies are only maintained at the expense of literally emptying some of the world’s great rivers, such as the Indus in Pakistan, the Yellow River in China and the Nile in Egypt. Elsewhere, underground reserves are being pumped dry.
But increasingly, countries are giving up on trying to feed their populations from their own resources and are switching to food imports. That means they are also importing the water embodied in the crops, or virtual water. Every ton of wheat arriving at a dockside carries with it, in virtual form, the thousand tons of water needed to grow it.
And if you're looking at meat, it's much higher -- about 2,500 gallons per pound of beef.
Similarly, it's not that you're going to get zapped by electricity when touching aluminum, but the amount of electricity required to extract that aluminum is vast.