An unpleasant fact of life in our desert is that we're not self-sustaining. Several thousand years ago, a low population could survive on the bounty of land: products of crops, the hunt, and wild crops. With a population of millions, this is no longer possible. Most of our needs have to come from without. Arid lands and cities in general form what ecologists call a sink. Visualize water swirling down the drain of a sink and you get the idea.
Much of the plight of arid regions can be summarized in terms of energy
expenditures. Buying a head of lettuce? Lettuce isn't known for being a rich supply
of energy, but perhaps we're looking at it all wrong. To raise and transport that
head took lots and lots of energy; energy to plow the field, energy to manufacture the
fertilizers, energy to harvest, energy to transport. One calorie of lettuce food energy
may have cost the world as much as 100 calories of petroleum energy. Good deal? Only as
long as the cheap petroleum supply holds out!
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.