Friday, January 20, 2006
What is an “ecological footprint”?
An “ecological footprint” is an estimate of how much land would be required to sustain some use. You may find calculators at sites such as http://www.redefiningprogress.org/ . I use the footprint values from “Radical Simplicity” by Jim Merkel. He notes that there is a balance between simplicity of use and accuracy to the method, so any calculations are of course estimates.
By one calculation, the Earth provides 4.7 acres of productive land per person. The typical American may use 20 acres (!). By some estimates, world wide consumption equals three or four entire earths, which is obviously not sustainable.
The energy estimates are of particular interest to me. The “footprint” of consuming, for example, a gallon of gas per month accounts for the energy needed extract and deliver the gas, as well as enough forest and ocean to absorb the carbon dioxide The footprint of consuming one gallon of gasoline a month is 500 square yards, or about one-one hundredth of an acre. The footprint of operating a car is greater than that of just burning the gasoline, as the metal and other materials in the car had an impact from mining, manufacturing, etc.
This method offers a tool other than economics to make choices about how we use energy. The “ecological payback” is often different than “economic payback”.
For small choices, it is more convenient to express the footprint in sqare yards (abbreviated sq.yd.) than in acres. There are 4840 sq.yd. in one acre.
By one calculation, the Earth provides 4.7 acres of productive land per person. The typical American may use 20 acres (!). By some estimates, world wide consumption equals three or four entire earths, which is obviously not sustainable.
The energy estimates are of particular interest to me. The “footprint” of consuming, for example, a gallon of gas per month accounts for the energy needed extract and deliver the gas, as well as enough forest and ocean to absorb the carbon dioxide The footprint of consuming one gallon of gasoline a month is 500 square yards, or about one-one hundredth of an acre. The footprint of operating a car is greater than that of just burning the gasoline, as the metal and other materials in the car had an impact from mining, manufacturing, etc.
This method offers a tool other than economics to make choices about how we use energy. The “ecological payback” is often different than “economic payback”.
For small choices, it is more convenient to express the footprint in sqare yards (abbreviated sq.yd.) than in acres. There are 4840 sq.yd. in one acre.
# posted by Theepdinker @ 8:03 PM 
