Our ecological footprint and agriculture
March 14th, 2008 by Jim JustThere’s a post by Jason Bradford at The Oil Drum that provides a pretty good introduction to ecological economics.
This chart shows the basic concept: that our economy is a subset of the Earth system, and is dependent on that ecosystem for sources and sinks. There are feedback loops between the economy and the Earth ecosystem, and scale becomes increasingly important as limits to source and sink capacity are approached.
One measure of whether the human economy is too large is the ecological footprint, which relates the consumption of resources and the build-up of wastes relative to resource regeneration rates and the waste-absorbing capacity of the environment. The human economy (population plus consumption and waste generation) is currently in a state of overshoot, meaning it is too large relative to the long-term capacity of the planet to cope.
A significant portion of our overdraft is the result of fossil fuel consumption and the resulting greenhouse gas wastes.
Fossil fuel extraction is reaching limits (peak oil) sooner than expected. Similarly, we’re seeing climate change (think “sinks”) arrive much more quickly than anticipated.
Bradford then looks at agricultural practices, and reports that the greatest energy savings could be achieved by:
- reduced use of petroleum-based fertilizers and fuel on farms,
- a decline in the consumption of highly processed foods, meat, and sugar,
- a reduction in excessive and energy intensive packaging,
- more efficient practices by consumers in shopping and cooking at home,
- and a shift toward the production of some foods (such as fruits and vegetables) closer to their point of consumption.
He looks at Brookside Farm, a 1-acre minifarm in Willets on what used to be school lawn, as an example of how small-scale, local farms could work to reduce our ecological footprint.
I posted a piece the other day about how grass seed production in the Willamette Valley has largely displaced food production. Bradford reports some fascinating data about grass:
There are three times more acres of lawns in the U.S. than irrigated corn. This means lawns – including residential and commercial lawns, golf courses, etc – could be considered the single largest irrigated crop in America in terms of surface area, covering about 128,000 square kilometers in all.
That means about 200 gallons of fresh, usually drinking-quality water per person per day would be required to keep up our nation’s lawn surface area. [Not to mention fertilizers and pesticides - ed.]
The 128,000 square kilometers of lawns is the same as 32 million acres. A generous portion of fruits and vegetables for a person per year is 700 lbs, or about half the total weight of food consumed in a year. Modest yields in small farms and gardens would be in the range of about 20,000 lbs per acre. Even with half the area set aside to grow compost crops each year, simple math reveals that the entire U.S. population could be fed plenty of vegetables and fruits using two thirds of the area currently in lawns.
You think we could find better things to do with Willamette Valley farm land?