What they’ve discovered is astonishing. According to researchers at the University of Michigan’s Center for Sustainable Agriculture, an average of more than 7 calories of fossil fuel is burned up for every calorie of energy we get from our food. This means that in eating my 400-calorie breakfast, I will, in effect, have consumed 2,800 calories of fossil fuel energy. (Some researchers claim the ratio is as high as 10 to 1.)
But this is only an average. My cup of coffee gives me just a few calories of energy, but to process 1 pound of coffee requires more than 8,000 calories of fossil-fuel energy — the equivalent energy found in nearly a quart of crude oil, 30 cubic feet of natural gas or about 2 1/2 pounds of coal.
I am not sure how my environmentally conscious friends can justify their coffee consumption.