On the metaphysics of a footprint

In this week's edition of The New Yorker, reporter at large Michael Specter writes thoroughly about the nuances of carbon footprints.  Through stories of nascent action by corporations, economics as well as food, Specter both confirms and challenges our intuitions about a low carbon world.  It's certainly worth a read.  I've shared a short excerpt below.  You can find the full piece here.

The environmental burden imposed by importing apples from New Zealand to Northern Europe or New York can be lower than if the apples were raised fifty miles away. "In New Zealand, they have more sunshine than in the U.K., which helps productivity," Williams explained.  That means the yield of New Zealand apples far exceeds the yield of those grown in northern climates, so the energy required for farmers to grow the crop is correspondingly lower.  It also helps that the electricity in New Zealand is mostly generated by renewable sources, none of which emit large amounts of CO2.  Researchers at Lincoln University, in Christchurch, found that lamb raised in New Zealand and shipped eleven thousand miles by boat to England produced six hundred and eighty-eight kilograms of carbon-dioxide emissions per ton, about a fourth the amount produced by British lamb.  In part, that is because pastures in New Zealand need far less fertilizer than most grazing land in Britain (or in many parts of the United States).  Similarly, importing beans from Uganda or Kenya--where the farms are small, tractor use is limited, and the fertilizer is almost always manure--tends to be more efficient than growing beans in Europe, with its reliance on energy-dependent irrigation systems.