HOW much is that doggy in the window? Waggly tail or not, owning a pet comes at a far higher cost than you might imagine. As you watch a large dog bounding out of the back of an SUV, you might mentally reprimand the owner for their choice of vehicle. You would do better to save your indignation for their choice of pet. Because, as we report on page 46, the ecological footprint of our companion animals can dwarf that of even the most gas-guzzling cars. Man’s best friend, it turns out, is the planet’s enemy.

According to the authors …