According to Robert and Brenda Vale, the environmentalist authors of Time to Eat the Dog: The Real Guide to Sustainable Living, feeding and caring for your pet pooch does as much harm to the planet as owning and operating an SUV. Growing the food necessary to feed a medium-sized dog creates roughly the same carbon footprint as driving a Toyota Land Cruiser 12,000 miles per year.

Which means if you’ve got two best friends waiting to lick your face you when you come home from the office — you know, so that they can keep each other company while you’re gone — you might as well put up a sign on your front lawn that says: “Earth Killer.”

This news is sure to sow dissension in the ranks of self-righteous greenies… many of whom cease lecturing the rest of us on the evils of our modern conveniences only long enough to snuggle up with Rover and Mr. Whiskers. (Cats have slightly less eco-impact than dogs… roughly equivalent to a Volkswagen Golf.) That is all to the good.

But the larger point made by the authors, architects who specialize in sustainable design, is more serious than their headline-grabbing title — namely, a genuine commitment to sustainability requires more than just singling out the usual bogeymen of the green movement. It requires hard sacrifice.

But are we prepared to trade in our cuddly pets for livestock animals whose meat we can harvest after they expire? For that matter, are we prepared for a world in which governments dictate to their citizens how many children they can have? Oh, and are we prepared to tell a billion Chinese and a billion Indians, anxious to escape the grinding poverty of their lives, that it’s better for Gaia if they forsake the creature comforts of the 21st century?

Just some thoughts to chew on… until Spot is done on both sides.