Which do you think takes a bigger toll on the environment, owning a dog, or owning an SUV?

So asks Arnold Kling on his excellent blog and there has been a merry and fasincating discussion on the site ever since. I have never even considered buying a new SUV (my ever-reliable Citroen has done only 20,000 miles in seven years) but I do have an eye on getting a puppy sometime soon and I hadn’t even considered whether I should consider the environmental impact!

As I hurtle through middle age, I am far more likely to spend an hour or two jogging and playing with my dog than I would watching tv; the marginal benefits of canine ownership and companionship are substantial to dog lovers, witness how many of them are prepared to pay huge vets bills to prolong their pets lives.

Kling makes the rather provocative statement ‘I personally have nothing against dogs. But it does seem to me that environmentalism inevitably points toward a policy of extermination of pet dogs. Unless environmentalism is simply hatred of industry.’ - presumably to send dog owning bloggers into a state of apoplexy!

What do you guys think?