Don’t you hate it when someone takes something you’ve said out of context and uses it to support the exact opposite point of view? Chris Goodall, British environmentalist and author of How to Live a Low-Carbon Life has found himself in that situation. Recently, in How Virtuous is Ed Begley, Jr, John Tierney of the NY Times mentioned that Goodall had calculated that it’s worse for the environment to walk 1.5 miles to the store and replace those calories with a glass of milk than it is to just drive there. Most of the commenters assume that Goodall is encouraging people to drive and lambast him under that assumption.
Like many assumptions, it’s totally off-base. Goodall isn’t using the numbers to say that driving is good; he’s trying to show that the current state of food production is terrible. When driving a mile and a half is better than drinking a glass of milk, something has gone terribly wrong. In Goodall’s view, it’s the whole factory farming system.
This analysis, and the similar one about biking at BicycleUniverse.info assumes that you’re buying into that system. If you’re buying local organic milk (or beef, for that matter), then you cut out a lot of carbon emissions (for pesticides, etc.) and reduce others (transportation).
As an aside, the assertion made on the BicycleUniverse.info page that cost implies energy (“Since the costs of water and energy for laundry are much lower than [the cost for driving], they can’t possibly use more energy than driving.”) drives me crazy. There’s almost no relationship between cost and energy density. Maggie and I have this argument all the time when we’re bemoaning the price of fuel. I’ll complain that gas is $3.30 a gallon and then Maggie one-ups me by saying that diesel is up to $4.50. Once you take into account the fact that diesel is more energy dense, though, Maggie spends about half as much as I do to go as far. As a more extreme example, burning wood that you cut yourself is very cheap but very polluting. It’d be much better to use solar to heat your shower water, even though it’s much more expensive.
But back to the original question. When is walking worse than driving? When your food drives out to meet you.