01/03/2008

Taking the Car: Good for the Environment?

John Tierney writes:
I came across an interesting challenge to the notion that taking short trips in a car is bad for the planet. This challenge comes from Chris Goodall, the author of “How to Live A Low-Carbon Life.” Mr. Goodall (...) questions how much good is being done by eliminating short trips by car. In fact, he says that in some circumstances it’s better to drive than to walk.

How can that be? Because Mr. Goodall takes into account something that a lot of environmentalists don’t: the human energy expended in averting fossil-fuel use. “Walking is not zero emission because we need food energy to move ourselves from place to place,” he writes. “Food production creates carbon emissions.” Now, you could argue that most people are oveweight and so could use the exercise anyway, but that doesn’t mean that they’re not going to consume calories to replace the ones they’ve burned. (...)

If you walk 1.5 miles, Mr. Goodall calculates, and replace those calories by drinking about a cup of milk, the greenhouse emissions connected with that milk (like methane from the dairy farm and carbon dioxide from the delivery truck) are just about equal to the emissions from a typical car making the same trip. And if there were two of you making the trip, then the car would definitely be the more planet-friendly way to go.

These results would vary, of course, depending on exactly what kind of car you’re using and what kind of food you eat (...). Michael Bluejay, who’s done some number-crunching at BicycleUniverse.info, says that walking is actually worse than driving if you replace the calories with food in the standard American diet and if the car gets more than 24 miles per gallon. He calculates that bicycling is a win for the environment because it’s 117 percent more efficient (in calories expended per distance) than walking is (...)

I don't have any of the necessary expertise to say anything about the veracity of these claims. But it is certainly an interesting thought to ponder. And I'm saying this as someone who likes walking and hates driving.

2 comments:

Bill said...

I would think that his so called number crunching takes for granted that the cars they are driving meet the minimum EPA standards, when these standards are not being enforced correctly for older cars in Most states. People are hanging on to cars longer and when they start smoking a little bit or even a lot in some cases they can continue to drive them and produce 10 times the pollution of a car that meets standards. How many states actually check emissions during state inspections.

Some states do not even require inspections, or if you are in a state like Louisiana, the inspection is nothing but another source of income, and the checks can be completed by just about any service station, or used car dealer who wants to make an easy buck.


This study lacks realism imo.

LemmusLemmus said...

Possible, I don't know.

I think it's an admirable approach, however, for not just assuming that walking=zero emissions because people expand energy and want to recoup that energy, which means eating food, and producing and transporting food means emissions.

As I said, I can't really say anything about how valid the conclusion is, but the premise certainly seems to be. If you really want to go into this, you'll have to look at the original reports, which I'm probably not going to.