I just saw a kinda disturbing article on fark.com and wondered what you would think of it. Could walking really be worse of the environment than driving?
When I read your question, I assumed that there was no way the article had any credibility... that it was written by an angsty high school student who was sick of people telling him what to do. But I was wrong, and that is scary.
Someone took the results of a scientific study on how inefficient our food production system is, did some really bad math, and then found themselves a glorious headline that would send shock waves throughout the blogosphere. You could call it sensationalism...I just call it evil.
Here's the "scientific" basis for their thesis:
"Driving a typical UK car for 3 miles [4.8km] adds about 0.9 kg of CO2 to the atmosphere ... If you walked instead, it would use about 180 calories. You'd need about 100g of beef to replace those calories, resulting in 3.6kg of emissions, or four times as much as driving."
Now I hope we can all see some gaping holes here, but maybe not all of them at first glance. So let's go through the five I came up with one by one.Most obviously, this assumes that 100% of the calories we use to walk come from beef. Actually roughly 75% of the calories most people burn come from plants (usually in the form of carbohydrates.) Plant calories are much less energy intensive to create. This leaves out Atkins dieters...but I hope they're offset by vegetarians.
Second, We need to pick our battles in this war. As both driving and eating inevitably add to the amount of CO2 in the atmosphere, these are both issues that we should be working on. But if we go 100% I'dl rather remove cars than exercise from my lifestyle. Not because it's better for the earth, but because it's better for me.
Third, we have the supposed correspondence between exercise and consuming food. Yes, if you exercise, you'll have to eat food to replace those calories, but the obesity epidemic is a testament to the fact that, frankly, most people eat because they want to, not because they need to.
Forth is probably the least obvious hole...but it might turn out to be the most important. Walkers don't travel thirty miles to go to the grocery store, but drivers do. Walkers opt for the corner grocer over the Wal-Mart. Driving doesn't encourage waste because just because it's inefficient. It also exponentially increases the amount of ground we can cover, creating sprawling cities and destroying local economies. Even if walking produced four times more CO2 emissions per mile than driving, walking reduces the number of miles traveled for most errands by ten to forty times.
Fifth, and this really is a huge omission, the study counts every piece of CO2 produced in the creation of the cow, but it only counts the carbon produced by burning the gasoline for the car. That'd be like only counting the CO2 that we exhale while walking. The hidden carbon costs of automobile travel are gigantic, more than double the final emissions for the car. They include the cost of mining and smelting the steel, pumping the oil, shipping the oil, refining the gasoline, shipping the gasoline, creation and maintenance of roads, construction of the car, etc etc. To leave out these costs while counting every drop of fertilizer sprinkled on a cow's pasture is extremely foolish and, frankly, disappointing.
So, in short, walking is better for you and the world than driving is. Biking, being even more energy efficient than walking, however, is indeed better for the Earth. However, the point of the original study rings true. Our food production system is foolishly inefficient and unhealthy. It must be reformed in order for this to become a healthy and sustainable world. And for more on that, I suggest Bill McKibben's Deep Economy.