Walking vs. Driving: Which is the Better Choice?
By NikkiJade • Jun 4th, 2008 • Category: Case Studies
To walk or to drive? That is the question for some. Indeed the environmental impacts of our daily choice to walk or drive as a form of transportation have always been in question, but have seen increased debate in recent times. The controversy was stirred with high-profile media claims that walking is worse for the environment than driving, based on the idea that a person who engages in physical activity will require a larger amount of calories, and will therefore consume more food, which in turn releases carbon emissions in its production.
The claim was explored by environmentalist Chris Goodall, who conducts a study of the emissions of driving versus walking for a 1.5 mile roundtrip in his book How to Live a Low-Carbon Life. Goodall, who is a proponent of reducing greenhouse gas emissions, comments that his intent is not to encourage driving, but rather, “to draw attention to the carbon intensity of modern food production, particularly of meat”.
He concluded that to replace the calories of walking 1.5 miles at a moderately fast 3.0 mph pace requires about 120 calories. He connects this to dietary needs required in replacing these calories, such as a cup of milk (emitting methane on the dairy farm and carbon dioxide from the delivery truck) or 2.4 oz/67 g of top sirloin. Goodall then compares the data using existing calculations, and discovers that it is almost equal and in some cases more efficient to just drive this 1.5 mile journey.
While Goodall’s purpose may not have been to encourage driving, the presentation of his study in the media, such as the Times (U.K) and the New York Times, seemed to overlook his original focus of bringing awareness about the carbon intense food production. Instead, the issue was highlighted instead with claims that driving is better for the planet.
The controversial headlines led to the Pacific Institute’s, Michael Cohen and Matthew Heberger, to explore Goodall’s study in a little more detail. In a thorough analysis, they discovered that the numbers behind the assertion were based only upon greenhouse-gas-intensive food–such as all beef. According to the Institute, “When more realistic assumptions about the walker’s varied diet are taken into consideration, the conclusion is actually reversed. If an average American diet is used, walking—even for a group of four—makes more sense for the environment than driving.”
With these “more realistic” assumptions in mind, Cohen and Heberger conducted a case study of their own, entitled: “Driving vs. Walking: Cows, Climate Change, and Choice”. Like Goodall’s work, their study also compares the lifecycle greenhouse gas emissions associated with driving, bicycling, and walking a given distance, except this time on diets of steak, ground beef, 2% milk, nonfat milk, an American vegan’s diet, and a typical American’s diet.
The study works with a given distance, 1.5 miles, with all caloric expenditures for an 189-pound, 35-year-old male, and car based calculations for a 2,853 pound Nissan Sentra. They then examine the emissions using the varying dietary trends. They certainly agree with Goodall’s assertion that high meat content diets are higher in carbon emissions. However, when exploring the typical American diet where beef and pork contribute about 10% of total daily caloric intake and dairy products about 7%, (statistics they determine using existing studies), they find that walking is the better choice by a factor of four.
Ultimately, these two studies are pretty bare bones with regards to accounting for all the factors of production that go into producing fuel or food, not to mention the car itself. Of course, this is not necessarily by accident, as to complete a case study on all aspects of manufacturing for the means of transportation would require vast amounts of time and resources. These studies are great for their own purpose of bringing awareness about the carbon intense process of food production, as well as the actual environmental differences, big or small, that one can have by making simple lifestyle choices.
Furthermore, the coverage of the events and interpretation of the results demonstrated how quickly data can be manipulated to present a certain point, particularly by the media. It also displayed how significantly results of a study can vary based on the factors assumed. The environmental impacts of our choices call for shrewd analysis not just from the scientists conducting the study, but also from the recipients of the information. In this case, the saying “take everything you hear with a grain of salt” was completely applicable.
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Creative Commons Attribution: “Walking to work, redux“, Flickr, preciouskhyatt
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NikkiJade is Co-Founder of TheGreenRocket.com, an indoor cycling instructor and Honours Economics and Global Studies student at Wilfrid Laurier University with a focus in econometrics, environmental and development economics, and ecotourism. Nicole is passionate about everything green, as she believes nature’s services can be used more efficiently to generate sustainable development in all areas of the world.
Twitter: @NikkiJade
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Interesting study, just goes to show everyone how important is is to believe half of what you hear : ) and to ensure all research is picked apart.
At fist I immediately thought, how ridiculous, of course waling is better for the environment. Then I read on. Very interesting indeed. Thanks for the great environment awareness!!
All I know is that I enjoy putting food in my mouth more than I enjoy putting gas in my car.
I can second that Bill
! Now when I drop the bills down on a full tank I can only think about the amazing meal that would have paid for… even for TWO people WITH wine…
I can at least enjoy the money I spent on the food. I rarely enjoy the money I’m spending on gas.
Food is definitely more satisfying, but I have to note that part of the outcome of these studies was the point that some foods are just as much an issue in terms of carbon emissions as gas consumption — so while you may enjoy it more, what you eat still has consequences for the environment (and not to mention your health with regards to some foods…)
On a side note: my thoughts on fuel efficiency — fuel efficient cars may just mean people are going to drive more kilometres. I’m all for walking and better public transportation systems.
[...] Walking vs. Driving: Which is the Better Choice? (4) NikkiJade: Food is definitely more satisfying, but I have to note that part of the outcome of these studies was the point that some foods are just as much… NunoXEI: I can second that Bill
! Now when I drop the bills down on a full tank I can only think about the amazing meal that would have paid for…… Bill: All I know is that I enjoy putting food in my mouth more than I enjoy putting gas in my car. Protesters Fail to Disrupt Australia Kangaroo Cull (2) NunoXEI: I’m all for this as well. If people don’t eat kangaroo meat I think some specialty cook out in Oz (or the world) needs to think of a… jmccallum: Do people eat kangaroo meat? I have no doubts that kangaroo population needs to be continuously monitored and checked with events such as a… [...]
[...] looking for the article again I also found a counterview/follow up to it entitled “Walking vs. Driving: Which is the Better Choice?“ which alters the calculations done based on a different diet and concludes that walking is [...]