Friday, February 06, 2009

Less meat...smaller footprint

photo by Sally Kneidel

Sally often says, when speaking to others about the impact of eating less meat, that what you eat is more important than what you drive. The UN document "Livestock's Long Shadow" says that our diet choices impact climate change more than transportation. I shared that with my Biology class and sensed some disbelief, so I decided to use, a website where you can caluclate your ecological footprint, as a way to convince them that this is true. Your footprint tells you how many worlds it would take to support the human population if everyone in the world lived just like you.

I worked through the footprint questions, choosing all of the default or "average" values as answers. The only answer that I intentially set away from the average, was my diet. First, I chose "top of the food chain - I eat meat, seafood, or dairy at almost every meal" as a description of what I eat. This trial resulted in a footprint of 7.04 worlds. I then repeated the questionnaire, changing only one thing - my diet from "top of the food chain" to "vegan". The footprint dropped to 5.24, a 26% reduction. Impressive!

I then repeated the footprint two times. Both times I let my diet description stay at "omnivore", the default setting, so food choice didn't vary. What I did change was the car I drive. Both times I chose 20,000 miles as the amount that I drive each year, but in one run I chose a "truck or SUV" as my car (this resulted in 7.34 worlds), and the other I swtiched to a hybrid (resulting in 5.99 worlds). The reduction this time was 18%.

Looks like the UN report is right! (Or, more likely, the footprint modelers used the report in writing their computer model.) I know I could have had my students read the report (it's on-line), but this was a much simpler way to get the point across. They had already calculated their footprint, so it was a result they could easily grasp. Most of the students had calculated their footprints to be in the 5-7 range. They were distressed and felt trapped a bit. As teenagers they couldn't easily change the house they live in or the cars their family drives. But they do have control over what they eat. Eating less meat offers an easy way to lower one's environmental impact.

By Ken Kneidel, PhD

Keywords:: ecological footprint effect of meat on environment environmental effect of meat livestock's long shadow impact of animal products


Unknown said...

I did the same thing with calculator a while back and got a very similar result:

Anonymous said...

It's awesome how you came up with that carbon-footprint experiment!

Glad I found this blog post, it's not easy to find other blogs talking about the greenhouse gas emissions from meat..Please check out my blog ( for more on this topic.

I agree it's not easy for teens / young people to easily lower their carbon footprint. With a small budget it might be hard to eat less meat too, when one is presented with few meat-less options.