Got this link from Jeff a while ago: Walking to the shops 'damages planet more than going by car.'
The idea is that, assuming one re-consumes the calories one burns while disdaining a car in order to walk to a destination, the carbon emissions coming from the raising, slaughtering, and transporting your caloric food source actually outstrip the carbon emissions from burning the small amount of gasoline you would have burned to drive instead. The big greenwashed news: everything you thought about being a "green" citizen was a lie! Just drive baby, drive!
This article is extremely silly, either because the author didn't sum the book (How to Live a Low-Carbon Life) it draws from correctly, the author of the book (Chris Goodall) didn't have his thinking together, or both. The title is rigged and oversimplified merely to create sensationalism. Although meat consumption is extremely heavy on the greenhouse gases; what with the landspace required in raising the animals and the food for 'em, the CO2 in slaughtering packing and transporting, and the methane, 20 times more potent a GG than CO2, that cows...err, emit with regularity--there are still several, hummer-sized holes in the argument.
First is the simplicity of the one data point which drives the whole statement:
“If you walked [3 km] instead [of driving], 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."
When people need between 1500 and 3500 calories per day, 180 is hardly noteworthy, whether you eat beef or anything else. With obesity and/or weight-obsession being what it is, many people could stand to or would love to just not replace those 180.
Certainly it's not entirely helpful for me to say that calories burned by being more active should not be replaced, but this argument is negated by its oversimplification in another way as well. Pardon me for being one of those pushy holier-than-thou vegetarians, but is 100g of beef really the only way to replace 180 calories? The article was written for a British audience, a country for which a majority of most foods both animal and vegetable are shipped long distances--but beef was specifically chosen as the data point that arrived at the four-times-as-much touchpoint. I know some people do see meat-as-whole-meal, but they may often not be the people who are walking 3km instead of driving to begin with. The reality of the matter is that people do eat too much meat to curb our carbon emissions, but the one-to-one beef-for-calories argument is way too oversimplified. I want to see the carbon comparison for something besides carnivory.
Granted, on the isolated and rainy Great Island Monarch, many food choices make carbon emissions. The article is saying that life-cycle consideration are important. So important, in fact, that the failure of the author to include life-cycle costs in the thing he is comparing--the life-cycle cost of drilling for, refining, and shipping that gasoline, or the materials for your automobile, for that matter--is as glaring error in logic.
I haven't researched them, so I don't know what those life-cycle costs are directly, thus I can't say how they compare to the CO2 and methane of 100g of beef. Perhaps the author of the book, if not the article, has looked into them. However, they are not mentioned, and some critical thinking suggests that such an omission is hardly trivial. Drilling uses fossil fuels, and certainly removes any trees and greenery--natural carbon sinks--from the land in question. Refining the stuff is going to use some energy, to say the least. And fossil fuel isn't exactly Britain's great natural resource, either, so just as you're boating and flying and trucking in the meat and out-of-season fruits and vegetables, so are you flying and boating and trucking in the oil. Car parts are also mined, forged, assembled, and shipped all over the world.
Perhaps the carbon emissions from beef are still worse. But you can't make conclusive statements until you consider all of the evidence, especially when the whole premise of your argument is based on considering hidden factors.
So the article may have some food for thought in it (pardon the pun), but it's not actually saying anything particularly profound. In fact, considering what it has left out, it may not be saying anything new at all. If you want to save the environment, you're better off reducing your meat consumption AND walking 3 kilometers.