Wednesday, May 14, 2014

Vegetarians vs. omnivores: the battle since time immemorial

by Martta Paavola

We have to eat – there’s no way around it. And unless you’re growing potatoes in your backyard and keeping cows in your toolshed, cultivating your food is likely a huge burden on the environment. Conscientious consumers wish to know how to minimize their own impact, and it is said that a rather effective way of doing this is cutting back eating meat. How exactly does meat production compare to vegetable cultivation, and would the planet be better off if we all became celery-munchers and carrot-chewers?

The answer is more complicated than one might suspect. This is partly because there are numerous ways of assessing the impact that a certain type of food has on the environment, including the water it consumes, the land it requires or the waste it produces. But there is no dearth of research exploring this very issue, from all possible angles.

Environmental Working Group (EWG) did a lifecycle assessment of 20 different types of meat and vegetable proteins on the basis of how much CO2 the production of each emits. According to their findings, beef, lamb, pork and salmon are the worst offenders, but cheese is also right up there, meaning that dairy-consuming vegetarians are not entirely absolved. But the greenhouse gases emitted depend heavily on the fertilizers used, the differences in soil conditions, and the extent to which practices such as cover cropping and manure managements are implemented. One lettuce farm may be much less environmentally friendly than a neighboring one, depending on the farming methods.

Full lifecycle greenhouse gas emissions of various food products
(based on data from EWG)

An article in The Star suggests that instead of comparing meat with plants in terms of the greenhouse gases each generates, or the feed or fertilizer that goes into its production, the comparison should be done in terms of the calories that each item provides. For example, a kilogram of beef contains 2280 calories, whereas a kilogram of broccoli contains only 340 cal, meaning you would have to eat 6.7 kg of broccoli to get the same amount of calories. This requires a whole lot of nutrients, water and space to grow.

What the calorie-based approach fails to take into consideration, however, is the calories that went into producing that one kilogram of beef in the first place. Livestock are fed mainly corn and soy, and resources and land that has gone into the growing of these crops could have been used to grow food for human consumption, instead. To avoid this issue, some livestock is fed only grass and hay, which is generally considered a more sustainable choice.

Another thing that The Star article points out is that where your meat comes from counts. Should you eat a wild animal whose overpopulation does damage to its habitat, you will be doing a favor to the environment. Of course, this is not an actual solution, because no wild populations of animals could possibly sustain the numbers required by the demand for meat. A tragic example of a species once estimated to number in the billions, but hunted into extinction in the late 19th century largely for its meat, was the passenger pigeon. These North American birds once flew in flocks so large it took hours for them to pass, but once the massive commercial exploitation of the species started, their numbers plummeted, and the last known passenger pigeon died in 1914.

But the type of meat and its origin certainly play a part in how environmentally friendly it is, and these issues are often more complicated than seems at a first glance. The grass-feed diet, mentioned above, is better because it leaves the food crops for human consumption, plus grazing can sometimes be done in areas where no crops can be grown, thus providing more efficient use of our dwindling land resources. But in the stomachs of ruminant animals, grass and hay also produce more methane, which has 23 times the global warming potential of carbon dioxide; furthermore, the Food and Agriculture Organization of United Nations estimates that 20% of the world’s pastures have already been degraded by grazing livestock.

In the end, there are so many factors affecting one’s choice of diet that it is almost impossible to give any bite-sized advice. That doesn’t stop environmental groups from trying. The report by EWG boils down to a few basic things: get more of your protein from lentils, beans and tofu, consume only organic dairy products, waste less and buy only what you eat, choose chicken rather than beef, and try to at least have one meat-free day per week. Many big changes start from little ones.

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