Friday, October 18, 2013

Carbon intensity of foods

Like food?
OK, dumb question.

Concerned about what's in the food you eat?
Have a look at this recent post to learn how to determine what's inside that package of your favorite bread or yogurt.

Interested in minimizing your food's carbon footprint?
Here's a simple but thought-provoking video that helps explain the energy, or carbon intensity (CO2 equivalent), needed to produce a kilogram of various common food items.

In brief, foods like potatoes that don't produce methane during cultivation (no large animals involved!) and don't require much tilling or fertilizer will tend to have lower carbon footprints. The more inputs, transport, and animal feed and waste associated with producing your food, the higher its carbon footprint.

You can, of course, apply the criteria to other foods as well. Typically, eating locally (less transport), eating lower on the food chain (veggies), and, of course, growing your own food all reduce carbon dioxide emissions.

However, trying to "green" your diet is not simple. For example, green beans from Kenya are commonly sold in Britain when British beans aren't in season. "[Kenyan beans] are grown using manual labour - nothing is mechanised," says Professor Gareth Edwards-Jones an expert on African agriculture at U.K.'s Bangor University. "They don't use tractors, they use cow muck as fertiliser; and they have low-tech irrigation systems in Kenya. They also provide employment to many people in the developing world. So you have to weigh that against the air miles used to get them to the supermarket."

waste going to a landfill compost
photo: Liz Martin/SourceMedia Group News
Clearly, it's complicated.

Producing food not only emits carbon dioxide and methane, it also converts natural vegetation (and associated animal communities) to an agricultural monoculture, loses soil through erosion from downslope tilling, diverts water to irrigate fields and produce energy, and pollutes water and soil microbe communities with nutrients and chemicals.

This doesn't even get into the sustainability of producing our food and the energy used to deal with food waste...

Help! Any tips on eating with minimal negative environmental impacts?

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