AGW in general > Walking the walk

Meat Consumption and Global Warming

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Lynn Shwadchuck:
Here are a few key points gleaned from Vaclav Smil on this topic. The whole chapter from his book Population and Development Review is available here:

Animal foods provided generally less than 15 percent of all dietary protein, and saturated animal fats supplied just around 10 percent of all food energy for preindustrial populations.

In 1900 just over 10 percent of the world’s grain harvest was fed to animals, most of it going to energize the field work of draft horses, mules, cattle, and water buffaloes rather than to produce meat. By 1950 the global share of cereals used for feeding reached 20 percent, and it surpassed 40 percent during the late 1990s (USDA 2001a). National shares of grain fed to animals now range from just over 60 percent in the United States to less than 5 percent in India.

In macronutrient terms, meat now supplies 10 percent of all food energy and more than 25 percent of all protein in rich countries, while the corresponding shares are, respectively, merely 6 percent and 13 percent for the poor world.

Grain harvests in highly carnivorous countries, or in countries producing feeds for export, must be multiples of those needed for direct human consumption, and the food demand of a modern urbanite has to be a multiple of the area claimed by an overwhelmingly (or entirely) vegetarian subsistence peasant.

At least 80 percent and as much as 96 percent of all protein in cereal and leguminous grains fed to animals are not converted to edible protein.

An overwhelmingly vegetarian diet produced by modern high-intensity cropping needs no more than 800 m2 of arable land per capita. A fairly balanced Chinese diet of the late 1990s, containing less than 20 kg of meat, was produced from an average of 1,100 m2/ capita; the typical Western diet now claims up to 4,000 m2/capita.

Adequate water supply is now widely seen as one of the key concerns of the twenty-first century. Few economic endeavors are as waterintensive
as meat production in general and cattle feeding in particular.

The modern separation of large-scale livestock production from field agriculture makes it impossible to recycle the large volume of wastes produced by thousands of animals concentrated in huge feedlots or sties.

Meat production is also a significant source of greenhouse gases. Enteric fermentation in bovines is a major source of methane (CH4), a greenhouse gas whose global warming potential (GWP, over a period of 100 years) is 23 times that of carbon dioxide (CO2) during the first 20 years of its atmospheric residence (CDIAC 2001). And denitrification of nitrates in synthetic fertilizers and in animal manures releases nitrous oxide (N2O), a greenhouse gas with a GWP nearly 300 times that of CO2 (CDIAC 2001). But because meat production requires heavy inputs of agrochemicals and inputs of fuel and electricity for manufacturing and operating field and barn machinery, its most important impact on global warming is, nevertheless, due to CO2 generated from the combustion of fossil fuels used to make these additional inputs. CO2 is also released from the burning of tropical forests that are being converted to pastures.

.... end of clipped quotes....

Only a globally implemented carbon tax that reflects the true cost of this food will change deeply embedded eating habits, I believe. However, it does help to set an example of an alternate way of feeding ourselves. This has been my little soapbox for about three years now.

A more enjoyable read on this topic is Michael Pollan's The Omnivore's Dilemma.


The below facts are from Angela Fritz's blog at Wunderground.  She has started a series on ways to conserve water usage, this first post showed how much water can be saved by just not eating beef two days a week.  Since AGW/CC are going to lead to water shortages worldwide, I thought that this was very pertinent to this topic.

"According to the Water Footprint Network, it requires about:
• 1,799 gallons to produce one pound of beef
• 468 gallons per pound of chicken
• 576 gallons per pound of pork
• 880 gallons per gallon of milk

Copious volumes of water are needed to grow feed for animals, and then additional water is used to care for animals, process meat, and distribute and sell animal products. By contrast, raising fruit, vegetables, and grains requires a fraction of the water:

• Carrots require only 6.5 gallons of water per pound
• Apples, nearly 100 gallons per pound
• Peas, 10.2 gallons per pound
• Blueberries, 13.8 gallons per cup
• Potatoes, 119 gallons per pound

By avoiding red meat for two days this week, you can reduce your water footprint by about 953 gallons. By continuing this practice, you can save nearly 50,000 gallons of water in a year."

Lynn Shwadchuck:
Interesting, Old L., that carrots are so efficient. They were my best garden crop last summer and they've done well in our first-year root cellar. I plan to grow more this year.

Another point here, for those who worry about getting enough protein without so much meat, is that it has been shown that vegetables, not just seeds and legumes, provide more protein than previously thought. Even potatoes are quite nutritious. If you Google The China Study, you'll get a lot of negative commentary all over the internet from one element of the grass-fed beef lobby, but it's an awesomely well-researched and argued book.

Also, Smil's chapter makes it clear that milk and eggs are quite efficient users of inputs.

Lucas Durand:
My family and I have been reducing our meat intake for a while now.
While I think I'd have a hard time giving up meat completely, I haven't found it that hard to cut back significantly.
One thing I've noticed is that by cutting back on the amount of meat we eat, we save money that can be used to buy better quality local meat for the occasions that we do eat meat.

Lynn Shwadchuck:
Yes, we find a locally produced artisan sausage or a free-range organic chicken is a treat that we can feel good about. Even when I was raising my boys on daily meat dishes, I made a lot of soups and served them with fresh bread. No need to be a stickler.

Supporting local small farmers is a great way to plan for a future that might be quite different than what we're used to. Wendell Berry's very worried about food production and warns urbanites that they should expect to have to get their hands dirty.


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