Sunday, July 10, 2005

"Cut global warming by becoming vegetarian"

From a referral by Jorn Borger's Robot Wisdom (the original "weblog"), here is a summary of an article in this month's Physics World:
Global warming could be controlled if we all became vegetarians and stopped eating meat. That's the view of British physicist Alan Calvert, who thinks that giving up pork chops, lamb cutlets and chicken burgers would do more for the environment than burning less oil and gas.

Writing in this month's Physics World, Calvert calculates that the animals we eat emit 21% of all the carbon dioxide that can be attributed to human activity. We could therefore slash man-made emissions of carbon dioxide simply by abolishing all livestock.

Moreover, there would be no adverse effects to health and it would be an experiment that we could abandon at any stage. "Worldwide reduction of meat production in the pursuit of the targets set in the Kyoto treaty seems to carry fewer political unknowns than cutting our consumption of fossil fuels," he says.
This summary leaves a lot of questions, of course, but without a subscription they will have to go unanswered for now. For example, I think carbon is meant, not carbon dioxide, because the significant greenhouse gas that "livestock" emit is methane, CH4, which in fact is much more effective in contributing to the greenhouse effect than CO2 is.

The summary also mentions only the animals themselves. But there is also a tremendous amount of carbon emissions from the energy used to grow and harvest food for them. It requires 40 times more energy to produce a calorie of beef than a calorie of soy. Only 10% of the plant protein they eat is in the animals' flesh when it is eaten by humans, so it is a rather wasteful expenditure of energy.

Another issue is the destruction of rain forest (an area about the size of Connecticut every year) to create grazing land for beef. Trees, of course, are a crucial carbon sink. After deforesting much of the northern hemisphere, we should be restoring forests, not ravaging the southern hemisphere as well.

The environmental impact doesn't stop at carbon emissions. It takes 200 times more water to produce a pound of beef than a pound of wheat. Feedlots and slaughterhouses are responsible for more water pollution than all other industrial and household sources combined. Eighty percent of the corn and 95% of the oats grown in the U.S. go to feeding animals that will be slaughtered for food. Eighty-seven percent of U.S. agricultural land is devoted to the animal-flesh industry.

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