Human World

Christopher Weber finds environmental cost high for beef

Researchers at Carnegie Mellon have found that eating less red meat and more chicken can help cut back on the greenhouse gas emissions now implicated in climate change.

Christopher Weber: When the bacteria in the cows’ stomachs digest food, they produce a gas called methane. Methane is a very potent greenhouse gas – it’s about 20 times more potent than CO2.

Christopher Weber and his colleagues work in what’s called a ‘life cycle assessment’ – figuring out the effects that a product has on its environment across its life. Cows, said Weber, are environmentally expensive.

Christopher Weber: The second big difference is that to produce one calorie of beef requires a lot more grain than to produce one calorie of chicken. It actually takes about twice as much grain to make a pound of beef as it does to make a pound of chicken.

Then, of course, there’s the manure factor.

Christopher Weber: The amount of manure coming out of a cow happens to be a lot more per pound of meat than the amount coming out of chicken. When manure degrades it releases two very potent greenhouses gases.

Weber said that, in general, producing food, including red meat, creates far more greenhouse gas emissions than the vehicles used to transport it. He said if you gave up a day each week of red meat and dairy, it would have the same impact as driving 1,500 miles less in a year.

Christopher Weber: The point we’re trying to make is not that eating locally is bad, per se, but that if you’re trying reduce the greenhouse gases associated with your food, it’s easier to do that by shifting away from some of the red meat and dairy products you’re eating towards something else than it is to go locally, just because the production side is so important.

Weber stressed that this whole analysis was done in terms of an ‘average person’s’ diet, but there is no true ‘average person.’ He said that how much an individual can affect greenhouse gas emissions by reducing red meat in the diet depends on a variety of factors, including each person’s overall diet and how much he or she needs to drive in the course of a year.

Our thanks to:
Christopher Weber
Carnegie Mellon

October 18, 2008
Human World

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