What's the Deal with Cattle and Methane?

On my recent vacation, my dad asked me about the science regarding cattle and methane in connection with global warming. As much as I would like others to think that I know everything, I unfortunately do not, so I could only give a vague answer. I've since done a little poking around on the internet to find out more, and I figured I would post it here for anyone interested.

Here is a two-minute summary:

Methane (CH4), of course, is the main component of natural gas and is produced in a variety of places in nature. Like carbon dioxide, methane is a greenhouse gas because it traps heat in the atmosphere. Before the year 1750, methane levels in the atmosphere averaged around 700 parts per billion; now the level is around 1,700 parts per billion.

Ruminant livestock such as cattle, sheep, and goats have a special digestive system that allows them to break down plant material. Methane is a by-product of their digestion (enteric fermentation), and is released into the atmosphere. Livestock account for around 20-30% of human-related methane production; in the U.S. livestock and landfills are the top two human-related sources of methane.

Efforts at reducing livestock methane emissions are focused on better efficiency, genetics, and nutrition, especially in the beef industry.

For more information, see the following links to the EPA: here, here, and here.

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