Science Forums 2

[TeleMad]

Originally Posted by Qfwfq

This produces a lot of methane which is better for the environment than other hydrocarbons, as well as alcohol. More hydrogen and less carbon. The methane is usually just dispersed into thin air.

Methane released into the atmosphere is far from innocuous.

While manure-derived methane is proving very useful, the methane cows burp is causing problems. Methane is a greenhouse gas and, in the atmosphere, contributes to global warming. Cows burp an abundant supply of it every day — about 280 liters per animal (in other words, the average cow could fill 140 two-liter soda bottles with gas daily). Unfortunately, burped methane is more difficult to collect, with the result that about six million metric tons of it float blissfully up into the atmosphere every year. And that's just from herds in the United States. (Worldwide, ruminant livestock — including cattle, sheep, goats, and buffalo — produces about 80 million metric tons of methane per year, accounting for 22% of anthropogenic methane emissions.)

Methane is second only to carbon dioxide in the list of greenhouse gases. According to the Intergovernmental Panel on Climate Change, it's 21 times better at trapping heat in the atmosphere than CO2 (a fact that can be attributed to the larger size of CH4 molecules). The six million tons of methane that North American cows burp annually are equivalent to 36 million tons of carbon dioxide.
(http://www.riverdeep.net/current/200...cowpower.jhtml)