Climate Management Issues

49The Role of Greenhouse Gases

in which to digest their food. These include cattle, sheep, goats, camels,

bison, and musk ox. In their digestive system, their large fore- stomach hosts

tiny microbes that break down their food. This process creates methane gas,

which is released as atulence. Livestock also emit methane when they belch.

In fact, in one day a single cow can emit one-half pound of methane into the

air. Each day 1.3 billion cattle burp methane several times per minute.

Methane is also a by-product of natural gas and decomposing organic mat-

ter, such as food and vegetation. Also present in wetlands, it is commonly

referred to as “swamp gas.” Since 1750, methane has doubled its concentra-

tion in the atmosphere, and it ...