Livestock and the Environment FAQs

Livestock and the Environment


To begin, we will provide basic information on greenhouse gases and the relationship with beef cattle production.

What are greenhouse gases and what do they do?

A greenhouse gas (GHG) refers to a gas that absorbs heat from the earth's surface and prevents it from dissipating completely into the atmosphere, with some of the heat directed back towards earth. The reflected heat causes an increase in ground surface and water temperatures.
Carbon dioxide is the most abundant greenhouse gas followed by methane, nitrous oxide and other fluorinated gases.

What are agriculture's contributions to greenhouse gases?

Agriculture is responsible for approximately 8% of total greenhouse gases. The majorities of agricultural emissions originate from soil management strategies, enteric fermentation, energy use and manure management.

U.S. Greenhouse gas inventory with electricity distributed to economic sectors (EPA, 2013)
U.S. greenhouse gas inventory with electricity distributed to economic sectors (EPA, 2013)

What are beef cattle's contributions to greenhouse gasses?

Within agriculture, beef cattle are responsible for the largest amount of greenhouse gas emissions. These are predominately due to methane produced from enteric fermentation (the natural digestive process of ruminants). Ruminants have a stomach comprised of four compartments with the microbial community in the first compartment responsible for the breakdown of feed. Methane is produced by the microbes as a by-product and released from the animal through belching.

Methane is the second most abundant greenhouse gas so why is there an emphasis on reducing methane emissions?

Even though methane emissions accounted for only 9% of total greenhouse gas emissions in 2011, it traps greater amounts of heat than carbon dioxide. This results in an increase in global climate change.

How do ruminants produce methane?

Ruminant livestock have a special digestive system that enables them to consume unusable plant materials as a feed source. Methane is produced during the digestive process and emitted into the atmosphere.

What are the sources of agriculture greenhouse gases?

Land used for crop production and enteric fermentation by ruminants are the major contributors to total greenhouse gases in agriculture.

Pie chart - Energy use - 15%, Enteric fermentation - 28%, Manure management - 14%, Cropland soils - 30%, Grassland soils - 12%, other - 1%
Sources of Agriculture Greenhouse Gases
(Adapted from Animal Agriculture and Climate Change: Sources of Greenhouse Gases)