Air Emissions and Animal Agriculture

Greenhouse gases

Most people are concerned about reducing greenhouse gases, but do you know what they really are? Below are some common questions and answers related to greenhouse gases and animal agriculture.

What is a greenhouse gas?

Greenhouse gases are gases that trap radiation in the atmosphere and ultimately tend to lead to the warming of the planet. Although radiation can enter the atmosphere, the greenhouse gases make it more difficult for the radiation to be released again. This is good and bad—we need some energy to be trapped so that the planet stays warm enough to live on, but too much trapped energy could ultimately make the earth uninhabitable.

What are the most common greenhouse gases?

The most common greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide and fluorinated gases (HFCs and PFCs). All but the fluorinated gases enter the atmosphere through natural processes as well as from humans. Fluorinated gases are only created through human activities.

Carbon dioxide is created every day, simply by exhaling. It also comes from burning fossil fuels (oil, natural gas and coal) to obtain energy. Many other chemical reactions occur in our daily lives produce carbon dioxide. However, it is also removed from the atmosphere, as plants consume it.

Methane is the primary enhancer of the greenhouse effect. It is produced in many organic processes, through agriculture and the decay of wastes. The production and transportation of fossil fuels also results in methane emission. Since 1750, methane levels in the atmosphere have increased by 150%. It is also 21 times more effective at warming than carbon dioxide, although it has a much shorter chemical lifetime, as it goes through chemical reactions commonly called “sinks”.

Microbes in the soil emit nitrous oxide naturally. However, much of the nitrous oxide in the atmosphere comes from human processes. Agriculture and industrial human activities are primary sources of emissions, with agricultural soil management being the leading contributor. It is 296 times more effective at warming than carbon dioxide.

Fluorinated gases are synthetic, industrially produced gases, specifically, hydrofluorocarbons (HFCs), chlorofluorocarbons (CFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6). Although they are produced in smaller quantities, they are very powerful greenhouse gases. They are “ozone-depleting substances” (ODS) and under the Clean Air Act, are progressively being replaced.

How much does animal agriculture effect these emissions?

These gases are emitted from animal feeding operations, as well as many other agricultural operations. Methane is the greatest concern in animal agriculture followed by nitrous oxide. Although these operations range in the amount of greenhouse gases produced, they do not produce the most. Many other human-related activities greatly contribute to greenhouse gas levels in the atmosphere. Additionally, the earth has a naturally fluctuating temperature cycle. It has sped up, though, with the amount of greenhouse gases being produced.

Last Updated 10/31/2011