Causes of Climate Changes: Agriculture / Industrial Farming

Causes of Climate Change: Large Scale Agriculture / Industrial Farming

Agricultural activities, that is the cultivation of crops and livestock for food , contribute to greenhouse gas emissions in a variety of ways:

Nitrous oxide (N2O) - from fertilizer application to methods of irrigation and tillage. The EPA estimates that management of agricultural soils accounts for over half of the emissions from the Agriculture sector.Management of agricultural soils can also lead to emissions of carbon dioxide (CO2). The EPA includes these under a different category: under the Land Use, Land-Use Change, and Forestry sector.
Methane (CH4) produced by Livestock, (especially cattle) as part of their digestion. This accounts or almost one third of the emissions from the Agriculture sector. To put it bluntly, cows burp and fart methane. A lot.
Methane and Nitrous Oxide (CH4 and N2O) emissions from manure storage - The methods and the amount of exposure to oxygen and moisture can affect how these greenhouse gases are produced. Manure management accounts for about 13% of the total greenhouse gas emissions from the Agriculture sector in the United States.

Smaller sources of emissions include

rice cultivation, which produces CH4, and
burning crop residues, which produce CH4 and N2O

More national-level information about emissions from agriculture can be found in the agriculture chapter in the Inventory of U.S. Greenhouse Gas Emissions and Sinks.

Agricultural Emissions and Trends

In 2012, greenhouse gas emissions from agriculture accounted for approximately 9% of total U.S. greenhouse gas emissions.
Greenhouse gas emissions from agriculture have increased by approximately 19% since 1990.

One driver for this increase has been the 55% growth in combined CH4 and N2O emissions from livestock manure management systems, reflecting the increased use of emission-intensive liquid systems over this time period. Emissions from other agricultural sources have either remained flat or changed by a relatively small amount since 1990.