Effects on the Environment

Agriculture is the world’s oldest and largest industry; more than one-half of all the people   in the world still live on farms. Because the production, processing, and distribution of food all alter the environment, and because of the size of the industry, large effects on the environment are unavoidable.

Agriculture has both primary and secondary environmental effects. A primary effect, also called an on-site effect, is an effect on the area where the agriculture takes place. A secondary effect, or off-site effect, is an effect on environment away from the agricultural site, typically downstream and downwind.

Major environmental problems that result from agriculture include deforestation, desertification, soil erosion, overgrazing, degradation of water resources, salinization, accumulation of toxic metals, accumulation of toxic organic compounds, and water pollution, including eutrophication.

Global Effects of Agriculture  

 Modern agriculture increases carbon dioxide in two ways. As a major user of fossil fuels, it contributes to the increased concentration of carbon dioxide in the atmosphere, adding to the buildup of greenhouse gases. Also, clearing land for agriculture increases the decomposition of organic matter in the soil, transferring the carbon stored in organic matter into carbon dioxide, increasing its concentration in the atmosphere.

Agriculture can also affect climate through fire. Fires associated with clearing land for agriculture may have significant effects on the climate because they add small particulates to the atmosphere.

Another global effect of agriculture results from the production of nitrogen fertilizer, which may be leading to significant changes in global biogeochemical cycles.

Agriculture affects species diversity. The loss of competing ecosystems (because of agricultural land use) reduces biodiversity and increases the number of endangered species.