Food and Water
In this section, we review major environmental impacts of agriculture, including land use, energy consumption, and greenhouse gases. We review farming's water needs separately.
Agriculture is the largest land use impact that humans exert .
Since 1961, world cropland area has been steadily growing, while pasture land may have peaked .
Following are estimates of land use required by particular crops.
Agriculture, including upstream energy to manufacture equipment, fertilizers, and pesticides, accounts for about 4% of world energy consumption.
Wealthier countries tend to have higher crop yields and higher energy inputs, suggesting a tradeoff between land use and energy consumption in agriculture . In 2011, energy accounted for over 30% of corn, sorghum, and rice production costs , underscoring the importance of energy as a factor in food affordability.
The growing of crops is just a portion of energy consumption in the larger food system.
Agriculture is responsible for about 20% of world greenhouse gas emissions.
Other aspects of the world food system, such as packaging and transportation, contribute 15-25% of the emissions detailed above .
Following are estimates of greenhouse gas emissions from select foods.
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