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Food and Soil

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"Ninety percent of the world's food is derived from just 15 plant and 8 animal species." 2

"Biodiversity - and especially the maintenance of wild relatives of domesticated species - is essential to sustainable agriculture."1

75% of the genetic diversity of crop plants has been lost in the past century. 1

"In 1960, when the world population numbered only 3 billion, approximately 0.5 hectare of cropland per capita was available, the minimum area considered essential for the production of a diverse, healthy, nutritious diet of plant and animal products like that enjoyed widely in the United States and Europe."3

Increases in grain production brought about by irrigation and synthetic fertilizer-pesticide inputs have peaked and begun declining. As consumption surpasses production, the world's stocks of stored grain have been falling relative to each year's use. When supply can no longer meet demand, free market price competition may starve the poor.

"Nitrogen production requires a large and affordable supply of natural gas." 5
"Natural gas is a key feedstock (up to 90 percent of the total costs) in the
manufacturing of nitrogen fertilizer for which there is no practical substitute... Nitrogen
fertilizer prices tend to increase when gas prices increase." 4

For more information on the world's supply of energy and natural gas, see the Energy Supply page.

"10 kcalories (kilogram-calories or 'large calories') of exosomatic energy are spent in the U.S. food system per calorie of food eaten by the consumer. Put another way, the (US) food system consumes ten times more energy than it provides to society in food energy." 6

About 2 billion hectares of soil, equivalent to 15 per cent of the Earth's land area (an area larger
than the United States and Mexico combined), have been degraded through human activities.1

"Over the past 40 years, approximately 30% of the world's cropland has become unproductive."2

"During the past 40 years nearly one-third of the world's cropland (1.5 billion hectares) has been abandoned because of soil erosion and degradation." 7

"About 2 million hectares of rainfed and irrigated agricultural lands are lost to production every year due to severe land degradation, among other factors." 8

"It takes approximately 500 years to replace 25 millimeters (1 inch) of topsoil lost to erosion. The minimal soil depth for agricultural production is 150 millimeters. From this perspective, productive fertile soil is a nonrenewable, endangered ecosystem." 3,9

1. World Summit on Sustainable Development 2002, "A Framework for Action on Biodiversity and Ecosystem Management",
2. "Food, Land, Population and the U.S. Economy", Pimentel and Giampietro, Nov. 1994
3. "Soil as an Endangered Ecosystem", David Pimental, Bioscience; Nov 2000
4. US GAO report: "Natural Gas: Domestic Nitrogen Fertilizer Production Depends on Natural Gas Availability and Prices", Oct. 2003,
5. The Fertilizer Institute,
6. "The Tightening Conflict: Population, Energy Use, and the Ecology of Agriculture", Pimentel and Giampietro, 1994,
7. "Food, Land, Population and the U.S. Economy, Pimentel and Giampietro, Nov. 1994
8. World Bank: "Land Resources Management", 11ByDocName/
9. "Population Growth and the Environment: Planetary Stewardship", Pimental, Dec 98,
10. UN World Water Development,