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Estimates for rangeland cover vary between 31 and 51% of the land surface of the Earth (Allen-Diaz, 1996; WRI, 2000); the upper estimate includes tundra grasslands. Rangelands support human populations at low densities (Batchelor et al., 1994) on almost every populated continent. The latest figures suggest a population of at least 938 million people—or about 17% of the world's population (WRI, 2000).
The World Resources Institute report (WRI, 2000) assesses the food/fiber production and biodiversity of rangelands as "fair" (on a scale of excellent, good, fair, poor, and bad) over the past 20-30 years, but the underlying biological ability of the rangelands to continue to support that productivity and biodiversity is declining, suggesting that productivity and the biodiversity assessment may not hold in the future. Livestock production in rangelands is estimated to be 65 Mt in 1998 (WRI, 2000), with global meat production estimated at 225 Mt. Nineteen percent of the world's centers for plant diversity are found in rangelands. For carbon stores, the WRI assessment of rangelands is "good"; again, however, the underlying ability is judged to be declining (WRI, 2000). IPCC (2000) estimates carbon stores in rangelands as 84 Gt C in vegetation (of a global total of 466 Gt), 750 Gt C in soils (of a global total of 2,011 Gt). WRI (2000) gives a range of 405-806 Gt for total carbon stores. Both estimates suggest that rangelands are important carbon stores.
Many of the people in rangelands rely on fuelwood for their daily cooking and heating needs. Estimated fuelwood use as a percentage of total energy use in 1993 for countries dominated by rangelands is about 60-90% (e.g., in Afghanistan, Mozambique, Swaziland); the world average is 6%, and Africa's average is 35% (WRI, 1998).
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