Thursday, September 29, 2011

Fighting Climate Change in the Fields

Graze your way to sustainability.
The centerpiece of Savory’s work is the 2,630-hectare Dimbangombe Ranch in northwestern Zimbabwe near Victoria Falls, home to his Africa Centre for Holistic Management. In the hot, dry, depleted landscape of this region, “the rains are not what they used to be” is a frequent refrain. But Dimbangombe looks as though it’s been uniquely favored by the rain gods. It has lush, varied grasses, flowing rivers and streams, and thriving livestock—some four times the number of neighboring ranches. Thanks to the renewed flow of the Dimbangombe River, elephant herds no longer have to travel to pools but can water on the river. Women who used to walk as much as five kilometers daily for water now have it available in their communities. Dimbangombe has become productive and vibrant while its neighbors, and similar environments around the globe, are turning to desert. How? “Two things: we brought in increased cattle numbers with holistic planned grazing, and [we] minimized the fires,” says Savory.
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Desertification—and associated problems such as flooding, wildfires, and water shortages—can be seen as a symptom of the carbon cycle gone awry, says Savory. In the same way that plants need animals, as seen in the relationship between ruminants and grasses, soil needs plants. “For soil to form, it needs to be living, and to be living, soil needs to be covered,” says Australian scientist Christine Jones. Without a cover of plants in various stages of growth and decomposition, much of the carbon oxidizes and enters the atmosphere as CO2.So soil carbon has huge implications for climate change. Rattan Lal, Distinguished Professor of soil science in the School of Environment and Natural Resources at Ohio State University, estimates that soil-carbon restoration can potentially store about one billion tons of atmospheric carbon per year. This means that the soil could effectively offset around one-third of human-generated emissions annually absorbed in the atmosphere. Building soil carbon would also enhance food production; and, because carbon-rich soil holds significantly more water than its dried-out counterpart, it would help to secure watersheds and protect against flooding and drought.

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