Zimbabwe's foremost land degradation expert has come up with a readily available solution for reversing the spread of deserts around the planet and slowing climate change in the process: He wants to let cows and sheep eat their way through the problem.

In a provocative appearance on the video blog Ted Talks, biologist Allan Savory said desertification of the world's grasslands may be releasing more carbon into the atmosphere than burning fossil fuels. Savory should know: He has been studying the spread of deserts for more than 50 years.

But the former revolutionary turned scientist recently came to a surprising conclusion about how best to bring back grasslands and in the process help address poverty and social breakdown in some of the poorest corners of the planet. He turned to holistic management of livestock like cattle and sheep, overriding his own belief that grazing animals had been part of the problem when it came to green, fertile lands widely becoming barren and dry.

That notion, Savory said, was dead wrong. He cited an experiment he conducted in the 1950s in the country then known as Rhodesia, when he helped exterminate more than 40,000 grazing elephants to protect land thought to be stressed and dying from their annual trampling rituals.

He called that project "the saddest and greatest blunder" of his life.

"We were once just as certain that the world was flat," Savory said on the Ted Talks appearance. "We were wrong then, and we're wrong again."

Savory said the annual rite of movement through a region by large herds actually protects the environment. A wildebeest migration in central Africa, for instance, eats up grasses as it moves along and leaves behind a protective layer of trampled dung, dust and soil.

Trying to mimic the roles of wild herds

That protective layer, it turns out, is vital for healthy soils that trap carbon, break down methane and produce more grasses every year to feed returning grazers. In turn, those herds feed predators like lions, cheetahs and, yes, human beings.

So Savory decided to mimic the great herds of old, which have died out in many regions or persist in far reduced numbers, with managed "strategic" herds of grazing vegetarians. The sheep and cattle picked for the project, if managed properly, would theoretically bring nature back to its normal cycle in semiarid regions where rains for part of the year are followed by long dry spells.

Savory said his experiments have worked, and he showed a number of before-and-after pictures as evidence during his talk. He thinks the same approach can be taken in the two-thirds of the planet that is rapidly desertifying, including parts of the American Southwest.

Fire has long been used as a means to kill woody vegetation in semiarid regions and restore soils, but Savory said that solution has never quite panned out because fire can strip land of its base layers, not to mention release carbon. So he turned to cattle and sheep.

"There was only one option left to climatologists and scientists, and that is to do the unthinkable: Use livestock bunched and moving as a proxy for former moving herds and predators," he said.

Savory's experiments with livestock have reversed degraded dry lands in Zimbabwe, Mexico, the Horn of Africa and Argentina, he said. He added that putting the same idea into motion in just half the world's troubled grasslands would result in bringing the planet back to preindustrial levels of greenhouse gas emissions.

"I can think of nothing that offers more hope for your planet," he said.

Click here to view the video.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500