Khartoum, SudanMohammed Al-Murawih remembers thinking what a joy it would be if the desert was always green. He wouldn’t have to lead his camels on many mile-long migrations in pursuit of pasture, and he wouldn’t run the risk of losing livestock in lean years. Never again would his family go hungry.

So when, about a decade ago, a host of brilliantly lush shrubs began to protrude from the sand and rocks around his home village in North Kordofan, to the southwest of Khartoum, the Sudanese capital, Murawih was jubilant. At last some proper vegetation, he thought, and at last some major sustenance for his livestock, who’d been looking increasing emaciated after frequent droughts. His fellow herders were similarly enamored of this new