"The shifting sands have swallowed thousands of Chinese villages along the fabled Silk Road and sparked a sharp increase in sandstorms; dust from China clouds the skies of South Korea and has been linked to respiratory problems in California.
Since 2001, China has spent nearly $9 billion planting billions of trees, converting marginal farmland to forest and grasslands and enforcing logging and grazing bans.
The policy is driven in part by concerns over food, as farmland yields not only to the deserts but also to pollution and economic development. China has less than 7 percent of the world's arable land with which to feed 1.3 billion people -- more than 20 percent of the world's population. By comparison, the United States has 20 percent of the world's arable land to feed 5 percent of the population."