China's falling water tables and overgrazing in the country whose landmass is already one-third desert are resulting in a giant dust bowl across northern China, converting large swathes of arable land to desert and triggering sandstorms whose impact carries across the Pacific. "There are huge areas there that were once productive grassland that are now desert," says Lester Brown of the Earth Policy Institute. Sandstorms were this year exacerbated by droughts across northern and western China, that were also contributing to forest fires raging in Inner Mongolia and Heilongjiang. Water tables were diminishing in north China, causing rivers and land to dry out and affecting grain harvests, especially of wheat, which is grown predominantly in the drought-stricken northern provinces.