China has but 7% of the world's arable farmland to feed 20% of the world's population. The math isn't good and it's getting worse by the day.
Fully one-third of China is now desert and that's spreading. From the Associated Press:
"In a problem that's pervasive in much of China, over-farming has drawn down the water table so low that desert is overtaking farmland. Authorities have ordered farmers here in Gansu province to vacate their properties over the next 3 1/2 years, and will replace 20 villages with newly planted grass in a final effort to halt the advance of the Tengger and Badain Jaran deserts.
"The relocation program is part of a larger plan to rein in China's expanding deserts, which now cover one-third of the country and continue to grow because of overgrazing, deforestation, urban sprawl and droughts.
"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.
"The battle against deserts is playing out across much of western China. Desertification has caused as much as $7 billion in annual economic losses, the China Daily reported.
"Over the past decade, Chinese deserts expanded at a rate of 950 square miles a year, according to Wang Tao of the Chinese Academy of Sciences in Lanzhou.
"'There are quite a few countries with this problem but none on the scale of China because it is so big,' said Lester Brown, president of Earth Policy Institute. 'You only have to go to northwest China and see that the numbers and size of dust storms are increasing.'
"Expanding deserts have contributed to a nearly six-fold increase in sandstorms in the past 50 years to two dozen annually, Wang said.
"Global warming will worsen the problem, as rising temperatures lead to widespread drought and melt most glaciers on the Tibetan Plateau, depriving lakes and rivers of a crucial water source, according to the U.N.-funded Intergovernmental Panel on Climate Change."