Biogas in China

Guangxi in southern China. A fat, grunting sow feeds her piglets; they look plump and healthy. But things are not as jolly as they might seem. Over the next 12 months, this sow and her piglets will, according to one estimate, release 9 tonnes of carbon dioxide into the atmosphere through the methane generated by their droppings.

About one-third of the world's farmers - more than 210 million agricultural families - live in China. They own more than 9 billion cows, pigs and chickens which, according to China's Ministry of Agriculture, generate more than 3 billion tonnes of manure each year. All ready to expel more methane.

But despite being labelled by many as a major greenhouse polluter, the evidence on the ground is that millions of Chinese farmers are helping trim greenhouse emissions - by using pig manure (and more).

The Guangxi Zhuang Autonomous Region government, with help from the International Fund for Agricultural Development (IFAD), a UN agency, is actively supporting villagers to build simple yet effective biogas digesters that capture the expelled methane so farmers can use the gas for heating, cooking and lighting. The digester tanks also produce a rich fertilizer that improves crop yields and quality.

"What we are trying to do is convert that human and animal waste into biofuel," says Li Jingming, secretary general of the China