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Eliza Barclay

Eliza Barclay

Guest Blogger

Johns Hopkins Center for a Livable Future

Biogas digesters for industrial agriculture in China

Biogas Digester for 8,000 pigs in Zhejiang Province

Biogas Digester for 8,000 pigs in Zhejiang Province

While researching meat consumption and production in China last month, I visited two farms that have installed large-scale biogas digesters. These intriguing, bulbous contraptions capture animal waste, prevent pollution, make use of a renewable source of energy (methane), and transform the icky stuff into a rich fertilizer for crops. Biogas digestion  has not been widely used by farmers in the U.S. (for reasons I’m still trying to understand) but has long been part of China’s rural energy strategy: the government estimates that today some 35 million small farmers have small-scale digesters installed in their backyards, a figure reflecting decades of work to distribute them. China has been called “biogas capital of the world” and now is making another big push to encourage large-scale farms, which are a key part of the government’s agricultural intensification strategy, to install them too.

How does it work? Well, biogas is a byproduct of the fermentation of waste. Micro-organisms go to work in anaerobic conditions, though I understand some digesters operate under aerobic conditions. As the bacteria work their way through the waste, they kill off the pathogens, and release a mixture of gas heavy on methane with a touch of carbon dioxide. That gas can then be used to power a stove, a farm, and can even go back into the grid if there’s enough of it and the transmission lines are set up.

In my conversations with Chinese farmers and even officials from the Ministry of Agriculture it was difficult to get a handle on exactly how many biogas digesters are in use on industrial-scale farms in China. This is an important question as small farms are increasingly replaced by big farms and farmers grapple with mounting piles of waste that can pollute waterways and contribute to dead zones in the ocean. (According to the Ministry of Agriculture, the volume of livestock and poultry manure increased from 3.8 billion tons in 2000 to 4.8 billion tons in 2008 and is responsible for much of the phosphorus and nitrogen discharges into waterways.) But an article recently published in China Daily cites a discouragingly low number: less than one percent of the 4.2 million large-scale farms for pigs, cattle and chicken use biogas digesters to dispose of livestock waste. I learned that some provincial governments are offering a number of incentives and subsidies — up to 50 percent of the cost of installation in some places — but apparently this coupled with the myriad environmental benefits of using the digester is not enough to lure most farmers.

Promoting the low-carbon life (and food choices) in Beijing

A few months ago, I described a segment on the Chinese state television’s English channel about food as part of the “low carbon life” in China. The program explored this new lifestyle through the burgeoning vegetarian restaurant scene in Beijing, and a handful of consumers who claimed to eschew meat out of consideration for the environment. It was a bit narrow in focus but suggested that some people are making this connection, and reducing their meat consumption as a consequence.

The question of whether the Chinese are indeed considering the climate impact of their food choices is one of many I am asking during my travels in China this month on my Innovations Grant. Meat consumption is rising at a fierce pace in China; according to the most recent figures from the FAO,  beef consumption in China will increase by 1.5 million tons and sheep meat by more than 1 million tons within the decade (both products are benefiting from a current hotpot craze, supplanting ever-popular pork in many urban restaurants). This is a phenomenon that has many experts (especially those in the West) from the food security, public health, food safety, animal welfare, and environmental communities in a tizzy. I can say that two weeks in  I don’t perceive most urban consumers in Beijing as pondering the environmental costs of their beloved pork-filled dumplings or roast duck or beef-garnished noodles or food production in general. Read More >

Vegetarian and low-carbon diets emerging in China?

Yesterday I spotted a segment on the China Central Television (CCTV) web site describing the vegetarian restaurant scene in China and the emergence of a low-carbon diet trend. Meat consumption has risen dramatically in China in the last few decades; research by Barry Popkin at the University of North Carolina at Chapel Hill and others has shown that as income has increased in China, adults proportionally increase their intake of animal protein.  But there are apparently some Chinese who are choosing a vegetarian diet in part because of the environmental impact of meat production.

A manager of a vegetarian restaurant tells CCTV that the average age of his customers is under thirty-three years old. “They’re particularly interested in the concept of eating for a low carbon life,” the manager says. “Young people are more environmentally aware and more open to new ideas. They love to be in the trend or lead the trend.”

It seems that China may also have its own future Meatless Mondays advocate: Liao Sha, owner of four restaurants in Beijing, says she thinks people should give up meat once a week. But even if vegetarian restaurant owners and managers are eager for people to go vegetarian at least once a week, the reasons for going meatless seem to be shifting. There were once 80 vegetarian restaurants in Beijing, many likely tied to Buddhist traditions, but the number has dropped to 50. Sha believes vegetarian dining can make a comeback, in part because “the vegetarian diet is aligned with the Chinese philosophy of harmony between the body and nature.” And if Chinese increasingly understand the climate as a key part of nature under threat, then the low-carbon diet may show up as a real trend, albeit difficult to measure.

The segment is part of a series called My Low-Carbon Life, which includes episodes on transportation, water conservation, and clean energy in China. Watch the low-carbon eating video here.