China's new strategy is for giant pig farms to sell carbon credits to finance their waste treatment facilities. Western environmental groups have questioned whether a surge of Chinese pig farms offering to sell carbon credits to foreign buyers really needed the credits to build biogas facilities, so China has created its own carbon-trading mechanism for pig farms with relaxed standards. Since the Chinese carbon market is only for large scale CAFOs (Concentrated Animal Feeding Operations), Chinese news media are assuring the public that industrialized farms are "green" too.
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| A pig farm operated by Muyuan Foods. The dark rectangle in the back is the manure collection lagoon. Source: Xinhua News Agency. |
In December 2025 China's Ministries of Environment and Agriculture jointly issued a methodology for China's Certified Voluntary Emission Reduction (CCER) covering utilization of biogas from livestock manure at large-scale pig farms. According to the document large-scale farms constructing anaerobic biogas reactors to treat swine farm manure and wastewater can be validated as voluntary greenhouse gas emission projects because they prevent methane emissions that would otherwise occur during liquid storage. The methane recovered through these biogas projects can be utilized for power generation, biogas supply, or the production of biomethane, thereby reducing carbon dioxide emissions by displacing fossil fuels. A second methodology covered concentrated treatment of agricultural wastes such as crop stalks and straw or manure delivered by small and medium pig farms.
China is the world's largest producer of agricultural waste. Ten years ago China produced 3.6 billion metric tons of livestock waste, of which 40% was untreated or unutilized. That's surely an under-estimate considering that China's meat output has risen 16% since the estimate was made: from 87 million metric tons (mmt) in 2016 to 100 mmt in 2025. Pork output is up 12% (including an upward revision after the 2017 agricultural census). According to another estimate the volume of crop residues grew from 753 mmt to 864 mmt between 2011 and 2022. Since the 1980s, Chinese officials have launched numerous campaigns to produce biogas and organic fertilizer from livestock manure--mainly to clean up severe water pollution problems--and to utilize crop residues that had created air pollution from burning in rural stoves or in fields after harvest.
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| Water pollution is China's main concern in cleaning up hog waste. This is a map of chemical oxygen demand from livestock production (a measure of water pollution) from about 10 years ago presented by an agriculture ministry analyst. The level is high except in mountainous, grassland and desert areas. |
Last December, a Chinese green energy company explained that the reduction in CO2 emissions achieved by the pig farm biogas projects can be traded on the national voluntary greenhouse gas emission reduction trading market in China, thereby generating economic benefits for owners. Methane gas captured from swine waste collected on the farm is used to generate electricity that displaces fossil fuels.
Western environmentalists have always viewed CAFOs with disdain, but China's scaled-up farms--often in multi-story enclosed buildings--are the vanguard of its "green" agriculture campaign. An article in Chinese media earlier this month sought to prove CAFOs can be environmentally friendly by describing the "decarbonization" efforts of Muyuan Foodstuffs, the world's biggest CAFO. Muyuan is the prototype factory farm, turning out 78 million hogs in 2025 (more than most countries) from an integrated feed manufacturing, breeding, fattening, and slaughter chain at dozens of sites sprawled across the country. The article praised Muyuan for reducing carbon emissions to 0.883 kg of CO2e per kg of pork--said to be 26% below international benchmarks. It was claimed that Muyuan reduced carbon emissions by more than 6 million tons across its entire supply chain for the year. Specifically, the article claims that Muyuan minimizes use of high-carbon raw materials, uses unheated housing, uses power from biogas and photovoltaic cells, minimizes waste through precision feeding and air filtration, and uses waste heat recovery in slaughter and processing.
The article claimed that a closed loop cycle between livestock and crop cultivation transforms the "unidirectional consumption" structure of agricultural systems. The one example given celebrated use of swine waste in place of chemical fertilizers on rice farms in Jilin Province, but China exports rice from that region and none of it is used as pig feed. There is a clear geographic separation of the expansion of China's hog production and expansion of China's corn production--the country's largest crop which is mostly used for animal feed.
China may have created its own hog farm carbon trading because their eagerness to sell carbon credits overseas ran into a brick wall of skepticism from Western environmental groups. A Dutch article in 2024 investigated Europe-based airline EasyJet's purchase of carbon credits from Muyuan to satisfy a French Government mandate to offset emissions on new routes. At the time four of Muyuan's projects had been certified by an external organization with 40 more in the queue--an unprecedented number of requests for carbon offset certifications. The article displayed satellite images showing that Muyuan had already incorporated biogas digesters in the construction of its pig farms years before EasyJet paid for carbon credits. Muyuan's claim that carbon credits were needed to finance reductions in pig farm emissions was further undermined by citing the company's large profits and government subsidies for the facilities. A Chinese government action plan that called for construction of pig-farm biogas facilities undermines the "voluntary" nature of Muyuan's emissions reductions.
A December 2025 article in China's Environmental Protection News promoting the Chinese methodology explained, "large-scale pig farms are subject to stringent biosecurity regulations and are required to construct on-site biogas facilities for treatment of concentrated waste streams."
The Dutch article also linked Muyuan's importation of soybeans to deforestation. This critique may explain why Muyuan was ahead of other Chinese companies in publicizing its reduction of soybean meal via incorporation of low-protein diets that feature use of amino acids. The Dutch publication, however, said it received no comments on the article from Muyuan or the carbon credit certification organization.
This week Dialogue Earth highlighted a study "Evidence of non-additional pig manure offset projects" by San Francisco-based CarbonPlan that investigated inconsistencies in Chinese pig farm applications for a greenhouse gas emission reduction for manure management. The program had received only 34 project proposals during 2006-2021 before being overwhelmed with 96 applications from Chinese pig manure projects during 2022-24. This study found a failure to document cost savings from generating heat and electricity from biogas, and it concluded that only 31 percent of the projects would be "non-additional" based on proper accounting.
Since additionality of the projects is hard to establish, the new Chinese methodology issued in December 2025 waives the additionality requirement. The Environment Ministry's 2023 general document on voluntary greenhouse gas reduction does include the additionality requirement. However, item 6.2 of the December 2024 document on pig manure projects cites their high cost of construction, operation and maintenance as a barrier to investment in declaring, "Projects that meet the criteria set forth in this document are exempt from the requirement to demonstrate additionality." China's Environmental Protection News explained that additionality is waived because internal rates of return are so low. An article describing the Chinese methodology explained that the exemption from "additionality" lowers the threshold for participation and facilitates entry of a greater number of projects to the carbon market.
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| This is the methane capture facility on a hog farm in 2017. In the background is a cover that captures methane like a giant balloon.  Pig farms are often built on mountains or "waste" land not designated for grain production. |
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