Methane emission inventories for enteric fermentation and manure management of yak, buffalo and dairy and beef cattle in China from 1988 to 2009

Abstract

Large ruminant production systems (dairy, beef, buffaloes and yaks) in China have experienced significant changes during the last 30 years driven by increased demand for milk and meat consumption and discontinued use of beef cattle and buffaloes as draft animals. The present study aimed to evaluate the effects of these changes on methane (CH4) emissions from enteric fermentation and manure management in large ruminants in China. The emissions were developed using Tier 1 and 2 methodologies of the International Panel on Climate Change. The Tier 2CH4 emission for each species was a sum of emissions calculated from several groups based on their physiological states, e.g. milking cows, dry cows, sires and steers/heifers at various ages. Total CH4 emission inventory for dairy cattle, beef cattle, buffaloes and yaks in China increased gradually from 5530 to 6761Gg/year or 4514 to 5777Gg/year calculated using the Tier 1 or 2 method during the period of 1988–2009. This increase was driven by increased population and production of dairy and beef cattle (e.g. Tier 2CH4 emissions increased respectively from 125 to 1028Gg/year and from 2915 to 3689Gg/year). However, during the same period Tier 2CH4 emissions from buffaloes and yaks reduced from 860 to 593Gg/year and 614 to 467Gg/year, respectively. Beef cattle were main emitters which produced 63.8% of total emissions in 2009, followed by dairy cattle (17.8%), buffaloes (10.3%) and yaks (8.1%). There was a large difference in provincial contributions. In 2007, the 3 highest emission provinces (Sichuan, Tibet and Henan) each contributed 8.5–10.5% to national emissions, and the lowest 3 accounted for only 0.1–0.2% (Beijing, Zhejiang and Shanghai). The uncertainties associated with these inventories were discussed. These results provide benchmark information for Chinese authorities to develop appropriate policies and mitigation strategies to reduce carbon footprint in the large ruminant production sector in China.