畜牧业“碳排放”到“碳足迹”核算方法的研究进展

全球变暖趋势日益加剧,不仅影响农业可持续发展,而且威胁到人类生存。畜牧业碳排放因其在农业碳排放中乃至全球碳排放中占比较大而日益备受关注。准确核算畜牧业碳排放是制定切实可行的碳减排政策的前提,也为我国在气候变化下承担共同但有差别的减排责任提供话语权。本文基于研究范式的演进,对畜牧业碳排放到碳足迹核算方法的研究发展进行了系统梳理,研究表明,在学者的不断研究与质疑下,畜牧业碳排放到碳足迹的核算方法经历了从OECD核算法、IPCC系数法到生命周期法与投入-产出法的演变与完善,学术界认为区域异质性、养殖规模与管理方式均影响碳足迹;散养比规模化养殖产生更多的碳排放,舍饲比户外放牧排放更多的碳。畜牧业碳足迹核算能够更加全面地反映畜牧业全生命周期的碳排放情况,但由于研究假设、研究方法及研究样本等差异导致不同区域、不同畜产品的碳排放核算结果存在不确定性。运用生命周期法和投入-产出法对欧盟成员国畜牧业碳排放的核算结果基本一致,但运用IPCC系数法和全生命周期法对中国畜牧业碳排放核算中,牛、猪和羊的碳排放量排序结果不尽一致。鉴于核算结果的差异性,本研究对不同核算方法的起源、最早采用时间、特点、局限性等方面进行了归纳总结,并建议后续研究探讨基于生命周期评价的畜牧业碳足迹研究边界的延伸性,标准化畜牧业碳排放或碳足迹核算,避免学者重复核算畜牧业碳排放,以便深入展开畜牧业碳排放其他方面的研究。

Review of research from carbon emissions to carbon footprint in livestock husbandry

The increasing trend of global warming both affects the sustainable development of agriculture and threatens human survival.Livestock have caught growing concern for the large proportion in agricultural carbon emissions.Accurate calculation of livestock carbon emissions is the precondition of feasible reduction policy.It also provides voice for distinct responsibility of China in climate change.Based on the research paradigm evolution,this article presents the research development of livestock from carbon emissions to carbon footprint.The results show carbon emissions methods for livestock have experienced the OECD method,the IPCC coefficient method,the life cycle assessment (LCA) method and input-output method.Scholars thought the regional heterogeneity,the scale of farming and the management mode all affect the carbon footprint.Carbon emissions of livestock grazing are more than large scale livestock breeding.Shelter feeding has more carbon emissions than outdoor grazing.Carbon footprint assessment more fully reflects the whole life cycle carbon emissions of livestock husbandry.However,due to the differences of research hypothesis,methods and samples,there are uncertainties on carbon emissions assessment results of different regions and animal by-products.Based on LCA and input-output methods,livestock carbon emissions of the European Union are basically identical,but it is different in China by the whole LCA and IPCC coefficient method in cattle,pigs and sheep.Therefore,this study makes the comparison of different methods in the origin,the earliest time used,characteristics,limitations,etc.The study also recommends the extended boundary of livestock based on LCA and standardized carbon footprint of livestock.Only in this way can the scholars avoid repeating accounting carbon emissions of livestock and expand further research in this field.