Decomposition of impacting factors of animal husbandry carbon emissions change and its spatial differences in China

Abstract: Animal husbandry greenhouse gas emissions account for 18% of total greenhouse gas emissions of all human activities, and have become one of the most important contributors to global greenhouse gas emissions increase. Using life cycle assessment (LCA) method, animal husbandry carbon emissions in the 31 provinces, municipalities and autonomous regions of China from 2000 to 2014 have been comprehensively measured. Based on logarithmic mean Divisia index (LMDI) method, the changes of animal husbandry carbon emissions were decomposed into the contributions from 5 factors, including animal husbandry production efficiency, agricultural structure adjustment, agricultural productivity gains per agricultural labor, urbanization and total population growth. Using the data of animal husbandry carbon emissions measured by LCA, the driving effects of the 5 factors on animal husbandry carbon emissions change were measured from the spatial and temporal perspective. The results showed: 1) Total amount of animal husbandry carbon emissions in China increased from 137.423 million tons to 150.563 million tons from 2000 to 2014, and its average annual growth rate was 0.654%, of which the carbon emissions from gastrointestinal fermentation of livestock and manure management systems were the 2 key sources, accounting for 65.58%- 73.23% of the total amount of animal husbandry carbon emissions. 2) No matter from spatial or temporal perspective, animal husbandry production efficiency improvement was the most important factor to restrain the sustained growth of the animal husbandry carbon emissions; the increase of agricultural productivity gains per agricultural labor was the most important factor to promote the sustained growth of the animal husbandry carbon emissions, which was particularly outstanding in prairie pasturing areas and pasturing areas in major grain producing areas, however, the effect of the increase of agricultural productivity gains per agricultural labor on animal husbandry carbon emission growth was limited in developed areas. Population growth was another important factor to promote the growth of the animal husbandry carbon emissions, especially to the developed areas with massive population influx and the ethnic minority areas in most western part of China. 3) The increase of urbanization level ranked the second to restrain animal husbandry carbon emissions from 2000 to 2014, while the effect of agricultural structure adjustment on animal husbandry carbon emissions changed from positive to negative, and this characteristic was particularly obvious in eastern-central China with higher animal husbandry efficiency.