Research On Evolution Of Embodied Carbon Emissions Flow Structure Among Chinese Industrial Sectors Based On Complex Network

Since the reform and opening up,China has achieved world-renowned economic development achievements,but at the same time it has also brought about energy shortages and environmental damage.At present,China has surpassed the United States to become the world's largest energy consumer and carbon dioxide emitting region,and the Chinese government is facing double carbon emission pressures from international and domestic sources.The industrial sector is not only an important engine for China's socio-economic development,but also a major source of carbon emissions,and it bears an important responsibility for carbon emission reduction.Due to the complex production and consumption activities between industrial sectors,a considerable amount of carbon emissions in the industrial sectors are not used to meet the demand for the final products of the sector,but flow into other downstream industrial sectors in the form of embodied carbon emissions,through the industrial chain and the circulation of intermediate products.Therefore,it is of great practical significance to formulate a scientific and reasonable industrial carbon emission reduction policy by comprehensively analyzing the flow structure and evolution characteristics of embodied carbon emissions between Chinese industrial sectors and identifying the position and role of each industrial sector in the entire industrial system.Based on the significance of the research on the embodied carbon emissions flow among Chinese industrial sectors,the embodied carbon emissions flow between Chinese industrial sectors is calculated based on the Input-output method.On this basis,according to the matrix of embodied carbon emission flows between industrial sectors and the theory of complexnetworks,with industrial sectors as nodes and the embodied carbon emissions flow between sectors as edges,embodied carbon emissions flow network between China's industrial sectors in 2005,2007,2010,2012,2015 and 2017 are constructed.Finally,with the help of complex network technical indicators,the structural characteristics of the embodied carbon emission flow network and its dynamic evolution are analyzed from the aspects of small-world characteristics,key sectors,community structure,key paths and so on.The research results show that:(1)During the study period,Electric and Heat Power,Metal Smelting and Chemical industry had large direct carbon emissions and embodied carbon emissions,and carbon emission reduction potential is also relatively large.The direct carbon emissions of construction and other service are small,while the embodied carbon emissions are large.(2)The embodied carbon emissions flow network among Chinese industrial sectors is a high-density network and has a small-world nature,indicating that the network is well-connected and accessible.(3)There are obvious clustering features in the network.30 industrial sectors are divided into 3-5 communities.From 2005 to 2017,the major industrial communities include construction-related industries(communities?),coal-related industries(communities?),manufacturing and service-related industries(communities?),and petroleum-related industries(communities?).The positions and roles of various communities were relatively stable during the study period: communities?and ?are absorption sites for embodied carbon emissions in the network,communities ?and ?are divergent sites for embodied carbon emissions in the network.During the study period,the modularity showed an overall downward trend,the number of communities changed from5 to 3,and the network integrity became stronger and stronger.(4)Electric and Heat Power,Fuel Processing,and Non-metallic Products are important "suppliers" of embodied carbon emissions,Construction,Other Service,Transport,Ware housing and Postal are important "recipients" of embodied carbon emissions,Non-metallic Products plays an important "bridge" role in the network,Non-metallic Products,Metal Products,General Equipment Manufacturing and other manufacturing related sectors have higher efficiency and independence in terms of the transmission of embodied carbon emissions,however,Metal Smelting and Chemical industry play multiple core roles in the network at the same time.In addition,the central role of important "suppliers" and "recipients" of embodied carbonemissions has become increasingly prominent over time.(5)The distribution of the edge-weights of the embodied carbon emission flow network over the years has a long-tail characteristic,which indicates that very few edges have great edge-weights.About 11.82%-15.68% of the edges carry 80% of the embodied carbon emissions.Over the years,the key flow path of embodied carbon emissions has changed little,and the embodied carbon emissions on key paths generally flow into the tertiary industry through the construction industry.