Dynamic Life Cycle Carbon Budget Assessment Of China’s Wood-based Panel Industry Based On The Carbon Neutrality Goal

On September 22,2020,President Xi Jinping solemnly announced in the general debate of the 75th session of the United Nations General Assembly that“China will strive to peak its carbon dioxide emissions by 2030 and work towards achieving carbon neutrality by 2060”.The doctoral dissertation on“Dynamic life cycle carbon budget assessment of China’s wood-based panel industry based on the carbon neutrality goal”is a methodological research result to achieve this strategic goal.It is also the research report of the National Social Science Foundation’s key project“Research on the Composition and Early Warning Mechanism of China’s Forestry National Carbon Pool in Response to Climate Change”.As a pillar of China’s forestry industry,the wood-based panel industry not only achieves comprehensive utilization of wood resources,but also delays the release of carbon sequestered in forest biomass for decades or even centuries later.Wood-based panel products are mainly used in the construction and furniture industries,and their replacement of highly energy-intensive products and fossil energy products effectively relieves the pressure of emission reduction.In the process of low-carbon transition of the wood-based panel industry,how to measure the contribution of China’s wood-based panel industry to carbon emissions and carbon removals,and how to make the optimal choice of emission reduction paths are important questions to be addressed in this study.The wood-based panel industry is the most visible link in the“forest-wood products”chain in terms of net greenhouse gas（GHG）emissions to the atmosphere and mitigation of climate change impacts.In this study,it necessary to empirically analyze the resource inputs and environmental outputs of each link in the wood-based panel industry chain,and to explore the carbon budget of the entire industry.In order to do this,the dynamic life cycle carbon budget assessment model must be accounted for.Life cycle assessment（LCA）has become the main tool to measure the environmental impact of the wood-based panel industry chain.This study firstly systematically evaluates the life-cycle carbon budget,the dynamic changes and its influencing factors of China’s wood-based panel industry from 1990 to 2018,covering three subsystems:forest carbon budget,wood-based panel life-cycle and wood-based panel substitution.Secondly,this study provides a list of material inputs and environmental outputs for the entire life cycle of plywood,fiberboard and particleboard,reveals the characteristics of carbon emissions and their relationships in each segment of China’s wood-based panel industry.Thirdly,this study proposes a methodological system for dynamic life cycle assessment,and explores the optimal management scheme for China’s wood-based panel industry in a carbon neutral manner.The specific work and innovation points of this study are as follows.Firstly,based on the characteristics of the wood-based panel industry chain,we construct a“carbon constrained industry chain structure optimization system”.This paper explores the emission reduction pathways of the structural optimization system of the wood-based panel industry chain from the perspective of social science.This study starts from the Industrial Economics,and uses the comprehensive and mufti-disciplinary knowledge of Forestry,Economics of Climate Change,Circular Economy,Management Science and Resource Science to enhance the understanding of the interactions between forest management,wood-based panel production and waste management system with empirical results,and to demonstrate and clarify the potential synergy opportunities of each life cycle The thesis has a new blend of disciplinary knowledge.Thus,this study is characterized by a new integration of disciplinary knowledge.Secondly,the misconception of immediate carbon neutrality of forestry biomass is demonstrated and corrected,and the scientific application of climate neutrality is expanded.Carbon neutrality only considers greenhouse gases,while the influence of climate neutrality is not only greenhouse gases,but also radiation effects,which are more complex but better reflect the substantial climate impact of the industry chain.In this paper,the theoretical basis of carbon budget accounting is established by considering both“carbon neutrality”and“climate neutrality”goals through an improved dynamic life cycle assessment model.Therefore,this study is a new breakthrough in academic theoretical perspective.Thirdly,the shortcomings of traditional life cycle theory and methods are systematically reviewed,and improvement paths are proposed for the application of life cycle assessment methods that incorporate time parameters.The linear relationship of“activity-emissions-emissions impact assessment”is extended on the basis of the traditional LCA model.By introducing time-dependent characteristic functions instead of steady-state characteristic factors in the impact assessment,a dynamic and non-linear model is established,including economic mechanisms and climate neutralization time（ecosystem recovery time）,which improves the accuracy of climate impact assessment of the wood-based panel industry.Therefore,this study has a new exploration of methodologies.Fourthly,the dynamic life cycle assessment model of the wood-based panel industry is constructed based on the coupled“forest-wood-based panel”system.The model integrates the forest carbon analysis module,the wood-based panel life cycle module and the substitution benefits module.The model includes the subsystem of forest carbon income and expenditure analysis in the forest ecosystem,as well as the techno-system of carbon emission from fossil sources,carbon income and expenditure from biological sources and alternative emission reduction.More importantly,the model breaks through the limitations of traditional static LCA that ignore the time factor and biogenic carbon factor,and enhances the systemic nature of the existing industrial carbon emission measurement models,which can better provide emission reduction suggestions for climate action in the man-made board industry chain.Therefore,the research results have a new value of applicability.The main findings of this study show that:（1）Carbon budget results.The cumulative carbon removal of China’s wood-based panel industry from 1990 to 2018 was 339.77 Mt CO₂-eq（million tons CO₂-eq）,of which plywood and particleboard exhibited net carbon sinks with cumulative carbon removals of 402.72 and 225.35 Mt CO₂-eq,respectively.While fiberboard exhibited net carbon sources with cumulative carbon emissions of 288.31 Mt CO₂-eq.From 1990 to 2018,China’s wood-based panel industry reduced the radiative forcing by 2.39E-03 W·m^-2（watts per square meter）cumulatively,of which plywood and particleboard contributed to climate cooling,reducing radiative forcing by 3.62E-03 and 3.09E-03 W·m^-2,respectively,and fiberboard contributed to climate warming,increasing by 4.32E-03 W·m^-2 of radiative forcing.（2）Industry chain carbon emissions.The on-site production stage is the largest GHG emission source,accounting for 65.03%,88.39%and 76.46%of the total carbon emissions of plywood,fiberboard and particleboard,respectively,followed by the wood raw material acquisition stage,accounting for 7.96%,0.65%and 1.66%,respectively.The transportation stage accounts for 7.62%,0.68%,and 1.64%,respectively.Relatively speaking,the waste disposal of products consumes the least amount of energy,accounting for 1.51%,0.25%and 0.67%,respectively.（3）Industry chain carbon removals.The alternative emission reduction subsystem has the largest contribution,with initial alternative emission reduction benefits of-1750.32,-1930.53 and-1801.80 kg CO₂-eq（negative values indicate net GHG emission reduction）for plywood,fiberboard and particleboard,respectively.Due to the decay of gases and the uptake by carbon sink systems such as land,the substitution benefits of the three panel products are reduced to-665.63,-819.06 and-764.45 kg CO₂-eq by 100 years.（4）Carbon emission reduction pathways.Extending the rotation period of poplar plantation to 15 years can advance the carbon neutrality target by two years,and the emission reduction contribution increases by 210 Mt CO₂-eq;the carbon emissions from fossil energy generated by plywood,fiberboard and particleboard in the on-site production stage account for 65.03%,88.39%and 76.46%of the total carbon emissions,and increasing the proportion of forest biomass energy consumption is more beneficial to the emission reduction efforts;reducing the annual 1%alternative emission reduction factor by 1%per year,the cumulative carbon removal is 387.71 Mt CO₂-eq,which increases 47.95 Mt CO₂-eq relative to the baseline scenario emission reduction;when the methane released is treated through all landfills and recovered for energy use,the cumulative carbon removal is 2135.27 Mt CO₂-eq,which is 6.28 times of the baseline scenario emission reduction contribution.Finally,the thesis puts forward management and policy recommendations for the forestry sector to focus on the management of forests and wood products in mitigating climate change.Management suggestions:（1）coordinate and optimize the life cycle of wood-based panels,and promote the comprehensive and systematic response of the wood-based panel industry to climate mitigation;（2）upgrade the market structure,integrate the wood-based panel industry,and increase the market share of high-quality particleboard;（3）optimize the industrial chain,implement the forest-board integration strategy,and promote the wood cascade use.Policy recommendations:（1）strengthen the construction of the“forest-wood products”coupling system,and build a big data platform for environmental impact assessment of the entire life cycle of forestry;（2）give full play to the market value of forestry carbon emission reduction,and improve the institutional mechanism of forestry participation in the carbon emission trading market;（3）give full play to the comparative advantage of forestry in international trade,and establish a carbon labeling system for China’s wood products.