林产品生物碳通量的动态生命周期评估

Assessing biogenic carbon fluxes of wood products with a dynamic life cycle assessment approach

将时间因素和生物碳通量纳入林产品生命周期碳足迹评估,通过动态生命周期分析法(Dynamic Life Cycle Assessment,DLCA),确定林产品生产、使用和废弃阶段替代化石能源的净温室气体减排和对森林碳损失的净弥补时间。首先,建立温室气体排放和封存的动态生命周期清单,评估刨花板全生命周期的碳动态和碳足迹;其次,根据ISO 14040和PAS 2050标准提供的静态生命周期分析法分别核算包含与不包含碳储计算的碳足迹,量化时间因素和生物碳通量对于碳足迹结果差异的影响程度;最后,对比自然生长状态的森林碳汇情境,评估刨花板使用和废弃阶段替代化石燃料实现净气候减排所需的时间。研究表明:①时间因素和生物碳通量核算对碳足迹结果影响较大(223.34%),忽视时间因素会低估刨花板的减排贡献(18.98%)。②动态生命周期分析法可准确评估生物碳和温室气体排放的时间问题,但对时间范围非常敏感(75.19%和113.25%)。③生产、使用林产品以及林产品对化石能源的替代是实现长期气候减排的有效方式,在100a的时间范围能够弥补因森林砍伐造成的碳损失,从而实现碳中性。

This study quantified how different assumptions about timing aspects and biogenic carbon flows affected the outcome of global warming impact assessment of wood products using a dynamic life cycle assessment(DLCA)approach.This study also attempted to assess the net greenhouse gas(GHG)emission effects of wood products and the offset time to carbon neutrality from a life cycle aspect,regarding the potential for climate mitigation from non-harvest forests.Firstly,we established a dynamic life cycle inventory to assess the carbon footprint(CF)and carbon dynamics of particleboard.Secondly,to quantify the degree to which the timing issues and biogenic carbon fluxes affect the differences in results,carbon footprint with and without biogenic carbon storage were calculated according to the ISO 14040 and PAS 2050 standards respectively.Finally,the non-harvest forest growth model was used to analyze the offset time of achieving net greenhouse gas reduction by using particleboard as an alternative to fossil fuels at end-of-life disposal.The results show that:①Timing issues and biogenic carbon accounting had a great impact on carbon footprint(223.34%).Ignoring timing issues would underestimate the contribution of particleboard to emission reduction(18.98%).②The dynamic life cycle assessment approach allowed a more accurate assessment of biogenic carbon and the timing of greenhouse gas emissions.However,it was particularly sensitive to the choice of time horizon(75.19%and 113.25%).③The production and use of wood products,as well as using them as alternatives to fossil fuels were effective ways to achieve long-term climate mitigation,which could offset the carbon loss caused by harvesting within a 100-year range,so as to achieve carbon neutrality.