北京市住宅建筑生命周期碳足迹

从生命周期角度看,建筑碳足迹与能源和建材生产系统具有密切关系。随着技术的进步和节能政策的推进,中国能源的生产和使用,以及建材生产过程中的环境排放都随着时间在持续降低,这将间接地影响到建筑的环境表现。依据1990—2010年期间每5a的中国能源与建材生命周期清单数据,对北京市20年间住宅建筑系统开展生命周期评价和碳足迹核算,以揭示北京市住宅建筑系统的环境负荷变化特征。结果表明,北京市住宅建筑生命周期碳足迹随时间推移呈现降低趋势,主要来自能源系统和建材生产系统的碳减排贡献。不同结构建筑的碳足迹尽管有差异,但也呈现了相似的下降趋势。从生命周期阶段看,建筑碳足迹主要体现在建筑使用阶段和建材生产阶段。尽管建筑使用阶段的节能对于降低建筑生命周期碳足迹具有重要贡献,但节能在经济成本及环境成本方面而言是有限度的。在可持续的环境政策管理制定中,应从生命周期角度,统筹考虑协调各行业减碳的协调发展。论文同时也验证了在生命周期评价中考虑时间变量将有助于更好地利用生命周期评价结果支持环境可持续管理。结论对于城市规划的政策制定、量化环境表现是有益的。     

环境足迹的核算与整合框架——基于生命周期评价的视角

环境足迹及其与生命周期评价(LCA)的关系是工业生态学关注的新热点。从探讨环境足迹与LCA的关系入手,以碳足迹、水足迹、土地足迹和材料足迹为例,分别对每一项足迹指标两个版本的核算方法进行了比较。根据清单加和过程的特点,将所有足迹指标划分为基于权重因子和基于特征因子两类,总结了两者的适用性和局限性。在此基础上提出了一个环境足迹核算与整合的统一框架。该框架基于LCA视角建立,但对系统边界和清单数据的要求相对灵活,因而也适用于生命周期不甚明确的情形。研究在一定程度上揭示了足迹指标的方法学实质,同时也为环境影响综合评估提供了一条规范化的途径。     

区域旅游业碳排放和旅游消费碳足迹研究述评

全球气候变化是当今世界面临的最富挑战性的问题之一,旅游业是世界第一大产业,其碳排放(碳足迹)的测度和控制对全球减排目标的实现具有重大意义。对旅游业碳排放和旅游消费碳足迹相关领域的研究成果进行了深入梳理,探讨已有研究存在的不足之处和薄弱环节,并为进一步的研究指明方向。国内外关于旅游业碳排放和旅游消费碳足迹的研究已有较好基础,但已有研究的核算结果缺乏不确定性分析,信度、效度难以确定,旅游业和旅游消费的碳强度和生态效率尚未厘清,其原因在于,已有研究在概念内涵和外延、系统边界、核算口径、研究方法等方面还存在一些争议和值得探讨的领域。进一步的研究方向应有3个方面发展:明确界定概念内涵和外延、统一系统边界和核算口径以及构建旅游业碳排放和旅游消费碳足迹测度的方法体系。     

城市餐饮业食物浪费碳足迹——以北京市为例

食物浪费及其造成的环境影响已成为全球广泛关注的热点。无论从生命周期还是碳足迹的视角来看,食物浪费意味着生产、运输、加工与储存这些被浪费掉的食物过程中所投入的各种资源的浪费以及不必要的温室气体排放。以北京市餐饮食物浪费问题为切入点,在通过问卷调查和称重方法对餐饮食物浪费状况进行调查的基础上,将整个食物生命周期各供应链环节相应的温室气体排放纳入考量,估算了北京市餐饮食物浪费的碳排放量。研究结果表明:北京市餐饮食物浪费总量为39.86×10~4t/a。其中,蔬菜类浪费量最高,约占浪费总量的43.16%,其次为肉类和主食类,分别占食物浪费总量的20.59%和16.66%。北京市餐饮食物浪费所产生的总碳足迹为192.51×10~4—208.52×10~4t CO_2eq。其中,农业生产阶段的碳排放量最大为99.34×10~4t CO2eq,占食物浪费总碳足迹的47.64%。其次是消费阶段的碳足迹77.96×10~4t CO_2eq,占食物浪费总碳足迹的37.39%,再次是餐厨垃圾处理阶段的碳足迹28.54×104tCO2eq,占食物浪费总碳足迹的13.68%。这些不同供应链环节的碳排放比例,为透视食物浪费所带来的环境影响提供了新的认知,也为遏制食物浪费提供了科学的理论依据。     

旅游风景区旅游交通系统碳足迹评估——以南岳衡山为例

随着全国各地旅游业的蓬勃发展,旅游风景区内碳排放总量不断攀升,严重影响了旅游业的可持续发展。选择南岳衡山旅游风景区为典型案例区,运用生命周期评价理论,构建了南岳风景区旅游交通系统碳足迹计算模型。结果表明:①从总量来看,不同类型交通方式的碳足迹情况相差甚远。公路旅游交通对旅游景区的环境威胁最大,碳足迹总量是索道旅游交通的2.6倍,人行道旅游交通的46.1倍;②从阶段构成来看,公路和索道旅游交通系统运营使用阶段碳足迹占整个生命周期的大部分,所占比率分别为79%和96%.而人行道旅游交通系统中建造施工和运营后期阶段能源消耗比较大;③从来源构成来看,在使用期内公路旅游交通的碳足迹比重最大,约占碳足迹总量的71%,其次是索道旅游交通占27%,人行道旅游交通仅占2%。研究结果有利于实现旅游风景区低碳旅游发展目标,为旅游风景区节能减排提供理论支撑。     

基于碳足迹的传统农业系统环境影响评价——以青田稻鱼共生系统为例

现代农业在带来粮食高产的同时也产生许多生态环境问题,这促使人们再次把目光转向传统农业系统。一些传统农业系统不仅具有突出的经济、社会和文化价值,还具有多种重要的生态功能,如温室气体减排。然而,已有研究缺乏对传统农业系统整个生命周期的固碳减排能力的测算及其环境影响的评价。为此,基于农户调研数据,运用生命周期评价法对青田稻鱼共生系统的碳足迹进行了测算,并与当地水稻单作系统进行比较。研究发现:(1)青田稻鱼共生系统和水稻单作系统碳足迹分别为6266.7 kgCO_2-eq/hm~2和7520.0 kgCO_2-eq/hm~2,单位产值碳足迹分别为0.12 kgCO_2-eq/元和0.21 kgCO_2-eq/元。与水稻单作系统相比,稻鱼共生系统排放的温室气体更少,环境影响更小,生态和经济效益更高。(2)农业生产过程中积累的CH_4是碳足迹的最主要来源,农业生产资料投入中的化肥是碳足迹的的第二大来源。农业生产资料投入中的饲料则是稻鱼共生系统碳足迹的另一重要来源。通过碳足迹的方法对青田稻鱼共生系统的环境影响进行量化,不仅丰富了碳足迹在实际应用中的适用类型,对于其他传统农业系统的环境影响评价也具有借鉴意义。     

中国省际碳足迹广度、深度评价及时空格局

借鉴三维生态足迹方法构建了碳足迹广度、深度测算模型,对吸纳碳排放所占用的自然资本流量、存量进行区分,核算了2000—2016年中国30个省(市、自治区)碳足迹广度和碳足迹深度,并对其进行空间关联性分析。结果显示:①中国碳足迹广度受碳足迹和碳生态承载力的综合影响,由0.173 hm~2/人升至0.329 hm~2/人又降至0.301 hm~2/人;碳足迹广度高值区集中于东北、西北和西南地区,其自然资本流量尚未完全占用,低值区集中于东部沿海和中部,其自然资本流量已不足以补偿碳排放。②2008年起中国碳足迹深度突破自然原长1,数值由1.04升至1.42又降至1.31;研究期内碳足迹深度始终处于自然原长1的有10个地区,高值区集中于东部沿海和中部,尤其是上海可达298.83,以存量资本耗竭为主且生态持续性弱。吸纳碳排放所占用的流量资本和存量资本存在地域互补性。③中国碳足迹广度、深度呈显著的空间正相关。碳足迹广度H-H集聚区分布于东北和西北,该类集聚有减弱趋势;碳足迹深度H-H集聚区主要分布于东部沿海且向中部扩散,该类集聚有增强趋势。通过引入碳足迹广度、深度两项指标对碳足迹的研究方法进行了深化和完善,在碳排放对生态环境影响规模的刻画和表达上取得了较优于传统碳足迹的评价结果。     

生命周期管理研究述评

生命周期管理起源于生命周期思想,它是生命周期思想在实践中的具体应用,是面向可持续生产和消费,对产品、工艺和服务的全生命周期环境影响进行的综合管理,是解决复合生态系统中结构无序、效率不高和代谢冗余的有效途径,是基于生命周期评价原则与框架的一种环境管理手段或环境管理体系。全面回顾了生命周期管理的起源与内涵,阐述了生命周期管理与生命周期评价的区别与联系,梳理了生命周期管理与环境管理体系的关系。对生命周期管理在产品、企业、行业及城市等层次上的具体应用进行了总结与述评,并对其今后需深入研究的方向进行了展望。     

生命周期方法在产业共生系统环境效益评价中的应用——研究进展及问题分析

近年来,产业共生作为产业生态学最具特征的领域引起了相关研究者的广泛关注。当前的研究逐渐从产业共生系统的定性描述分析转向定量的系统评价上。传统的产业共生系统环境效益评价仅仅关注共生系统本身,而忽视了占环境影响20%—50%的上、下游过程及替代过程的环境影响,为了得到客观的、系统的环境影响评价,将生命周期分析方法引入产业共生效益评价显得尤为重要。首先回顾了生命周期分析方法在产业共生研究中的发展过程,接着评述了3种生命周期分析方法在产业生态研究中的优劣势。并重点分析了将生命周期思想引入产业共生效益评价方法存在的功能单位设定问题及系统边界的选择问题。最后,呼吁为避免隐形污染的转移,必须尽快将生命周期分析的方法和管理理念引入我国生态工业园设计、规划、评价和管理的全过程中。     

基于ISO 14046的工业产品水足迹评价研究——以电缆为例

水足迹国际标准(ISO 14046)于2014年发布,基于生命周期评价(LCA)的思想,水足迹被定义为量化与水相关潜在环境影响的指标。在ISO14046的原则、要求和方法学框架基础上,介绍了工业产品水足迹的计算和评价方法,并以铜电缆和铝合金电缆为例进行研究,分别评价了两类电缆生命周期过程产生的与水相关环境影响。与水足迹网络(WFN)的方法侧重于计算生产产品所需要的水资源总量不同,ISO的方法更关注于产品全生命周期过程的环境影响评价。案例研究表明:铜电缆生命周期全过程耗水量与铝合金电缆相比少24.8%,水短缺足迹相比则少97.9%。这是因为铜电缆生产地江苏的水压力指数(WSI)小于铝合金电缆生产地河北的WSI。由此,在江苏地区生产电缆使用的水资源对当地水环境压力造成的影响远小于在河北地区生产电缆造成的影响。采用科学合理的水足迹评价方法,量化工业产品全生命周期带来的环境影响,能为我国实现工业布局的合理规划和水资源的可持续利用提供科学依据。     

Biogenic Carbon and Temporary Storage Addressed with Dynamic Life Cycle Assessment

A growing tendency in policy making and carbon footprint estimation gives value to temporary carbon storage in biomass products or to delayed greenhouse gas (GHG) emissions. Some life cycle‐based methods, such as the British publicly available specification (PAS) 2050 or the recently published European Commission's International Reference Life Cycle Data System (ILCD) Handbook, address this issue. This article shows the importance of consistent consideration of biogenic carbon and timing of GHG emissions in life cycle assessment (LCA) and carbon footprint analysis. We use a fictitious case study assessing the life cycle of a wooden chair for four end‐of‐life scenarios to compare different approaches: traditional LCA with and without consideration of biogenic carbon, the PAS 2050 and ILCD Handbook methods, and a dynamic LCA approach. Reliable results require accounting for the timing of every GHG emission, including biogenic carbon flows, as soon as a benefit is given for temporarily storing carbon or delaying GHG emissions. The conclusions of a comparative LCA can change depending on the time horizon chosen for the analysis. The dynamic LCA approach allows for a consistent assessment of the impact, through time, of all GHG emissions (positive) and sequestration (negative). The dynamic LCA is also a valuable approach for decision makers who have to understand the sensitivity of the conclusions to the chosen time horizon.     

Toxicity impacts in the environmental footprint method: calculation principles

The International Journal of Life Cycle Assessment - The EU environmental footprint (EF) is a life cycle assessment (LCA)-based method which aims at assessing the environmental impacts of...     

The contribution of PAS 2050 to the evolution of international greenhouse gas emission standards

Background, aim, and scope  The assessment of greenhouse gas (GHG) emissions arising from products (goods and services) is emerging as a high profile application of life cycle assessment (LCA), with an increasing desire from retailers and other supply chain organizations to better understand, and in some cases communicate, the carbon footprint of products. Publicly Available Specification 2050:2008, Specification for the assessment of the life cycle greenhouse gas emissions of goods and services, addresses the single-impact category of global warming to provide a standardized and simplified implementation of process LCA methods for assessing GHG emissions from products. This paper briefly reviews the development process followed for PAS 2050, before examining the treatment of GHG-specific contribution of PAS 2050 to product carbon footprinting. Materials and methods  PAS 2050 was jointly sponsored by the Carbon Trust and the UK Department for Environment, Food and Rural Affairs and was published by the British Standards Institution on 29 October 2008. An independent steering group oversaw the development of the specification, including the establishment of an expert workgroup program, comprehensive international consultation, and expert input on the requirements of the specification. Results  The development process for PAS 2050 resulted in a specification that includes specific requirements that limit the interpretation of the underlying LCA approach to product carbon footprinting. These requirements, including goal setting and life cycle inventory assessment, aspects of system boundary identification and temporal aspects of GHG emissions, clarify the approach to be taken by organizations implementing product carbon footprinting, and simplify the application of LCA procedures in relation to product carbon footprinting. Discussion  Assessment of the emissions arising from the life cycle of products has a clear international component, and delivering consistent results across the supply chain requires the application of consistent methods. There is an emerging recognition that further standardization of methods for product carbon footprinting is needed, and the specific requirements resulting from the PAS 2050 development process make a valuable contribution across a range of GHG assessment issues. Conclusions  The widespread interest in PAS 2050 from individuals and organizations, together with the development of similar guidance by other organizations, confirmed that there is a need for clarification, certainty, and requirements in the field of product carbon footprint analysis. The use of PAS 2050 to refine, clarify, and simplify existing LCA methods and standards has resulted in specific approaches to key GHG assessment issues being developed; it is important that future standards development work considers the impact of these approaches and their further refinement. Recommendations and perspectives  It is the consumption of goods and services by individuals around the world that drives global GHG emission, and PAS 2050 is a first attempt to provide integrated, consistent approaches that directly address the role of consumption at the product level in contributing to GHG emissions. Climate science and GHG assessment techniques are both evolving areas and it will be necessary to review the approach taken by PAS 2050 in the future: a formal review process for PAS 2050 will commence towards the end of 2009 and practitioners are encouraged to participate in this review process.

In reply to hertwich & pease, Int. J. LCA 3 (4) 180 — 181, “ISO 14042 restricts use and development of impact assessment”

Life Cycle Impact Assessment describes indicators and does not predict actual impacts. The value of an LCA is its comprehensive review of all stages of a product’s life cycle and its synoptic view of all relevant environmental issues. The current version of the 14042 draft describes the uniqueness of Life Cycle Impact Assessment approach which is distinct from other assessment techniques. The wording was designed to help users of the standard understand how and why LCIA is distinct from other assessment methods. In closing, we would like to highlight our opinion that the present document on the level of a DIS is sound, stable and practical within the ISO 14040 series of standards. We do not agree withHertwich & Pease that the present document prevents the use of LCIA. It makes a choice regarding the exclusion of weighting across categories in order to prevent misuse in deriving inappropriate claims. And for characterisation it has achieved a well founded synthesis. In addition, we strongly believe that this standard will stimulate the international scientific discussion of LCA and will substantially contribute to enhanced and more valuable applications of LCA in the future.     

Life cycle inventory analysis - A case study of steel used in Brazilian automobiles

Data acquisition to perform LCA is time and capital consuming. There is already international data about environmental aspects in several processes. This study aims to verify the possibility of adapting international data to Brazilian conditions. Therefore, a Life Cycle Inventory was conducted to compare the use of national and international data for steel used in automobiles. This was done in three steps: objective and scope definition, inventory analysis and interpretation. LCI is a simplification of Life Cycle Assessment (LCA) as impact assessment is not taken into account. Even so, LCI takes into account all life cycle stages of a product, that is, from its extraction through its deposition. In this study, three phases of the life cycle were considered: steel manufacturing, automobile use and disposal. In the case studied, the amount of steel evaluated was 263 kg, which would be possible to be replaced by other materials in a 1,300 kg automobile. Resources and energy consumption, atmospheric emissions and solid residues production were taken into account within the analysis done. Results show that automobile use and materials manufacturing are responsible for the bulk of energy and resources consumption. Solid residues occur mainly in the discard phase, due to the low level of recycling. Several differences were also achieved between national and international data, which implies the need of environmental databases development.     

中国生命周期评价理论与实践研究进展及对策分析

主要分析了我国生命周期评价的理论与实践研究进展与数据库构建现状,针对当前我国生命周期评价理论与应用研究的关键薄弱环节即不确定性分析、本土化数据库构建、本土化生命周期环境影响评价模型构建,指出了利用泰勒系列展开模型进行符合我国产业链生产现状的精确、完整、具有代表性、具有时空动态特征的生命周期数据库构建的必要性;并指出需要根据我国国情(例如:环境、地理、人口、暴露等)来构建生命周期环境影响评价模型的紧迫性。     

The New International Standards for Life Cycle Assessment: ISO 14040 and ISO 14044

Background, Aims and Scope The development of the international standards for life cycle assessment (ISO 14040:1997, ISO 14041:1999, ISO 14042:2000, ISO 14043:2000) was an important step to consolidate procedures and methods of LCA. Their contribution to the general acceptance of LCA by all stakeholders and by the international community was crucial. Currently, the process of the revision of this first generation of LCA standards is close to completion. The paper explains the outline as well as formal and technical changes of the coming new international standards of LCA, i.e. the new ISO 14040 and ISO 14044. Methods The paper refers to life cycle assessment based on the international standards for LCA (ISO 14040:1997, ISO 14041:1999, ISO 14042:2000, ISO 14043:2000). The content relates to the Final Draft International Standard (FDIS) versions of the new ISO 14040 and ISO 14044. Results and Discussion With the publication of the two new standards, ISO 14040 and ISO 14044, the existing four standards ISO 14040:1997, ISO 14041:1999, ISO 14042:2000 and ISO 14043:2000 are technically revised, cancelled and replaced. According to the scope of the revision, the core part of the technical contents remains unchanged. Improved readability and the removal of errors and inconsistencies was the focus of the revision. However, despite the fact that the main technical content was confirmed to be still valid, some relevant formal and technical changes were made. On the technical side these include e.g. the addition of principles for LCA, the addition of an annex about applications, the addition of several definitions (e.g. product, process, etc.), clarifications concerning LCA intended to be used in comparative assertions intended to be disclosed to the public, clarifications concerning the critical review panel, clarifications concerning system boundary, etc. On the formal side, changes include the reduced number of standards, a reduced number of annexes, a reduced number of pages that contain requirements, alignment of definitions and clarification of compliance with the standards. Conclusion The two new standards, ISO 14040 and ISO 14044, reconfirm the validity of the main technical content of the previous standards. Errors and inconsistencies were removed and the readability was improved. The added technical content is in line with the previous requirements and serves mainly as a clarification of the technical content. The unanimous vote on the Draft International Standard versions proved that this was achieved on the basis of the broadest possible international consensus. Recommendation and Outlook Currently the national member bodies undertake the final voting on the FDIS-versions of the standards. Based on the voting results at the previous stages of the documents, a positive result is expected. The publication of the new international standards for life cycle assessment (ISO 14040 and ISO 14044) is expected around mid-2006. For the sake of the international and stakeholder acceptance of LCA, it is recommended that the new standards serve as core reference documents for the users and practitioners of LCA.     

A Systems Approach to Sustainable Technical Product Design

Many existing methods for sustainable technical product design focus on environmental efficiency while lacking a framework for a holistic, sustainable design approach that includes combined social, technical, economic, and environmental aspects in the whole product life cycle, and that provides guidance on a technical product development level. This research proposes a framework for sustainable technical product design in the case of skis. We developed a ski under the Grown brand, benchmarked according to social, environmental, economic, and technical targets, following an initial sustainability assessment, and delivered the first environmental life cycle assessment (ELCA) and the first social life cycle assessment (SLCA) of skis. The framework applies a virtual development process as a combination of ELCA to calculate the environmental footprint as carbon equivalents of all materials and processes and a technical computer‐aided design (CAD) and computer‐aided engineering (CAE) simulation and virtual optimization using parameter studies for the nearly prototype‐free development of the benchmarked skis. The feedback loops between life cycle assessment (LCA) and virtual simulation led to the elimination of highly energy intensive materials, to the pioneering use of basalt fibers in skis, to the optimization of the use of natural materials using protective coatings from natural resins, and to the optimization of the production process. From an environmental perspective, a minimum 32% reduction in carbon equivalent emissions of materials in relation to other comparably performing skis has been achieved, as well as a pioneering step forward toward transparent communication of the environmental performance by the individual, comparable, and first published ski carbon footprint per volume unit.     

Exploring the Use of Ecological Footprint in Life Cycle Impact Assessment

Ecological footprint (EF) is a metric that estimates human consumption of biological resources and products, along with generation of waste greenhouse gas (GHG) emissions in terms of appropriated productive land. There is an opportunity to better characterize land occupation and effects on the carbon cycle in life cycle assessment (LCA) models using EF concepts. Both LCA and EF may benefit from the merging of approaches commonly used separately by practitioners of these two methods. However, few studies have compared or integrated EF with LCA. The focus of this research was to explore methods for improving the characterization of land occupation within LCA by considering the EF method, either as a complementary tool or impact assessment method. Biofuels provide an interesting subject for application of EF in the LCA context because two of the most important issues surrounding biofuels are land occupation (changes, availability, and so on) and GHG balances, two of the impacts that EF is able to capture. We apply EF to existing fuel LCA land occupation and emissions data and project EF for future scenarios for U.S. transportation fuels. We find that LCA studies can benefit from lessons learned in EF about appropriately modeling productive land occupation and facilitating clear communication of meaningful results, but find limitations to the EF in the LCA context that demand refinement and recommend that EF always be used along with other indicators and metrics in product‐level assessments.     

Methodology for developing gate-to-gate Life cycle inventory information

Life Cycle Assessment (LCA) methodology evaluates holistically the environmental consequences of a product system or activity, by quantifying the energy and materials used, the wastes released to the environment, and assessing the environmental impacts of those energy, materials and wastes. Despite the international focus on environmental impact and LCA, the quality of the underlying life cycle inventory data is at least as, if not more, important than the more qualitative LCA process. This work presents an option to generate gate-to-gate life cycle information of chemical substances, based on a transparent methodology of chemical engineering process design (an ab initio approach). In the broader concept of a Life Cycle Inventory (LCI), the information of each gate-to-gate module can be linked accordingly in a production chain, including the extraction of raw materials, transportation, disposal, reuse, etc. to provide a full cradle to gate evaluation. The goal of this article is to explain the methodology rather than to provide a tutorial on the techniques used. This methodology aims to help the LCA practitioner to obtain a fair and transparent estimate of LCI data when the information is not readily available from industry or literature. Results of gate-to-gate life cycle information generated using the cited methodology are presented as a case study. It has been our experience that both LCI and LCA information provide valuable means of understanding the net environmental consequence of any technology. The LCI information from this methodology can be used more directly in exploring engineering and chemistry changes to improve manufacturing processes. The LCA information can be used to set broader policy and to look at more macro improvements for the environment.