足迹家族:概念、类型、理论框架与整合模式

足迹研究是当前生态经济学和可持续发展领域的热点与前沿课题。探讨了足迹类指标的内涵,将其定义为一类评估人类资源消费和废弃物排放等活动环境影响的指标;介绍了生态足迹、碳足迹、水足迹、能源足迹、化学足迹、氮足迹和生物多样性足迹7类典型足迹指标的概念与研究进展;在此基础上提出了普适性的足迹家族概念,总结了足迹家族的选择性、开放性、系统性和不确定性特征,并根据足迹类指标的一般运算流程构建了足迹家族的理论框架;基于大量文献成果系统比较了生态足迹、碳足迹和水足迹3类关键足迹的特征差异,提出了在足迹家族层面增强指标兼容性的措施;通过逐一测试各关键足迹与27项环境问题的相关程度,从决策相关性的角度初步探索了该足迹家族的整合模式;展望了未来足迹(家族)研究的重点方向。     

水足迹研究进展

水为生命之源,水资源的合理分配与科学管理是区域可持续发展与流域综合管理的核心环节;水足迹作为一种全面核算人类活动对水资源真实占用的综合指标,将人类消费终端与水资源利用密切关联,为维护流域水资源安全、提高区域水资源利用效率提供了重要的科学依据,已成为当前国际水资源管理的前沿研究领域。在明确水足迹及水资源生态足迹相关概念的基础上,对比分析了水足迹与生态足迹、水资源生态足迹模型的异同,明晰了过程、产品及区域等不同研究对象的水足迹核算方法,系统梳理了产品和区域水足迹评价、基于水足迹的区域水资源安全研究、区域水足迹可持续性分析等水足迹主要研究内容的近今进展,并展望了进一步的重点研究方向,即水足迹综合研究、水足迹评价不确定性分析、水足迹与物质流核算的关联研究,以及基于足迹整合的可持续发展多维测度等。     

污染足迹及其在区域水污染压力评估中的应用——以太湖流域上游湖州市为例

传统生态足迹理论虽然在可持续发展评价等方面得到了广泛的应用,但却仍然无法全面衡量人类活动对生态系统造成的各种影响。其无法全面评估人类活动的根源在于,土地功能排他性假设限制了其对利用生态系统非生物生产性产品和服务的人类活动的衡量。为了摆脱传统生态足迹理论的局限性,建议承认土地功能多样性的客观事实,将生态足迹构建于多种生态系统服务功能之上。针对传统生态足迹对定义中废弃物吸纳的考虑不足,提出了基于污染物吸纳功能的生态足迹,即污染足迹。污染足迹不是对传统生态足迹中能源足迹的简单置换,而是能够囊括人类活动产生的大部分污染物,并可以根据不同的污染物类别或类型进一步细化的足迹类型。构建了太湖流域有机物、氮和磷污染足迹模型,并利用该模型对流域上游湖州市的水污染压力进行了综合评估。结果表明:(1)2007年湖州市污染足迹为39948.73 hm²,东部平原地区污染足迹较大,西部丘陵地区污染足迹相对较小;(2)湖州市人类活动排放的氮磷污染物对水域空间的生态占用已经远远超过了有机污染物;(3)2007年湖州市污染承载力为20896.00 hm²,污染赤字为19052.73 hm²,人类排污活动俨然超出了当地水域的承载能力;(4)2007年湖州市污染压力指数为1.91,当地水环境总体上处于轻度接近中度污染压力;(5)湖州市水污染压力较大的地区,区域内人类活动的维持建立在区域水环境质量恶化或污染物向下游输移的基础之上。     

台州市城市生态足迹

城市生态足迹分析可定量反映城市人类活动对自然生态环境产生的压力和影响程度,这种方法为城市生态系统研究提供了新的思路和研究方向。本文在介绍生态足迹的理论和计算模型的基础上,以台州市为例,计算了台州市2002年的生态足迹。结果表明,2002年台州市生态足迹为1．33084hm^2·人^-1,可利用的生态承载力为0．25800hm^2·人^-1,生态赤字为1．07284hm^2·人^-1,反映了台州市的生产、生活强度超过了生态系统的承载能力。因此,台州市需注重提高其资源利用效率,提倡节约型的生产和生活消费模式,减少其生态足迹,通过生态城市建设,实现城市的可持续发展。     

生态足迹的模型修正与方法改进

生态足迹是测定人类活动的资源消费需求,判明自然资产是否被过度利用的有效工具。介绍了生态足迹的基本概念和模型,简单分析基本模型存在的主要缺陷和争论,重点解析了近年来生态足迹模型在参数调整、项目计算、账户扩展等方面的演变和修正。介绍生态足迹研究的传统方法:综合法和组分法,评述了生命周期评价,基于投入产出分析,三维模型,净初级生产力,能值理论,时序分析等的方法改进。对未来的研究方向提出自己的看法,期望对我国的生态足迹研究有一定的启示作用。     

生态足迹模型研究进展

生态足迹模型是从具体的生物物理量角度来衡量人类对自然资源利用程度以及自然界为人类提供的生命支持服务功能的方法。自从该模型提出以来,受到国内外众多学者广泛关注,应用范围不断扩大。为此,从可持续发展角度出发,介绍了生态足迹模型的产生背景、理论基础和计算方法,综述了近年来国内外研究最新进展,评价了模型应用的优点和不足,提出了生态足迹研究动态和研究重点。     

青海湖自然保护区人类数字足迹及草地生物量的人类活动暴露度的时空模式分析

开展保护区人类活动压力定量评估对保护区内生态系统安全、降低人类活动影响具有重要意义。许多学者从人类活动对生物多样性、生物的生境或生态系统服务及其价值的影响等角度已开展了大量研究, 但由于反映人类活动的统计数据在时空尺度上较粗, 难以精细刻画保护区内短期动态的人类活动干扰。本研究尝试通过记录人的位置到访信息的高时空分辨率数字足迹数据, 以青海湖国家级自然保护区为研究区域, 利用0.01°逐日的定位请求数据和草地生物量数据, 从人类数字足迹覆盖率、数字足迹强度和草地生物量的人类活动暴露度3个指标上对青海湖自然保护区内人类数字足迹入侵强度及其对生态环境的影响开展了研究。研究结果显示, 青海湖保护区人类数字足迹具有“多尖峰、南高北低、景区节律”的时空模式; 每日人类数字足迹覆盖率和足迹强度呈现按月聚集模式, 最大值分别为7.42%和5.24; 草地生物量的人类活动暴露度显示人类数字足迹对青海湖二郎剑-黑马河沿线的草地生物量影响最大, 此时草地生物量的人类活动暴露度水平在热门旅游景点较高, 最高达到2.24。通过位置大数据挖掘青海湖保护区内人类数字足迹的时空变化及其对于生态环境的影响, 不仅证明了数字足迹用于人类活动对于生态环境影响研究的有效性, 也为保护区生态环境精细化的管理提供支撑。     

基于科学知识图谱的生态足迹研究演进、框架与前沿中外比较

生态足迹是评估人类活动下生态可持续性的有效工具。基于1999-2020年CNKI中文核心期刊与1994-2020年Web of Science核心合集有关生态足迹研究文献共5104篇,运用CiteSpace可视化软件,绘制中外研究高频词时区、关键词聚类及突现词时间分布科学知识图谱,梳理中外生态足迹相关研究演进路径、基本理论框架与动态前沿。研究结果表明:(1)中外生态足迹研究演进路径均可分为三个阶段,但演进方式有所差异,且国内研究较国外相对滞后;(2)中外生态足迹研究均已形成以生态足迹模型方法为工具、以足迹测算为基础、以生态安全为落脚点、以促进人与生态协调发展为目标的基础框架体系,国外侧重基础框架构建、宏观尺度研究与微观机制分析,国内侧重模型和方法优化与外部环境分析;(3)当前国外前沿方向为环境库兹涅茨曲线假设验证研究与生态网络分析,国内为碳足迹和水资源足迹的测算、三维生态足迹模型下的自然资本评估以及生态补偿问题。     

人类最大可持续海洋足迹的模拟

在William Rees ＆ Mathis Wackernagel最初提出的生态足迹模型理论所划分的六类基本生态生产性土地面积中,海洋以其能为人类提供鱼类等海产品而被单独列为水域一项。海洋生物资源是一种典型的可再生资源,人类只有采取合理的开发策略方可保证海洋生物资源最大的可持续生产量。借用生态足迹、生物承载力概念的内涵,提出海洋足迹、海洋承载力两个新概念;运用非线性科学理论在海洋足迹与海洋承载力呈二次非线性关系的假设下,建立海洋承载力二次非线性开发的动力模式,并运用稳定性分析理论对其求解、分析。结果表明：（1）海洋承载力与其增长率呈正相关关系,与海洋足迹增长率呈负相关关系;（2）为保证海洋生物资源的可持续利用,人类必须控制最大海洋足迹增长率为r/xm（r为海洋承载力增长率,xm为最大海洋承载力）,方可获得可持续的最大海洋足迹为rxm/4,此时海洋承载力可以维持在稳定的平衡态（为其最大承载力的一半）。     

农产品水足迹研究进展

水是人类生产生活的重要资源,科学合理地评价人类活动对水资源的影响是实现水资源可持续利用的重要保障.水足迹概念的提出创新性地将人类活动消耗的水资源区分为绿水、蓝水和灰水,拓展了水资源可持续利用的评价思路.基于虚拟水(VW)的水足迹理论和基于生命周期(LCA)的水足迹理论将水质与水量的概念相结合,成为了农业水资源管理研究的热点内容.基于VW的水足迹理论主要包括绿水足迹、蓝水足迹和灰水足迹的计算,以及水环境可持续性评价,而基于LCA的水足迹理论体现了水资源的消耗和污染及其对环境造成的综合影响.本文详细介绍了这两种水足迹理论的计算方法与环境可持续评价的研究进展,对比分析两种水足迹理论在描述农产品生产用水及其环境影响方面的差异性,并对其研究前景进行了展望.     

Theoretical exploration for the combination of the ecological,energy, carbon,and water footprints: Overview of a footprint family

Over the past two decades, a continuously expanding list of footprint-style indicators has been introduced to the scientific community with the aim of raising public awareness of how humanity exerts pressures on the environment. A deeper understanding of the connections and interactions between different footprints is required in an attempt to support policy makers in the measurement and choice of environmental impact mitigation strategies. Combining a selection of footprints that address different aspects of environmental issues into an integrated system is, therefore, a natural step. This paper starts with the idea of developing a footprint family from which most important footprints can be compared and integrated. On the basis of literature review in related fields, the ecological, energy, carbon, and water footprints are employed as selected indicators to define a footprint family. A brief survey is presented to provide background information on each of the footprints with an emphasis on their main characteristics in a comparative sense; that is, the footprints differ in many aspects more than just the impacts they are addressed. This allows the four footprints to be complementarily used in assessing environmental impacts associated with natural resource use and waste discharge. We evaluate the performance of the footprint family in terms of data availability, coverage complementarity, methodological consistency, and policy relevance and propose solutions and suggestions for further improvement. The key conclusions are that the footprint family, which captures a broad spectrum of sustainability issues, is able to offer a more complete picture of environmental complexity for policy makers and, in particular, in national-level studies. The research provides new insights into the distinction between environmental impact assessment and sustainability evaluation, properly serving as a reference for multidisciplinary efforts in estimating planetary boundaries for global sustainability.     

Tracking resource use relative to planetary boundaries in a steady-state framework: A case study of Canada and Spain

There is a growing understanding of the biophysical processes that regulate the stability of the Earth-system, yet human pressures on the planet continue to increase rapidly. Here, recent advances in defining Earth-system thresholds using the planetary boundaries framework are translated down to national and sub-national levels. A set of 10 indicators is developed in a biophysical accounting framework that links the sustainability of resource flows from the biosphere to final consumption. The indicator set includes three measures of physical stocks, three measures of aggregate resource consumption, and four indicators of sustainable scale. The four scale indicators are ratios of (i) cumulative carbon footprint relative to carbon budget, (ii) nutrient use relative to biogeochemical boundaries, (iii) blue water consumption relative to monthly basin-level availability, and (iv) land footprint relative to biocapacity. Taken together, the indicators measure how close high-consuming societies are to meeting the conditions of a “steady-state economy”, defined here as an economy with non-growing physical stocks and flows maintained within shares of planetary boundaries. The framework is applied over a 15-year period to the economies of Canada and Spain, along with two sub-national regions (Nova Scotia and Andalusia). Nova Scotia is the only study site experiencing stable or decreasing biophysical stocks and flows. None of the study sites are consuming resources within their shares of all four planetary boundaries. Overall, the set of indicators provides guidance for prioritizing which environmental pressures need to decline (and by how much) for societies to be more effective stewards of Earth-system stability.     

National environmental footprints and planetary boundaries: from methodology to policy implementation 59th LCA forum,Swiss Federal Institute of Technology,Zürich,June 12, 2015

The 59th LCA forum was held on 12 June, 2015 to discuss the situation with regard to national environmental footprints and their relation to planetary boundaries and to the global carrying capacity. This conference report presents the highlights of the LCA forum. Several approaches of how to quantify a safe operating space of the Earth were presented, such as the planetary boundary concept published by Rockström et al. (Nature 462:472–475, 2009) and the ecological footprint (Bastianoni et al. 2013). Several presenters showed how they transformed environmental planetary boundaries to national and per capita allowances. In a research project funded by the Swiss Federal Office for the Environment safe and unsafe areas were determined by combining the level of overshoot, the level of confidence in the information and the trend in the environmental load. The areas of climate change, biodiversity losses and nitrogen losses show a large overshoot on a global level but also from the point of view of Swiss consumption. Other organizations use the planetary boundary concept to identify companies which qualify for environmentally sustainable funds. Finally, life cycle impact assessment methods are being developed using the planetary boundary concept. The weighting step is based on the level of overshoot, which is close to “distance to target” approaches. It was discussed that the nine planetary boundaries face some consistency and operationalisation problems. For instance, land use changes cause biodiversity losses, which is a planetary boundary parameter in its own. Chemical pollution on the other hand is a general topic, for which a quantification approach has to be developed first (load as well as its planetary boundary). The discussion forum showed that individual countries and political entities like the European Union start monitoring their consumption based environmental footprint. Within this context, approaches and concepts are needed to define the environmentally safe operating space. The LCA forum showed that there is still basic research needed to reliably and consistently quantify relevant planetary boundaries (avoiding overlapping indicators) and to transfer these boundaries to per capita allowances.     

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。     

Footprints of carbon and nitrogen: Revisiting the paradigm and exploring their nexus for decision making

Paradigms used for developing footprint metrics define the efficacy of these metrics for guiding decisions in the correct direction. Several metrics in use are developed from a narrow viewpoint of only looking at the output side impact of human activities on natural systems. This underestimates or overlooks other impacts on natural systems that occur due to input side interaction of human systems with natural systems. We revisit the paradigms used for development of footprint metrics and analyze the carbon and nitrogen footprints from these perspectives. Based on our analysis, utilizing both input and output side footprint measures is suggested such that heterogeneity of the nature of impact on both sides is not ignored. Utilizing these viewpoints, updated carbon and nitrogen footprints are proposed. Eco-LCA data for 2002 US economy is used to study the effect on decisions if these updated metrics are used. We also highlight the importance of understanding the multidimensional nature of environmental impacts that does not get captured by a single footprint, thus necessitating attention to the nexus of various footprints in decision making. Thus, the nexus between the updated carbon and nitrogen metrics is studied to show the shift in decisions resulting from looking at multidimensional impacts. Results for the US economy show that revisiting the paradigm for development of footprint metrics is a crucial step to avoid pushing decisions in incorrect directions due to use of narrowly focused footprint measures.     

Sharing the safe operating space: Exploring ethical allocation principles to operationalize the planetary boundaries and assess absolute sustainability at individual and industrial sector levels

In the light of increasing human pressures on the Earth system, the issue of sharing in the face of scarcity is more pressing than ever. The planetary boundary framework identifies and quantifies nine environmental boundaries and corresponding human pressures. However, when aiming to make the concept operational for decision support it is unclear how this safe operating space (SOS) within each of the planetary boundaries should be shared. This study proposes a two‐step approach, where the operating space is first downscaled to the individual level using ethical allocation principles and next scaled up to a higher organizational level using different upscaling methods. For the downscaling, three allocation principles are demonstrated: egalitarian (equal per capita); grandfathering (proportional to current share of the total impacts); and ability to pay (proportional to economic activity). For upscaling from the individual level final consumption expenditure is used as a proxy for the priority that the individual gives to the product or sector. In an alternative upscaling approach, an additional upscaling factor is based on the eco‐efficiency (ratio between turnover and environmental impact) of the product or sector. A demonstration of the method's application is given by applying the framework to two of the planetary boundaries, climate change and biogeochemical flows, with the Danish, Indian and global dairy sectors as cases. It is demonstrated how the choices of allocation and upscaling approaches influence the results differently in the three cases. The developed framework is shown to support an informed and transparent selection of allocation principles and upscaling methods and it provides a step toward standardization of distributing the SOS in absolute environmental sustainability assessments.     

Emergy and end-point impact assessment of agricultural and food production in the United States: A supply chain-linked Ecologically-based Life Cycle Assessment

The concept of tracing the ecologically-based life cycle impacts of agricultural and food industries (AFIs) has become a topic of interest worldwide due to their critical association with the climate change, water and land footprint, and food security. In this study, an in-depth analysis of ecological resource consumption, atmospheric emissions, land and water footprints of 54 agricultural and food industries in the U.S. were examined extensively. Initially, the supply-chain linked ecological life cycle assessment was performed with Ecologically-based Life Cycle Assessment (Eco-LCA) tool. Then, the results of life cycle inventory were used to assess the mid and end-point impacts by using the ReCiPe approach. Thirdly, ecological performance assessment was performed using well-known metrics, including loading and renewability ratios and eco-efficiency analysis. As a novel comprehensive approach, the integrated framework that consists of the Eco-LCA, ReCiPe and linear programming-based ecological performance assessment is of importance to have an overall understanding about the extent of impacts related to agricultural and food production activities across the U.S. Results indicated that grain farming, dairy food, and animal production-related sectors were found to have the greatest shares in both environmental and ecological impact categories as well as endpoint impacts on human health, ecosystem and resources. In terms of climate change, animal (except poultry) slaughtering, rendering, and processing (ASRP), cattle ranching and farming (CRF), fertilizer manufacturing (FM), grain farming (GF), fluid milk and butter manufacturing (FMBM) were found to be the top five dominant industries in climate change impacts accounting for about 60% share of the total impact.     

典型移民城市食物氮足迹估算分析——以深圳市为例

城市食物源氮消费产生的环境排放是全国氮污染的重要源头,城市食物氮足迹评估可反映维持城市人口基本食物需求的活性氮排放以及对周边环境的潜在影响。以典型移民城市深圳市为例,基于改进N-Calculator模型的基础上,估算了2010-2015年间因城市人口流动导致的城市食物氮足迹变化,并分析其时空异质性及其与城市化间的关系。结果表明：深圳市不同类型城市居民食物氮足迹不一致,其中常住户籍居民人均食物氮足迹从14.63 kg N a^-1增加至15.17 kg N a^-1,高于非户籍居民食物氮足迹13.09 kg N a^-1,其主要体现在瓜果、肉类、水产品等食物消费上。总体上,深圳城市食物氮足迹呈增长趋势,5年增幅11.50%,增幅最大为常住户籍居民食物氮足迹,但目前深圳非户籍居民的食物消费主导着城市食物氮足迹。深圳城市内部区域食物氮足迹呈高度空间异质性与聚集性,各区域增长量差异明显,街道尺度城市食物氮足迹增长热点主要分布在城市的西部沿海区域,部分热点区域单位增长量数量级比肩区级尺度单位的增长量,城市区域食物氮足迹与人口城市化的关联性不明显,但与经济城市化存在一定的关联性。当前城市移民落户趋势及居民高氮饮食倾向不利于城市氮足迹的削减,减少食物生产上游活性氮流失为深圳市贯彻粤港澳大湾区协同可持续发展的关键。