足跡家族研究綜述

方 愷

1荷蘭萊頓大學環境科學系，萊頓 2333CC 2浙江大學環境與能源政策研究中心，杭州 310058

足跡家族研究綜述

方 愷1,2,*

1荷蘭萊頓大學環境科學系，萊頓 2333CC 2浙江大學環境與能源政策研究中心，杭州 310058

綜合測度人類社會的可持續發展狀態是生態經濟學者追求的重要目標。足跡家族由生態足跡、碳足跡和水足跡等一系列足跡類指標整合而成，旨在為決策者系統評估與權衡人類活動的環境影響提供理論和技術支持。從理論探索、整合實踐和分類比較等三方面對足跡家族的研究現狀進行了綜述；在此基礎上圍繞極具爭議的足跡定義、計算方法和加權方式等問題，深入分析了阻礙當前研究進一步推進的關鍵性因素；指出未來應從建立足跡類型學、完善跨區域投入產出模型、細化產品和機構環境足跡標準等方面入手，推動實現足跡家族的量化整合；并首次提出了足跡家族與行星邊界耦合的構想，以期為監測和預警人類活動的生態閾值、促進環境影響評價向可持續性評價轉變提供科學依據。

足跡家族；量化整合；指標分類；行星邊界；進展

現代生態學之父Odum[1]通過查考生態學(ecology)與經濟學(economics)的希臘語詞源，認為這2個分屬自然科學和社會科學的學科之間應具有某些天然的聯系[2]。生態學家與經濟學家之所以在某些問題上持對立觀點，是因為雙方的研究視角都有一定的局限性。在這樣的背景下，生態經濟學(ecological economics)應運而生。作為連接生態學與經濟學的交叉學科，生態經濟學具有彌合分歧、促進融合的重要意義[3]。

以生態足跡、碳足跡和水足跡等為代表的足跡類指標，是生態經濟學研究的重要對象和手段，正日益受到學界、政府乃至公眾的廣泛關注[4]。隨著人類對環境問題的復雜性、整體性與全球性特征的認識不斷加深，任何單一足跡指標已無法滿足環境影響綜合評估的需要[5]。足跡家族概念的提出，標志著足跡研究重心正逐步由單指標的定量測度向多指標的集成整合演進[6]。足跡家族研究開展僅短短數年，但已經取得了一批重要的階段性成果。本文在系統梳理足跡家族研究進展的基礎上，聚焦限制當前研究進一步深入的主要問題，并據此展望未來發展方向，以期為我國學者開展相關研究提供參考。

1 研究現狀與進展

1.1 足跡家族理論探索

國際上的足跡研究由3大學術群體共同主導：全球足跡網絡(Global Footprint Network, GFN)主導生態足跡[7]；水足跡網絡(Water Footprint Network, WFN)主導水足跡[8]；生命周期評價(Life Cycle Assessment, LCA)主導碳足跡[9]。足跡家族概念的提出，是一次將系統論觀點引入生態經濟學理論的有益嘗試，有助于打破目前這種單打獨斗、各自為戰的局面，加強學術群體之間的溝通與交流。

1.2 足跡家族整合實踐

足跡整合是足跡家族研究的重點與難點。國際上一些學者以此為切入點進行了有益的嘗試(表1)，歸納起來主要包括以下幾方面：

(1) 組成多樣化 理論上，任何2類及以上的足跡指標都可以組成特定的足跡家族[6]。在整合實踐中，足跡家族研究大多包含了碳足跡和水足跡，以及生態足跡、能源足跡和土地足跡等足跡中的一種或幾種類型。

(2) 模型規范化 多數研究基于LCA或一系列MRIO模型，對不同足跡指標的計算過程進行規范化、可視化操作，以便實現足跡類指標的方法學融合，從而保證計算結果的一致性與可比性。

(4) 數據網絡化 在Ewing[20]、Galli[21]等一批國際學者研究的基礎上，歐盟建立起EUREAPA在線數據庫[24]，完成了全球45個國家和地區及其57個產業部門的生態足跡、碳足跡和水足跡計算，所有數據均免費下載并可模擬不同情景下的足跡變化趨勢。

表1 足跡指標整合研究文獻綜述Table 1 Literature review of the studies on integrating footprint indicators

*DDT: 目標距離法Distance-to-Target；**MRIO: 跨區域投入產出Multiregional Input-Output；***IPCC: 政府間氣候變化專門委員會Intergovernmental Panel on Climate Change；****NPP: 凈初級生產力Net Primary Production

1.3 足跡指標比較與分類

正如家庭成員存在角色分工一樣，不同足跡指標在足跡家族中的地位與作用也有顯著差異[6]。綜合當前足跡比較研究的主要成果(表2)，可以得出以下結論：①每類足跡指標都只能反映環境影響的一個方面，故不宜單純依靠某類指標進行決策；②足跡指標往往具有此消彼長的關系，降低某一足跡可能導致其他足跡指標的增高，因此需要權衡不同減排方案的潛在影響；③足跡指標在決策支持方面具有互補性，通盤考量才能較為全面、客觀地評估人類活動的環境影響；④隨著LCA廣泛應用于足跡指標的量化，有必要系統分析基于LCA方法的足跡指標與基于非LCA方法的足跡指標在清單分析、環境影響評價等方面的方法學差異，辯證看待LCA與足跡研究之間的關系[31]。

此外，足跡指標的分類研究也是近年來的熱點之一。常見的生態足跡、碳足跡、水足跡、能源足跡[32]、生物多樣性足跡[33]、化學足跡[34]、氮足跡[35]和磷足跡[36]均旨在評估由資源消費或廢料排放導致的某一類具體環境影響，可視為影響導向型足跡；而如產品足跡[37]、部門足跡[38]、國家足跡[39]則致力于研究特定尺度對象的局部或全局環境影響，屬于對象導向型足跡。從嚴格意義上來說，任何足跡應用研究均需要同時指明所屬的對象類型和影響類型，如某一產品的碳足跡、部門的水足跡、國家的生態足跡等。

表2 足跡指標比較研究文獻綜述Table 2 Literature review of comparative studies of footprint indicators

2 主要問題與爭論

2.1 足跡概念的定義

圍繞如何定義“足跡”概念而展開的爭論由來已久(表3)。起初，人們習慣將其等同于Wackernagel[7]所定義的生態足跡，即人類的生物資源消費和化石能源碳排放所需占用的生態生產性土地和水域面積。Hammond[41]據此斷言足跡必須以空間物理量為單位，并改稱碳足跡為碳質量。而隨著碳足跡和水足跡等指標的引入，足跡概念的外延日趨寬泛和多樣化，很多學者將其視為表征資源消費水平或環境影響強度的指標。近年來，一系列經濟社會領域足跡指標的興起，如經濟足跡[13]、社會足跡[13]、天堂足跡[48]、雇傭足跡[49]等，使得上述定義的合理性再次遭受質疑。為此，UNEP/SETAC[44]、Peters[45]、Steen-Olsen[46]分別從全球可持續性和消費者負責等視角重新審視足跡概念。可以預見，隨著足跡家族成員陣容的擴大，足跡概念的內涵與外延也將繼續深化和擴展，體現可持續發展環境、經濟、社會三重支柱的廣義足跡概念更能反映該領域發展的實際趨勢。

表3 足跡定義文獻綜述Table 3 Literature review of the definitions of the footprint concept

*GDP: 國內生產總值Gross Domestic Product

2.2 計算方法的選取

足跡類指標的計算方法雖然眾多，但均有一定的適用條件。因此，找尋規范化的計算路徑頗有意義。目前，有關足跡計算的方法學討論主要集中在生態足跡、碳足跡和水足跡，以這3類足跡指標為例(表4)，同時適用的量化方法主要包括以下幾種：

(1) LCA 產業生態學的重要分析方法，用于評估產品系統物質流輸入、輸出的一系列潛在環境影響[73-74]。由于LCA覆蓋“從搖籃到墳墓”的產品全生命周期，有助于破除“有煙囪才有污染”的末端治理觀念，加之技術框架成熟、分析過程規范、定量結果可靠，目前已成為足跡類指標特別是碳足跡計算的常規方法。基于過程的LCA是一種自下而上(bottom-up)的分析方法，在確定系統邊界的過程中不可避免地存在截斷誤差，對數據精度的要求也較高，因此基本不適用于區域及以上尺度足跡研究。

(2) IOA 與LCA相反，是一種典型的自上而下(top-down)分析方法，由Leontief[75]提出并用于國民經濟核算。該方法通過編制投入產出表，運用線性代數構建數學模型，既清晰地揭示了社會最終需求與各生產和再生產部門之間投入產出的復雜聯系[76]，又節省了大量的人力物力成本。不過該方法只能反映部門平均水平，難以針對具體產品。隨著人類產業活動引發的生態環境問題日益嚴重，IOA也被用于研究溫室氣體排放和自然資源(水、土地、原材料等)利用的結構與數量等環境問題，相繼與生態足跡、碳足跡和水足跡等足跡指標結合，成為部門、區域和國家尺度上足跡計算的主要方法。

(3) 混合方法(hybrid method) 兼具LCA和IOA的優勢，既能保證研究精度又能節省人力物力，因而有著更為廣泛的適用范圍[20,45,66]。值得注意的是，表4所謂的方法學大類“自下而上”和“自上而下”，盡管理論上計算過程完全相反[77]，但實際界定并不十分清晰。以生態足跡的經典計算方法NFA為例[7,57]，GFN原先認為其屬于IOA(自上而下)的一個特例[78]，后又將其歸入過程分析(自下而上)的范疇[79]，可見自下而上與自上而下兩種方法之間存在交叉重疊，這一部分不妨也視為混合方法。

上述3類方法的適用范圍如圖1所示。盡管各尺度上的足跡指標均有對應的計算方法，但仍然缺乏一個橫跨材料尺度到全球尺度的普適性方法。如何破解尺度轉換性障礙是足跡家族研究面臨的重大挑戰。

2.3 權重系數的確定

權重賦值始終是指標整合研究中一個極具爭議的話題[80-81]。足跡家族力圖揭示可持續發展復雜系統的運行機制，不可避免地需要通過指標加權來綜合評估和權衡人類活動的影響。表5對比了7類足跡指標內部各自的加權方式，發現均采用的是線性加權聚合，遵循“總體等于部分之和”的思想，這顯然與系統論的核心理念“總體不等于部分之和”相抵觸[86]。此外，由于權重的確定多少會帶有一些主觀性[80]，所以無論是生態足跡的均衡因子加權，還是水足跡的等量加權，都存在質疑和批評聲[87-88]。但碳足跡是一個例外，其權重賦值基于反映環境機理的GWP特征化模型，能夠客觀地描述不同溫室氣體對氣候變化的潛在影響，因而具有廣泛的科學共識[16,80,88]。

表4 生態足跡、碳足跡和水足跡在不同尺度研究中的方法歸納[14]Table 4 Summary of the approaches to the ecological, carbon and water footprints across scales[14]

*IOA: 投入產出分析Input-Output Analysis；**NFA: 國家足跡核算National Footprint Accounts；***MEA：千年生態系統評估Millennium Ecosystem Assessment;凡文獻未詳細說明采用何種方法，均粗略劃分為“自下而上”或“自上而下”

圖1 不同尺度生態足跡、碳足跡和水足跡的適用方法 Fig.1 The range of applicability for different footprint approaches across scales

通過分析足跡指標內部的加權方式，對足跡間權重賦值的啟示有以下幾點：①目前的線性加權特別是等量加權，具有很大的主觀性和不確定性，故很難反映復雜環境系統的客觀實際；②部分足跡指標的核算賬戶有重疊(如碳足跡與能源足跡)，進一步限制了足跡間加和的可能性；③解決各類足跡指標的計量單位不一致問題(如生態足跡基于面積、碳足跡基于質量、水足跡基于體積)，一個可行的途徑是結果標準化，對應的參考系既可以是特定的產品系統，也可以是某一區域乃至全球；④為降低二次加權(足跡內部和足跡之間)的不確定性，在采用如DDT等方法進行足跡間加權之前，在各類足跡內部的清單物質(如生態足跡中的土地類型、碳足跡中的溫室氣體)的分析及加和過程中，最好用科學的特征化因子取代人為權重系數。

3 研究展望

3.1 足跡類型學研究

隨著新興足跡的不斷涌現(圖2)，足跡類型學研究顯得愈加重要。值得一提的是，我國學者近年來在海洋足跡[89]、化工足跡[90]、污染足跡[91-92]以及基于生態系統服務的生態足跡[93-94]等方面做了大量有益的探索，豐富和擴大了足跡家族的內涵與外延。有必要全面分析和歸納現有的足跡指標，考察其特性與共性，對某些有鮮明共性的指標進行歸類，從而建立一批具有特定功能指向的足跡家族，以適應多角度、多層次評估人類活動影響的需要。例如，碳足跡雖然標榜指示氣候變化，但事實上溫室效應僅是氣候變化的一個重要部分[45]，其他如土地利用變化引發的碳源/匯改變，臭氧層空洞導致的紫外線輻射增加，硫化物、氮氧化物以及其他顆粒物對大氣理化性質的影響等，長期而言均會對氣候造成一定影響。因此，由這些對應環境足跡組成的足跡家族將比單單碳足跡更好地反映人為氣候變化效應。

表5 各類足跡指標的加權方式Table 5 Summary of the weighting schemes for different footprints

*碳足跡的組成采用京都議定書所推薦的6大類溫室氣體，GWP: 全球暖化潛值Global Warming Potential;這里取100a時間跨度，其單位為碳質量當量(kg CO2-eq.)；**等量加權(equal weighting)即指所有組分的權重系數均為1，此時權重系數略去不寫；***能源足跡的權重系數是指每1000kg不同類型燃料折算成足跡時需要乘以的系數[83]；****非生物資源足跡主要考慮金屬和礦物等的稀缺性，ADP: 非生物消耗潛值Abiotic Depletion Potential;根據1999年主要非生物資源的全球儲量及當年開采速度進行計算[85]，其單位為銻質量當量(kg Sb-eq.)；*****由于相關資料缺乏，生物多樣性足跡等量加權所有可能威脅物種數量的因素

此外，足跡類型學研究也將為探尋更加科學、合理和有針對性的足跡概念奠定基礎。任何定義都有其適用的邊界條件，即便是同一名稱的足跡指標，也應根據采用的具體方法界定其所屬類型。這無疑有賴于對足跡指標背后方法學異同的精準辨析。以水足跡為例，除了常規的WFN水足跡外，Pfister[95]、Ridoutt[68]提出基于水稀缺性指數(Water Scarcity Index, WSI)計算本地水足跡。WSI可以視為類似于GWP的特征化因子，所以基于WSI的水足跡應與碳足跡、而不是WFN水足跡歸為一類。當然，足跡分類并非一成不變，應該根據研究需要靈活進行。有理由相信，通過推進足跡類型學，整個足跡家族研究的深度和廣度都將得到拓展。

圖2 足跡指標發展的時間軸Fig.2 Timeline of the development of footprint indicators

3.2 基于MRIO模型的足跡指標量化研究

IOA自創立以來，在定量研究區域經濟及其環境問題方面發揮了主導作用。在此基礎上，區域間投入產出(Interregional Input-Output, IRIO)和MRIO等IOA擴展模型相繼提出，旨在精準描繪部門間和區域間的全部投入產出關系。與IRIO相比，MRIO對數據資料要求較少，計算區域內技術系數和區域間貿易系數的過程也大幅簡化[96-97]。作為經濟學原理成功應用于環境研究的范例，MRIO模型能夠清晰追蹤環境影響的地理空間分布信息[97]，從而為量化廢料排放或資源消費的跨區域轉移與分布提供了一條切實可行的途徑。總之，MRIO模型已成為中、宏觀尺度上足跡類指標計算的重要方法[14,98]。

圖3 基于MRIO系列模型的多足跡量化研究指標網絡 Fig.3 Indicator network of the multi-footprinting quantitative analyses based on a series of MRIO models節點間的緊密度隨實線、長虛線和短虛線遞減。土地足跡和能源足跡分別對應生態足跡中的生物生產性土地和碳吸收地部分。

采用文獻計量學手段，對基于標準MRIO、環境擴展MRIO(EE-MRIO)或混合環境擴展MRIO(hybrid EE-MRIO)模型的多足跡指標(≥2)研究論文進行全面分析，發現當前MRIO足跡研究呈現碳足跡與水足跡雙核驅動的指標分布網絡，且此2節點間的聯系也最為緊密(圖3)。這也基本上反映了不同足跡指標在足跡家族中的地位差異。總之，開展基于MRIO模型的足跡指標量化研究，既可以保證計算方法的一致性與兼容性，又能為指標結果的標準化和權重化奠定基礎，是目前中、宏觀尺度足跡家族量化整合的首選模型。

3.3 產品和機構環境足跡標準研究

歐盟于近期發布了產品環境足跡(Product Environmental Footprint, PEF)和機構環境足跡(Organization Environmental Footprint, OEF)標準方法導則[99-100]，首次提出從生命周期的角度規范化地評估產品和機構的整體環境影響。無論是OEF還是PEF都與足跡家族的概念緊密相連：PEF可以有效避免因依賴單一指標(如碳足跡)而導致的環境負擔轉嫁問題[101]，未來還可能以標簽的形式貼在每件出廠產品上，從環保角度為消費者選購商品提供參考；OEF由于涉及對所研究機構(工廠、企業、學校、社區等)生命周期系統邊界的明確定義，并以此為基礎分析整個系統內部及其與外部的復雜物質流動和交換，因而較之PEF更具挑戰性[102]。

值得注意的是，上述兩份導則乍一發布就引發了兩種截然不同的看法：支持者認為相較于現有LCA方法優勢明顯[38]；反對者則認為與目前的LCA標準相抵觸，不僅無益于方法統一，反而會加深學科內部的分歧與對立[37]。筆者認為，若要真正實踐PEF和OEF，在影響類型的選取、權重系數的確定等問題上都需要更加詳盡的操作細則。此外，厘清PEF與現有產品LCA[103-104]等領域的關系將會對合理界定足跡概念起到借鑒作用，比如不少關于產品貿易隱含碳、虛擬水、虛擬土地的研究盡管沒有采用“足跡”式稱謂，但基本思路與碳足跡、水足跡、生態足跡相似甚至完全一致，是否一并納入足跡研究范疇值得思考。

3.4 足跡家族與行星邊界耦合研究

足跡家族表征人類活動作用于地球環境系統的影響，屬于靜態的回顧性評估，缺乏實際的決策咨詢價值，無法回答產生影響的壓力源是否可控[14,105]。鑒于此，可以考慮將承載力的研究成果引入目前研究。行星邊界(planetary boundaries)是近年來承載力領域最重要的一項成果，由Rockstr?m[106-107]于2009年提出，旨在為全球尺度的重要環境問題劃定“生態紅線”。如表6所示，行星邊界共設置了10項地球環境系統過程的生物物理參數閾值，并對工業革命以前和現在的水平進行估算，據此判斷人類活動的“越界”程度。由于行星邊界實現了對地球拐點的定量預測預警，Nature及其子刊曾辟專欄加以評論。國內迄今未見相關的文獻報道，令人遺憾。

表6 行星邊界概念框架[106-107]Table 6 Conceptual framework for planetary boundaries

當然，與很多生態環境領域研究成果一樣，行星邊界理論也招致了激烈的抨擊和質疑[108-110]。一個關鍵性的問題在于其對現狀參數的估計全部基于專家知識，因而帶有較大的主觀成分，而現狀影響評估恰恰是足跡類指標的強項。因此，將足跡家族與行星邊界結合起來，有望真正實現由環境影響評價向可持續性評價的轉變[111]：一方面，足跡研究相對成熟的量化手段能夠為行星邊界提供更加客觀、準確的現狀評估結果作參照；另一方面，行星邊界又為足跡家族預測人類活動的臨界值、劃定剩余的安全操作空間提供了可能。足跡家族與行星邊界耦合研究亟需一批不同專業知識背景(如生態學、環境科學、資源科學、地球科學、系統科學、社會科學等)的專家學者廣泛參與，跨學科、跨團隊的國際學術合作勢在必行。

[1] Odum E P, Barrett G W.Fundamentals of Ecology.5th ed.Belmont: Thomson Brooks/Cole Publishing Company, 2005.

[2] 陽含熙.生態學的過去、現在和未來.自然資源學報, 1989, 4(4): 355-361.

[3] 包慶德, 張秀芬.《生態學基礎》: 對生態學從傳統向現代的推進——紀念E.P.奧德姆誕辰100周年.生態學報, 2013, 33(24): 7623-7629.

[4] 徐中民, 程國棟, 張志強.生態足跡方法的理論解析.中國人口·資源與環境, 2006, 16(6): 69-78.

[5] Chapman P M, Maher B.The need for truly integrated environmental assessments.Integrated Environmental Assessment and Management, 2014, 10(2): 151-151.

[6] 方愷.足跡家族：概念、類型、理論框架與整合模式.生態學報, 2015, 35(6): 1-13, doi: 10.5846/stxb201305211128

[7] Wackernagel M, Rees W E.Our Ecological Footprint: Reducing Human Impact on the Earth.Gabriola Island: New Society Publishers, 1996.

[8] Hoekstra A Y, Hung P Q.Virtual water trade: A quantication of virtual waterows between nations in relation to international crop trade // Value of Water Research Report Series (No.11).Delft: UNESCO-IHE Institute for Water Education, 2002.

[9] Wiedmann T, Minx J.A denition of ‘carbon footprint′.ISAUKResearch Report (No.07-01), Durham, 2007.

[10] Giljum S, Hinterberger F, Lutter S.Measuring natural resource use: context, indicators and EU policy processes.SERI Background Paper 14.Vienna: SERI, 2008.

[11] Stoeglehner G, Narodoslawsky M.Implementing ecological footprinting in decision-making processes.Land Use Policy, 2008, 25(3): 421-431.

[12] Galli A, Wiedmann T, Ercin E, Knoblauch D, Ewing B, Giljum, S.Integrating ecological, carbon and water footprint into a “Footprint Family” of indicators: Definition and role in tracking human pressure on the planet.Ecological Indicators, 2012, 16: 100-112.

[13] Cˇucˇek L, Kleme? J J, Kravanja Z.A review of Footprint analysis tools for monitoring impacts on sustainability.Journal of Cleaner Production, 2012, 34: 9-20.

[14] Fang K, Heijungs R, de Snoo G R.Theoretical exploration for the combination of the ecological, energy, carbon, and water footprints: Overview of a footprint family.Ecological Indicators, 2014, 36: 508-518.

[15] Hoekstra A Y, Wiedmann T O.Humanity′s unsustainable environmental footprint.Science, 2014, 344: 1114-1117.

[16] Ridoutt B G, Pster S.Towards an integrated family of footprint indicators.Journal of Industrial Ecology, 2013, 17(3): 337-339.

[17] Cagiao J, Gómez B, Doménech J L, Mainar S G, Lanza H G.Calculation of the corporate carbon footprint of the cement industry by the application of MC3methodology.Ecological Indicators, 2011, 11(6): 1526-1540.

[18] Cˇucˇek L, Varbanov P S, Kleme? J J, Kravanja Z.Total footprints-based multi-criteria optimisation of regional biomass energy supply chains.Energy, 2012, 44(1): 135-145.

[19] de Benedetto L, Kleme? J.The Environmental Performance Strategy Map: an integrated LCA approach to support the strategic decision-making process.Journal of Cleaner Production, 2009, 17(10): 900-906.

[20] Ewing B R, Hawkins T R, Wiedmann T O, Galli A, Ercin E A, Weinzettel J, Steen-Olsen K.Integrating ecological and water footprint accounting in a multi-regional input-output framework.Ecological Indicators, 2012, 23: 1-8.

[21] Galli A, Weinzettel J, Cranston G, Ercin E.A Footprint Family extended MRIO model to support Europe′s transition to a One Planet Economy.Science of the Total Environment, 2013, 461-462: 813-818.

[22] Ridoutt B G, Page G, Opie K, Huang J, Bellotti W.Carbon, water and land use footprints of beef cattle production systems in southern Australia.Journal of Cleaner Production, 2014, 73: 24-30.

[23] Shepon A, Israeli T, Eshel G, Milo R.EcoTime—An intuitive quantitative sustainability indicator utilizing a time metric.Ecological Indicators, 2013, 24: 240-245.

[24] Roelich K, Owen A, Thompson D, Dawkins E, West C.Improving the policy application of footprint indicators to support Europe′s transition to a one planet economy: The development of the EUREAPA tool.Science of the Total Environment, 2014, 481: 662-667.

[25] Chakraborty D, Roy J.Energy and carbon footprint: numbers matter in low energy and low carbon choices.Current Opinion in Environmental Sustainability, 2013, 5(2): 237-243.

[26] Cˇucˇek L, Kleme? J J, Varbanov P S, Kravanja Z.Life cycle assessment and multi-criteria optimization of regional biomass and bioenergy supply chains.Chemical Engineering Transactions, 2011, 25: 575-580.

[27] de Meester S, Callewaert C, de Mol E, van Langenhove H, Dewulf J.The resource footprint of biobased products: a key issue in the sustainable development of biorefineries.Biofuels, Bioproducts &Biorefining, 2011, 5(5): 570-580.

[28] Hanafiah M M, Hendriks A J, Huijbregts M A J.Comparing the ecological footprint with the biodiversity footprint of products.Journal of Cleaner Production, 2012, 37: 107-114.

[29] Hoekstra A Y.Human appropriation of natural capital: a comparison of ecological footprint and water footprint analysis.Ecological Economics, 2009, 68(7): 1963-1974.

[30] Page G, Ridoutt B, Bellotti B.Carbon and water footprint tradeoffs in fresh tomato production.Journal of Cleaner Production, 2012, 32: 219-226.

[31] Fang K, Heijungs R.Rethinking the relationship between footprints and LCA.Environmental Science &Technology, 2015, 49(1): 10-11.

[32] Ferng J J.Toward a scenario analysis framework for energy footprints.Ecological Economics, 2002, 40(1): 53-69.

[33] Lenzen M, Moran D, Kanemoto K, Foran B, Lobefaro L, Geschke A.International trade drives biodiversity threats in developing nations.Nature, 2012, 486(7401): 109-112.

[34] Guttikunda S K, Tang Y H, Carmichael G R, Kurata G, Pan L, Streets D G, Woo J-H, Thongboonchoo N, Fried A.Impacts of Asian megacity emissions on regional air quality during spring 2001.Journal of Geophysical Research, 2005, 110(D20), D20301, doi: 10.1029/2004JD004921.

[35] Leach A M, Galloway J N, Bleeker A, Erisman J W, Kohn R, Kitzes J.A nitrogen footprint model to help consumers understand their role in nitrogen losses to the environment.Environmental Development, 2012, 1(1): 40-66.

[36] Wang F, Sims J T, Ma L, Ma W, Dou Z, Zhang F.The phosphorus footprint of China′s food chain: implications for food security, natural resource management, and environmental quality.Journal of Environmental Quality, 2011, 40(4): 1081-1089.

[37] Finkbeiner M.Product environmental footprint—breakthrough or breakdown for policy implementation of life cycle assessment?.The International Journal of Life Cycle Assessment, 2014, 19(2): 266-271.

[38] Pelletier N, Allacker K, Pant R, Manfredi S.The European Commission Organisation Environmental Footprint method: comparison with other methods, and rationales for key requirements.The International Journal of Life Cycle Assessment, 2014, 19(2): 387-404.

[39] GFN.National Footprint Accounts.2012ed.[2014-04-25].http://www.footprintnetwork.org/images/article_uploads/National_Footprint_Accounts_2012_Edition_Report.pdf.

[40] Costanza R.The dynamics of the ecological footprint concept.Ecological Economics, 2000, 32(3): 341-345.

[41] Hammond G.Time to give due weight to the ‘carbon footprint′ issue.Nature, 2007, 445(7125): 256-256.

[42] Lenzen M.An outlook into a possible future of footprint research.Journal of Industrial Ecology, 2014, 18(1): 4-6.

[43] Lifset R.Frontiers in footprinting.Journal of Industrial Ecology, 2014, 18(1): 1-3.

[44] UNEP/SETAC.Life cycle management—how business uses it to decrease footprint, create opportunities and make value chains more sustainable.[2011-10-05].http://www.unep.fr/shared/publications/pdf/DTIx1208xPA-LifeCycleApproach-Howbusinessusesit.pdf.

[45] Peters G P.Carbon footprints and embodied carbon at multiple scales.Current Opinion in Environmental Sustainability, 2010, 2(4): 245-250.

[46] Steen-Olsen K, Weinzettel J, Cranston G, Ercin A E, Hertwich E G.Carbon, land, and water footprint accounts for the European Union: Consumption, production, and displacements through international trade.Environmental Science &Technology, 2012, 46(20): 10883-10891.

[47] Vogelsang K M.Footprint: ignoring the facts that don′t fit the theory.Nature, 2002, 420(6913): 267-267.

[48] Kocsis T.Looking through the dataquadrate: characterizing the human-environment relationship through economic, hedonic, ecological and demographic measures.Journal of Cleaner Production, 2012, 35: 1-15.

[49] Alsamawi A, Murray J, Lenzen M.The employment footprints of nations.Journal of Industrial Ecology, 2014, 18(1): 59-70.

[50] Huijbregts M A J, Hellweg S, Frischknecht R, Hungerbühler K, Hendriks A J.Ecological footprint accounting in the life cycle assessment of products.Ecological Economics, 2008, 64(4): 798-807.

[51] Simmons C, Lewis K, Barrett J.Two feet-two approaches: a component-based model of ecological footprinting.Ecological Economics, 2000, 32(3): 375-380.

[52] Limnios E A M, Ghadouani A, Schilizzi S G, Mazzarol T.Giving the consumer the choice: A methodology for Product Ecological Footprint calculation.Ecological Economics, 2009, 68(10): 2525-2534.

[53] Hubacek K, Giljum S.Applying physical input-output analysis to estimate land appropriation (ecological footprints) of international trade activities.Ecological Economics, 2003, 44(1): 137-151.

[54] Bastianoni S, Galli A, Pulselli R M, Niccolucci V.Environmental and economic evaluation of natural capital appropriation through building construction: practical case study in the Italian context.AMBIO: A Journal of the Human Environment, 2007, 36(7): 559-565.

[55] Zhao S, Song K, Gui F, Cai H W, Jin W H, Wu C W.The emergy ecological footprint for small fish farm in China.Ecological Indicators, 2013, 29: 62-67.

[56] Lenzen M, Kanemoto K, Moran D, Geschke A.Mapping the structure of the world economy.Environmental Science &Technology, 2012, 46(15): 8374-8381.

[57] Borucke M, Moore D, Cranston G, Gracey K, Iha K, Larson J, Lazarus E, Morales J C, Wackernagel M, Galli A.Accounting for demand and supply of the biosphere′s regenerative capacity: the National Footprint Accounts′ underlying methodology and framework.Ecological Indicators, 2013, 24: 518-533.

[58] Venetoulis J, Talberth J.Refining the ecological footprint.Environment Development and Sustainability, 2008, 10(4): 441-469.

[59] Burkhard B, Kroll F, Nedkov S, Müller F.Mapping ecosystem service supply, demand and budgets.Ecological Indicators, 2012, 21: 17-29.

[60] Zhao S, Li Z Z, Li W L.A modified method of ecological footprint calculation and its application.Ecological Modelling, 2005, 185(1): 65-75.

[61] Chen B, Chen G Q.Modified ecological footprint accounting and analysis based on embodied exergy—a case study of the Chinese society 1981—2001.Ecological Economics, 2007, 61(2/3): 355-376.

[62] Carballo-Penela A, Doménech J L.Managing the carbon footprint of products: the contribution of the method composed of financial statements (MC3).The International Journal of Life Cycle Assessment, 2010, 15(9): 962-969.

[63] Virtanen Y, Kurppa S, Saarinen M, Katajajuuri J M, Usva K, M?enp?? I, M?kel? J, Gr?nroos J, Nissinen A.Carbon footprint of food-approaches from national input-output statistics and a LCA of a food portion.Journal of Cleaner Production, 2011, 19(16): 1849-1856.

[64] Huang Y A, Lenzen M, Weber C L, Murray J, Matthews H S.The role of input-output analysis for the screening of corporate carbon footprints.Economic Systems Research, 2009, 21(3): 217-242.

[65] Sanyé E, Oliver-Solà J, Gasol C M, Farreny R, Rieradevall J, Gabarrell X.Life cycle assessment of energy flow and packaging use in food purchasing.Journal of Cleaner Production, 2012, 25: 51-59.

[66] Berners-Lee M, Howard D C, Moss J, Kaivanto K, Scott W A.Greenhouse gas footprinting for small businesses—The use of input-output data.Science of the Total Environment, 2011, 409(5): 883-891.

[67] Hertwich E G, Peters G P.Carbon footprint of nations: a global, trade-linked analysis.Environmental Science &Technology, 2009, 43(16): 6414-6420.

[68] Ridoutt B G, Pfister S.A revised approach to water footprinting to make transparent the impacts of consumption and production on global freshwater scarcity.Global Environmental Change, 2010, 20(1): 113-120.

[69] Chapagain A K, Hoekstra A Y, Savenije H H G., Gautam R.The water footprint of cotton consumption: An assessment of the impact of worldwide consumption of cotton products on the water resources in the cotton producing countries.Ecological Economics, 2006, 60(1): 186-203.

[70] van Oel P R, Mekonnen M M, Hoekstra A Y.The external water footprint of the Netherlands: Geographically-explicit quantification and impact assessment.Ecological Economics, 2009, 69(1): 82-92.

[71] Zhao X, Chen B, Yang Z F.National water footprint in an input-output framework—a case study of China 2002.Ecological Modelling, 2009, 220(2): 245-253.

[72] Hoekstra A Y, Mekonnen M M.The water footprint of humanity.Proceedings of the National Academy of Sciences of the United States of America, 2012, 109(9): 3232-3237.

[73] Guinee J B, Heijungs R, Huppes G, Zamagni A, Masoni P, Buonamici R, Ekvall T, Rydberg T.Life cycle assessment: past, present, and future.Environmental Science &Technology, 2010, 45(1): 90-96.

[74] 施曉清, 李笑諾, 楊建新.基于生命周期視角的產業資源生態管理效益分析——以虛擬共生網絡系統為例.生態學報, 2013, 33(19): 6398-6410.

[75] Leontief W.Input-Output Economics.2th ed.New York: Oxford University Press, 1986.

[76] 曹淑艷, 謝高地.基于投入產出分析的中國生態足跡模型.生態學報, 2007, 27(4): 1499-1507.

[77] Feng K S, Chapagain A, Suh S, Pfister S, Hubacek K.Comparison of bottom-up and top-down approaches to calculating the water footprints of nations.Economic Systems Research, 2011, 23(4): 371-385.

[78] Kitzes J, Galli A, Bagliani M, Barrett J, Dige G, Ede S, Erb K, Giljum S, Haberl H, Hails C, Jolia-Ferrier L, Jungwirth S, Lenzen M, Lewis K, Loh J, Marchettini N, Messinger H, Milne K, Moles R, Monfreda C, Moran D, Nakano K, Pyh?l? A, Rees W, Simmons C, Wackernagel M, Wada Y, Walsh C, Wiedmann T.A research agenda for improving national Ecological Footprint accounts.Ecological Economics, 2009, 68(7): 1991-2007.

[79] Weinzettel J, Steen-Olsen K, Hertwich E G., Borucke M, Galli A.Ecological footprint of nations: Comparison of process analysis, and standard and hybrid multiregional input-output analysis.Ecological Economics, 2014, 101: 115-126.

[80] Finnveden G, Hauschild M Z, Ekvall T, Guinée J, Heijungs R, Hellweg S, Koehler A, Pennington D, Suh S.Recent developments in life cycle assessment.Journal of Environmental Management, 2009, 91(1): 1-21.

[81] Ahlroth S, Nilsson M, Finnveden G, Hjelm O, Hochschorner E.Weighting and valuation in selected environmental systems analysis tools-suggestions for further developments.Journal of Cleaner Production, 2011, 19(2/3): 145-156.

[82] IPCC.Climate change 2007: The physical science basis.Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change.Cambridge: Cambridge University Press, 2007.

[83] 方愷, 董德明, 林卓, 沈萬斌.基于全球凈初級生產力的能源足跡計算方法.生態學報, 2012, 32(9): 2900-2909.

[84] Fang K, Heijungs R.Moving from the material footprint to a resource depletion footprint.Integrated Environmental Assessment and Management, 2014, 10(4): 596-598.

[85] van Oers L, de Koning A, Guinée J B, Huppes G.Abiotic resource depletion in LCA.Road and Hydraulic Engineering Institute, Ministry of Transport and Water, Amsterdam, Netherlands, 2002.

[86] 張金萍, 秦耀辰, 張二勛.中國區域可持續發展定量研究進展.生態學報, 2009, 29(12): 6702-6711.

[87] van den Bergh J C J M, Grazi F.Ecological footprint policy? Land use as an environmental indicator.Journal of Industrial Ecology, 2014, 18(1): 10-19.

[88] Berger M, Finkbeiner M.Methodological challenges in volumetric and impact-oriented water footprints.Journal of Industrial Ecology, 2013, 17(1): 79-89.

[89] 陳成忠, 林振山, 王暉.人類最大可持續海洋足跡的模擬.生態學報, 2008, 28(2): 656-660.

[90] 范小杉, 高吉喜.中國食品生產消費過程中農用化學品足跡分析.現代化工, 2008, 28(5): 79-84.

[91] 閔慶文, 焦雯珺, 成升魁.污染足跡: 一種基于生態系統服務的生態足跡.資源科學, 2011, 33(2): 195-200.

[92] 焦雯珺, 閔慶文, 成升魁, 袁正, 李靜, 戴忱.污染足跡及其在區域水污染壓力評估中的應用——以太湖流域上游湖州市為例.生態學報, 2011, 31(19): 5599-5606.

[93] 盧小麗.基于生態系統服務功能理論的生態足跡模型研究.中國人口·資源與環境, 2011, 21(12): 115-120.

[94] 張義, 張合平.基于生態系統服務的廣西水生態足跡分析.生態學報, 2013, 33(13): 4111-4124.

[95] Pfister S, Koehler A, Hellweg S.Assessing the environmental impacts of freshwater consumption in LCA.Environmental Science &Technology, 2009, 43(11): 4098-4104.

[96] Wiedmann T.A review of recent multi-region input-output models used for consumption-based emission and resource accounting.Ecological Economics, 2009, 69(2): 211-222.

[97] 姚亮, 劉晶茹, 王如松, 尹科.基于多區域投入產出(MRIO)的中國區域居民消費碳足跡分析.環境科學學報, 2013, 33(7): 2050-2058.

[98] Tukker A, Poliakov E, Heijungs R, Hawkins T, Neuwahl F, Rueda-Cantuche J M, Giljum S, Moll S, Oosterhaven J, Bouwmeester M.Towards a global multi-regional environmentally extended input-output database.Ecological Economics, 2009, 68(7): 1928-1937.

[99] EC.Product Environmental Footprint (PEF) Guide.[2013-05-01].http://ec.europa.eu/environment/eussd/pdf/footprint/PEF%20methodology%20final%20draft.pdf.

[100] EC.Organization Environmental Footprint (OEF) Guide.[2013-05-01].http://ec.europa.eu/environment/eussd/pdf/footprint/OEF%20Guide_final_July%202012_clean%20version.pdf.

[101] Laurent A, Olsen S I, Hauschild M Z.Limitations of carbon footprint as indicator of environmental sustainability.Environmental Science &Technology, 2012, 46(7): 4100-4108.

[102] Fang K, Heijungs R.There is still room for a footprint family without a life cycle approach—Comment on “towards an integrated family of footprint indicators”.Journal of Industrial Ecology, 2014, 18(1): 71-72.

[103] 楊建新, 王如松, 劉晶茹.中國產品生命周期影響評價方法研究.環境科學學報, 2001, 21(2): 234-237.

[104] Hauschild M Z.Assessing environmental impacts in a life-cycle perspective.Environmental Science &Technology, 2005, 39(4): 81A-88A.

[105] 劉某承, 王斌, 李文華.基于生態足跡模型的中國未來發展情景分析.資源科學, 2010, 32(1): 163-170.

[106] Rockstr?m J, Steffen W, Noone K, Persson ?, Chapin III F S, Lambin E F, Lenton T M, Scheffer M, Folke C, Schellnhuber H J, Nykvist B, de Wit C A, Hughes T, van der Leeuw S, Rodhe H, S?rlin S, Snyder P K, Costanza R, Svedin U, Falkenmark M, Karlberg L, Corell R W, Fabry V J, Hansen J, Walker B, Liverman D, Richardson K, Crutzen P, Foley J A.A safe operating space for humanity.Nature, 2009, 461(7263): 472-475.

[107] Rockstr?m J, Steffen W, Noone K, Persson ?, Chapin III F S, Lambin E, Lenton T M, Scheffer M, Folke C, Schellnhuber H J, Nykvist B, de Wit C A, Hughes T, van der Leeuw S, Rodhe H, S?rlin S, Snyder P K, Costanza R, Svedin U, Falkenmark M, Karlberg L, Corell R W, Fabry V J, Hansen J, Walker B, Liverman D, Richardson K, Crutzen P, Foley J.Planetary boundaries: Exploring the safe operating space for humanity.Ecology and Society, 2009, 14(2): 32-32.

[108] Barnosky A D, Hadly E A, Bascompte J, Berlow E L, Brown J H, Fortelius M, Getz W M, Harte J, Hastings A, Marquet P A, Martinez N D, Mooers A, Roopnarine P, Vermeij G, Williams J W, Gillespie R, Kitzes J, Marshall C, Matzke N, Mindell D P, Revilla E, Smith A B.Approaching a state shift in Earth′s biosphere.Nature, 2012, 486(7401): 52-58.

[109] Brook B W, Ellis E C, Perring M P, Mackay A W, Blomqvist L.Does the terrestrial biosphere have planetary tipping points? Trends in Ecology &Evolution, 2013, 28(7): 396-401.

[110] Lenton T M, Williams H T.On the origin of planetary-scale tipping points.Trends in Ecology &Evolution, 2013, 28(7): 380-382.

[111] Fang K, Heijungs R, de Snoo R G.Understanding the complementary linkages between environmental footprints and planetary boundaries in a footprint-boundary environmental sustainability assessment framework.Ecological Economics, 2015, 114: 218-226.

Footprint family: current practices, challenges and future prospects

FANG Kai1,2,*

1InstituteofEnvironmentalSciences(CML),LeidenUniversity,Leiden2333CC,Netherlands2EnvironmentalandEnergyPolicyCenter,ZhejiangUniversity,Hangzhou310058,China

It is increasingly widely accepted that anthropogenic impacts on the earth′s systems should stay within critical thresholds for humanity to preserve the planet as a pleasant living place and as a source of welfare.It is therefore a high priority for ecological economists to identify and quantify the state of sustainable development of the human society.Efforts have been made to build up a footprint family in which a suite of footprint-style indicators, such as the ecological, carbon, and water footprints, are combined to measure the environmental impacts associated with human activities in multiple dimensions.The footprint family concept stems from the firm belief that environmental issues are getting increasingly complex, and that wise policies in most cases cannot be formulated without some form of trade-offs among an ever-expanding number of stressors.This highlights the importance of identifying ways to quantitatively integrate different footprints and to minimize the total footprint from a system perspective, rather than emphasizing “net zero” solutions to individual footprints.As a fast-growing interdisciplinary topic, a number of footprint family studies have received great attention over recent years since its first appearance in the literature.By labeling current studies with theoretical exploration, integrated practice, and comparison and classification, a comprehensive review of the footprint family research is provided.Challenges remain in developing a truly integrated footprint family, especially in defining the footprint concept in a generally accepted way.The scarcity of calculation methods that are valid for various footprints on multiple scales ranging from a product, an organization, a nation, and even globally, and the uncertainty of dealing with weighting both within and between footprints, provide obstacles as well.To remove all these obstacles, the remainder of this paper presents a research agenda for updating the footprint family framework in future work.We call for the investigation of footprint typology, the development of multiregional input-output models, the concretization of operational guidelines for product and organizational environmental footprints, and the combination of footprint family and planetary boundaries.We believe that many well-grounded footprint models have the potential to consolidate the scientific foundation of planetary boundaries by providing a robust and reliable assessment of current environmental impacts and, conversely, that the planetary boundary concept could allow footprints to benchmark against thresholds for environmental impacts that humanity is placing on the planet, as a clear recognition of sustainable limits to human interference is lacking in many of the existing footprint accounts.Thus, we come to the conviction that the joint use of a footprint family and planetary boundaries would contribute to the assessment of global sustainability from a broader point of view, in which current environmental impacts and forecasted threshold boundaries can be synchronously quantified and compared.In this manner, the footprint-boundary alignment makes it possible for policy makers to monitor the extent to which critical thresholds are being approached or exceeded, and to warn about critical transitions that may have profoundly undesirable consequences for environmental quality, ecosystem stability, and human health in large parts of the world.

footprint family;quantitative integration;indicator classification;planetary boundaries;advance

國家公派留學基金項目(20113005)

2014-07-03; < class="emphasis_bold">網絡出版日期:

日期:2015-05-21

10.5846/stxb201407031373

*通訊作者Corresponding author.E-mail: fang@cml.leidenuniv.nl

方愷.足跡家族研究綜述.生態學報,2015,35(24):7974-7986.

Fang K.Footprint family: current practices, challenges and future prospects.Acta Ecologica Sinica,2015,35(24):7974-7986.