Environmental Impact of Scrap Steel Resource Recycling in Taiwan

從1970年代開始永續發展做為一人類發展的概念開始席捲全球，日前Griggs發表了永續的新定義，其中認為永續發展必須要考慮地球系統的運行以及人類活動的平衡。另一方面，瑞典斯德哥爾摩韌度研究中心Rockstrom 等人亦發表了基於韌度（resilience）理論以及環境負載力的九大地球限度（planetary boundaries）並指出許多限度已超過環境負載力，因此永續轉型是必要的。 永續物質管理（SMM）和永續生產與消費（SCP）分別為兩個轉型概念。兩者之轉型目標皆希望降低環境負荷或衝擊、減少對於自然資源的消耗，並且不同程度地將經濟成長納入考量。再深入檢視其轉型策略，兩者皆是以生命週期的角度貫穿，並對於產品各階段的生命週期有對應的轉型策略，其中原料取得階段，策略包含提高資源回收率技術等，其短期具體做法是檢視國內衝擊較大之產業，了解資源供需情況，並提出廢棄物/資源進出口管理政策建議；舊品即廢品再利用/處置階段，可藉由回收再利用，發展我國短缺資源之再利用技術達成，從這兩方面亦可發現資源循環在永續發展中之地位。因此，本研究欲針對台灣廢鋼資源循環，分別以資源循環以及進出口政策做為兩轉型路徑，探究為了滿足消費需求，台灣廢鋼鐵之資源循環對於環境之影響。 研究方法透過建立台灣廢鋼鐵投入產出（WIO）、合併台灣整合性環境評估模式（TWIEA），對於台灣鋼鐵資源循環做一以廢棄物端出發的生命週期評估，檢視台灣鋼鐵資源循環下所造成的環境衝擊。結果從兩方面討論之，一為台灣廢鋼鐵於不同回收率的環境衝擊，其中發現台灣為了滿足鋼鐵需求，故在實行資源循環、提高回收率時，從國外進口原物料，反而使得全球環境衝擊增加，出現環境債留他國的問題，也發現實行資源循環時，產生環境衝擊的間接排放產業並非一般所認為排放貢獻量高之熱點產業；另一為模擬台灣鋼鐵政策之下實行資源循環所造成的環境衝擊，若將台灣粗鋼需求成長率視為經濟成長率，則台灣在經濟成長的同時，可以使各衝擊指標皆「相對脫鈎」。最後，資源循環和進出口政策雖皆為轉型路徑，對於環境衝擊的影響程度卻大為不同，管理者於決策時應同時考慮多方轉型路徑，選擇較為有效之面向進行，以達永續發展之最終目的。Human activities have caused environmental damage which affects not just the environment but also the society and the economy. There are several innitiatives that address environmental degradation and implement the concept of sustainable development. Two of the important initiatives are Sustainable Materials Management (SMM) and Sustainable Consumption and Production(SCP). Resource recycling can reduce the use of raw materials, and is considered to be more sustainable. However, it is important to take the whole economic system into consideration while discussing recycling. The main objective of this research is by investigating resource recycling sector with Extended Input-Output analysis, which includes all production sectors, to discuss its effect on the environment in a more comprehensive way. The iron and steel industry in Taiwan serves as a case study. The analytical method includes two models, Taiwan Integrated Environmental Assessment Model (TWIEA) and Waste Input-Output model (WIO). To improve the limitation of IO, which dose not consider the interaction between the flow of products and wastes properly, the WIO model can account for waste generation in each sector more precisely and also cover the cost of each waste treatment sector. Using the recycling rate in Taiwan as a variable, this research investigates the recycling rate of iron and steel industry in Taiwan to analyze the environmental impacts in the categories of human health, eco-quality, climate change, resources, and water resources. The first part of the result shows that recycling is not always environmental friendly in order to meet the needs of an economic system but may cause environmental debts. When the recycling rate of waste iron increases in Taiwan, the impact of global climate change decreases; but the impacts of global human health, eco-quality, resources and water resources increase. The main indirect emissions which may impact ecosystems are from mining and mineral manufacturing sectors that emit sulfur oxides and nitrogen oxides in foreign countries. The main indirect emissions which lead to lack of water resources are from middle-east’s crude oil exploration. The second part of the result evaluates the environmental impacts while conducting resource recycling based on the international trade data. The results show that while the crude steel consumption grows, the environmental impacts’ increase rate is lower and thus there is “relative decoupling”. The study indicates that international trading is a more effective way to decrease the impacts. Though both recycling and international trading are transition pathways which is the key to more sustainable world, there are great differences between them. The decision makers should implement a policy with a more effective transition pathway