以都市代謝方法建構永續都市指標

Abstract

1987年，聯合國世界環境發展委員會(World Commission on Environment and Development, WCED)將永續發展定義為:「既滿足當代人之需求，又不損及後代人追求本身的發展」，此為永續發展之濫觴。在二十一世紀章程中，強調永續發展需配合各地政經情勢與環境狀況作調整，即為「全球思考，地區行動」的概念。 都市扮演著全球是否能永續發展的重要角色，在我們共同的未來一書中，指出21世紀全球將有50%人口居住於都市地區，根據UN統計，1950年時，只有29%人口世界人口居住於都市，人口超過一百萬人被稱為超大城市的也只有紐約與東京。在2010年時，世界人口來到了70億，城市人口也成長到了35億人，約占總人口的50% (UN, 2009)，城市增長速率最高的是亞洲與非洲 (Satterthwaite etc.，2010)。都市具有低生產、高消費與高廢棄的特性，因人口不斷的增加，都市使用的能資源相當可觀，因此在探討都市的永續發展時，都市的能資源使用為一大熱點，是相當關鍵的議題。 永續發展指標為一種可直接或間接提供評量標的永續性程度之具體描述工具，各都市也依循此脈絡發展出各自的永續都市指標作為評量都市永續程度之工具。綜觀目前永續都市指標具有下列幾點問題: (1)指標過度簡化及過於龐雜，其代表性不足，且缺乏比較性。(2)缺少能資源供給面的指標。(3)無法評量或量化都市浪費的能資源。(4)鮮少考量都市涵容能力及乘載能力。(5)缺少都市代謝概念。都市代謝的概念是以系統性之方式來評析整體都市系統中能資源的流動狀態。建構永續都市代謝指標，將可有效彌補現有指標之不足，並使用物質流方法做為計算指標之工具，做為永續都市評價之參考。

依據永續都市定義:「在考量涵容能力及維持都市特定機能的運作下，確保能資源的穩定供給、提高能資源使用效率、減少資源的浪費與妥善的處理及回收廢棄物。」因此，本研究在建構永續都市代謝指標時，須符合以下三個永續都市之原則: (1)考量能資源的可及性、足夠性與安全性。(2)提升能資源的使用效率並減少浪費。(3)考量都市的涵容及處理能力。以此三大原則並結合都市代謝之特性，將都市系統分成三大部分:供應、消費及廢棄面向，建立三個面向的永續都市代謝指標。在建立三項指標後，以台北市的食物及水進行實證研究，並給予永續都市代謝指標發展之相關建議及管理策略。

In 1987, World Commission on Environment and Development (WCED) define sustainable development as meets the needs of the present without compromising the ability of future generations to meet their own needs. Agenda 21 emphases on sustainable development must comply with the country’s political and economic situation and environmental condition to adjust, namely concept of think globally, act locally. Cities play an important role in sustainable development. In Our Common Future point out that about 50% population will live in urban area in 21 century. According to UN statistics, only 29% of the population lived in cities and more than one million people, called megacities, only in New York and Tokyo. In 2010, the world’s population up to 7 billion .Cities population has grown to 3.5 billion, about 50% of total population (UN, 2009). The highest urban population growth rate in Asia and Africa (Satterthwaite etc., 2010). Cities were places with low production, high consumption and high waste. Due to the increase in cities population, cities use enormous recourses and energy. Therefore, when it comes to sustainable development, the use of recourses and energy in cities was a central issue. Sustainable development indicator is a tool to provide a direct or indirect measure of detailed description in Specific subject of the degree of sustainability in the future. Following this context, cities develop their own sustainable city indicators. But current sustainable city indicators with following problems: (1) Indicator oversimplification and too much, lack of representativeness and comparability. (2) Lack of energy and resources supply indicators. (3) Cannot assess or quantify city’s waste of energy and resources. (4) Rarely consider the carrying capacity and load capacity of the city. (5) Lack of urban metabolism. Urban metabolism is a systemic way to assess the state of energy and material in city. Constructing the sustainable city metabolic indicators, can make up the shortage of existing indicators. Using material flow as a tool to calculate the indicators, it can be a way to evaluate the sustainable city. Sustainable development define as that in consideration of the carrying capacity and maintaining a specific function and operation of the city ensuring stable supply, improving efficiency of using, reducing waste of material and energy, and prospering and recycling of waste. Base on the definition, the sustainable city metabolic indicator must comply with the principles of follow three: (1) Consider the energy and materials availability, adequacy and security. (2) Improve the efficiency of the use of energy and materials, and reduce waste. (3) Consider the carrying and processing capacity. The urban can be seen into three parts: supply, consumption and waste, and establish sustainable city metabolic indicators in three dimensions. Do empirical research of Taipei’s food and water, and give advice of management strategy and sustainable city metabolic indicators development.