都市發展計畫對因應氣候變遷之綜效與權衡──以臺北都會區為例

Synergy and Trade-offs in Urban Development Planning for Climate Change-The Taipei Metropolitan Area as an Example

與都市發展相關的計畫多樣且複雜，不同計畫間之政策目標必然會產生互動效果。隨著都市化與氣候變遷間相互影響之衝擊加劇，都市發展計畫得同時考慮對調適與減緩氣候變遷的影響。都市因應氣候變遷政策的效果與回饋過程，是都市化與環境變遷重要的研究議題之一，IPCC AR4與AR5均有對氣候變遷政策之綜效(Synergy)與權衡(Trade-offs)作定義。本文以都市發展相關計畫對氣候變遷減緩與調適間的複合關係為主軸，將都市發展相關計畫對減緩或調適氣候變遷同時產生正面效果界定為「綜效」，反之，一正一負則視為「權衡」。本文進一步探討臺北都會區都市化發展過程中，從二氧化碳排放量與淹水面積的角度分析都市發展相關計畫對因應氣候變遷減緩與調適的效益是否具有綜效或權衡。研究發現都市計畫、交通與水利等都市發展相關計畫對氣候變遷減緩與調適之間多為權衡效果，其中都市計畫的影響效果最為明顯，所導致的開發同時增加二氧化碳排放與淹水面積。即使是具有減緩二氧化碳排放的大眾運輸軌道建設計畫，興建後因交通可及性提升所促使的都市發展，皆可能加劇都市地區所面對的氣候變遷衝擊。水利計畫尺度愈大，能保護的淹水範圍愈大，但興建過程產生碳排放亦增加；現階段水利計畫對因應氣候變遷仍難以形成綜效效果。本文並建議後續應由系統觀點進一步分析都市計畫、交通建設與水利計畫間互為因果關係對因應氣候變遷之綜效與權衡。

Urban development planning has diverse, complex and inevitably conflicting goals. Because of the intensified impact of interaction between urbanization and climate change, urban development planning must address the influence of both climate change adaptation and mitigation. The feedback process in policymaking for urban planning considering climate change has become one of the most significant themes in urbanization and environmental change research. Furthermore, the“synergy”and“trade-offs”of climate change policies are clearly defined in IPCC AR4 and AR5. This study mainly focuses on investigating the complex relationship between climate change mitigation and adaptation in conjunction with urban development planning. Synergy is defined as a double-positive effect of urban development planning on both climate change mitigation and adaptation. Conversely, conditions with both positive and negative effects are defined as trade-offs. Considering the urban development process in the Taipei Metropolitan Area based on carbon dioxide emissions and flood hazards, this study investigates whether the effects of urban development planning for climate change mitigation and adaptation result in synergies or trade-offs. The findings show that relevant urban development planning such as urbanization, transportation and flood protection programs most likely result in trade-off conditions between climate change mitigation and adaptation. The urbanization program has incurred the most evident effects amongst these programs owing to large-scale development increasing carbon dioxide emissions and flooding areas. Even the public transportation railway project, which is intended to reduce carbon dioxide emissions, may produce considerable emissions during construction. Additionally, induced urban development may result in an increased climate change impact on the city. A larger scale of flood protection program gives greater for flood-prone areas, but also amplifies carbon dioxide emissions during construction. The flood protection program does not currently seem synergistic against climate change. Therefore, we suggest that future studies should analyze the causality of synergies and trade-offs between the urbanization, transportation and flood protection programs based on a systematic perspective.