低碳城市是近年追求之永續發展模式，在永續的原則下，仍著重都市成長之概念。其 理念是在不超過環境容受力的前提下，透過更少的環境消耗創造更好的生活品質，同時產生 更少的廢棄物，確保環境資源達到最有效率之利用。有鑑於此，本文嘗試以環境效率 (ecoefficiency) 之內涵發展低碳城市效率之評估架構，並以資料包絡分析法進行效率之分析與比 較，針對效率相對較低之都市，進一步以重要低碳策略項目進行效率影響因素分析。 實證結果顯示，「資源回收率」、「綠化面積比」及「都市密集度」是影響低碳城市效 率之關鍵因素。基隆市、臺南市及臺中市藉由都市密集度增加可有效提升效率，增加綠地則 成效較有限；臺北市及高雄市都市密集度已較高，再增加密集度反造成效率表現不佳；嘉義 縣、臺南縣、高雄縣、雲林縣、臺北縣、臺中縣及彰化縣等縣市，透過資源回收率的增加可 有效提升效率。研究發現，各縣市可依自身特性思索低碳策略的組合方案，藉以擬定較全面 且具成效之低碳城市發展策略。

The “low-carbon city” represents a new sustainable development model that emphasizes urban growth based on the principles of sustainability. The concept of the low-carbon city is to create better living quality and efficient usage of environmental resources below carrying capacity, while minimizing environmental consumption and waste. Therefore, this study prsents an efficiency evaluation framework for low-carbon cities according to the concept of eco-efficiency, and measures urban efficiency using data envelopment analysis. Furthermore, this sudy explores critical low-carbon strategies for non-efficient cities to enhance eco-efficiency. Analytical results reveal that “resource recovery rate”, “percentage of green area” and “urban density” are critical factors that affect the efficiency of a low-carbon city. The efficiency could be improved significantly by increasing the urban density, and insignificantly by increasing the green area in Keelung City, Tainan City and Taichung City. The efficiency could be improved ineffectively by increasing the urban density in Taipei City and Kaohsiung City. Furthermore, the efficiency could be improved by increasing the resource recovery rate in Chiayi County, Tainan County, Kaohsiung County, Yunlin County, Taipei County, Taichung County and Changhua County. Comprehensive and effective low-carbon strategy combinations vary by characteristics of cities.