基于能值改进的开放系统生态足迹模型及其应用--以深圳市为例

Emergy-based modification for ecological footprint accounting and application to open eco-economic system:a case study of Shenzhen City

对生态经济复合系统综合评价是实现区域可持续发展首先要面对的科学问题。针对传统生态足迹模型的系统封闭性和空间互斥性等不合理假设,利用从系统论出发并具有基于流量算法优点的能值分析理论,对传统生态足迹模型加以改进,同时将人类劳务纳入系统评价。改进后的模型仍然从供给与需求角度分析区域消费足迹与承载力,强调区域资源进出口,分析开放系统条件下区域发展状况,并将人类的作用纳入可持续发展评价范畴。以深圳市2006年发展状况为例对改进模型进行实证分析。计算结果显示:研究区域具有48.08ghm2的人均潜在生态承载力;在生物生产账户上存在3.60ghm2的人均生态赤字,需进口来弥补,而在工业产品账户上3.14ghm2的人均盈余,可供出口;具有约4.87ghm2的人均净承载力出口,为其他区域的发展做出了贡献;人力资源是深圳市可持续发展的重要保障,至少提供相当5.20ghm2的人均生态承载力;发展高新技术产业、低能耗的清洁工业,产出高能值转换率的产品,实现区域本地产品在能量系统等级的提升,是提升本地承载力的现实途径。结果表明,改进后模型突破了传统生态足迹模型偏生态的弱可持续性评价局限,成为综合反映区域生态经济发展状况的可持续性评价模型。

Comprehensively assessing the open eco-economic system is an important issue for the regional sustainable development. To get rid of the shortcomings of general ecological footprint model such as the irrational assumption of system closeness and spatial exclusivity, we proposed a modified ecological footprint model by using emergy theory and method, in which flux calculation and human labor services were incorporated. Although the regional consumption and carrying capacity of the ecological footprint was still analyzed according to the supply and demand in the modified ecological footprint model, it emphasizes import and export of regional resources, the openness of regional socioeconomic system, and incorporation of human labor services. To validate the proposed model, we computed the ecological footprint and carrying capacity with statistical data of Shenzhen City in 2006. The results show that per capita potential ecological carrying capacity in Shenzhen City was about 48.08ghm^2, and there existed a 3.60ghm^2 per capita ecological deficit in biological production account that needs to be offset by imports, but a 3.14ghm^2 per capita ecological surplus in industrial product account that can be used for exports. The per capita net ecological carrying capacity in 2006 was about 4. 87ghm^2 , which contributes to the development of other regions. Human resource of Shenzhen City can offer 5.20ghm^2 per capita ecological carrying capacity in 2006, which is important to ensure the sustainability of socioeconomic system. Developing advanced high-technology, low-energy consumption and cleaner industry, producing goods of higher emergy transformation rate, and promoting the energy hierarchies of native products are important approaches to regional sustainable development. The modified model solved some deficiencies in general ecological footprint model, by paying more attention to all the elements of eco-economic system but only the ecological components. So, it can be employed to comprehensively assess sustainability of regional eco- economic system.