全球主要国家环境可持续性综合评估——基于碳、水、土地的足迹-边界整合分析

An Integrated Assessment of National Environmental Sustainability by Synthesizing Carbon, Water and Land Footprints and Boundaries

随着地球生态系统的交互性、复杂性与整体性特征日益显现,综合分析和比较各类人为环境影响及其最大安全阈值,对于从整体上判断人类活动的可持续性、揭示承载力的超载程度具有重要意义。基于环境足迹和行星边界两项新概念,运用极差法和目标距离法对全球30个主要国家的碳、水和土地赤字数据进行了标准化与权重化处理,得到一个复合的国家环境可持续性压力指数,并结合3项环境赤字的实际分布状况,将所有国家划分为4类:环境强可持续性(3国)、环境弱可持续性(8国)、环境弱不可持续性(9国)、环境强不可持续性(10国)。总体上,环境可持续性压力呈现南美洲国家低、亚洲和非洲国家居中、欧美发达国家高的地域格局,亚洲是4类国家并存的唯一大洲。全球的碳、水和土地足迹-边界比分别为3.0、0.6、0.7,表明就全球尺度而言,温室气体排放已处于严重超载状态,水资源消费和土地利用尚处于盈余状态,这与现有文献结果相吻合,从而在一定程度上验证了本研究结论的可靠性。

The earth's ecosystems increasingly reveal their interactivity, complexity and integrality. In this context, it makes great sense to conduct an integrated analysis and comparison of human-induced environmental impacts and the related safety thresholds, whereby one can evaluate the sustainability of human activities and measure the extent to which the carrying capacity is overshot. Built on the complementary use of environmental footprints and planetary boundaries—two novel concepts proposed recently, this paper applies the range method and distance- to- target method to the normalization and weighting of carbon, water and land deficits for 30 nations. The national environmental sustainability pressure index(ESPI) is computed and further applied to cluster analysis, which allows the 30 nations to be classified into four categories. The results illustrate that there are respectively 22, 17 and 15 nations operating in the state of overshoot in terms of greenhouse gas emission, water use and land use. The national ESPI varies from 0.39 for Brazil to 12.67 for USA. There are 3 nations with strong environmental sustainability, 8 nations with weak environmental sustainability, 9 nations with weak environmental unsustainability, and 10 nations with strong environmental unsustainability. Asia is the only continent where the four categories of sustainability are all witnessed. The global greenhouse gas emission is operating in a state of overshoot, while the water use and land use are both found to run a surplus on the global scale, as indicated by the world-average carbon,water and land footprint-boundary quotients estimated at 3.0, 0.6 and 0.7, respectively. Our conclusions are in line with the recent leading studies on the same environmental issues, providing this study with a high degree of scientific certainty. This paper aims to provide policy makers with a new insight into the evaluation of environmental sustainability through the alignment of the boundary metrics and footprint metrics, and thus can be regarded as an attempt to fill in the gap between these two fields of research. To proceed with the development of a scientifically robust methodology for environmental sustainability assessment, further improvements on this footprint-boundary integrated framework would be desirable.