基于三维生态足迹模型优化的自然资本利用国际比较

维持自然资本存量恒定是人类社会可持续发展的基础。在介绍三维生态足迹模型的基础上,根据推导的区域足迹广度和区域足迹深度的计算公式,评估和比较2007年全球11个主要国家的自然资本利用状况,并分析模型优化前后的结果差异。结果表明:①全球自然资本流量的人均占用为1.71 hm²,人类需要1.55个地球才能支撑其资源消费量,化石能源碳排放是最主要的存量自然资本利用方式和生态超载驱动力;②各国的流量资本占用能力依次为加拿大>俄罗斯>美国>巴西>法国>德国>全球>意大利>中国>英国>日本>印度,存量资本消耗程度则基本呈逆向排列;③美、法、德等发达国家所利用的人均流量资本和存量资本均明显高于全球平均水平,应给予印、中等发展中国家一定的配额补偿;④模型优化后,全球人均足迹广度减少了0.09 hm²,足迹深度则增加了0.05,这更符合各国自然资本利用和生态赤字的实际;⑤中国面临增加国民收入和控制生态赤字的双重挑战,应将草地作为资本利用的优先方向,并适当控制城镇扩张速度。

International comparison of natural capital use:A three-dimensional model optimization of ecological footprint

Humanity can be considered sustainable only if the natural capital stocks remain constant. The basic concepts and methodologies of a three-dimensional model of ecological footprint were introduced by this paper. Then much emphasis was put on the derivation and calculation of two indicators - regional footprint depth and regional footprint size so as to optimize the model. Taking this as the basis, an assessment and comparison of natural capital use in 11 major countries in 2007 were performed. Moreover, the fact was provided that results differed before and after optimization. The results demonstrated the following. First, the world-average appropriation of natural capital flows per capita was 1.71 ha, and more than one and a half planets were necessary to support the resource consumption of world''s inhabitants. Fossil-fuel carbon emissions were the dominant pattern of natural capital use and the major driver of ecological overshoot on the globe. Second, the descending order of countries that occupy the capital flows was Canada, Russia, USA, Brazil, France, Germany, the world-average, Italy, China, UK, Japan and India. Conversely, the ascending order of countries that deplete capital stocks was Canada, Brazil, Russia (the three of them almost deplete nothing), the world-average, France, India, China, USA, Germany, UK, Italy and Japan. Third, some developed countries like the USA, France and Germany were obligated to pay compensation to developing countries, as the capital flows and stocks they used are both much more than the world average. Fourth, the world-average footprint size per capita decreased by 0.09 ha while the footprint depth increased by 0.05 comparing models with or without optimization. In particular, the optimized model offered a more conservative estimate on the sustainability of developed countries and thus a relatively optimistic estimate on that of developing countries. This was in accordance with the real situation of the natural capital use and ecological deficit in different countries. And the last, how to increase national income and control ecological deficit would be dual challenges for China. It is suggested that a priority for lands that support the use of natural capital should be given to grassland, and it is necessary to put constraint on the accelerating urban expansion.