Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS

A Modified Model of Ecological Footprint Calculation Based on the Theory of Emergy Analysis-Taking Jiangsu Province as an Example

  • 1. Department of Urban and Resource,Nanjing University,Nanjing 210093,China;
    2. Key Lab.of Land Use,Ministry of Land and Resources,Beijing 100029,China

Received date: 2005-11-22

  Revised date: 2006-01-06

  Online published: 2006-08-25


Associated with rapid development of economy and increase of population,we face a series of contradictions among the natural resources,environment and economy,such as resources depression,environmental deterioration and so on.To be sustainable,humanity must live within the limits of nature's carrying capacity.In the 1990s,Rees and Wackernagel put forward the ecological footprints model,which offers an easy and rapid method to measure the environmental situations of eco-economic system. The aim of the paper is to show a modified model of ecological footprint calculation by combining emergy analysis with conventional ecological footprint model of calculations,in the framework of the theory of ecological footprint,to apply the method of emergy analysis and introduce the concept of emergy density into the calculation models,in order to translate all kinds of energy flows in the eco-economic systems into the corresponding biological productive units.In this paper we present a new method of ecological footprint calculation,based on the emergy analysis.The translation of human demand of natural resources and the supply of nature services into understandable and quantifiable concepts is the main objective of this new method.Firstly,the amounts of human consumption corresponding to six categories of ecological productive areas and the amounts of natural supply are calculated.And then,these amounts are translated into common unit emergy through the emergy analysis.Thirdly,in this new method we are proposing,we will derive the ecological footprint and carrying capacity by dividing the emergy amounts by the emergy density.Finally,we compare the ecological footprint with the carrying capacity to measure the environmental status of sustainability in the given region. With Jiangsu Province in the year 2003 as an example,we apply the modified model to it to analyze the ecological environmental situations.According to the calculation equations,we get the annual total emergy amount of Jiangsu was 7.828×1021sej and its emergy density was 7.629×1021sej/ha.And then we get the carrying capacity of Jiangsu was 0.299 7ha/cap,the ecological footprint of biological resources and energy resources was 4.722 8ha/cap,and the ecological deficit was 4.423 2ha/cap.So we conclude that the ecological footprint of Jiangsu has exceeded its carrying capacity,which conforms with the calculation results of conventional model of ecological footprints.This indicates that the new method of ecological footprint calculation is effective and feasible. By analyzing the strong points of the modified model,we find that the calculation results of the modified model give a more realistic picture of the environmental situations of the eco-econo-mic systems,compared to the conventional one.

Cite this article

ZHANG Fang-yi, PU Li-jie, ZHANG Jian . A Modified Model of Ecological Footprint Calculation Based on the Theory of Emergy Analysis-Taking Jiangsu Province as an Example[J]. JOURNAL OF NATURAL RESOURCES, 2006 , 21(4) : 653 -660 . DOI: 10.11849/zrzyxb.2006.04.020