The Study Of Ecological Footprint Theory And Application

Ecological footprint (EF) is one of the most successful indicators to assess sustainable development and has gained much attention in the academic and policy maker since it was developed by Wackernagel and Rees in 1996. This method can be used to assess Sustainability by estimating the corresponding area of productive land and aquatic ecosystems required to produce the resources used, and to assimilate the waste produced, by a defined population at a specified material standard of living, and comparing with available biocapacity of difined ares.As a physical unit, area is very familiar to the general public and policy makers, and the results of EF calculations are easy to communicate and useful in raising public and political awareness of environment, moreover, it is simple, measurable. These aspects give the EF analysis wide application and much interest. The EF calculation framework has become a starting point for many national and regional accounting of ecological flows and services. Several organizations have already calculated EF at different scale levels, ranging from individual, organization, urban, region, nation and worldwide. Studies, show that human runs ecological deficit globally, and natural capital will exhaust unless effective policies or measures are taken.EF method has been further developed while initially introduced in the 1990s. In order to sum different land categories with different productivity up, 'equivalence factor' was introduced into the calculation. 'Yield factor' was presented to reflect the relative biocapacity between local and world average yield. All kinds of greenhouse gases including CO₂, CH₄, NO_x, etc, were considered in the calculation of Lenzen and Murray (2001). Input-output method was used to detail EF calculation. Time series EF analysis is carried out to cube the static weakness of traditional EF methods. EF calculation was even combined with other indictors, such as energy, and GDP.Because there is no commonly accepted procedure of calculation EF, to improve EF methods and reflect "actual land demand"of China, standardized hectares method using local yield is proposed on the basis of traditional method framework similar to the global yields approach. Therefore, local yields in stead of global average yields to answer the question of how much area equivalent to native productivity is actually occupied by the economic metabolism of a given population; neither equivalent factors nor yield factors are used in this paper. Moreover, embodied energy (EE) is considered in EF calculation procedure and the effect of embodied energy on EF is quantified; the impact of Returning Farmland to Forest Program (RFFP) on Sustainability is assessed using EF method and time series of future EF is predicted.Comparing with global average yield, methods with standardizing hectares to domestic productivity will reduce EF and BC about 10%—20%, but ecological deficit remains the same with both approaches. However, for a specific country, standardized local hectares are more meaningful and relevant to realism. As indicated in this study, 1.35 times Chinese territories are actually occupied by China in 1999, while it will be 1.54 times Chinese area equivalent to global average productivity in Loh (2002).China is a net importer of EE since 2000, and EE of international trade plays an important supplemented role in Chinese energy supply. Both imported and exported EE are huge in absolute terms and tend to increase along time series, but the amounts of net balance are small, and this is the reason that EE is often neglected. Net imported energy would increase 38% and energy consumption will increase 2.8% in 2004 if EE were taken into account. If EE is not taken into the national energy budget, Footprint_energy, EF and ecological deficit of 2004 will be underestimated about 2.92%, 1.36%, 2.83%, respectively. Obviously, unsustainability procedure of China is accelerated by EE. 1.47 times Chinese territories are accurately occupied by China in 1996 while 1.71 times in 2004. Obviously, China is moving away from Sustainability, and its current consumption is met by overshooting local resources and long distance occupying of abroad resources.By quantifying the effects of policy, such as RFFP on EF, we will know whether we are moving towards or away from Sustainability guiding by this project in long term. According to the prediction, advices also can be given to government whether the project should be halt or be carried out continuously with some adjustment. By improving ecology and utility efficiency of resource, adjusting landuse pattern, RFFP can alleviate upward trend of EF and decline trend of BC, ED of China can be alleviated in certain degree also, therefore, RFFP leads China towards Sustainability. There is significant influence to EF, BC and ED of farmland, pasture and forest, but the net effects on total EF, BC and ED is small, which is -0.58%, 0.85% and -1.24%, respectively, because they are balanced by each other, resulting in too small effect on Sustainability to be neglected.