基于投入产出分析的中国生态足迹模型

Applying input-output analysis for calculation of ecological footprint of China

基于投入产出分析技术的生态足迹(EF)核算模型是目前国际生态承载力研究的热点模型之一。在已有研究的基础上,引入土地利用差异转化系数(某类土地利用的产量因子与其均衡因子的乘积)改进模型,以保证投入产出表的行、列组分加和操作的有效性。研究以货币型投入产出表为基础核算中国1997年的EF,分析表明:(1)1997年中国为EF净出口国,人均EF贸易逆差0.050 hm2,占生产包含足迹的3.4%;(2)最终使用的人均EF为1.435 hm2(能源足迹占45.1%),其中,2/3缘于居民消费,另1/3缘于资本形成;(3)第一、二、三产业包含的人均EF依次为0.499、0.721 hm2和0.183 hm2。其中,第一产业以直接占用生态空间为主,而第二、三产业以间接占用为主,如第二产业的隐藏性非能源足迹是其直接值的140余倍;(4)三大产业部门中,第三产业最终产品消费的EF最小,人均0.183 hm2,而其土地利用的经济效率最高,为0.898万元hm-2。实践表明基于投入产出分析的EF模型不仅承袭了EF基本模型的优点,而且结构性能好,能同时识别社会各生产和消费部门的生态压力及其在不同部门之间的流转情况,并可有效避免足迹组分的重复计算。

Over the past years, some studies have tried to combine ecological footprint （EF） accounting and input-output analysis （IOA） for the calculation of total land appropriation of production and consumption activities. The results derived from EF are able to visualize hidden ecological cost of an activity or population. Although this EF model has its own peculiarities and insights, it has roots in the work of Wackernagel and Rees. The EF model based on IOA has been firstly advanced by Bicknell et al, adjusted and modified by Ferng, and practiced by Hubacek et al, McDonald et al and Lai Let al. These researches express EF in Local Hectare. To compare EF results obtained from various analyses based on original EF model, this paper expresses EF in Global Hectare. Therefore, a modification has been made to the existing IOA based on EF model framework by introducing diversity conversion factors which is defined as the multiplier of a land users yield factor and its equivalent factor. This modification can make useful additive calculations along both the column and row in the input-output table. This calculation employs China monetary input-output table in 1997 as the base table. The results indicate the followings： （1） the Chinese EF embodied in domestic production sectors is 1. 485 hectares per capital （hm^2 cap^-1 ）, of which 1. 435 hm^2 cap^-1 was appropriated by domestic final consumption and 0. 050 hm^2 cap^-1 by net export thanks to the fact that China was situated in net EF trade deficit in international market in 1997; （2） two thirds of the 1. 435 hm^2 cap^-1 appropriated by Chinese final use is attributed to household consumption and one thirds to capital formation ; （3） the EF of the primary, secondary and tertiary sector varies from 0. 499, 0.721 and 0. 183 hm^2per capital, respectively, and these sectors＇ indirect land footprint is 1.24, 143.11 and 16.11 times of their direct ones respectively, indicating the primary sector（ s ecological pressure is mainly from direct land use, and the other two sectors＇ from hidden appropriation. Among the three production sectors, the per capital EF embodied in the production of the tertiary sector ranks the lowest with a value of 0. 183 hm^2, but the per hectare footprint output is the highest with a figure of 8980 RMB. Therefore, further enhancing its position in and contribution to Chinese economic sectors will weaken ecological impacts imposed by social metabolism. The analysis shows that IOA based EF model has a good structure, can identify where the EF actually takes place and how EF component flows among production and consumption sectors, and avoid from double accounting. It should be noted that the new EF model is still facing incomplete accounting of pollutants emissions, and inevitably has methodological shortcomings observed in general input-output analysis.