生态效率变动的产业及要素推动:基于投入产出和系统优化模型

论文以Leontief 投入产出分析为基础,利用系统优化模型测算中国的生态效率,并分析生产要素、产业产出和污染物对效率水平的影响;为了聚焦于低碳经济发展,模型仅包括温室气体一种污染物。从1997 到2010 年,中国生态效率约下降一半,要素投入和产出变动均是效率降低的原因。在劳动、资本和土地三种要素中,惟有高水平劳动影子价格为正、能够影响生态效率;1997-2010 年间,高水平劳动力实际利用率降低、稀缺性上升,加剧了实际生产与前沿面的距离、降低了生态效率。在18 类产业中,12 类产值上升、对生态效率贡献为正;食品、纺织、非金属制造、运输及公私服务业等6 类对生态效率作用为负。以上结果有助于明确实现保增长、减排放的关键产业部门和要素投入。

Eco-efficiency Change Driven by Products and Factors: Combining Input-Output and System Optimization Models

One of the goals of China's strategy for a smart, sustainable and inclusive growth is the reduction of CO₂ emissions in the meantime keeping economic growth, which requires an increase of eco-efficiency. This paper defines improving eco-efficiency as achieving more goods and service outputs with less resource inputs as well as less waste and emissions. With special focus on low-carbon economy and decoupling carbon emission from economic development, here only GHG is taken into consideration in measuring China's eco-efficiency.Starting from Leontief input-output analysis, this paper uses a system optimization model with the constraints for primary inputs to measure the eco-efficiency of an economy, and examine the contributions of individual production factors, desirable outputs and pollutions to eco-efficiency change over time. Employing a multiple objective optimization model an eco-efficiency frontier of the economy is generated, the solutions of which define the virtual eco-efficient decision making units. Then the eco-efficiency of the economy can be obtained as the difference between the potential of an economy and its actual performance. This model considers inputs, desirable outputs and undesirable output (GHG emission only) simultaneously, and takes into account both economical and ecological aspects. Having derived the score of eco-efficiency, a Luenberger productivity indicator is proposed to estimate the eco-productivity change over time; this is then decomposed in a way that enables one to examine the contributions of individual production factors, individual pollutants and individual commodities to eco-productivity change. The results allow an inference as to whether economic growth, primary input-saving or emission abatement are the underlying driving forces for eco-efficiency change.Based on China's input-output tables, this paper calculates and compares our country's ecoefficiency performance between 1997 and 2010. A clear eco-efficiency regress of 50% was observed in China during this period, mainly due to the changes in both factor uses and sectoral outputs. Out of the 0.0096 total absolute decrease of eco-efficiency score, primary factor contributes 0.0078, and sectoral output leads to 0.0066, while GHG reduction activities bring about 0.0048 increase. Therefore, it could be concluded that in the past over 10 years, industrial development as well as factor use did not achieve the efficiency frontier, while emission abatement made such a great progress that it improves the efficiency of the economy. Among labor, capital and land, skilled labor is the only scare factor of production which might affect eco-efficiency. During 1997-2010, decreasing utilization of scarce high-skill labor enlarged the distance between the actual production and the efficiency frontier, and thus reduced eco-efficiency. Twelve out of the 18 industries made positive contribution to the efficiency change, while the remaining six including food processing, textile, non-metallic products, transport and services acted as obstacles. The results above would help identify the key sectors and inputs towards the objective of low-carbon growth.