Analysis of Agricultural Sustainability: A Review of Exergy Methodologies and Their Application in OECD

The present paper proposed the combination of Cumulative Exergy Extraction from the Natural Environment (CEENE) and Extended Exergy Analysis (EEA) to analyse international environmental performance in agricultural production. The unified approach allowed the cumulative analysis of comprehensive extraction of all types of resources and services from the ecosystem in agriculture. The analysis, therefore, enabled a more accurate comparison of the environmental performance of different countries or systems based on different indicators of sustainability. The application was conducted for 29 OECD countries for the years from 1990 to 2003 with some important findings. Firstly, the organic contents in top soil, feed and total water withdrawal were the three types of resources that agricultural production extracted most from the environment. Secondly, during the fourteen years surveyed, the efficiency of using exergy in the livestock sector was much lower than the efficiency in the crop sector. Thirdly, the environmental loading of economic investment had increased slightly, implying a minor increase in the pressure on the environment overtime. In addition, the empirical study on OECD countries confirmed that rankings varied widely based on different indicators. The empirical results gave some evidence to support the use of Non-Renewability- Yield Ratio firstly defined in the present paper because the rankings based on this indicator was more consistent with many other indicators.