Ecological Safety Assessment of Tianjin City Based on Ecological Tension Index

Based on the principle of ecological footprint,put the ecological tension index as an indicator of ecological safety evaluation.Accordingly,the standard of rank is constituted.The ecological footprint and ecological capacity is calculated from 1989 to 2008 in Tianjin city.The ecological tension index and rank partition standard are used to measure ecological safety of Tianjin.The result shows that the ecological is at risk in Tianjin during the past 20 years.To change this situation,it can take the following measures:Firstly,use high technology to improve the unit area productivity of natural ecosystems.Secondly,control the population.Thirdly,protect the exiting resources and reduce the loss of arable land.Lastly,develop the cleaner production vigorously and achieve the energy-saving and pollution emission reduction.