Study on eco-city evaluation method based on emergy and ecological footprint model

Ecological footprint model is an important means for quantitative evaluation of eco-city, to get rid of the defect of general ecological footprint model; we proposed a modified model by using emergy theory. In the calculation of ecological carrying capacity, we added the carrying capacity of actual product output and virtual product supply based on the material input-output and people´s initiative; in the calculation of ecological footprint, we brought ecological footprint of the waste into evaluation system on the considering of the pollution caused by waste discharge. Finally, in order to validate the modified model, we take Tianjin City in 2001-2008 as a case to calculate the data from biological products and other aspects. The results showed that: Tianjin ecological carrying capacity is greater than the ecological footprint, and ecological surplus is expanding year by year, thus Tianjin is in a relatively sustainable development state.