Indicators for natural capital: Changes and forecasts

The current study aim is to introduce, analyze and examine the possibility of forecasting these indices in Iranian economy. To get the objective, time series data for 1980-2015 were applied. The introduced indices for natural capital are ecological footprint, biological capacity, ecological tension, ecological occupancy, and ecological-economic coordination. The findings showed that ecological footprint as the main index has experienced an annual growth of 2 percent. In terms of the contribution, carbon dioxide accounts for the most part of the ecological footprint growth. On the other hand, biological capacity showed a decreasing trend over the study horizon such that it has been exceeded by ecological footprint, giving rise to an ecological deficit. The ecological tension index showed that services demanded from the environment have exceeded its capacity as well as those of the global average, leading to ecological insecurity. The forecasting results also indicated a higher forecasting ability for neural network model compared to the ARMA one, providing forecasts with errors of as low as less than 3 percent for the most of the indices.