پرویز حاجیانی

The purpose of this research is for prediction the quality of biology in Iran during the years 1357 to 1392. For this purpose, it has used the Model of Grey(1,1), Verhulst Grey and multivariable Grey. It has used Carbon dioxide data for making model during the years 1357 to 1387 and from data during 1388 to 1392 for evaluating the power of offering method. The result of research indicated the Verhulst Grey model has more accuracy and less error in comparing to traditional Grey Model and Multi-variable Model. So by using Verhulst Method, the emission of Carbon dioxide predicted until 1404. The results indicates hat The amount of emission of carbon deoxid will have ascending trend until 1404 and will be equivalent to 1812.56 millions of tone.