Currently, the average carbon dioxide plays a crucial factor when evaluating the gross carbon dioxide. While different countries have different performance in this sector. The chart shows that the data from United Kingdom, Sweden, Italy and Portugal.

At first, the CO2 emission of UK and Sweden keep decreased from 1967 to 2007, however Italy and Portugal keep increasing from 1967 to 2007. In details, the CO2 emission in UK slightly decreased in forty years compare to Sweden, the CO2 emission increased and reached the peak in 1977 and then decreased greatly from 1977 to 2007. On contrary, the CO2 emission of Italy keep increasing but still lower than degree 4 until 2007, while the CO2 emission of Portugal keep increased but keep stable in 1977.

In conclusion, the CO2 emission is under the control in many countries, the emission has been reduced or keep stable with the time goes by..