Economy is related to natural resources and environment in the various dimensions of production and consumption. Population growth along with economic development are responsible for the low quality of resources as well as the high level of pollutants which are unbearable for natural environment. In the early 1990s, some attempts made for the extension of national accounts system to cover environmental degradation and income inequality which led to the introduction of the new concept of "green national product". By taking environmental degredation and natural resources depreciation into account, the criterion of green GNP, instead of GNP, can be obtained.;
Although free trade is often considered a positive and effective factor in economic development and higher level of welfare, increasing trade without taking environmental considerations into account and merely motivated by getting access to other markets, in some countries, has led to the extensive and improper use of resources and energy which results in pollution and emission of greenhouse gases.;
The study of the impact of free economy on environmental degradation during the period 1974-1996 shows that there is a positive correlation between the emission of dioxide carbon gas and environmental degradation;
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