From the time of Pigou until recently, the primary issue for economists with respect to the conservation of natural resources has been the optimal intertemporal utilization of these resources. However, the rates of consumption of natural resources during both world wars began to indicate that the resource base would ultimately be depleted. Nevertheless, the view that modern industrial economies can gain a large measure of independence from natural resources due to technological advances has more recently been gaining popularity. The core of this argument is that technological progress compensates for the depletion of higher quality natural resource stocks. There have, however, been warnings that the level of pollution and the deterioration of the physical landscape are increasing.
