It studies nature in relation to technology in most general contexts (exhaustibility of resources, limited assimilation capacity of the environment).

Traditional areas of environmental and natural resource economics include welfare theory, pollution control, resource extraction, and non-market valuation, and also resource exhaustibility, sustainability, environmental management, and environmental policy.

Specifically, this shows that exhaustibility does not occur until these factors weaken and play out: the availability of substitutes, the extent of recycling and its feasibility, more efficient manufacturing of the final consumer product, more durable and longer-lasting consumer products, and even a number of other factors.

Perhaps it's the exhaustibility of the material, a problem that doesn't arise in columns on current events, politics and Victor Navasky's slave-wage policies (those of us who have written for The Nation and been paid by Mr. Navasky in the "high two figures" constitute a Trillin minicult).