Should notions of sustainability separate economy (man-made ‘capital’)

from environment (natural ‘capital’) and as such apply different interest rates to each? For example, a zero rate applied to natural ‘capital’ to ensure preservation for future generations, and a normal rate applied to man-made ‘capital’ to stimulate investment and business activity.

Or can natural ‘capital’ and man-made ‘capital’ be considered as a whole (total ‘capital’), with gains in man-made stock substituting for loss of natural resources, such that total ‘capital’ remains constant?

Would a rate higher than zero see losses in natural resources balanced by growth in man-made ‘capital’?