Are we using up exhaustible resources at an unsustainable pace? Will economic growth eventually grind to a standstill because of mounting degradation of the environment? If National Accountants could provide acceptable measures of the economic depletion of exhaustible natural resources and the economic degradation of our natural world, these, added to those for economic depreciation and deducted from Gross Product, would yield measures of Net Product which might show whether or not we have been experiencing sustainable consumption.