However, there was a time in the 20th Century when rampant inflation prompted an interesting alternative method to be introduced (for a time) for valuation of assets - replacement cost. In this method, you valued by estimating how much it would cost to replace the asset, like for like, if you used it up in some way (eg by selling it). For a World Balance Sheet, this might be a good valuation method. It would recognise, for all assets, what it would take to replenish them all. It would be progressive, in the sense that the greater the stress on remaining natural assets, the greater the effort needed to replace them like-for-like, and therefore the greater the individual asset value. There would be some interesting inflection points, for example at the point when it became more value-adding to protect and maintain most natural assets rather than 'use' them and suffer the loss from the Balance Sheet, or have to replace them at ever-increasing amounts of effort.
Having not 'done the maths' on this, for all I know we might have already reached that point for many types of natural assets. the Planetary CFO could do with an analyst or two operating in the right circles to pull together some data on this. Any volunteers out there?