From Thermodynamics to Economics and Ecology - Thanatia: The Destiny of the Earth's Mineral Resources - page 82

Fig. 3.2 Conceptual diagram of cradle-to-grave and grave-to-cradle methodologies
- that is to say, the planet has lost all its natural bonus. Note that since the
grave-to-cradle process is hypothetical, the exergy replacement cost is not truly an
embodied exergy, it can be rather considered a hidden cost and hence both terms
cannot be used as synonyms, as was the case for cradle-to-grave analyses.
Both approaches are equally important. The cradle-to-grave one helps to opti-
mise the use of energy and materials throughout the life of a certain commodity.
In contrast, in the grave-to-cradle approach, conservation rather than e ciency is
the goal. This is because the Earth is seen as an finite provider of exergy resources,
each of which with an associated replacement cost. The higher the ore grade of
a given resource with respect to Thanatia, the greater the replacement cost, thus
advising for its conservation. The details about the grave-to-cradle approach are
later explained in Chap. 4.
3.5 Philosophical afterthoughts and warnings
Thermodynamics is arguably the branch of Physics closest to the human being.
Matters like to be or not to be, fate or death are treated in this science with an
absolute familiarity and with no regard as to how people may feel towards them.
Yet, whilst measuring, describing and giving sense to the depletion of Nature is
somewhat terrifying, it is ultimately required if one is to understand the world and
aims to manage it on more than a monetary (market) basis.