Geology Reference
In-Depth Information
The grave needs however further discussion. When analysing EoL of a given
material, the grave is usually taken as the landfill it arrives at. Drawing a parallel,
one can state that at planetary level, the grave could be an ultimate landfill where
all resources eventually end up and are irreversibly dispersed - the commercially
dead planet, towards which human civilisation is moving.
If one accepts this planetary grave as a hypothesis, the need for the development
of a model capable of adequately depicting the commercial end of the planet arises.
The authors coined this planet Thanatia (Valero et al., 2011; Valero D. et al., 2011)
and represented it through the Crepuscular Earth Model 25 . The latter has an
atmosphere, hydrosphere and continental crust (see Chap. 10). Nevertheless, as
opposed to that of the current Earth, the crepuscular crust contains no mineral
deposits with all non-fuel minerals having been extracted and dispersed and all
fossil fuels having been burnt. As a consequence, the CO 2 concentration of the
crepuscular atmosphere is much higher than it is at present. Similarly, all water
available in the hydrosphere, except for a tiny 2.5% due to the hydrological cycle
as it is now, is saline due to all freshwater and saltwater having mixed.
Upon defining the model of Thanatia, it becomes easy to evaluate the replace-
ment cost of minerals through a “grave-to-cradle” approach (see Chap. 4). Such
cost can be assessed as the useful energy (exergy) required to restore minerals from
the grave to the cradle, i.e. from Thanatia to the original mines.
It should be stated that there is as of yet no consensus regarding what fini-
tude means with many even failing to acknowledge and/or admit that there could
be a “commercial end”. It is thus unlikely that the need to determine a degraded
Earth will be easily accepted. However the sense of having a not-so-far expiry date
gives maturity to humankind and supports improved management of those remain-
ing resources. Moreover, the thermodynamic assessment of the mineral endowment
with Thanatia as reference allows for the physical quantification of the depletion
of resources. Depletion and finiteness can no longer be a “yes-or-no idea” but a
“plus-or-minus” concept. Furthermore, everything is evaluated using a single yard-
stick, (measured in kWh) exergy, thereby unifying dispersed data, allowing for a
unified vision of the global mineral wealth and facilitating comparisons between
commodities, countries, etc.
It is now the hour for humanity to begin to adequately manage its non-renewable
resources with intelligence and order, so that however finite they can be accounted
for, as can their loss. Society must therefore begin to estimate quantitatively orders
of magnitude whilst learning to truly appreciate them qualitatively so that con-
structive dialogue or better said trialogue between energy, environment and mineral
issues can begin and agreements signed for the creation of a common sustainable
global path. This is effectively the objective of the topic.
25 The Crepuscular Earth Model was developed by Dr. Alicia Valero in her Ph.D. thesis with
the help of the British Geological Survey and the department of petrology at the University of
Zaragoza, Spain.
 
Search WWH ::




Custom Search