Geology Reference
In-Depth Information
“Homo sapiens make tools to make tools, to make tools:::For these tools, which
are in fact detachable organs, we have come to tap in staggering measures re-
sources from the bowels of the Earth”(Georgescu-Roegen, 1983).
Truly, in a finite planet, with finite material resources, recycling is needed for
ecological salvation. For recycling, energy is essentially required and the greater the
material dispersion, the more energy is needed as will be seen later in Chap. 14.
As matter is increasingly subject to friction, cracking, chipping, blistering, corro-
sion, fatigue, mixing and alloying, it degrades and disperses, making the complete
recycling of matter an unattainable task. Man is thus doomed to extract cur-
rently available materials from the crust only to convert them subsequently into
unavailable ones, in order to sustain economic activities. This makes an everlasting
steady-state economy impossible (Daly, 1991).
The Second Law perfectly supports this idea and the exergy needed to concen-
trate an infinitely dispersed material is effectively infinite. Yet, to explain this fact,
Georgescu-Roegen (1977a) went further by promoting an unnecessary “Fourth Law
of Thermodynamics”. With his fourth law, Georgescu-Roegen (1977a) claimed that
matter behaves in a way parallel to the fact that available energy is irrevocably con-
verted into an unavailable one. Thus in his opinion, available matter irrevocably
becomes unavailable.
But this statement is scientifically wrong. It is in fact an outcome of the Second
Law. This can be explained through the following reasoning. The boundary mark-
ing, say, available heat and unavailable heat is its ambient temperature (Sec. 3.2.2).
The lower it is, the more heat can be transformed into useful work. At the limit,
a given heat flow could be completely converted into useful work if the ambient
temperature were able to reach zero Kelvin. This availability is independent of the
technology employed. Contrary to heat, matter has no such associated intensive
property
4
that could define what is available and what is not. In other words and
at least in theory, every minuscule piece of matter could be separated from the
rest if enough energy and separation precision is used. Accordingly, Georgescu-
Roegen's statement is rather a practical/economic one than any new physical law.
As a matter of fact, both energy and matter continuously and irrevocably degrade.
However, there is no need to define parallel material entropy
5
and its corresponding
material temperature to explain this phenomenon. Notwithstanding, the idea of
Georgescu-Roegen that “as time goes on, technologically crucial minerals may be-
come exhausted”, still holds and Thermodynamics allows for the calculation of this
exhaustion velocity through the exergy analysis as explained in this topic.
Appendix E provides a transcription of the interview that Antonio Valero con-
ducted with Nicholas Georgescu-Roegen in 1991, in which the aforementioned issues
were discussed.
4
Such as material temperature.
5
Which should be as numerous as the different chemical species.
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