Re: Re [Fis] Sustainable use of resources

>I would like to precise that in my opinion an energetic or an emergetic
>approach to sustainability (and so to ecological economics), can be just
>a little part of the sustainability problem. I would like to present
>here two different considerations: the first one underlines the
>informational aspect of the problem and the second one the scientific
>aspect.
>
>1) Emergy, exergy and information
>I don’t believe that emergy (no exergy or so on) could or should provide
>directly a new basis to root directly economic nor monetary values. We
>can rather say that individual and collective preferences should be
>better informed about the ecological value of goods. Through a “well
>tempered” market and policies, such wiser preferences could contribute a
>shift in the whole economic system, both in values determination and in
>its structure.
>It is very important, on the other side, to understand properly the role
>and the intrinsic limits of every classical thermodynamics-based sight,
>like emergy- or exergy-informed ones.
>There are radical differences on this subject, within people working
>with emergy: the orthodox position, that is dominant in the community
>and injurious for emergy itself, doesn’t accept to recognize the
>intrinsic limits of such a sight.
>So, there’s a growing need of an epistemological reflection. We can try
>to outline some aspects.
>Biosphere and ecosystems are far from thermodynamic equilibrium, so that
>classical thermodynamics cannot tell anything about them, without
>introducing intermediate assumptions.
>We could say that emergetics and exergetics are two parallel paths to
>adapt classical thermodynamics to the specific condition of our living
>biosphere, adopting – respectively – a diacronic and a syncronic
>perspective.
>Exergy researchers root themselves in the terrestrial specificity,
>defining, as a reference state, the mean composition of the earth crust,
>or of atmosphere, or of a peculiar local context, considered in a steady
>state and without introducing further assumptions about the datum.
>Emergy scientists, on the other side, base their descriptions on a
>previous knowledge of our biosphere, that has a very general tendency in
>concentrating energy in more and more condensed forms through trophic
>chains, the metabolism of organisms as well as through bio-geochemical
>cycles.
>On the first side we have a measure, surely closer to classical science
>canons, of the distance with a snapshot of our environment (or of a more
>restricted, local bulk), identified with its mean values.
>On the other side, the emergetic description is more dependent on the
>actual metabolism of the biosphere and its evolutionary history,
>building its “transformities” – the coefficients used to express the
>ecological value of a material, a flux or a specifical good – on that
>background.
>
>It has been told that thermodynamics is for physics (in our case for
>ecology) what logic is for philosophy: in this sense we can consider
>emergy or exergy sights as necessary, but not sufficient basis to
>express the actual ecologic value of a good, a material or a flux.
>Necessary, because they provide a way to root quantitatively our object
>of study in the limited amount of exergy, or negentropy, as to say of
>resources, available in the biosphere.
>Not sufficient, because thermodynamics is blind in front of meaning, or
>sense production.
>Emergy analysis can provide a budget of solar energy memory, necessary –
>for example – to produce a university-level book of 200 pages. In the
>same way we can express the exergetic value of that book, considering
>the uncompressible information of the text (giving 2,9 E-21 J for each
>bit of information) plus the chemical potential of the book, i.e. the
>energy extractable with a complete combustion of the book itself.
>But exergy, nor emergy, can say anything about the actual scientific or
>artistic content of the book, the meaning that it can provide to a
>reader.
>In the same way an exergetic potential, or an emergy storage or a raw
>information content could be both a resource or a toxic, depending on
>the specific ecological or cultural meaning that it will express when it
>will be in contact with a specific organism, an ecological association
>in the environment, or a cultural system.
>Emergy content, exergy or information, should be considered as first
>attributes of quality, or of ecologic value, but never definitive
>assumptions on the value of things. At any rate, these considerations
>don’t contrast with the Second Law of the Thermodynamics (Clausius) –
>entropy is ever-growing – that is an universal and non-reductionist law
>of nature. Of course, on the contrary, saying that DNA contains the
>whole information of the seed of the plant, is reductionism. The
>dangerous reductionism of the genetic engineering.
>
>2) Emergy and evaluation of environmental costs
>The present state of the biosphere is the result of a very slow
>evolution over millennia and the biosphere is a global steady state
>system: everything having the potential to push it far from the present
>steady state may introduce a possible instability, a change of state, an
>uncertainty whose consequences are hard to forecast. Thus, while the
>emergy content is the basis to evaluate the evolution of competing
>systems, only an emergy-based correction term, due to an increased
>adiabaticity of the atmosphere, can measure the real stress the
>biosphere is suffering.
>Thus, emergy analysis according to Odum’s theory can be used when
>systems are analysed and compared from the point of view of
>investigating the environmental cost of production: the emergy content
>would have the meaning of a measure of the nature work to provide a
>given item or flow, i.e. the amount of past and present ecosystem
>activity converging into the flow under study. On the contrary, when the
>stability of the steady state is analysed, an adiabatic correction term
>should be introduced. Such a corrected emergy can be considered the long
>run work potential: if negative, it means that the environment will have
>to work in the future, to push the system again towards the previous
>steady state. The correction term is thus a measure of the distance
>between a not sustainable and a sustainable state of the biosphere, as a
>consequence of the use of a given resource.
>An example: when fossil resources are used, their real work potential
>cannot be only expressed by their emergy content: it should be
>proportionally reduced to account for their ability to prevent
>waste-heat discharge towards outside space. We think that the amount of
>heat which is not discharged outside and is reirradiated towards the
>earth surface due to a higher CO2 concentration, could be considered a
>good measure of real work potential reduction. Thus, a quantity due to
>the absorption of infrared radiation by CO2 has to be subtracted from
>the total emergy of the resource, that is a correction adiabatic term.
>
>3) Concluding remarks
>In order to drive culture and society in an ecological direction, we
>need to shun “absolutist positions” and every fundamentalism, that can
>be identified in the following points:
>a) the myth of objectivity and neutrality of science;
>b) the faith in linear conclusions, as a result of a pure “rational”
>approach (we need to contrast the anti-biological dogma that requires to
>exclude instinct, aesthetics, quality, emotions from the scientific
>analysis;
>c) anthropocentric and individualistic positions;
>d) the negation of “reality”, of natural limits, founding knowledge only
>in the subject’s mind; the information network is a fruit of a millenary
>biological evolution and pre-exist to human knowledge;
>e) the extreme naturism, which falls in anthropocentrism and in the
>exaltation of human body;
>f) the deification of nature and the consequent idea of faith healing,
>i.e. of nature’s ability to recovering damages.
>These are all “absolutistic” positions, which want to give definite
>answers (but nature is uncertain and complex). Ecology is the science of
>limits and uncertainty, and also the “science of time”. In this
>difficult time for our history, ecology teaches us humility in the
>approach to nature. The human being is in fact strictly connected to the
>ancient network of nature and his learning process is part of the
>complex and still unknown history of nature. Biological tempos are not
>comparable with human (historical) tempos.
>
>4) References
>Tiezzi E., The Essence if Time, WIT Press, 2004
>Tiezzi E., Beauty and Science, WIT Press, in press.
>Tiezzi E., Bastianoni S. and Marchettini N., Environmental cost and
>steady state: the problem of adiabaticity in the emergy value,
>“Ecological Modelling”, Volume 90, Issue 1, September 1996, Pages 33-37.

Prof. Enzo Tiezzi
Dip. di Scienze e Tecnologie chimiche e dei Biosistemi
Via della Diana 2/a
53100 Siena (Italia)
Tel: +39-0577-232012
Fax: +39-0577-232004
Studio: +39-0577-45207

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Received on Tue Dec 9 13:48:34 2003