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Archive for October 2008

Entropy and Energy: Toward a Definition of Physical Sustainability (Paper)

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Posted by: Karl Ramjohn

A different perspective towards developing an “environmental” approach to defining sustainability…

Entropy and Energy: Toward a Definition of Physical Sustainability



Sustainable development is a growing concern expressed by many businesses, organizations and individuals. Yet, no workable quantifiable definition of sustainability is available for evaluation of specific projects or operations. 

This paper attempts to set a framework for such a definition in terms of the first and second law of thermodynamics. Specifically, the proposed description of sustainability relates the fundamental processes of chemical, physical or biological transformation, and mass transport to energy and entropy changes. 

Unlike previous applications of these concepts, the proposed definition is focused on the smallest unit operations and processes while allowing for aggregation into larger systems. The proposed description also explicitly considers the time horizon for sustainability. An example of sustainability analysis for a water treatment process is included.


Slawomir W. Hermanowicz, “Entropy and Energy: Toward a Definition of Physical Sustainability” (December 1, 2005). Water Resources Center Archives. Working Papers. Paper swr_v2.

Link to full paper (pdf) –>…8&context=wrca

Environmental Context – Sustainability, Biophysics & Ecological Character

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Posted by: Karl Ramjohn

If we define the environment as “the combined features and assets that provide the basis for economic and social development, natural resource management and conservation”, it becomes abundantly clear that, sustainable management strategies, options and “best practices” must be planned, implemented and maintained in the context of the processes, components and attributes of the abiotic, biotic and human factors in any developmental landscape.

Following on the earlier posts, this article examines a theoretical approach to management of impacts to the natural biophysical environment, associated with socio-economic development. This requires the establishment of a focus, for the development of a systems methodology based on measurable parameters which can be used to quantify changes in natural resource status, in relation to hypothetical marginal damages resulting from development impacts (industrial and other).

Issues related to the biophysical environment, in relation to development impacts on ecological, social and economic characteristics, generally encompass:

 ·       Physical features of the natural environment that potentially impact ON development activities; and

 ·       Physical resources of the natural environment potentially affected BY development activities.

 Physical Features of the Environment

 These are defined by the forcing functions (enduring features and driving variables) of the natural environment, that potentially impact on development activities. Physical features of the environment are generally determined by oceanographic, meteorological, climatological, topographic, geophysical and hydrological processes, characteristics and interactions, in relation to the variability of natural systems (e.g., seasonal, inter-annual and synoptic oscillations).

 These physical features have an important role in determining:

 ·       Dispersal and dissipation rates of pollutants by air, water, sediments and soil, both waste streams (process residues) and unplanned events (spill and leakages);

 ·       Risk of extreme weather events (e.g., floods, tropical storms and hurricanes);

 ·       Geophysical constraints and opportunities to landscape development (e.g., topography, soil structure and subsurface geology);

 ·       Risk of seismic and tectonic activity (e.g., earthquakes and volcanoes); and

 ·       Occupational hazards and safety in the workplace environment.

Physical Resources of the Environment

These comprise the physical components of the natural environment which are potentially at risk of being adversely affected by development (e.g., by waste streams of industrial facilities). Physical resources consist of air, soil, water (surface and subsurface) and sediments. These abiotic environmental components have a pivotal role in defining the “Ecological Character”, which refers to the structure and inter-relationships between the biological, physical and chemical components of the ecosystem. This dynamic character is driven by landscape-level features and ecological processes, which encourage the development and maintenance of critical ecosystem functions, that support key natural resource components. These act as life-support systems for flora, fauna and humans in the biosphere, by providing a number of essential goods, services, attributes, and values, including:

·       Control and stability of natural materials production, cycling and renewal systems (e.g., water, organic matter, and inorganic nutrients, and minerals);

·       Control and stability of natural energy conversion, cycling and renewal systems;

·       Support of an ecological structure (diversity of habitats, species and foodwebs);

·       Resistance to, and resilience from, adverse environmental impacts and other changes;

·       Support of economic (subsistence, commercial and recreational) activities for local area and resource-user communities; and

·       Supply of engineering media, raw materials, energy sources and waste treatment and assimilation systems (internally self-regulated within threshold limits).

The study of adverse changes to these resources, from industrial development impacts, can be achieved by measurement of environmental quality, in conjunction the physical features (forcing functions) described above. This will be elaborated upon and further developed in subsequent posts.


Ramjohn, Karl. 2000. Development of Methodology for Impact Detection and Monitoring in Accordance with The Certificate of Environmental Clearace Rules, Rule 10. M.Sc. Thesis, Science and Management of Tropical Environments. Faculty of Agriculture & Natural Sciences, University of the West Indies, St. Augustine, Trinidad & Tobago. September 2000; 117 pp.


Characteristics, Role & Functions of Sustainable Development in Environmental Management

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Posted by: Karl Ramjohn

In a previous discussion on the characteristics, functions, and significance of “sustainable development” in the context of environmental management, it was noted that in order to attempt a rationalization of sustainable development (or achieving “sustainability” in development activities) and how that relates to the environment, it may be useful to establish a proper understanding of some of these main concepts.

To begin with, what is the “environment” as it pertains to sustainable development? For this purpose, the “environment” can be considered as the combined features and assets that provide the basis for economic and social development, natural resource management and conservation. In this context, sustainable management strategies, options and “best design” practices must be planned and implemented in relation to the processes, components and attributes of abiotic (non-living), biotic and human factors in any given developmental landscape.

Or to use a more formal definition:

 Environment = The combined features and resource capital, that provide the basis for development, environmental management and conservation. Includes the processes and components of, and services provided by, atmospheric, hydrological, geophysical, biotic, human and landscape factors.

Environmental quality = The status or value of the natural resource capital at a particular location at a specified time, relative to development, environmental management and conservation.


Some further discussions on these concepts that characterize  “sustainable development”:

Development = The act of altering and modifying resources in order to obtain potential benefits. 

Environmental Degradation
 = Adverse effects (reversible or permanent) on biophysical, social and economic resources, or any other reduction of the set of options available to future generations.

Adverse Effects = Any reduction in environmental quality of a system, or other depletion of the environmental resource capital. Defined in terms of, and measured by, environmental impacts.

Environmental Impact = Change in environmental quality due to external disturbance to a system. Includes positive and negative, primary and secondary, cumulative, synergistic, short, medium and long-term, reversible and irreversible. Described in terms of magnitude (of effect), direction (of change) and probability (of occurrence), with or without mitigation


In terms of discussing “development” (the act of altering and modifying the resources of the natural environment in order to obtain potential economic and social benefits), it is important to note that it involves the application of human, financial and biophysical resources to satisfy social and economic needs, inevitably leading to some modification of the biosphere. The extent of development-induced modifications depend on the location, scale, intensity and duration of activities as well as adequacy of mitigation and compensatory measures, which define the scope for, and degree of balance in, environmental costs and benefits. As noted, ideally, for a development to be “sustainable” it should demonstrably be economically feasible and socially acceptable, without causing significant environmental impacts
or land degradation.

From a policy, regulatory and legislative perspective, very closely related to implementation of all of these characteristics of sustainable development, is the “Precautionary Principle” – a sustainability principle which states that if there are threats of serious irreversible environmental impact, lack of full scientific certainty will not be used as a reason for postponing measures to prevent environmental degradation.

Information Sources: