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close this bookEco-restructuring: Implications for Sustainable Development (UNU, 1998, 417 p.)
close this folder1. Eco-restructuring: The transition to an ecologically sustainable economy
View the document(introduction...)
View the documentIntroduction: On sustainability
View the documentThe need for holistic systems analysis
View the documentEnvironmental threats and (un)sustainability indicators
View the documentSharpening the debate
View the documentNon-controversial issues: Population, resources, and technology
Open this folder and view contentsControversial issues: Pollution, productivity, and biospheric stability
View the documentFinding the least-cost (least-pain) path
View the documentConcluding comments
View the documentNotes
View the documentReferences


1. Toxins and carcinogens are considered dangerous from a human health point of view and are therefore commonly placed under strict control, irrespective of whether ecological consequences are likely or not.

2. Phosphorus is the other nutrient element that is required in amounts greater than the earth's crust normally contains. It is not recycled biologically, however, but accumulates on the ocean floors where it is recycled by ocean currents and by tectonic action. If the earth ever ceased to be tectonically active, the land surface would eventually run out of phosphorus.

3. Agreeing on the common use of simple and crude measures is nothing new. The gross domestic product (GDP) has been used for decades as a measure of "welfare," despite serious doubts that it really measures any such thing. It omits important sectors. including subsistence agriculture and unpaid household work (mostly by women), and it omits environmental services. On the other hand, it includes dubious items, such as "defensive measures" to protect health and safety, despite the fact that the health and safety hazards result from human activity in the first place. Clearly, defensive expenditures make no contribution to net social welfare. Nevertheless, GDP is still being used by macroeconomists, almost universally, without any of the adjustments or corrections that numerous critics have advocated.

4. The Wuppertal calculations of mass moved, or mass disturbed, generally include more than material "inputs" in the strict sense. The difference may be quite significant in some cases.

5. For a more complete review of this controversy, see Ayres (1993).

6. It is unclear what should be meant by "middle class." To put a specific monetary equivalent on it seems futile. A more functional suggestion might be that the relevant criterion of middle-class-ness is that children do not contribute to the family income, but rather constitute a financial obligation.

7. Some scientists argue that organic synthesis of a sort may have been going on in the reducing atmosphere of the early earth by mechanisms as yet unknown.

8. The argument for "factor 4" is set forth in German by von Weizsacker et al. (1995); the argument for "factor 10" is summarized in Schmidt-Bleek (1994).

9. The phrase "closed cycle" should not be taken literally. Closure with respect to materials is possible, but the cycle cannot be closed with respect to exergy.

10. The "second-law" efficiency of any process is defined as the ratio of the minimum amount of energy theoretically needed for the process to the energy actually used. It can be defined consistently, in principle, for any process (given a suitable convention on the treatment of co-inputs and byproducts), although actual numerical determination can be difficult in some cases. It must be pointed out that there is another widely used definition of efficiency, namely the ratio of "useful" energy outputs to total energy inputs. In some cases, such as electric power generation, the two definitions are equivalent. However in other cases (such as heating units) there is a very big difference. Gas furnaces are often advertised as having "efficiencies" up to 90 per cent, which merely means that 90 per cent of the heat is "useful" and only 10 per cent is lost with the combustion products. However, it often happens that the same amount of final heating effect could have been achieved with much less energy expenditure (e.g. by means of a "heat pump"). In this sense, most heating systems are actually very inefficient.

11. Note that efficiency of use is quite independent of the amount of use. The United States uses far more energy per capita than India, for instance, because it receives more energy services. But many energy using activities in India, from electric power generation to cooking, nevertheless tend to be considerably less efficient than their Western counterparts.

12. For a more detailed review of this literature, see Ayres (1994).

13. This issue was highlighted in the 1994 White Paper, Growth, Competitiveness, Employment - The Challenges and Ways Forward into the 21st Century, issued by Jacques Delors, then Chairman of the European Commission (EC 1994).