The most basic and widely used of these is usually referred to as that of the Bruntland Commission, written under the auspices of the United Nations in 1987. The essence of this definition is (as in the slides for Lecture One): "Sustainability" involves... meeting the needs of the present generation without compromising the ability of all future generations to meet their own needs, and "sustainable development can only occur without any depletion of natural resources. Recognizing that natural resources can be viewed as either "renewable" or "non-renewable," we dis-cussed, in our second class, one difficulty with implementing this definition of sustainability in actual practice: the production and consumption of many goods, including all consumer electronics, electric vehicles, and so on, relies on the use of non-renewable resources (such as lithium for batteries), and as a consequence adhering to the Bruntland criteria for sustainability implies that we must do without such goods. However, there is a more fundamental, if also more subtle, paradox in this definition. This paradox can be seen when thinking about each succeeding generation attaining sustainability by strictly adhering to this definition by avoiding any depletion of non-renewable resources. To aid your thinking, consider what happens to the world's (constant) stock of non-renewable resources under each of the two circumstances below. 

A. If we assume individuals like to consume goods which require non-renewable resources and we further assume the number of future generations is finite (that is, there is a terminal period T beyond which human society disappears), what can you logically deduce about what will inevitably happen to the current global stock of non-renewable resources when succeeding generations strive to strictly abide by the conditions of the Bruntland definition? 

B. What happens to the stock of non-renewable resources under the alternative assumption that there is no "final" generation but rather an infinite number of generations continuing throughout the indefinite future 

C. Using the answers to (a) and (b)above, what can you conclude about the internal consistency of the Brundtland definition as well as all subsequent definitions that require the eternal preservation of the current stock of resources.