attac: Introductory Course by Roefie Hueting.

Environmental functions are defined as the possible uses of the non-human-made physical surroundings. Environmental sustainability is defined as a dynamic equilibrium by which vital environmental functions remain available for future generations. Environmentally sustainable national income (eSNI) is defined as the maximum attainable production level by which vital environmental functions remain available for future generations. A solution is given for the unsolvable problem of the valuation of environmental functions and for asymmetric entering.