Abstract: The search for the roots of the doctrine of unlimited growth leads to the traditional anthropocentric world view where the human has to relate himself only to a given nature. This dualism between a human with unlimited technological power and a static nature is not able to explain such phenomena as stagnating happiness indexes, continuous food and resource insecurity, health problems and climate change. A more holistic world view would position the human into a dynamic system in which all elements influence each other. Modern models of economic growth like the Solow-model have made evident that growth on a longer time scale is only possible due to technological process and increasing productivity. But the fact that there is a trade off between resource efficiency and labour/capital productivity underlines the need for a new understanding of technological process. In many cases a disintensification that increases the necessary manual labour can reduce environmental and social costs to a greater extend than the initial increase.
Taking these reflections into account this paper introduces a new model of economic growth which extends the neoclassical model of growth in two important points. The first consideration is that the value of economic output is very much influenced by the status of the environment. The availability and scarcity of resources, the biospherical conditions for growing, the (in)stability of natural cycles all have consequences in a production function that reflects the value of satisfaction, i.e. happiness, more adequately. Therefore environment or nature is considered as an input factor in the production function. The second consideration relies in the fact that nature has the ability to recover at a certain rate and that it also deteriorates depending on the impact that has our economy. The negative impact is expected to rise with a growing economy but can be slightly restricted by using less intensive technologies.
An analysis of this model leads to the conclusion that every growing economy reaches a state of instability where natural depletion causes an ongoing crisis. At this point technological progress and productivity growth can no more counterbalance the effect that depletion has on the economy. This condition consists until the shrinking economy reaches an output level of sustainability where human-caused deterioration is once more as small as nature’s capacity to recover. Under these circumstances technological progress does not generate further growth but only substitutes nature with items of artificial production due to depletion.
As the unwilling decline in economies that continue producing above the level of sustainability is unpreventible, an argument can be made for degrowth. It makes sense to degrow in a controlled manner to avoid the much more catastrophic depletion crisis. In that manner a richer biosphere can be maintained which allows a much less intensive technology for the same output. A less intensive technology denotes a higher probability to decrease also the impact per output. In conclusion degrowth helps to raise the level of sustainability and actually leads to a higher sustainable output in the long long run than unlimited but dangerous growth.

Contribution to the 3rd International Degrowth Conference for Ecological Sustainability and Social Equity in Venice in 2012.