Considering that all human activity interacts with the environment either by extracting resources or by discarding trash under the form of degraded matter and energy, the economic process - which operates within an open subsystem contained by the global ecosystem - has to observe limits. Hence, the notion of sustainable development. In the perspective of sustainability, the kind of economic process which matters is that which produces goods and services taking into consideration simultaneously all costs (or ills) that are inevitably associated with it. This is the task for a new model of development, and also for a science of the economy with ecological foundations. It is here that ecological economics finds its place. A fundamental change which it brings about concerns the perception of problems of resource allocation as well as how resources are considered. Likewise a reappraisal of the dynamics of economic growth is introduced. The aim of this endeavour is to unify the ecological and economic systems on bio-physical bases as interdependent, coevolutionary categories. It is not a question of proposing a new science, but an initiative (or commitment) among natural and social scientists, together with actors involved in concrete action for promoting development, to arrive at a new understanding of human reality, drawing lessons for analysis and policy. This way one obtains a true political economy of ecology.
sustainability; economy; ecological economics