Ecological economics was constituted in the late 1980 as a transdisplinary field of study attracting systems ecologists and dissident economists. Inspiration was drawn from N. Georgescu-Roegen´s The entropy law and the economic process (1971) together with work from ecologist H. T. Odum and economist K. Boulding. The complexity of living structures is achieved by "capturing" energy through photosynthesis and by dissipating energy to outside systems. The industrial economy, however, does not work only by using current photosynthesis. It burns irreplaceable stocks of fossil fuels, and it produces irreversible damage to the natural environment. The scale of the economy is too large, therefore the natural cycles cannot sustainably produce the resources or absorb or assimilate the waste such as, for instance, heavy metals or excessive carbon dioxide. Ecological economics encompasses money-valuation of positive environmental services and of negative externalities, and also physical appraisals of the environmental impacts of the human economy measured through new indicators. It also gives importance to social indicators. The study of the relations between property rights and management of natural resources is another important focus. Ecological economics favors multicriteria assessments over cost-benefit analysis, emphasizing incommensurability of values. It has also developed an ecological macroeconomics without growth.