Complexity, Problem Solving, and Sustainable Societies is a paper on energy economics by Joseph Tainter from 1996. Focus It focuses on the energy cost of problem solving, and the energy-complexity relation in manmade systems. This is a mirror of the negentropic tendencies of natural evolution, according to ecological economics, notably the arguments of Donella Meadows and her colleagues on the economic constraints of contemporary problem solving. The Limits to Growth, 1972, argued that "to raise world food production from 1951-1966 by 34%, for example, required increasing expenditures on tractors of 63%, on nitrate fertilizers of 146%, and on pesticides of 300%. To remove all organic wastes from a sugar-processing plant costs 100 times more than removing 30%. To reduce sulfur dioxide in the air of a U.S. city by 9.6 times, or particulates by 3.1 times, raises the cost of pollution control by 520 times." All environmental problem solving will face constraints of this kind, Tainter argues. It is not a question of expending a lot of energy to discover "more efficient" ways to do these things - that process amplifies the decline. Attempts Attempts to impose the "most efficient" means have other problems. In The Rise and Decline of Nations, Mancur Olson argues that "bureaucratic regulation itself generates further complexity and costs. As regulations are issued and taxes established, those who are regulated or taxed seek loopholes and lawmakers strive to close these. A competitive spiral of loophole discovery and closure unfolds, with complexity continuously increasing." "In these days when the cost of government lacks political support," Tainter argues, "such a strategy is unsustainable. It is often suggested that environmentally benign behavior should be elicited through taxation incentives rather than through regulations. While this approach has some advantages, it does not address the problem of complexity, and may not reduce overall regulatory costs as much as is thought. Those costs may only be shifted to the taxation authorities, and to the society as a whole. It is not that research, education, regulation, and new technologies cannot potentially alleviate our problems. With enough investment perhaps they can. The difficulty is that these investments will be costly, and may require an increasing share of each nation's gross domestic product. With diminishing returns to problem solving, addressing environmental issues in our conventional way means that more resources will have to be allocated to science, engineering, and government. In the absence of high