Thoughtful leaders increasingly recognize that we are not only failing to solve the persistent problems we face, but are in fact causing them. System dynamics is designed to help avoid such policy resistance and identify high-leverage policies for sustained improvement. What does it take to be an effective systems thinker, and to teach system dynamics fruitfully? Understanding complex systems requires mastery of concepts such as feedback, stocks and flows, time delays, and nonlinearity. Research shows that these concepts are highly counterintuitive and poorly understood. It also shows how they can be taught and learned. Doing so requires the use of formal models and simulations to test our mental models and develop our intuition about complex systems. Yet, though essential, these concepts and tools are not sufficient. Becoming an effective systems thinker also requires the rigorous and disciplined use of scientific inquiry skills so that we can uncover our hidden assumptions and biases. It requires respect and empathy for others and other viewpoints. Most important, and most difficult to learn, systems thinking requires understanding that all models are wrong and humility about the limitations of our knowledge. Such humility is essential in creating an environment in which we can learn about the complex systems in which we are embedded and work effectively to create the world we truly desire. The paper is based on the talk the author delivered at the 2002 International System Dynamics Conference upon presentation of the Jay W. Forrester Award. Copyright  2002 John Wiley & Sons,

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All models are wrong: reflections on becoming a systems scientist†

This Research Report addresses the following question: 'What evidence is there to support the proposition that the global supply of ‘conventional oil’ will be constrained by physical depletion before 2030?' The report is based upon a thorough review of the current state of knowledge on oil depletion, supplemented by data analysis and guided by an Expert Group

Global oil depletion - an assessment of the evidence for a near-term peak in global oil production

The limits to the limits of growth

The United States is currently undergoing a transition from rapidly depleting nonrenewable energy sources to ''backstop'' energy sources. A system dynamics model has been developed to analyze the macroeconomic effects of the energy transition. GNP, consumption, investment, wages and prices, and other major energy and economic aggregates are determined endogenously. The model shows how delays in substitution and the development of new energy sources arise and lead to substantial economic losses during the next several decades. The economic consequences of developing long lead time, capital-intensive, centralized technologies are contrasted against those attending development of short lead time, labor-intensive, decentralized technologies; the latter are found to be far more effective in reducing the vulnerability of the economy during the transition. 57 references, 7 figures, 7 tables.

Economic vulnerability and the energy transition

The effects of three categories of technological innovation on the use and price of nonrenewable resources

The limited reserves of mineral resources will soon become a problem facing all the countries of this globe. In an attempt to plan for the needed supply, the static reserve life index of a resource has been used as a measure of future availability. This static index is an inadequate measure of resource availability, one which could cause severe misjudg ments concerning resource supplies. Long-term re source planning requires a better understanding than that afforded by the static reserve life index. This paper illustrates that knowledge already available about the relationships governing the supply of and demand for resources is sufficient to develop a frame work, a simulation model, which can form the basis for more meaningful analysis of long-term resource utili zation.

William W. Behrens

Papers

The dynamics of natural resource utilization