Reconsidering Limits to Growth: Integrating energy transition and circular economy in an extended World3 framework

The 1972 study The Limits to Growth highlighted the risk of systemic overshoot and steep decline due to resource constraints, but was criticized for underestimating technological adaptation. This paper revisits that thesis by extending the World3 model to incorporate two major contemporary transformation strategies: the energy transition (ET) towards renewable energy sources and the circular economy (CE). It asks to what extent combined CE and ET strategies alter overshoot-and-collapse dynamics and whether they can prevent, rather than merely delay, systemic decline. To enable this analysis, the aggregated stock of non-renewable resources is disaggregated into distinct energy and material flow components. The CE module represents material life cycles, including durability constraints and a maximum recyclability rate of 90%. The ET module simulates renewable energy expansion under economic, environmental, and resource feedback constraints. Under the World3 model structure and the selected scenario assumptions, the results indicate that CE and ET individually delay systemic decline, but do not prevent it within the explored parameter space. Instead, resource pressures shift between the energy and material domains. The ET pathway alleviates the depletion of fossil energy, but accelerates the material demand for renewable infrastructure. In contrast, CE reduces primary material extraction but increases energy requirements. The combined CE & ET scenario exhibits the highest resilience, extending population stability and industrial output relative to the individual strategies. However, the system’s fundamental overshoot-and-decline dynamics persist. More broadly, the simulations should be understood as exploratory scenario experiments rather than predictive forecasts. These findings reaffirm the core message of the original study under the assumptions explored here: technologies and efficiency-oriented strategies alone are insufficient when continued exponential growth on a finite planet outweighs gains in resource productivity. This study contributes to the cleaner production literature by quantifying rebound effects, burden shifting, resource-efficiency limits, and energy–material trade-offs within an integrated system dynamics framework.