Global climate mitigation requires a renewable energy transition. Due to interactions between energy demand and material use, improvements in material efficiency promise to contribute to climate mitigation. To analyse such potentials, system dynamics modelling was applied to test four different scenarios towards a 100% renewable energy world. The model findings show that a 100% renewable energy world with zero greenhouse gas emissions seems feasible. However, the chosen pathway matters. While material efficiency reduces emissions and increases availability of secondary raw materials for renewable energy generation, only absolute reductions in energy demand through sufficiency-oriented lifestyles and sustainable choices in food, housing, and mobility seem able to achieve emission reductions needed to stay within 1.5-degree warming. Here, international policies are needed to create globally equitable opportunities for decent lifestyles in a safe and just planetary space
