Global Energy System Transformations to 1.5 °C: The Impact of Revised Intergovernmental Panel on Climate Change Carbon Budgets

The Paris Agreement calls for countries to pursue efforts to limit temperature increase to 1.5 °C. Scenarios that limit global warming to 1.5 °C describe fundamental transformations in energy systems and typically rely on emission reductions combined with carbon dioxide removal (CDR) from the atmosphere, mostly through large‐scale application of bioenergy with carbon capture and storage (BECCS). These options face several difficulties, such as reliance on underground CO 2 storage and competition for land with food production. Here, using the PROMETHEUS global energy system model, alternative deep mitigation pathways are explored, in light of the revised carbon budgets specified in the Intergovernmental Panel on Climate Change (IPCC) Special Report on 1.5 °C. The pathways assess the potential contribution of energy efficiency improvements and more rapid electrification of energy services based on renewable energy. Although these alternatives also face specific implementation challenges, they are found to significantly reduce the need for CDR and BECCS, but not fully eliminate it, and offer an effective way to diversify transition pathways to meet the Paris targets. Achieving the 1.5 °C target is technically feasible but requires immediate, ambitious, and global action, based on large‐scale deployment of renewables, early retirement of fossil‐based power plants, accelerated efficiency improvements, and expansion of carbon‐free options in end‐uses.