This article identifies and quantifies the 10 most important benchmarks for climate action to be taken by 2020–2025 to keep the window open for a 1.5°C-consistent GHG emission pathway. We conducted a comprehensive review of existing emissions scenarios, scanned all sectors and the respective necessary transitions, and distilled the most important short-term benchmarks for action in line with the long-term perspective of the required global low-carbon transition. Owing to the limited carbon budget, combined with the inertia of existing systems, global energy economic models find only limited pathways to stay on track for a 1.5°C world consistent with the long-term temperature goal of the Paris Agreement. The identified benchmarks include: Sustain the current growth rate of renewables and other zero and low-carbon power generation until 2025 to reach 100% share by 2050; No new coal power plants, reduce emissions from existing coal fleet by 30% by 2025; Last fossil fuel passenger car sold by 2035–2050; Develop and agree on a 1.5°C-consistent vision for aviation and shipping; All new buildings fossil-free and near-zero energy by 2020; Increase building renovation rates from less than 1% in 2015 to 5% by 2020; All new installations in emissions-intensive sectors low-carbon after 2020, maximize material efficiency; Reduce emissions from forestry and other land use to 95% below 2010 levels by 2030, stop net deforestation by 2025; Keep agriculture emissions at or below current levels, establish and disseminate regional best practice, ramp up research; Accelerate research and planning for negative emission technology deployment. Key policy insights These benchmarks can be used when designing policy options that are 1.5°C, Paris Agreement consistent. They require technology diffusion and sector transformations at a large scale and high speed, in many cases immediate introduction of zero-carbon technologies, not marginal efficiency improvements. For most benchmarks we show that there are signs that the identified needed transitions are possible: in some specific cases it is already happening.

For several reasons, the world needs an adapted energy system to accommodate its growing population: Climate change, depletion of natural resources, and a growing dependence on only a few energy suppliers are a threat to our current system. Renewable energy sources are therefore necessary for a sustainable balance. With emphasis on detailed developments and practical application, The Energy Report, published by Ecofys and the WWF in 2011, illustrates how almost 100% of all energy carriers, all regions, and all sectors of the global energy system can be renewable by 2050.

Our study presents a new analysis for a possible transition to a fully sustainable global energy system. It looks in detail at the various energy-using activities within each demand sector, charting their volume and physical energy intensities over time. The approach pays particular attention to maximising energy efficiency through the use of best available technologies. This leads to a reduction in total energy demand and a high share of electricity. The decrease in overall demand is achieved despite a growth in both, population and volume of energy services. The electrification occurs primarily in the Buildings and Transport sectors.We conclude that we can build a global energy system by 2050 which sources 95% of its energy from sustainable sources following an ambitious, but feasible pathway. The pathway is considered achievable because it is based on currently available technology and realistic deployment rates. Policy measures are necessary in all sectors to provide incentives for the transition and we briefly discuss the requirements for these policies. The energy system we propose is robust with respect to (small) variations in the pathway as it only uses a small fraction of each of the sustainable sources.