Despite faster-than-expected progress in clean energy technology deployment, global annual CO₂ emissions have increased from 2020 to 2023. The feasibility of limiting warming to 1.5 °C is therefore questioned. Here we present a model intercomparison study that accounts for emissions trends until 2023 and compares cost-effective scenarios to alternative scenarios with institutional, geophysical and technological feasibility constraints and enablers informed by previous literature. Our results show that the most ambitious mitigation trajectories with updated climate information still manage to limit peak warming to below 1.6 °C (‘low overshoot’) with around 50% likelihood. However, feasibility constraints, especially in the institutional dimension, decrease this maximum likelihood considerably to 5–45%. Accelerated energy demand transformation can reduce costs for staying below 2 °C but have only a limited impact on further increasing the likelihood of limiting warming to 1.6 °C. Our study helps to establish a new benchmark of mitigation scenarios that goes beyond the dominant cost-effective scenario design.

尽管清洁能源技术部署进展快于预期，但2020年至2023年全球每年CO ₂排放量有所增加。因此，将升温限制在1.5°C的可行性受到质疑。在此，我们提出了一项模型比对研究，该研究解释了 2023 年之前的排放趋势，并将具有成本效益的情景与具有机构、地球物理和技术可行性限制以及先前文献所告知的推动因素的替代情景进行比较。我们的结果表明，采用最新气候信息的最雄心勃勃的缓解轨迹仍然能够将峰值升温限制在 1.6 °C 以下（“低超调”），可能性约为 50%。然而，可行性限制，特别是在制度方面，将这一最大可能性大大降低至 5-45%。加速能源需求转型可以降低将气温控制在 2°C 以下的成本，但对于进一步提高将升温限制在 1.6°C 的可能性的影响有限。我们的研究有助于建立一个新的缓解情景基准，超越了占主导地位的成本效益情景设计。