The Miocene epoch, spanning 23.03–5.33 Ma, was a dynamic climate of sustained, polar amplified warmth. Miocene atmospheric CO₂ concentrations are typically reconstructed between 300 and 600 ppm and were potentially higher during the Miocene Climatic Optimum (16.75–14.5 Ma). With surface temperature reconstructions pointing to substantial midlatitude and polar warmth, it is unclear what processes maintained the much weaker-than-modern equator-to-pole temperature difference. Here, we synthesize several Miocene climate modeling efforts together with available terrestrial and ocean surface temperature reconstructions. We evaluate the range of model-data agreement, highlight robust mechanisms operating across Miocene modeling efforts and regions where differences across experiments result in a large spread in warming responses. Prescribed CO₂ is the primary factor controlling global warming across the ensemble. On average, elements other than CO₂, such as Miocene paleogeography and ice sheets, raise global mean temperature by ∼2°C, with the spread in warming under a given CO₂ concentration (due to a combination of the spread in imposed boundary conditions and climate feedback strengths) equivalent to ∼1.2 times a CO₂ doubling. This study uses an ensemble of opportunity: models, boundary conditions, and reference data sets represent the state-of-art for the Miocene, but are inhomogeneous and not ideal for a formal intermodel comparison effort. Acknowledging this caveat, this study is nevertheless the first Miocene multi-model, multi-proxy comparison attempted so far. This study serves to take stock of the current progress toward simulating Miocene warmth while isolating remaining challenges that may be well served by community-led efforts to coordinate modeling and data activities within a common analytical framework.

中文翻译：

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模拟中新世温暖：机会型多模型集合（MioMIP1）的见解

中新世纪跨度为23.03–5.33 Ma，是一个持续的，极性放大的温暖气候。中新世大气CO ₂浓度通常在300至600 ppm之间重建，并且在中新世气候最佳时期（16.75-14.5 Ma）可能更高。由于表面温度的重建指向中纬度和极地温暖，目前尚不清楚什么过程保持了比现代赤道到极点温差弱得多的温差。在这里，我们综合了几种中新世气候建模工作以及可用的陆地和海洋表面温度重建。我们评估了模型数据协议的范围，重点介绍了中新世建模工作和各个实验之间差异导致变暖响应大范围扩散的稳健机制。规定的CO ₂是控制整个全球变暖的主要因素。平均而言，中新世古地理和冰盖等CO ₂以外的元素使全球平均温度升高约2°C，并且在给定的CO ₂浓度下升温变暖（由于强加边界条件下的变暖的组合）和气候反馈强度）约等于CO _2的1.2倍加倍。这项研究使用了大量的机会：模型，边界条件和参考数据集代表了中新世的最新技术，但是它们是不均匀的，对于正式的模型间比较工作而言并不理想。意识到这一警告，这项研究仍然是迄今为止首次尝试的中新世多模型，多代理比较。这项研究旨在评估当前在模拟中新世暖化方面的进展，同时隔离可能由社区主导的在统一分析框架内协调建模和数据活动的工作可能很好解决的挑战。