The expansion of Homo sapiens across Eurasia marked a major milestone in human evolution that would eventually lead to our species being found across every continent. Current models propose that these expansions occurred only during episodes of warm climate, based on age correlations between archaeological and climatic records. Here, we obtain direct evidence for the temperatures faced by some of these humans through the oxygen isotope analysis of faunal remains from Bacho Kiro Cave, Bulgaria, the earliest clear record of H. sapiens in Europe. The results indicate that humans ∼45,000 years ago experienced subarctic climates with far colder climatic conditions than previously suggested. This demonstrates that the early presence of H. sapiens in Europe was not contingent on warm climates. Our results necessitate the revision of key models of human expansion and highlight the need for a less deterministic role of climate in the study of our evolutionary history.

中文翻译：

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欧洲最早的智人的亚北极气候

智人在欧亚大陆的扩张标志着人类进化的一个重要里程碑，最终将导致我们的物种在每个大陆被发现。根据考古和气候记录之间的年龄相关性，目前的模型表明，这些扩张仅发生在温暖气候时期。在这里，我们通过对来自保加利亚 Bacho Kiro 洞穴的动物遗骸的氧同位素分析获得了其中一些人面临的温度的直接证据，这是欧洲最早的智人明确记录。结果表明，人类约 45,000 年前经历了亚北极气候，其气候条件比以前认为的要冷得多。这表明智人的早期存在在欧洲并不取决于温暖的气候。我们的结果需要对人类扩张的关键模型进行修订，并强调气候在我们的进化史研究中的确定性作用较小。