Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.
School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China.
Nat Commun. 2022 Sep 10;13(1):5334. doi: 10.1038/s41467-022-33107-0.
The origin of the temperature divergence between Holocene proxy reconstructions and model simulations remains controversial, but it possibly results from potential biases in the seasonality of reconstructions or in the climate sensitivity of models. Here we present an extensive dataset of Holocene seasonal temperatures reconstructed using 1310 pollen records covering the Northern Hemisphere landmass. Our results indicate that both summer and winter temperatures warmed from the early to mid-Holocene (~11-7 ka BP) and then cooled thereafter, but with significant spatial variability. Strong early Holocene warming trend occurred mainly in Europe, eastern North America and northern Asia, which can be generally captured by model simulations and is likely associated with the retreat of continental ice sheets. The subsequent cooling trend is pervasively recorded except for northern Asia and southeastern North America, which may reflect the cross-seasonal impact of the decreasing summer insolation through climatic feedbacks, but the cooling in winter season is not well reproduced by climate models. Our results challenge the proposal that seasonal biases in proxies are the main origin of model-data discrepancies and highlight the critical impact of insolation and associated feedbacks on temperature changes, which warrant closer attention in future climate modelling.
全新世代代理代用记录与模型模拟之间的温度分歧的起源仍然存在争议，但这可能是由于重建记录的季节性或模型的气候敏感性存在潜在偏差所致。在这里，我们使用涵盖北半球大陆的 1310 个花粉记录提供了一个广泛的全新世季节温度重建数据集。我们的结果表明，夏季和冬季温度均从全新世早期到中期变暖（约 11-7 千年前），此后又变冷，但具有显著的空间变异性。强烈的全新世早期变暖趋势主要发生在欧洲、北美东部和北亚，这在模型模拟中可以得到普遍反映，可能与大陆冰盖的退缩有关。除了北亚和北美东南部外，普遍记录到随后的降温趋势，这可能反映了通过气候反馈减少夏季太阳辐射对跨季节的影响，但气候模型未能很好地再现冬季降温。我们的结果对代理中季节性偏差是模型数据差异的主要来源的说法提出了挑战，并强调了太阳辐射和相关反馈对温度变化的关键影响，这在未来的气候建模中值得密切关注。
