Here we evaluate Oscillayers, a new method that aims to estimate palaeoclimates for the past 5.4 Myr, and discuss the associated theoretical and methodological issues. We show that the theoretical foundation of Oscillayers is inherently limited, because the method cannot incorporate spatio‐temporal variation and different forcing mechanisms into climate reconstructions. In addition, several methodological weaknesses are clarified that entrench the palaeoclimatic reconstruction of Oscillayers to patterns of climate change observed between the Last Glacial Maximum and current climates. We test the utility of the Oscillayers method to produce palaeoclimatic reconstructions that are similar to general circulation model (GCM)‐based estimates. On average, only 55.6% of values in the mean annual temperature datasets across the Pliocene and Pleistocene were within ±3°C when compared with corresponding GCM‐based datasets. Furthermore, on average only 75.3% of values in the mean annual precipitation datasets across the Pliocene and Pleistocene were within ±200 mm of rainfall of the GCM‐based estimates. Our results demonstrate that the Oscillayers approach does not provide a robust approximation of palaeoclimatic conditions throughout the Plio‐Pleistocene. Thus, when these datasets are used for scientific analyses, the results should be interpreted with a full appreciation of their limitations, particularly for periods outside the last glacial cycle.

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对Oscillayers方法和数据集的严格评估

在这里，我们评估Oscillayers，这是一种旨在估计过去5.4 Myr的古气候的新方法，并讨论了相关的理论和方法问题。我们表明，震荡层的理论基础是固有的局限性，因为该方法不能将时空变化和不同的强迫机制纳入气候重建中。此外，还阐明了一些方法上的弱点，使震荡层的古气候重建根源于上一次冰河期末和当前气候之间观测到的气候变化模式。我们测试了Oscillayers方法的效用，以产生与基于一般循环模型（GCM）的估计相似的古气候重建。平均只有55。与相应的基于GCM的数据集相比，上新世和更新世的年平均温度数据集中的值的6％在±3°C以内。此外，在上新世和更新世的平均年降水量数据集中，平均只有75.3％的值在基于GCM估算的降雨量的±200 mm之内。我们的结果表明，Oscillayers方法不能在整个上新世更新世提供鲁棒的古气候条件近似值。因此，当将这些数据集用于科学分析时，应在充分认识到其局限性的情况下解释结果，尤其是在最后一次冰川周期以外的时期。在上新世和更新世的年平均降水数据集中，有3％的值在基于GCM估算的降雨量的±200 mm之内。我们的结果表明，Oscillayers方法不能在整个上新世更新世提供鲁棒的古气候条件近似值。因此，当将这些数据集用于科学分析时，应在充分认识到其局限性的情况下解释结果，尤其是在最后一次冰川周期以外的时期。在上新世和更新世的年平均降水数据集中，有3％的值在基于GCM估算的降雨量的±200 mm之内。我们的结果表明，Oscillayers方法不能在整个上新世更新世提供鲁棒的古气候条件近似值。因此，当将这些数据集用于科学分析时，应在充分认识到其局限性的情况下解释结果，尤其是在最后一次冰川周期以外的时期。