van Hoof Thomas B, Wagner-Cremer Friederike, Kürschner Wolfram M, Visscher Henk
TNO Geological Survey of The Netherlands, Princetonlaan 6, 3584 CB Utrecht, The Netherlands.
Proc Natl Acad Sci U S A. 2008 Oct 14;105(41):15815-8. doi: 10.1073/pnas.0807624105. Epub 2008 Oct 6.
Complementary to measurements in Antarctic ice cores, stomatal frequency analysis of leaves of land plants preserved in peat and lake deposits can provide a proxy record of preindustrial atmospheric CO(2) concentration. CO(2) trends based on leaf remains of Quercus robur (English oak) from the Netherlands support the presence of significant CO(2) variability during the first half of the last millennium. The amplitude of the reconstructed multidecadal fluctuations, up to 34 parts per million by volume, considerably exceeds maximum shifts measured in Antarctic ice. Inferred changes in CO(2) radiative forcing are of a magnitude similar to variations ascribed to other mechanisms, particularly solar irradiance and volcanic activity, and may therefore call into question the concept of the Intergovernmental Panel on Climate Change, which assumes an insignificant role of CO(2) as a preindustrial climate-forcing factor. The stomata-based CO(2) trends correlate with coeval sea-surface temperature trends in the North Atlantic Ocean, suggesting the possibility of an oceanic source/sink mechanism for the recorded CO(2) changes.
与南极冰芯测量相辅相成的是,对保存在泥炭和湖泊沉积物中的陆地植物叶片进行气孔频率分析,可以提供工业化前大气二氧化碳浓度的代用记录。基于荷兰栎(英国橡树)叶片遗迹的二氧化碳趋势,支持了过去一千年上半叶存在显著二氧化碳变率的观点。重建的年代际波动幅度高达百万分之34体积分数,大大超过了在南极冰中测量到的最大变化。推断的二氧化碳辐射强迫变化幅度与归因于其他机制(特别是太阳辐照度和火山活动)的变化幅度相似,因此可能会对政府间气候变化专门委员会的概念提出质疑,该委员会认为二氧化碳作为工业化前气候强迫因子的作用微不足道。基于气孔的二氧化碳趋势与北大西洋同期海面温度趋势相关,这表明记录到的二氧化碳变化可能存在海洋源/汇机制。