Ocean-atmosphere partitioning of anthropogenic carbon dioxide on multimillennial timescales
Ocean-atmosphere partitioning of anthropogenic carbon dioxide on multimillennial timescales
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DOI：
10.1029/2008gb003449
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发表时间：
2010-05-29
影响因子：
5.2
通讯作者：
Ridgwell, Andy
中科院分区：
文献类型：
--
作者：
Goodwin, Philip;Ridgwell, Andy
海洋沉积物与风化作用相互影响，在大于约1000年的时间尺度上，对人为排放的二氧化碳在大气中的留存量起着主要控制作用。本文提出了一种分析理论，该理论根据初始条件，预测了在深海沉积物中碳酸钙埋藏达到平衡之后，但在硅酸盐风化作用在大于10万年的时间尺度上清除所有多余二氧化碳之前，排放的二氧化碳在大气中剩余的比例。针对GENIE - 1地球系统模型的独立积分，对最终大气二氧化碳分压的理论预测进行了检验，结果发现，对于高达约4000拍克碳的总排放量，两者的吻合度在10%以内。预测的理论关系是线性的，其基于以下假设：当碳酸钙埋藏达到新的稳定状态时，海洋碳酸根离子浓度得以恢复，并且全球海洋二氧化碳*的稳定状态变化与大气二氧化碳的变化成正比；其中二氧化碳*是水溶液中二氧化碳和碳酸的总浓度。我们发现，即使已知海洋[碳酸根离子]浓度在控制富含碳酸钙的沉积物堆积的深度区间方面很重要，但无需明确使用该浓度，也能够确定大气中人为二氧化碳的剩余比例。这里所提出的简单理论特别适用于高效评估地质记录中所记载的事件，以及人为二氧化碳对冰盖长期稳定性的影响。
Ocean-sediment and weathering interactions exert the primary control on how much anthropogenic-emitted CO2 remains in the atmosphere on timescales longer than about 1 kyr. Analytical theory is presented which predicts, from initial conditions, the remaining atmospheric fraction of emitted CO2 after equilibrium with CaCO3 burial in deep-sea sediments but before silicate weathering removes all excess CO2 on a > 100 kyr timescale. The theoretical predictions of final atmospheric CO2 partial pressure are tested against independent integrations of the GENIE-1 Earth system model and are found to agree to within 10% for total emissions up to about 4000 PgC. The predicted theoretical relationship is linear and is based on the assumptions that ocean carbonate ion concentration is restored when CaCO3 burial reaches a new steady state, and that the steady state change in global ocean CO2* is proportional to the change in atmospheric CO2; where CO2* is the combined concentration of aqueous CO2 and carbonic acid. We find that the residual fraction of anthropogenic CO2 in the atmosphere can be determined without explicit use of ocean [CO32-], even though this concentration is known to be important in controlling the depth interval over which CaCO3-rich sediments accumulate. The simple theory developed here is particularly suited for efficient assessment of events recorded in the geological record as well as anthropogenic CO2 influences on the long-term stability of ice sheets.