Abstract The last time Earth's climate experienced geologically rapid global warming was associated with the last glacial termination, when atmospheric CO2 concentrations rose from 180 ppmv during the Last Glacial Maximum (LGM, 26-19 kaBP) to ∼260 ppmv by the early Holocene (12-8 kaBP). About one quarter of that difference is thought to be due to a stronger biological pump during glacial times, driven by increased aeolian dust deposition and hence greater iron availability in ocean surface waters. However, dust supply did not change uniformly or in synchrony over the deglacial transition and what is not known is the relative importance of different oceanic regions and how this may have changed in time. Using an Earth system model of intermediate complexity, we quantify the sensitivity of atmospheric CO2 to regional changes in iron supply, and test six different global dust reconstructions in order to explore uncertainty in past dust changes. We confirm the Southern Ocean (>34°S) as the region most sensitive to iron fertilization, with the Atlantic and Pacific sectors accounting for about 41 ± 23 % and 16 ± 10 %, respectively, of the total CO2 reduction from global iron fertilization. However, the North Pacific contributes 28 ± 3 % to the total implying an important role for Northern Hemisphere processes in driving deglacial CO2 rise. In addition, our analysis reveals an unexpected regional-temporal disparity, and while Southern Hemisphere iron fertilization influences atmospheric CO2 relatively constantly throughout the termination the impact of the Northern Hemisphere only occurs during the later stages of the termination.

中文翻译：

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末次冰期终止期间海洋铁肥化和CO2下降的区域格局和时间演变

摘要 地球气候上一次经历地质上快速的全球变暖与最后一次冰川终止有关，当时大气 CO2 浓度从末次盛冰期（LGM，26-19 kaBP）期间的 180 ppmv 上升到全新世早期（12 -8 kaBP）。大约四分之一的差异被认为是由于冰川时期更强的生物泵造成的，这是由增加的风尘沉积导致的，因此海洋表层水中铁的可用性更高。然而，在冰消期过渡期间，尘埃供应并没有统一或同步变化，并且不知道不同海洋区域的相对重要性以及这可能如何随时间变化。使用中等复杂性的地球系统模型，我们量化了大气 CO2 对区域铁供应变化的敏感性，并测试六种不同的全球尘埃重建，以探索过去尘埃变化的不确定性。我们确认南大洋 (>34°S) 是对铁肥最敏感的地区，大西洋和太平洋地区分别占全球铁肥减少二氧化碳总量的 41 ± 23 % 和 16 ± 10 % . 然而，北太平洋占总量的 28±3%，这意味着北半球过程在推动冰消期 CO2 上升方面发挥着重要作用。此外，我们的分析揭示了出乎意料的区域-时间差异，虽然南半球铁肥化在整个终止期间相对持续地影响大气 CO2，但北半球的影响仅发生在终止的后期阶段。