Two-million-year-old snapshots of atmospheric gases from Antarctic ice
Two-million-year-old snapshots of atmospheric gases from Antarctic ice
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DOI：
10.1038/s41586-019-1692-3
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发表时间：
2019-10
期刊：
影响因子：
64.8
通讯作者：
Yuzhen Yan;M. Bender;E. Brook;H. Clifford;P. Kemeny;A. Kurbatov;Sean L. Mackay;P. Mayewski;J. Ng;J. Severinghaus;J. Higgins
中科院分区：
文献类型：
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作者：
Yuzhen Yan;M. Bender;E. Brook;H. Clifford;P. Kemeny;A. Kurbatov;Sean L. Mackay;P. Mayewski;J. Ng;J. Severinghaus;J. Higgins
在过去的80万年里，冰川-间冰期周期以10万年为一个周期（“10万世界”）。冰芯和海洋沉积物数据表明，大气二氧化碳，南极温度，深海温度和全球冰量在100 k世界中彼此密切相关。在大约280万年到120万年前，冰川循环的规模较小，持续时间较短（“40 k世界”）。来自深海沉积物的代用数据表明，40 k世界的大气二氧化碳的变化也低于100 k世界，-，但我们没有直接观测到这一时期的大气温室气体。在这里，我们报告的恢复地层不连续冰超过200万年的艾伦山蓝冰区，东南极洲。在200万年前的冰芯样本中，二氧化碳和甲烷的浓度已经被呼吸作用改变，但一些较年轻的样本是原始的。回收的冰芯将对大气二氧化碳、甲烷和南极温度（基于氘/氢同位素比δDice，区域温度的替代物）的直接观测扩展到40 k世界。80万年前的所有气候特征都在南极连续深层冰芯观测的范围内，这些冰芯是10万年世界的特征。然而，在40 k世界中测得的最低二氧化碳和甲烷浓度以及南极温度远高于过去80万年的冰川值。我们的研究结果证实，冰川间冰期的大气温室气体和南极气候的变化幅度在40 k的世界，并从40 k到100 k的世界的过渡是伴随着最低二氧化碳浓度的下降在冰川极大。
Over the past eight hundred thousand years, glacial–interglacial cycles oscillated with a period of one hundred thousand years (‘100k world’). Ice core and ocean sediment data have shown that atmospheric carbon dioxide, Antarctic temperature, deep ocean temperature, and global ice volume correlated strongly with each other in the 100k world, , , –. Between about 2.8 and 1.2 million years ago, glacial cycles were smaller in magnitude and shorter in duration (‘40k world’). Proxy data from deep-sea sediments suggest that the variability of atmospheric carbon dioxide in the 40k world was also lower than in the 100k world, –, but we do not have direct observations of atmospheric greenhouse gases from this period. Here we report the recovery of stratigraphically discontinuous ice more than two million years old from the Allan Hills Blue Ice Area, East Antarctica. Concentrations of carbon dioxide and methane in ice core samples older than two million years have been altered by respiration, but some younger samples are pristine. The recovered ice cores extend direct observations of atmospheric carbon dioxide, methane, and Antarctic temperature (based on the deuterium/hydrogen isotope ratio δDice, a proxy for regional temperature) into the 40k world. All climate properties before eight hundred thousand years ago fall within the envelope of observations from continuous deep Antarctic ice cores that characterize the 100k world. However, the lowest measured carbon dioxide and methane concentrations and Antarctic temperature in the 40k world are well above glacial values from the past eight hundred thousand years. Our results confirm that the amplitudes of glacial–interglacial variations in atmospheric greenhouse gases and Antarctic climate were reduced in the 40k world, and that the transition from the 40k to the 100k world was accompanied by a decline in minimum carbon dioxide concentrations during glacial maxima.