| Glacial-Interglacial Atmospheric CO2 Change—The Glacial Burial Hypothesis |
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| 作者姓名： | Ning ZENG |
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| 作者单位： | DepartmentofMeteorologyandEarthSystemScienceInterdisciplinaryCenter,UniversityofMaryland,USA |
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| 摘 要： | Organic carbon buried under the great ice sheets of the Northern Hemisphere is suggested to be the missing link in the atmospheric CO2 change over the glacial-interglacial cycles. At glaciation, the advancement of continental ice sheets buries vegetation and soil carbon accumulated during warmer pe-riods. At deglaciation, this burial carbon is released back into the atmosphere. In a simulation over two glacial-interglacial cycles using a synchronously coupled atmosphere-land-ocean carbon model forced by reconstructed climate change, it is found that there is a 547-Gt terrestrial carbon release from glacial maximum to interglacial, resulting in a 60-Gt (about 30-ppmv) increase in the atmospheric CO2, with the remainder absorbed by the ocean in a scenario in which ocean acts as a passive buffer. This is in contrast to previous estimates of a land uptake at deglaciation. This carbon source originates from glacial burial,continental shelf, and other land areas in response to changes in ice cover, sea level, and climate. The input of light isotope enriched terrestrial carbon causes atmospheric δ^13C to drop by about 0.3‰ at deglaciation,followed by a rapid rise towards a high interglacial value in response to oceanic warming and regrowth on land. Together with other ocean based mechanisms such as change in ocean temperature, the glacial burial hypothesis may offer a full explanation of the observed 80-100-ppmv atmospheric CO2 change.
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| 关 键 词： | CO2 大气科学 冰期-间冰期循环 气候变化 二氧化碳 浓度 有机碳掩埋 北半球 |
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