DOI: 10.1038/s41561-021-00693-5
论文题名: The future lifespan of Earth’s oxygenated atmosphere
作者: Ozaki K. ; Reinhard C.T.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2021
卷: 14, 期: 3 起始页码: 138
结束页码: 142
语种: 英语
英文关键词: air-water interaction
; Archean
; atmosphere-ice-ocean system
; atmosphere-ocean coupling
; biogeochemistry
; climate modeling
; haze
; heterocyclic oxygen compound
; oxygen
; surface water
英文摘要: Earth’s modern atmosphere is highly oxygenated and is a remotely detectable signal of its surface biosphere. However, the lifespan of oxygen-based biosignatures in Earth’s atmosphere remains uncertain, particularly for the distant future. Here we use a combined biogeochemistry and climate model to examine the likely timescale of oxygen-rich atmospheric conditions on Earth. Using a stochastic approach, we find that the mean future lifespan of Earth’s atmosphere, with oxygen levels more than 1% of the present atmospheric level, is 1.08 ± 0.14 billion years (1σ). The model projects that a deoxygenation of the atmosphere, with atmospheric O2 dropping sharply to levels reminiscent of the Archaean Earth, will most probably be triggered before the inception of moist greenhouse conditions in Earth’s climate system and before the extensive loss of surface water from the atmosphere. We find that future deoxygenation is an inevitable consequence of increasing solar fluxes, whereas its precise timing is modulated by the exchange flux of reducing power between the mantle and the ocean–atmosphere–crust system. Our results suggest that the planetary carbonate–silicate cycle will tend to lead to terminally CO2-limited biospheres and rapid atmospheric deoxygenation, emphasizing the need for robust atmospheric biosignatures applicable to weakly oxygenated and anoxic exoplanet atmospheres and highlighting the potential importance of atmospheric organic haze during the terminal stages of planetary habitability. © 2021, The Author(s), under exclusive licence to Springer Nature Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/169802
Appears in Collections: 气候变化与战略
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作者单位: Department of Environmental Science, Toho University, Funabashi, Japan; NASA Nexus for Exoplanet System Science (NExSS), Atlanta, GA, United States; School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, United States; Alternative Earths Team, NASA Astrobiology Institute, Riverside, CA, United States
Recommended Citation:
Ozaki K.,Reinhard C.T.. The future lifespan of Earth’s oxygenated atmosphere[J]. Nature Geoscience,2021-01-01,14(3)