Cooke, GJ, Marsh, DR orcid.org/0000-0001-6699-494X, Walsh, C orcid.org/0000-0001-6078-786X et al. (2 more authors) (2022) A revised lower estimate of ozone columns during Earth’s oxygenated history. Royal Society Open Science, 9 (1). 211165. ISSN 2054-5703
Abstract
The history of molecular oxygen (O2) in Earth’s atmosphere is still debated; however, geological evidence supports at least two major episodes where O2 increased by an order of magnitude or more: the Great Oxidation Event (GOE) and the Neoproterozoic Oxidation Event. O2 concentrations have likely fluctuated (between 10−3 and 1.5 times the present atmospheric level) since the GOE ∼2.4 Gyr ago, resulting in a time-varying ozone (O3) layer. Using a three-dimensional chemistry-climate model, we simulate changes in O3 in Earth’s atmosphere since the GOE and consider the implications for surface habitability, and glaciation during the Mesoproterozoic. We find lower O3 columns (reduced by up to 4.68 times for a given O2 level) compared to previous work; hence, higher fluxes of biologically harmful UV radiation would have reached the surface. Reduced O3 leads to enhanced tropospheric production of the hydroxyl radical (OH) which then substantially reduces the lifetime of methane (CH4). We show that a CH4 supported greenhouse effect during the Mesoproterozoic is highly unlikely. The reduced O3 columns we simulate have important implications for astrobiological and terrestrial habitability, demonstrating the relevance of three-dimensional chemistry-climate simulations when assessing paleoclimates and the habitability of faraway worlds.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 The Authors. This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) |
Keywords: | ozone layer, Proterozoic Earth, habitability, Faint Young Sun Paradox, Earth system modelling, atmospheric chemistry |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Funding Information: | Funder Grant number STFC (Science and Technology Facilities Council) ST/T000287/1 MRC (Medical Research Council) MR/T040726/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 28 Jan 2022 11:36 |
Last Modified: | 28 Jan 2022 11:36 |
Status: | Published |
Publisher: | The Royal Society |
Identification Number: | 10.1098/rsos.211165 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:182609 |