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Effects of high CO2 levels on surface temperature and atmospheric oxidation state of the early earthOne-dimensional radiative and photochemical models are used to determine how much CO2 must have been present to maintain a temperate early climate and to examine the consequences that are implied for the controls on atmospheric oxidation state. It is shown that CO2 concentrations of the order of 1000 PAL are required to keep the average surface temperature close to the present value, if albedo changes and heating by reduced greenhouse gases were relatively unimportant. The oxidation state of such a high-CO2, prebiotic atmosphere should have been largely determined by the balance between the H2O2 rainout rate and the rate at which hydrogen escaped to space, with only a weak dependence on the volcanic outgassing rate or on other speculative sources of H2. The implied upper limit on the ground-level O2 mixing ratio is approximately 10 to the -11th and is subject to less uncertainty than the results of previous models.
Document ID
19850029935
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kasting, J. F.
(NASA Ames Research Center Moffett Field, CA, United States)
Pollack, J. B.
(NASA Ames Research Center Moffett Field, CA, United States)
Crisp, D.
(NOAA, Geophysical Fluid Dynamics Laboratory, Princeton NJ, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1984
Publication Information
Publication: Journal of Atmospheric Chemistry
Volume: 1
Issue: 4, 19
ISSN: 0167-7764
Subject Category
Geophysics
Accession Number
85A12086
Distribution Limits
Public
Copyright
Other

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