Greenhouse warming by CH4 in the atmosphere of early Earth

Alexander A. Pavlov, James F. Kasting, Lisa L. Brown, Kathy A. Rages, Richard Freedman

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367 Scopus citations

Abstract

Earth appears to have been warm during its early history despite the faintness of the young Sun. Greenhouse warming by gaseous CO2 and H2O by itself is in conflict with constraints on atmospheric CO2 levels derived from paleosols for early Earth. Here we explore whether greenhouse wanning by methane could have been important. We find that a CH4 mixing ratio of 10-4 (100 ppmv) or more in Earth's early atmosphere would provide agreement with the paleosol data from 2.8 Ga. Such a CH4 concentration could have been readily maintained by methanogenic bacteria, which are thought to have been an important component of the biota at that time. Elimination of the methane component of the greenhouse by oxidation of the atmosphere at about 2.3-2.4 Ga could have triggered the Earth's first widespread glaciation.

Original languageEnglish (US)
Article number1999JE001134
Pages (from-to)11981-11990
Number of pages10
JournalJournal of Geophysical Research E: Planets
Volume105
Issue numberE5
DOIs
StatePublished - May 25 2000

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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