Swansong biospheres II: The final signs of life on terrestrial planets near the end of their habitable lifetimes

Jack T. O'Malley-James (Lead / Corresponding author), Charles S. Cockell, Jane S. Greaves, John A. Raven

    Research output: Contribution to journalArticle

    19 Citations (Scopus)

    Abstract

    The biosignatures of life on Earth do not remain static, but change considerably over the planet's habitable lifetime. Earth's future biosphere, much like that of the early Earth, will consist of predominantly unicellular microorganisms due to the increased hostility of environmental conditions caused by the Sun as it enters the late stage of its main sequence evolution. Building on previous work, the productivity of the biosphere is evaluated during different stages of biosphere decline between 1 and 2.8Gyr from present. A simple atmosphere-biosphere interaction model is used to estimate the atmospheric biomarker gas abundances at each stage and to assess the likelihood of remotely detecting the presence of life in low-productivity, microbial biospheres, putting an upper limit on the lifetime of Earth's remotely detectable biosignatures. Other potential biosignatures such as leaf reflectance and cloud cover are discussed.
    Original languageEnglish
    Pages (from-to)229-243
    Number of pages15
    JournalInternational Journal of Astrobiology
    Volume13
    Issue number3
    Early online date14 Jan 2014
    DOIs
    Publication statusPublished - Jul 2014

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