2013/10/17 by Jack T. O'Malley-James, Charles S. Cockell, Jane S. Greaves +2 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Earth Systems and Cosmic Evolution #Origins and Evolution of Life #Space Science and Extraterrestrial Life #astro-ph.EP
paper · pdf · doi:10.1017/s1473550413000426
Accepted for publication in International Journal of Astrobiology
arxiv created 2013/10/17 · openalex publication_date 2014/01/14 · arxiv updated 2015/06/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 2.8 Gyr 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.