arXiv:1310.4841astro-ph.EP
Swansong Biospheres II: The final signs of life on terrestrial planets near the end of their habitable lifetimes
Early discovery. Linked by one identifiable commenter. This paper is outside the main ranking; a mention is not an endorsement.
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 Gyr 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.
Eventually the oceans will boil, but wikipedia links to paper evaluating the atmosphere in “1 Gyr and 2.8 Gyr from present” or 1 to 2.8 billion years not 500. It’s suggesting that life should stick around on earth for ~2.8 billion years though the total number of living cells…
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