Re:The future lifespan of Earth’s oxygenated atmosphere
by mannykannot on Wednesday March 03, 2021 @10:33AM
(#26329656)
That is in line with what I thought was the scientific consensus too, but when I read the abstract (I should have done that first!) I see it saying "Our results suggest that the planetary carbonate–silicate cycle will tend to lead to terminally CO2-limited biospheres and rapid atmospheric deoxygenation", where I assume the carbonate-silicate cycle is the reactions between CO2 and rocks/soil, and if so, then this model seems to be suggesting that this will come into play before a runaway greenhouse scenario.
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Re:The future lifespan of Earth’s oxygenated atmosphere
by Robotbeat on Wednesday March 03, 2021 @10:42AM
(#26329801)
In that case, I think they’re saying that both CO2 and O2 will be absorbed over time by minerals (as well as CO2 being absorbed by plants), and once CO2 levels drop too much, photosynthesis stops (or slows), which means oxygen stops (or slows) being replenished as well, so oxidization of minerals will also lead to a reduction in oxygen levels.
(And less volcanic activity over time also means less CO2 being added back to the atmosphere, so the chemical weathering process that absorbs both CO2 and O2 into minerals will no longer have an active counterbalancing force from volcanoes.)