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According to a 2013 Daily Mail article :

greater evaporation and chemical reactions with rainwater will take away more and more carbon dioxide.

In less than a billion years, its levels will be too low for photosynthesising plants to survive, say scientists. When that happens, life as we know it on Earth will cease to exist.

A more scientific version of this is Swansong Biospheres: Refuges for life and novel microbial biospheres on terrestrial planets near the end of their habitable lifetimes International Journal of Astrobiology.

This article says:

Increased Temperatures --->

Increased weathering of silicate rock --->

Carbon drawdown --->

Plate tectonics slows --->

Carbon recycling slows --->

Pant life unsustainable <10 ppm CO2
~0.9 Gyr

As background see Carbonate–silicate cycle. Carbon Dioxide is removed from the atmosphere by the chemical reaction:

CaSiO3(s) + 2CO2(g) + H2O(l) → Ca2+(aq) + 2HCO3-(aq) + SiO2

Is this really accepted science, that plant-life on Earth will end, due to too little CO2, in less than one billion years?

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DavePhD
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    Strange article. *Currently experts are trying to find ways to cut levels of the greenhouse gas to prevent global warming running out of control.* **immediately followed by** *But as the Sun ages and grows hotter, greater evaporation and chemical reactions with rainwater will take away more and more carbon dioxide*. As if there is a relation between a time scale of centuries and one of a billion years. –  Jan 26 '17 at 15:19
  • @JanDoggen They shouldn't connect the two like that, but I still want to know how accepted it is that plant life will end for lack of CO2. I guess this would be due to the carbonate-silicate geochemical cycle removing all the CO2. https://en.wikipedia.org/wiki/Carbonate%E2%80%93silicate_cycle – DavePhD Jan 26 '17 at 15:24
  • OTOH the long term trend in CO2 levels on geological timescales is down unless something intervenes. Indeed the last 50m years has seen a major new metabolic pathway developed by plants so they work better at low CO2 levels. – matt_black Jan 26 '17 at 15:26
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    It's obviously disregarding the fact that life always evolves to adapt to changing environmental conditions. Initially all life was CO2 consuming and Oxygen was a waste product. About 2.5B years ago, Oxygen started to accumulate killing off many of these life forms. However oxygen breathers evolved and since the exhale CO2 a balance was formed. – Hilmar Jan 26 '17 at 16:47
  • Something else to consider. If oxygen levels increase by just a percent or two in the atmosphere, both tundra and rain forest will burn, exasperating the problem if O2 replaces the carbon dioxide in your thesis. –  Jan 26 '17 at 17:59
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    @DavePhD Hopefully this is not used by climate change deniers to argue that increasing CO2 levels is a good thing? – ventsyv Jan 26 '17 at 18:15
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    @ventsyv " Do you want to save the planet? Fire up the SUV this holiday weekend and go for a pleasure ride; burn some more coal..." http://www.thenewamerican.com/tech/environment/item/15905-study-too-little-carbon-dioxide-will-destroy-earth – DavePhD Jan 26 '17 at 18:18
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    @KDog exacerbating? – phoog Jan 26 '17 at 19:20
  • Maybe it'd be helpful to emphasize that the question is not "Will plant life end" (there's no way we can know what *will* happen) but "Do widely accepted models predict that it will?" Certainly it is widely accepted that life on Earth will *eventually* end, due to one cause or another. – Nate Eldredge Jan 26 '17 at 21:49
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    Our planet has on multiple occasions created conditions that very much work against the continuation of life (e.g., snowball Earth and the end Permian). Drawing CO2 down to levels that are insufficient to sustain complex life is unsustainable is one of the many possible ways that our planet may eventually become naturally uninhabitable (i.e., without human help). What may or may not happen a billion years from now does not give us free reign to do whatever we please.This is one of the saddest excuses for climate denial I've seen. – David Hammen Jan 27 '17 at 04:12
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    I'm quite sure in "just" a thousand years humankind will be able to control the composition of the Earth's atmosphere so it's really not worth worrying about. – TheMathemagician Jan 27 '17 at 11:29
  • I don't think this question is answerable as posed as I suspect it is unlikely that scientists have produced a study on how plants could evolve over a billion years in response to gradually reducing CO2 levels. Imagine a Triassic scientist wondering what CO2 levels plants of that era could have adapted to given sufficient time. They might well have thought no plant could survive at only 400ppmv! ;o) –  Jan 27 '17 at 12:01
  • @DavidHammen It could also be a way to artificially return atmospheric CO2 to pre-industrial levels, by mining Ca and Mg silicate bearing rocks. Although there would be side effects, it seems like a real possibility to me. – DavePhD Jan 27 '17 at 13:30
  • In pre-industrial times the CO2 level was an equilibrium between input from volcanoes and burial in marine sediments. The article ends with "By the point at which all life disappears from the planet, we’re left with a nitrogen/carbon-dioxide atmosphere". Seems like confused science journalism. – Keith McClary Jan 29 '17 at 23:42
  • I found the papers [here](https://www.cambridge.org/core/journals/international-journal-of-astrobiology/article/div-classtitleswansong-biospheres-refuges-for-life-and-novel-microbial-biospheres-on-terrestrial-planets-near-the-end-of-their-habitable-lifetimesdiv/023CF64F11A555FC55798825E9D1B955) and [here](http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9288810&fulltextType=RA&fileId=S1473550413000426). – Keith McClary Jan 29 '17 at 23:42

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