# Is our releasing CO2 to Earth's (very) long-term benefit? **URL:** \ **Category:** Great Debates\ **Created:** [June 5, 2008, 3:26pm UTC](https://boards.straightdope.com/t/is-our-releasing-co2-to-earths-very-long-term-benefit/451892 "2008-06-05T15:26:35Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [June 5, 2008, 3:26pm UTC](https://boards.straightdope.com/t/is-our-releasing-co2-to-earths-very-long-term-benefit/451892/1 "2008-06-05T15:26:35Z")
I heard this the other day and thought it interesting and amusing enough to post here. Plants absorb CO2 and animals eat plants and CO2 gets turned into coal and oil and limestone, so CO2 gets gradually removed from the atmosphere. Vulcanism releases CO2 into the atmosphere, but over the eons the trend has been downwards. So, eventually, won’t there come a point where there is too little CO2 in the atmosphere to support life as we know it? The amount of CO2 in the atmosphere today is very very small indeed. So, isn’t it to Earth’s longer term benefit to release that stored CO2 so it can be re-used? There would, of course, be no immediate benefit, but what about in (hundreds of) millions of years’ time? ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [June 5, 2008, 6:48pm UTC](https://boards.straightdope.com/t/is-our-releasing-co2-to-earths-very-long-term-benefit/451892/2 "2008-06-05T18:48:33Z")
I read a book that touched upon this a couple of years back: [The Life and Death of Planet Earth: How the New Science of Astrobiology Charts the Ultimate Fate of Our World](http://www.amazon.com/Life-Death-Planet-Earth-Astrobiology/dp/0805075127). Take the following with a grain of salt; I read the book a while back. IIRC: In the very long run (next few hundred million years or longer), volcanism will slow and ultimately stop as the Earth’s core continues to cool. At that point the level of CO[sub]2[/sub] will decrease until it can no longer support plant life, which will likely lead to the end of life on Earth. This process competes with the gradual increase in the Sun’s output, which will eventually evaporate the oceans and increase surface temperatures to the point where life is no longer possible. It’s anyone’s guess as to which phenomena will end life on Earth: the end of plant life, or the end of the oceans. In the long run, IIRC, the authors discount any CO[sub]2[/sub] added to the air by burning fossil fuels. The time scales are too different. Anything we do in the short term (next few thousand years) will not significantly affect things hundreds of millions of years out. (However, the authors do discuss the possibility of short-term increases in CO[sub]2[/sub] levels in mitigating the effects of the next ice age–after all, we are in an interglacial period. I have been meaning to start a GD thread on this for some time, but haven’t ever gotten around to it.) ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [June 5, 2008, 7:32pm UTC](https://boards.straightdope.com/t/is-our-releasing-co2-to-earths-very-long-term-benefit/451892/3 "2008-06-05T19:32:49Z")
[QUOTE=robby] In the long run, IIRC, the authors discount any CO[sub]2[/sub] added to the air by burning fossil fuels. The time scales are too different. Anything we do in the short term (next few thousand years) will not significantly affect things hundreds of millions of years out. [/QUOTE] Indeed…Even though a small fraction of what we emit is likely to remain around quite a long time by our standards ([), these are still short times compared to the sort of timescales being talked about. Also, it should be pointed out that on geologic timescales, there [url=[Faint young Sun paradox - Wikipedia](http://en.wikipedia.org/wiki/Faint_young_sun_paradox)]are hypothesized to be](]estimates are that 7% will remain after 100,000 years[/url) some negative feedback processes that would keep the CO2 levels from dropping too low for very long: > [@](#): > > the inorganic version of the carbon cycle can be expected to provide negative feedback towards an Earth with liquid water. Carbon dissolved in liquid water can form carbonic acids, which can then interact with calcium to produce calcium carbonate. If rainfall were to cease and the oceans froze over, then this part of the inorganic carbon cycle would shut down. Periodic explosions from volcanoes would then cause a net increase in the atmospheric carbon dioxide and methane levels with no liquid water to absorb these emitted gases. Eventually the concentrations would become large enough that the surface temperature would rise due to the greenhouse effect. When the surface temperature became large enough for the oceans to melt and rainfall to resume the other half of the inorganic carbon cycle would turn on and moderate the greenhouse gas concentrations. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [June 8, 2008, 11:06am UTC](https://boards.straightdope.com/t/is-our-releasing-co2-to-earths-very-long-term-benefit/451892/4 "2008-06-08T11:06:31Z")
[QUOTE=robby] (However, the authors do discuss the possibility of short-term increases in CO[sub]2[/sub] levels in mitigating the effects of the next ice age–after all, we are in an interglacial period. I have been meaning to start a GD thread on this for some time, but haven’t ever gotten around to it.) [/QUOTE] I think we actually discussed that a while back and the answer was that we don’t know.