# The extra carbon dioxide in the atmosphere amounts to how much in tonnes? **URL:** \ **Category:** Factual Questions\ **Created:** [November 24, 2013, 9:57pm UTC](https://boards.straightdope.com/t/the-extra-carbon-dioxide-in-the-atmosphere-amounts-to-how-much-in-tonnes/674707 "2013-11-24T21:57:56Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [November 24, 2013, 9:57pm UTC](https://boards.straightdope.com/t/the-extra-carbon-dioxide-in-the-atmosphere-amounts-to-how-much-in-tonnes/674707/1 "2013-11-24T21:57:56Z")
In another thread, I got to thinking about carbon as a building material. And I got to wondering about the excess carbon dioxide in the atmosphere. If we can figure out a way to use carbon as a building material, and we wanted to bring the CO[sub]2[/sub] levels in the atmosphere back to historical levels, how much CO[sub]2[/sub] would we have to pull out of the atmosphere to do this? Millions of tonnes? Billions? How much oxygen would we get as a byproduct after we split it from the carbon? How much energy would it take? ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [November 24, 2013, 10:04pm UTC](https://boards.straightdope.com/t/the-extra-carbon-dioxide-in-the-atmosphere-amounts-to-how-much-in-tonnes/674707/2 "2013-11-24T22:04:03Z")
Each part-per-million in the atmosphere is about 1.2 gigatons (billion tons.) Given that we’re about 120 ppm over the pre-Industrial Revolution average (400 now, 280 then), I’d say about 144 billion tons. Once you take those tons out, you’ll be able to harvest a fairly equivalent amount of carbon that’ll come out of the oceans as the atmospheric concentration drops. So start thinking about what to do with about 300 billion tons. ---
**Author:** ![Telperion](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telperion/32/509_2.png) [@Telperion](https://boards.straightdope.com/u/Telperion)\ **Post date:** [November 24, 2013, 10:18pm UTC](https://boards.straightdope.com/t/the-extra-carbon-dioxide-in-the-atmosphere-amounts-to-how-much-in-tonnes/674707/3 "2013-11-24T22:18:20Z")
We already have a way to use atmospheric carbon as a building material. It’s called a tree. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [November 24, 2013, 10:28pm UTC](https://boards.straightdope.com/t/the-extra-carbon-dioxide-in-the-atmosphere-amounts-to-how-much-in-tonnes/674707/4 "2013-11-24T22:28:43Z")
Cool, thanks! It’s a lot more than I was expecting. Now we just need to figure out what to build with 300 billion tonnes of carbon. Now, if we can get it as diamond blocks… [Wikipedia](http://en.wikipedia.org/wiki/Diamond) tells me that diamond has a density of 3.5 g/cm[sup]3[/sup]. So 300 billion tonnes of diamond would take up… lessee… 300 billion tonnes = 3 \* 10[sup]11[/sup] tonnes = 3 \* 10[sup]17[/sup] grams of carbon. 3 \* 10[sup]17[/sup]g / 3.5 g/cm[sup]3[/sup] = 8.7 \* 10[sup]16[/sup] cm[sup]3[/sup] = 8.7 \* 10[sup]10[/sup] m[sup]3[/sup] = a cube 4.4 km on a side, if I’m doing my math right. 🙂 ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [November 24, 2013, 10:34pm UTC](https://boards.straightdope.com/t/the-extra-carbon-dioxide-in-the-atmosphere-amounts-to-how-much-in-tonnes/674707/5 "2013-11-24T22:34:30Z")
> [@Telperion](#): > > We already have a way to use atmospheric carbon as a building material. It’s called a tree. you wood say that. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [November 25, 2013, 3:16am UTC](https://boards.straightdope.com/t/the-extra-carbon-dioxide-in-the-atmosphere-amounts-to-how-much-in-tonnes/674707/6 "2013-11-25T03:16:26Z")
> [@johnpost](#): > > you wood say that. Aw geez, are you gonna lumber us saps with a bunch of tree puns? ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [November 25, 2013, 3:36am UTC](https://boards.straightdope.com/t/the-extra-carbon-dioxide-in-the-atmosphere-amounts-to-how-much-in-tonnes/674707/7 "2013-11-25T03:36:39Z")
> [@Sunspace](#): > > Aw geez, are you gonna lumber us saps with a bunch of tree puns? Until he leaves. ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [November 25, 2013, 4:19am UTC](https://boards.straightdope.com/t/the-extra-carbon-dioxide-in-the-atmosphere-amounts-to-how-much-in-tonnes/674707/8 "2013-11-25T04:19:25Z")
> [@Napier](#): > > Until he leaves. or gets to the root of the problem.