Thursday, September 05, 2019

Eli Explains It All: Amazon and Oxygen Edition

Eli, as readers of this blog know, often explains it all,  often belatedly, but allow the Bunny to put to rest your fears that burning in the Amazon will deplete oxygen in the atmosphere.

The concentration of CO2 in the atmosphere is ~400 ppm.  Oxygen is approximately 20%.  That translates out to 200,000 ppm. If CO2 doubles to 800 ppm that would at worst put O2 at 199,600 ppm. 

It's as simple as that, but if you insist on long reads, have at it.


Layzej said...

If we owe almost all of our oxygen to fossilized carbon, does that mean (assuming we could develop the technology to locate and extract even those "more rarefied deposits") that if we burned all of the available fossil fuel we could achieve 200,000 PPM CO2?

EliRabett said...

Basically Layjej you are talking about burning dirt. While it is true that peat and lignite are not far away from burning dirt, most of the CO2 from the early Earth has been incorporated into carbonate rocks and carbon which has been used in the production of O2 is in soils, plants and people. From memory (and Eli being very old, don't trust the Bunny on this), there is estimated to be enough fossil fuels to get to ~1200 ppm CO2. Eli stands ready for an update on that estimate.

Old_salt said...

We went through a similar concern about the Amazon rain forest and losing oxygen in the 1970's. Wally Broecker at the time said "If you are concerned about oxygen, bury a tree".

Here is his blog on oxygen and the biosphere--worth reading:

Jan Galkowski said...

BAU (e.g., RCP 8.5) produces, per Lenton, et al, 2006 and Foster, et al, 2017 (see "Discussion") about 2000 ppmv by 2250 CE. If we really work hard at it, getting into "exotic fuels", can get to 5000 ppm by 2400 CE. Some odds things seem to happen at elevated temperatures which I don't understand, e.g., land becoming a Carbon source at 2100 CE even under BAU.

Unknown said...

Thanks Old Salt and Jan. Eli thinks that at high temperatures humus and such start breaking down like crazy.