Unused Fossil Fuels = Why we have Oxygen

[cthulu2016]

In an atmoshere with Oxygen everything that can burn eventually burns. Iron rusts. Plants decay. Elements that can form compounds with oxygen do so.

So why do we have free oxygen in the air to breathe? The simple answer is that plants take CO2 (cardon dioxide) and bust apart the C and the O2 to use the carbon for other purposes. (All organic molcules involve carbon.) And the stripped away O2 drifts off into the atmoshpere.

But that gain is only temporary. Every carbon atom the plants strip from CO2 is happy to reconnect with oxygen again someday. A tree produces some O2 for us to breathe, but when that trees eventually burns or rots it takes that O2 right back out of the atmosphere.

There is no source of new oxygen on Earth. Elements are only transmuted inside stars. So there are the same number of oxygen atoms on Earth as there were back when we had no free oxygen in our atmosphere. (Discounting getting hit by comets and such, which have very little free oxygen anyway.)

So why can we breathe?

Because over millions and billions of years plants separated out Carbon and Hydrogen as building materials and then got buried in such a way that oxygen had a hard time getting at the rotting material. Think of a peat bog. Millions of years of wet plant matter piled up in a way that air couldn't get at it all. That's why peat burns... it still has componants that would like to unite with oxygen given the chance. Same thing with oil, methane, coal... all fossil fuels are ancient plant material that for one reason or another did not recombine with oxygen.

And the amazing upshot of all this is that if we burned all fossil fuels then our atmosphere would be back to something like it was billions of years ago. (And we would all be dead.)

Fortunately, we cannot possibly get at all the fossil fuel so we will not be able to burn all of it. But if we did, it would match up with the free oxygen in our atmosphere pretty much one-to-one because that's where our oxygen came from int eh first place.

(There is a delightful aside In Dawkin's ANCESTOR'S TALE about all of this.)

[ProSense]

1. This

"Fossil Fuels = Why we have Oxygen"

...reminds me of Reagan's claim that trees cause pollution.

[cthulu2016]

2. Sucks to be you, I guess

People who read the OP for comprehension will have a more rewarding experience

[ProSense]

3. Actually, no

on both points.

[cthulu2016]

4. In light of your difficulties I have ammended the headline

If you insist on reading "fossil fuel" as "burning fossil fuel" then it is possible... just possible, that some other reader may share that disability.