Ok cool. Now I wanna pull our focus into the carbon cycle for a minute. In lieu of explaining each of the process, I'll show you a diagram that explains it pretty well.
And to clarify, it's NOT the "CO2 cycle"...just carbon.
View attachment 347964
So to be clear, this is a BIT of a skematic, but it shows how a molecule of carbon is not something that just sits there in one form. It moves through a whole system accomplishing several tasks and binding with different other molecules in those processes.
What I would bring your attention to, is the bottom of the chart where it says "dead organisms and waste products" (and of course what's underneath). Assuming you're not a YEC, we can continue with the idea that, over the course of hundreds of millions of years, the dead and decaying organisms in certain parts of the world, managed to, with just the right amounts of time, pressure and heat, convert swampland, brush, and dead animals and plants into the fossil fuels we see below the surface.
Now you'll note that the "Dead organisms" section of the cycle has an arrow moving AWAY from it as well. Because you know if you have a compost pile, your decaying plant material is losing carbon both through the air, and as food for micro and macroorganisms, and is being leached back into the soil (or, of course, purposefully distributed within your compost, to other parts of your soil).
Anyways, you note that our current "dead organisms" are part of the cycle. In fact, the cycle is pretty much closed. You'll note that you COULD take the human made source from this diagram and the cycle would still function normally. But you'll also note that, fossils just sitting under the surface of the planet are not a part of the cycle. They are just sitting there. Doing nothing.
What that means is the planet has had a natural "bank" or storage area for MASSIVE amounts of carbon. Over hundreds of millions of years, carbon was being sequestered underground. In fact, it was, very very slowly, being removed from that carbon cycle on the surface. This carbon was and is being stored as the fossils fuels you are more than aware of.
I'm hoping this is all making sense so far.
Now the question is:
Are you aware of how much carbon (or carbon dioxide) have humans released since the mid 18th century when urbanization, industrialization and coal burning began to pick up?