No matter was created. The plant material and the bodies of the tiny animals fell to the bottom of the giant swamp where there was no oxygen to breakdown and decay the material. It is not CO2. Carbon is found in the structure of the plants and the tiny animal bodies. When we extract that carbon, and burn it, that releases the long sequestered carbon back into the carbon cycle as CO2.
Let me try to make my confusion clear (is that an oxymoron?):
Sequestration started at some point in time (millions of years ago). Was there a higher percentage of atmospheric co2 then?
The Paleozoic Era
So, before the Carboniferous period, Earth would have had much higher concentrations of co2 in the atmosphere, right?
Then, there is this:
"On long timescales, atmospheric CO2 concentration is determined by the balance among
geochemical processesincluding organic carbon burial in sediments, silicate rock
weathering, and
volcanism. The net effect of slight imbalances in the
carbon cycle over tens to hundreds of millions of years has been to reduce atmospheric CO2. On a timescale of billions of years, such downward trend appears bound to continue indefinitely as occasional massive historical releases of buried carbon due to volcanism will become less frequent (as earth mantle cooling and progressive exhaustion of
internal radioactive heat proceeds further). The rates of these processes are extremely slow; hence they are of no relevance to the atmospheric CO2 concentration over the next hundreds or thousands of years.
In billion-year timescales, it is
predicted that plant, and therefore animal, life on land will die off altogether, since by that time most of the remaining carbon in the atmosphere will be sequestered underground, and natural releases of CO2 by radioactivity-driven tectonic activity will have continued to slow down.
[29] The loss of plant life would also result in the eventual loss of oxygen. Some microbes are capable of photosynthesis at concentrations of CO2 of a few parts per million and so the last life forms would probably disappear finally due to the rising temperatures and loss of the atmosphere when the
sun becomes a red giant some four billion years from now.
[30]"
Carbon dioxide in Earth's atmosphere - Wikipedia
Summary:
The earth had much higher concentrations of co2, but due to fewer volcanic events as the Earth's mantle cools, co2 will continue to decrease, due to natural, unavoidable sequestration that cannot easily be reversed.
Looks to me like we are prolonging the Earth's life by de-sequestrating co2, no?
