We live on blood sugar. Sugar is a carbohydrate. When you burn sugar those carbon atoms need to go somewhere, they are not destroyed.

We breathe CO2 out, plants breathe it in.

That's how this planet works.

You can plant a tree in a small pot, confine it to it for life, it will grow tall (as much as it can), and it will not consume the dirt. Very little carbon is taken from the soil.

We eat plants (or animals that ate plant), turn them into sugar, turn sugar into CO2, breathe CO2 out, plants breathe it in and grow, and so on.