> All the fossil-sourced carbon we've put into the air the last 100 years or so was, at one point or another put into the ground, mostly by vegetation. As I u

> All the fossil-sourced carbon we've put into the air the last 100 years or so was, at one point or another put into the ground, mostly by vegetation. As I understand it, carbon comes from plant matter indeed, back from the Carboniferous period. Back then no life form had evolved that was able to break down wood lignin, so wood could not decompose. That stopped around 300 million years ago when certain fungi evolved, which is why carbon is no longer produced and thus remains a fossil fuel. Forests are essentially carbon neutral according to every source I can find. I'll be happy to learn otherwise.