11. Fossile bioenergy (Greetings from the Miocene)

What do we, today, have to do with the Miocene? This geological epoch had Douglas fir trees but no people. It was significantly warmer than today – and in some regions the big natural oxygen and energy cycles between plants and the atmosphere were interrupted.
This is the time the huge brown coal seams stem from. Which influences did the formation of these seams have for the climate? And what are the consequences if we burn this coal today – likewise for the black coal from the Carboniferous period?
Since a few decades we know that fossil resources are not inexhaustible. But can we even afford to exploit all coal resources until exhausted?