Grumpa discovering fire was one beginning but there was a second "beginning" shortly after the start of the Industrial Revolution.
This second beginning was the discovery of the "greenhouse effect."
Here we see Frenchman Joseph Fourier sitting in his chilly Paris apartment in 1824 theorizing that something in the atmosphere must be keeping part of the sun’s energy from radiating back into space. Otherwise, he suggested, Paris and the rest of the earth would be even colder.
As yet, he has no idea what that something might be....