If only they had stopped using fossil fuels and used wind power and solar instead, and eaten a vegan diet instead of meat things would have been okay.
Actually they have used mostly renewables in the ancient times. Wind, water, biomass, Sun.
It was the arrival of industrial age, when fossil fuels started to play major rule.
Rule of the thumb - the more advanced society, the more fossil fuels! Even now, when we are regressing. Less fossil fuels, more regression.