> Yeah you do. Compare the casualties and destruction in 19th century and 20th century wars.
Looking at Wikipedia's list of wars by death toll[0], it seems that people were capable of massive casualties and destruction without fossil fuels, too. Like the Taiping Rebellion in 1850–1864, with a death toll of 20–70 million. The Mongol invasions in 1206–1368, with a death range of 20–60 million, and the Three Kingdoms period in 184–280, with a death range of 34 million.
Looking at Wikipedia's list of wars by death toll[0], it seems that people were capable of massive casualties and destruction without fossil fuels, too. Like the Taiping Rebellion in 1850–1864, with a death toll of 20–70 million. The Mongol invasions in 1206–1368, with a death range of 20–60 million, and the Three Kingdoms period in 184–280, with a death range of 34 million.
0: https://en.wikipedia.org/wiki/List_of_wars_by_death_toll