> 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.
"With no reliable census at the time, estimates of the death toll of the Taiping Rebellion are speculative. Most of the deaths were attributed to plague and famine".
That just means there was a large population around that could die from the effects of the war.
> The Mongol invasions in 1206–1368 [168 years]... and the Three Kingdoms period in 184–280 [96 years]
If WW2 [6 years] had gone on as long as the Mongol invasions the death toll would've topped 1 billion.
Casualties from Mongol invasion are very likely much less than what was given in Wikipedia. There are good arguments that in fact probability of being killed has not changed throughout the history. It just in modern times wars are less frequent but are more devastating.
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