Unsustainable prosperity fueled by fossil fuels.

We had fossil fuels during both world wars.

the many men, women and children they kill daily to get it.

just because there's no colonial empires fighting each other, doesn't mean there's peace.

The number of people killed 'daily' is vastly less than it has been at any other point in history. Why is it more peaceful now?

Trade, democracy?

The Greeks and Romans had varying levels of democracy and vast trade networks for hundreds (arguably thousands) of years.