In the context of energy…
19th Century overview
Humans in parts of Europe and the United States replace the biomass fuels that had served Homo sapiens for tens of thousands of years with the highly energy-intensive fossil fuel coal. Coal fuels the industrial revolution. Machine technology and the corporate form of business organization — punctuated by passage of the British Limited Liability Act of 1855 — facilitate both the extraction of coal and the deployment of coal’s energy to reshape civilization’s infrastructure and way of life. U.S. consumption of fossil fuels surpasses that of wood in the early 1880’s. During the second half of the 19th century, the average U.S. per capita supply of all energy increases by 25%; utilization of coal increases by a factor of ten.*
20th Century overview
Oil and gas join the arsenal of high energy fossil fuels, in particular fueling new modes of rapid global land, sea, and air transportation. Coal is the predominant fuel in the production of electricity. Total energy consumption worldwide experiences unprecedented growth. Between 1900 and 2000, consumption of fossil fuels rises almost fifteen-fold. As Vaclav Smil notes, “[I]n spite of the near quadrupling of global population — from 1.6 billion in 1900 to 6.1 billion in 2000 — average annual per capital supply of commercial energy more than quadrupled from just 14 GJ[gigajoules] to roughly 60 GJ…” U.S. residents are far and away the largest consumers of energy. Between 1900 and 2000 annual per capita energy supply in the United States more than triples to about 340 GJ/capita, or more than five times the global average.**
*Vaclav Smil, Energy at the Crossroads: Global Perspectives and Uncertainties (Cambridge: MIT Press, 2005), 1.