One of my favorite books is the annual World Almanac and Book of Facts. Some of the book covers topics which don't interest me in the slightest, e.g., entertainment facts and much (but not all I hasten to admit) sports information. But it is chock full of nuggets to please a fact and number junkie such as myself.
I thought I'd look into per capita energy consumption in the United States and see how it's increased in the range of time covered by the Almanac for such information. In 1960 the U.S. consumed 45.09 "quads." A quad is a quadrillion, or 10^15, btu's (british thermal units). This is total consumption of every kind - industrial, agricultural, commercial, transportation, etc., and from all sources. In 2006 the consumption was 100.41 quads.
To get these figures to a unit with which we are familiar, energy per time (quads/year) is power, so the figure for 1960 converts to 1.51*10^12 watts. In 2006 the figure is 3.36*10^12 watts. The population in 1960 was 179,323,175 for a per capita power usage (that is, rate of energy consumption per unit of time) of 8421 watts per person. In 2006 with a population of 298,444,215 we consumed energy at the rate of 11,248 watts per person, a 33.6% increase in consumption rate. Frankly, this is a smaller increase than I would have guessed.
Just to put this into perspective, this is as if, in 2006, each of us had 112 100 watt light bulbs lit 24 hours per day, seven days per week. Or, since 11,248 watts is 15.1 horsepower, each of us had about 15 lawn mowers following us around 24/7.
Let's take a look at a comparison of the U.S. with China. In 2006, the U.S. consumed energy at a rate of 11,248 watts per capita. China, with a total consumption of 59.57*10^15 quads and a population of 1,313,973,713 consumed energy at a rate of 1,514 watts per capita, or about 13.4% of the U.S. rate of consumption. I'd be curious to know how much of China's figure relates to production of consumer goods for shipment to the United States.
Worldwide, in 2005 humanity consumed 446*10^15 quads, or used energy at the rate of
1.49*10^13 watts. With a population of about 6.4 billion, we consumed energy at the rate of about 2330 watts per capita, about 21% of the U.S. rate. This is very scary stuff. Standard of living is very strongly correlated with rate of energy consumption, so to bring the world to "our" standard of living, we'd have to approximately quintuple our rate of energy consumption on a worldwide basis. This seems ludicrous. Never mind climate change, there is no chance of converting (all human energy use is conversion, never creation) energy at such prodigious rates.
How about looking at it from the other direction? How much energy consumption could we, as a society, forgo? I think I personally could struggle by on 1/2 the personal energy consumption. Remember, though, that this would include reducing the energy content of my consumer purchases, my food, etc., since the numbers above are all-inclusive. As I look around, listen to the television on downstairs, listen to the waterfall in my pool as water is pumped through the filtration system, listen to my wife in the shower as the heater provides hot water, etc., I know there's a long way to go.