“ Life is the art of drawing sufficient conclusions from insufficient premises. ”
— Samuel Butler
Per capita energy consumption in the U.S., total, has been falling for years and is now at 1968 levels.
https://www.google.com/publicdata/ex...n_US&ind=false
... but what does this mean?
How can we, veterans of PF, demonstrate to others, how to gain a scientific understanding of what this sort of information is telling us.
Reading that reference: the current energy use "now = 2014" is not provided. Presumably mheslep is referring to the 2012 figure when talking about "now". What does the chart say when we look at it?
The chart shows a flat trend (the chart goes up and down about the same amount) from about 1980 to 2007, and a downturn since then - in the
per capita energy use.
Notice that this observation does not contradict what mheslep has said - it is clarifying it.
"Lower then 1968" is a funny comparison to make though, it's also lower than a lot of other years so it is not clear what to make of this. I think a better comparison is to ask "when was the last time per-capita energy consumption was most closely comparable?"... and that would be the previous year - 1967.
So what does this mean? In 2012, individual Americans used the same energy, on average, each, as they did is 1967. But the discussion was about total energy use, and the US population has increased since the 60's.
In round figures:
The population of the USA in 1967 was about 200 million
The population of the USA in 2012 was about 300 million
(source: Population Division, U.S. Census Bureau)
Note: not the "almost double" from SteamKing.
This means that the USA is using 33% more energy now than in 1967.
If mheslep meant, by the comparison, that total energy use was down from 1967/8, then the figures disagree with that assertion. But what about the overall sense of mheslep's argument?
As we can see, the short-term trend is down.
Individual Americans seem to be using less and less power - even as the population increases.
It does not make sense to compare 2012 figures with 1997/8 figures - trends change.
OTOH: there has also been an economic downturn, unrest in the middle east, and so on. Those things may have had an impact on Americans energy habits, which may be temporary - once those factors are alleviated (peace breaks out in the middle east, consumer confidence improves... stuff like that) then it is not unreasonable to suppose that the per-capita energy consumption would return to at least pre 2007 levels.
But maybe not. Let's be optimistic. Let's say that there are other, stronger, factors driving the reduction - maybe the machines are all getting more energy efficient? Perhaps Americans are just more frugal in nature now? Shall we also assume that future economic growth will no longer mean increased energy use - at least on a per-capita basis? Lets. What does than mean?
To find out, we need to know the trend for energy use per capita, and the trend for US population growth, and we need the figures from 2007 to 2012 (ideally to "now" but let's keep using the reference we've been given as well.)
Energy growth:
-100x(7758-6793)/7758 = 12% over 5 years.
It's steeper at the start and shallower at the end ... so split the difference:
So call it about 2% per annum decrease.
How fast is the US populaton increasing?
In July 2012, it was 313.91mil
In July 2007, it was 301.23mil
That is +4% over the same period.
So the per-capita energy use decline, given all the assumptions stated before, is faster than the population increase - by roughly 8% over 5 years. If this continues, this should result in a net demand drop. This result supports mhesleps position so it is puzzling that he didn't do this calculation himself.
How good are those assumptions? Probably depends on how cynical (or optimistic, depending on your POV) you are.
There are people who do this for a living:
The IEA is projecting no near-term change in energy demand for the US. You can kinda see why.
We've already, in previous posts, see what happens if levels stay flat like the "experts" say.
But remember how we go here - the thing that kept raising red flags for me was the reference to how much resources are needed to keep up current consumption. This is because current consumption cannot be kept up. The fall is good news. The question becomes - how do we turn this short-term result into a long term trend?
I will bow out here - I do not want to be constantly checking everyone's facts for them. You should be doing that yourself all the time anyway. I hope to have illustrated the importance of doing the maths, and also which maths you need to be doing. We have to try not to favor those figures and statements which support our own position. Remember: an important quality for a scientist is to question everything but question even harder ones
own deeply help beliefs.