Am I missing something, or hasn't energy per capita in the developed world already stopped growing? As well as population growth in rich societies?
Exponential Economist Meets Finite Physicist (2012)
11–20 of 174 posts
Re: Exponential Economist Meets Finite Physicist (2012)
#12Earlier quoted context omitted.
Actually, they dismissed it pretty quickly I thought.
I believe the "dismissal" is this cogent argument: Shuffling bits around takes energy; if your virtual reality services grow exponentially and energy production doesn't, then the price of energy must also increase exponentially or else one of your VR companies could buy all the energy and shut down the competition. Energy production (and computation) are limited by the capacity of the earth to vent heat into space at…
The price of energy is capped at the cost to privately produce it for yourself, which is probably pretty low in the scheme of all encompassing virtual real estate fiscal gods.
Re: Exponential Economist Meets Finite Physicist (2012)
#13It’s not clear how meaningful these measurements are anyway. Consider two years: in the first, 1000 tonnes of wheat are produced, and in the second, 500 tonnes of wheat and 300 of steel. Which year, one asks, is more productive? We can measure everything in wheat-equivalent or steel-equivalent or (commodity-basket)-equivalent (i.e. PPP) but ultimately such calculations are just as arbitrary as reduction to wheat bush…
This is why, as all economists agree, measurements of economic growth are completely arbitrary and the economy hasn't changed in any meaningful way that can be called "growth" since the middle ages.
... Oh, wait, or maybe growth actually can be expressed as a quantifiable concept?
In this case, the author chooses energy as an objective measurement, because all economic transactions must consume energy in order to occur.
Re: Exponential Economist Meets Finite Physicist (2012)
#14Tom Murphy's website occasionally comes up in futurist circles. His general point that unbounded exponential growth is impossible is obviously correct, but I find his condescending attitude tiresome and he often exaggerates the apparent validity of his pessimism through questionable arguments.
For example, he first insists that the conversation about energy consumption be confined to Earth and ignore space exploration, which is reasonably sensible because of the large energy cost of space travel. He moves from there to a thermodynamic bound on energy dissipation from Earth into space via black-body radiation. This argument is self-contradictory: if we were producing so much energy that it were able to heat the atmosphere (>1000x today), we would certainly have enough energy to fly into space. (The linked article "Why not space?" contains no math and few real arguments: https://dothemath.ucsd.edu/2011/10/why-not-space/ )
Also, this paragraph is relatively good evidence he didn't talk to a real economist:
>But if energy became arbitrarily cheap, someone could buy all of it, and suddenly the activities that comprise the economy would grind to a halt. Food would stop arriving at the plate without energy for purchase, so people would pay attention to this. Someone would be willing to pay more for it. Everyone would. There will be a floor to how low energy prices can go as a fraction of GDP.
None of this hemming and hawing about infinity answers the real question: is it possible for the global economy to grow until nobody has to live in mud-huts without air conditioning? The answer is almost certainly yes.
Re: Exponential Economist Meets Finite Physicist (2012)
#15Earlier quoted context omitted.
I believe the "dismissal" is this cogent argument: Shuffling bits around takes energy; if your virtual reality services grow exponentially and energy production doesn't, then the price of energy must also increase exponentially or else one of your VR companies could buy all the energy and shut down the competition. Energy production (and computation) are limited by the capacity of the earth to vent heat into space at…
The price of energy is capped at the cost to privately produce it for yourself, which is probably pretty low in the scheme of all encompassing virtual real estate fiscal gods.
Not unless the physical economy is growing at about the same rate as the virtual one. Or else how is that extra power generation capacity being added?
Re: Exponential Economist Meets Finite Physicist (2012)
#16Am I missing something, or hasn't energy per capita in the developed world already stopped growing? As well as population growth in rich societies?
Energy consumption has not stopped growing in rich societies... so long as the economy grows, energy consumption grows. The relationship isn't perfectly linear only because the available metrics are imperfect, but if you have any data that outright contradicts this rather reasonable assupmtion, please show us.
Re: Exponential Economist Meets Finite Physicist (2012)
#17It’s not clear how meaningful these measurements are anyway. Consider two years: in the first, 1000 tonnes of wheat are produced, and in the second, 500 tonnes of wheat and 300 of steel. Which year, one asks, is more productive? We can measure everything in wheat-equivalent or steel-equivalent or (commodity-basket)-equivalent (i.e. PPP) but ultimately such calculations are just as arbitrary as reduction to wheat bush…
This is why, as all economists agree, measurements of economic growth are completely arbitrary and the economy hasn't changed in any meaningful way that can be called "growth" since the middle ages. ... Oh, wait, or maybe growth actually can be expressed as a quantifiable concept? In this case, the author chooses energy as an objective measurement, because all economic transactions must consume energy in order to occ…
But as is pointed out, energy isn’t, because efficiency exists.
I am not denying that the economy has changed in meaningful ways; I am merely denying that we can quantify the overall state of the economy over time such as to enable simple comparisons implicit in concepts like “growth”—and that with the caveat that the problem isn’t too severe over short periods of time.
Re: Exponential Economist Meets Finite Physicist (2012)
#18It’s not clear how meaningful these measurements are anyway. Consider two years: in the first, 1000 tonnes of wheat are produced, and in the second, 500 tonnes of wheat and 300 of steel. Which year, one asks, is more productive? We can measure everything in wheat-equivalent or steel-equivalent or (commodity-basket)-equivalent (i.e. PPP) but ultimately such calculations are just as arbitrary as reduction to wheat bush…
This is why, as all economists agree, measurements of economic growth are completely arbitrary and the economy hasn't changed in any meaningful way that can be called "growth" since the middle ages. ... Oh, wait, or maybe growth actually can be expressed as a quantifiable concept? In this case, the author chooses energy as an objective measurement, because all economic transactions must consume energy in order to occ…
At least one pretty well-known economist does echo heraclius' point:
"The fact that two incommensurable collections of miscellaneous objects cannot in themselves provide the material for a quantitative analysis need not, of course, prevent us from making approximate statistical comparisons, depending on some broad element of judgment rather than of strict calculation, which may possess significance and validity within certain limits. But the proper place for such things as net real output and the general level of prices lies within the field of historical and statistical description, and their purpose should be to satisfy historical or social curiosity, a purpose for which perfect precision — such as our causal analysis requires, whether or not our knowledge of the actual values of the relevant quantities is complete or exact — is neither usual nor necessary. To say that net output to-day is greater, but the price-level lower, than ten years ago or one year ago, is a proposition of a similar character to the statement that Queen Victoria was a better queen but not a happier woman than Queen Elizabeth — a proposition not without meaning and not without interest, but unsuitable as material for the differential calculus. Our precision will be a mock precision if we try to use such partly vague and non-quantitative concepts as the basis of a quantitative analysis."
(J.M. Keynes)
Re: Exponential Economist Meets Finite Physicist (2012)
#19I generally liked the Do The Math posts but I thought this was one of the weakest.
Physicist: "Right, if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span."
It's not phenomenally faithful. There's an inflection point visible even in his large graph going back all the way to 1650. US primary energy consumption in 1977 was 78 quadrillion BTU (quads). At 2.9% annual growth it would have risen to 245 quads by 2017. Actual US primary energy consumption in 2017 was only 98 quads. The per capita primary energy consumption in the US was actually higher in 1977.
Physicists don't need to imagine future limits to growth. The limits are already visible in the historical record. But, contra the fears of many scientists circa 1960, the limits to growth showed up on the demand side before the supply side. We ended up with a world where widespread obesity is a problem and predicted gigadeaths from starvation did not actually happen.
For any product you can imagine consuming, there are "obesity"-type limits to how much more of that same product you can consume before the marginal utility goes negative. For any service you might use, similar limits apply since there are only 24 hours in a day.
The physicist character gives the more correct answer but his supporting evidence is flawed. The economist has the much worse answers, but only (I suspect) because he's a strawman constructed for didactic purposes. Economists generally don't make 1400 year forecasts of any sort.
Re: Exponential Economist Meets Finite Physicist (2012)
#20I just want to say that this discussion is a charming read so far (the salad just arrived - I can’t wait!)