Dialogue between an economist and a physicist

 [[{“value”:”Interesting, but I think highly flawed on both sides.  Here is one excerpt from the physicist: Physicist: True enough. So we would likely agree that energy growth will not continue indefinitely. But two points before we continue: First, I’ll just mention that energy growth has far outstripped population growth, so that per-capita energy use has surged dramatically over
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Interesting, but I think highly flawed on both sides.  Here is one excerpt from the physicist:

Physicist: True enough. So we would likely agree that energy growth will not continue indefinitely. But two points before we continue: First, I’ll just mention that energy growth has far outstripped population growth, so that per-capita energy use has surged dramatically over time—our energy lives today are far richer than those of our great-great-grandparents a century ago [economist nods]. So even if population stabilizes, we are accustomed to per-capita energy growth: total energy would have to continue growing to maintain such a trend [another nod].

Second, thermodynamic limits impose a cap to energy growth lest we cook ourselves. I’m not talking about global warming, CO2 build-up, etc. I’m talking about radiating the spent energy into space. I assume you’re happy to confine our conversation to Earth, foregoing the spectre of an exodus to space, colonizing planets, living the Star Trek life, etc…

At that 2.3% growth rate, we would be using energy at a rate corresponding to the total solar input striking Earth in a little over 400 years. We would consume something comparable to the entire sun in 1400 years from now. By 2500 years, we would use energy at the rate of the entire Milky Way galaxy—100 billion stars! I think you can see the absurdity of continued energy growth.

I think it is easy enough for the economist to argue that energy, at some margin, has diminishing returns for creating utility.  So we then have dematerialized economic growth, not an ever-growing population (oscillation back and forth?), and thus we do not fry the planet, or for that matter the galaxy.  A general lesson of national income statistics is that if you play out exponentials for long enough, over centuries you are simply talking about very different things, rather than a simple exponential growth of present conditions.

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 Economics, Science, Uncategorized