3 ms·

This physicist has done a number of blogs on physical restraints on economic growth. https://dothemath.ucsd.edu/2012/04/economist-meets-physicist/ https://doth

This physicist has done a number of blogs on physical restraints on economic growth. https://dothemath.ucsd.edu/2012/04/economist-meets-physicist/ https://dothemath.ucsd.edu/2012/04/economist-meets-physicist... For example, if economic growth persists black body ration independent of power source raises the surface temperature of the earth to boiling in a few hundred years.

shoo 8y ago
this link is _fantastic_ , thank you for sharing it, i haven't heard this argument before . First: For a given constant T > 0 there exists C > 0 such that Temp(earth) <= T implies Energy(earth) <= C > 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. The situation for the whole world is similar. So how long > do you think we might be able to continue this trend? > Alright, the Earth has only one mechanism for releasing heat to space, and > that’s via (infrared) radiation. We understand the phenomenon perfectly > well, and can predict the surface temperature of the planet as a function of > how much energy the human race produces. The upshot is that at a 2.3% growth > rate (conveniently chosen to represent a 10× increase every century), we > would reach boiling temperature in about 400 years. [Pained expression from > economist.] And this statement is independent of technology. Even if we > don’t have a name for the energy source yet, as long as it obeys > thermodynamics, we cook ourselves with perpetual energy increase. > At that 2.3% growth rate [of global energy consumption], 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. 2500 years is not that long, from a > historical perspective. We know what we were doing 2500 years ago. I think > I know what we’re not going to be doing 2500 years hence. > If we tried to generate energy at a rate commensurate with that of the Sun > in 1400 years, and did this on Earth, physics demands that the surface of > the Earth must be hotter than the (much larger) surface of the Sun. Second: Energy(earth) / GDP(earth) >= K > 0 > Then in order to have real GDP growth on top of flat energy, the fractional > cost of energy goes down relative to the GDP as a whole. > How far do you imagine this can go? Will energy get to 1% of GDP? 0.1%? Is > there a limit? > if energy became arbitrarily cheap, someone could buy all of it, and > suddenly the activities that comprise the economy would grind to a halt That is, assuming we want Temp(earth) <= T for some constant temperature T, then there exist positive constants C > 0, K > 0 such that Energy(earth) <= C and Energy(earth) / GDP(earth) >= K > 0 . Therefore GDP(earth) <= C / K .
- wav-part 8y ago
  We do not consume energy. We consume goods and services which require energy to produce. This model completely ignores past and future advancments in energy efficieny.

shoo 8y ago

this link is _fantastic_ , thank you for sharing it, i haven't heard this argument before . First: For a given constant T > 0 there exists C > 0 such that Temp(earth) <= T implies Energy(earth) <= C > 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. The situation for the whole world is similar. So how long > do you think we might be able to continue this trend? > Alright, the Earth has only one mechanism for releasing heat to space, and > that’s via (infrared) radiation. We understand the phenomenon perfectly > well, and can predict the surface temperature of the planet as a function of > how much energy the human race produces. The upshot is that at a 2.3% growth > rate (conveniently chosen to represent a 10× increase every century), we > would reach boiling temperature in about 400 years. [Pained expression from > economist.] And this statement is independent of technology. Even if we > don’t have a name for the energy source yet, as long as it obeys > thermodynamics, we cook ourselves with perpetual energy increase. > At that 2.3% growth rate [of global energy consumption], 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. 2500 years is not that long, from a > historical perspective. We know what we were doing 2500 years ago. I think > I know what we’re not going to be doing 2500 years hence. > If we tried to generate energy at a rate commensurate with that of the Sun > in 1400 years, and did this on Earth, physics demands that the surface of > the Earth must be hotter than the (much larger) surface of the Sun. Second: Energy(earth) / GDP(earth) >= K > 0 > Then in order to have real GDP growth on top of flat energy, the fractional > cost of energy goes down relative to the GDP as a whole. > How far do you imagine this can go? Will energy get to 1% of GDP? 0.1%? Is > there a limit? > if energy became arbitrarily cheap, someone could buy all of it, and > suddenly the activities that comprise the economy would grind to a halt That is, assuming we want Temp(earth) <= T for some constant temperature T, then there exist positive constants C > 0, K > 0 such that Energy(earth) <= C and Energy(earth) / GDP(earth) >= K > 0 . Therefore GDP(earth) <= C / K .

wav-part 8y ago
We do not consume energy. We consume goods and services which require energy to produce. This model completely ignores past and future advancments in energy efficieny.