Current growth rates need an exponential increase in resources.
Even if we -after some technological singularity- could expand a sphere of influence that brings everything in the expanding bubble to complete subatomic level of control, this would mean at most sustainable cubic growth (available resources are growing cubically).
So our current situation is exceptional and not steady state and can't continue indefinitely (wasn't going to anyway).
I think his main most valuable point is that the status quo can't - and that stands.
Personally chasing constant growth doesn't sound like what we need to be aiming at anyway.
It would be saner to be engineering some long term stable state that we adjust as soon as new potentials become available.
Like aiming at a fixed upper limit maximum human population on earth with an acceptable minimal standard of life as opposed to letting blind growth search out the natural feedback loops instead.
I think they are talking about "economic" growth rates, which are independent of population growth rates.
This actually makes me lean towards saying that the economist is right, money is arbitrary anyway so if the argument is actually that the economy can increase forever I see no reason that can't happen physically. It's not real, it can't be real in the future and it's barely real now.
Well, if we are going to talk about nominal growth, I'll throw this in.
Our money system does need endless growth just to function properly but it only needs endless nominal growth. If inflation is high enough then real interest rates are negative. No need for real growth.
Numbers going up does not mean increased productivity and there are human (and technological) limits to that, even if you make everyone into work slaves. Which would be completely immoral.
But there is a limit.
Current growth rates need an exponential increase in resources.
Even if we -after some technological singularity- could expand a sphere of influence that brings everything in the expanding bubble to complete subatomic level of control, this would mean at most sustainable cubic growth (available resources are growing cubically).
Not exponential growth.