Even if we all cooked & heated our homes that way, it doesn’t change the argument – just delays it slightly.

A large part of the historical growth is down to population increase rather than per capita usage. So, even if our average usage was burning 500W of wood rather than 2000W of fossil fuels then we would still reach resourse limits, just a few years later.

Although, of course, since we’re not going to be able to cover the whole world with solar panels, and still have space for food we will reach the limits much sooner, and the population will plateau around 2070, or even go into catastophic collapse.

All new technologies like fusion power will do is push back the dates a little.

So I guess the question is: If we manage to get to a sustainible population level, so energy use only grows with the supply of new resources (deeper mines, asteroids etc) and improvements in energy production/efficiency. When do we outstrip the Earth/Sun etc. ?

eg. if of (using his figure) the 2.3% historical growth in energy half was due to population growth, then rather than 350 years before the resultant heat from our energy use heats the Earth significantly, maybe it gets pushed out to 600 years.

If we use anything other that Solar for our energy source, and since if we use it to do work then it ends up as heat eventually, then it will heat up the Earth.