[nhaehnle]

The rate of CO2 emission per GDP is already decreasing thanks to technological advances. There's no fundamental reason why the same couldn't happen to the ratio of energy use per GDP. So finite supply of resources is not a problem per se, and certainly won't be within our lifetimes, which is what we need to deal with.

[pygy_]

You can't be more than 100% energy efficient, so, while there may be some headroom in that direction, there's a hard limit as well.

Edit: Also, while there seems to be a positive correlation between GDP per capita and energy efficiency, the most efficient nations in the world have a very low GDP per capita... I wonder why it is the case.

https://en.wikipedia.org/wiki/Energy_intensity#Economic_ener...

[pdonis]

> You can't be more than 100% energy efficient

Yes, you can, practically speaking. The amount of energy needed to produce a given amount of value to humans is not fixed; it can be decreased, and in principle can be made as small as we like given sufficient advances in technology. That means the amount of value to humans that can be produced with a fixed amount of energy can increase, in principle as much as we like. That's what the parent to your post was saying.

Obviously it will be a while before we have technology advanced to the point where, say, the amount of value currently being produced per year on Earth can be produced with one tenth or one hundredth or less of the energy it currently takes. But we also have a while before we hit any hard limits of the sort you are referring to.