The Exponential Growth Assumption

The NY Times just posted an article stating that a steady-state (no growth) economy is unconscionable and therefore should not be considered when discussing the effects on the environment and climate change.  But this ignores the fact that economic growth has always required additional energy (and other resource) use.  

Some (including me) argue that exponential growth is simply untenable.  If not now, then very soon.  Tom Murphy, a Physics Professor at UCSD has looked at the available energy to us on Earth (or in the Solar System) to determine how much growth we could sustain.  Check it out.