He's the guy who came up with the theory of catabolic collapse.  Which is probably the most doomerish outcome I can imagine.

The sad thing is, I fear he is correct.

You should read some of his more recent posts, Leanan.  If his pessimism was perhaps extreme in the past, it has moderated somewhat lately.  For example, he now thinks that the collapse will be gradual and protracted (rather than sudden and abrupt), spanning many decades, and that this will leave room for those aware of the situation to implement productive measures for what he terms our "predicament."  I wouldn't say that he is without hope for the long-term future by any stretch of the imagination.
He has always thought that way.  That is what catabolic collapse means.

The reason I see that as the most doomerish outcome possible is that it means we do not change our ways.  Instead, we keep trying to do what we are doing, switching to ever poorer sources of energy.  Until all resources and capital are converted to waste, and we simply cannot continue.

The result is a crash to a lower population level and level of complexity than existed before the complex society arose or arrived, because the environment is so poor that it cannot support anything else.

The good news?  I probably won't have to worry about it, since it will take a hundred years or more.  :-/

This is exactly how I feel.  It would be so nice to live in an age of renaissance, even if it had to be preceeded by an abrupt shock.  But, I fear I may live in an age of slow, relentless descent.  
Another drawback of the slow, relentless collapse scenario is that it greatly facilitates denial on the part of Peak Oil-naysayers; an abrupt collapse would at least be strongly convincing.