I've found two reports that outline ways to migrate to renewables. They are sobering, but actually achievable.
A common thread among those who create actual concrete plans for running on renewable energy is this: We must use less energy to have our energy needs met by renewable sources.
(Their projections do account for the growth of newly industrialized nations, so it's not double-trouble.)
Some of the use-less-energy changes we would notice (how we get the food that reaches our table), and other changes we could integrate and not notice at all (lots of energy escapes buildings for no good reason, and that could change with different process + design becoming more dominant).
A cool part is that they don't see higher cost as long-term issue (that renewable energy is only temporarily expensive because it's uncommon and used in small doses).
Another kinda optimistic thing is that parts of the world that are still becoming "industrialized" have somewhat of an advantage (as they do with leapfrogging any kind of tech generation), and in some cases are being born with more renewable systems to begin with.
I completely understand those who overlook renewable sources because of the amount of energy we currently use is more than we can produce with them. It's not a dumb conclusion. But after going over these reports, I don't think using less energy is any more of an imposition than changing any other kind of infrastructure, and in many cases is stuff we're moving towards anyway.
http://getsatisfaction.com/wwf/topics/debate_the_energy_repo... http://assets.panda.org/downloads/101223_energy_report_final... [pdf, pdf, pdf! i warned you] http://www.greenpeace.org/er-ship/Global/international/publi... [pdf]