What "fundamental debate"?
Think Progress notices that President Bush said in his big speech today, "First of all, the globe is warming. The fundamental debate is it manmade or natural?" Of course, there's not actually a fundamental debate to be had here; scientists have overwhelming evidence that global warming is man-made.
The only "debate" over the causes of global warming seems to be the one carried out in the media, where, as Ross Gelbspan reported a few months ago in Mother Jones, industry-funded scientists and climatologists are given equal time on TV and in print, despite the fact that one side is right and the other's, well, making stuff up. "Teach the controversy," as it's called in another context. Maybe that's what Bush means.