Energy Independence/Global Warming

The BP Gulf disaster has people--notably President Obama--buzzing about the pressing need for energy independence.  Al Gore used the opportunity to write an essay in The New Republic calling for an aggressive move toward a carbon tax so as to wean ourselves from dependence on coal and oil.  Today TNR published a counterpoint blog post which makes the good point that as sure as we can be that global warming will occur, predictions as to the dire consequences for human civilization are far less certain.  The IPCC's worst case scenario suggests that a 4C increase in average global temperature over the next century would lead to a shocking 3% reduction in global GDP as compared to what it would be without any warming at all.   

These are difficult numbers to ignore.  I continue to believe that we need to take efforts to price fossil fuels in such a way as to factor in their adverse environmental effects.  This means some sort of carbon tax.  (Whether you call it a tax or cap-and-trade, it's still a tax.) But if global warming is unlikely to destroy civilization, wrecking our economy to get to carbon-neutral status ASAP doesn't make much sense.  One has the feeling that what a lot of the more committed anti-climate change advocates like Gore and Bill McKibben are getting worked up about has more to do with a sentimental, aesthetic sense that it is bad for humankind to exert such profound effects on global ecosystems than any clear belief that global warming is going to cause civilization to collapse.