(Update: Eli argues in the comments that this quote sort of slyly backs into Pielke's actual position, rather than advocating it. Note the telltale "when" and the "inevitably" in "when these sorts of approaches inevitably fail", and this LATimes article wherein he describes himself as a "non-skeptic heretic".)
Unrestrained emissions of carbon dioxide into the atmosphere will no doubt have effects on the global earth system, including the oceans, atmosphere, and land surface. There is a chance that these effects could be relatively benign, but there is also a chance that the effects could be quite severe. I personally lean toward the latter view, ...and here's an interview with Jeffrey Sachs who seems to get much more attention in the UK than he does on this side of the pond, for some reason:
I am certainly not opposed to efforts to put a price on carbon, but at the same time we also need to be fully aware of the realities of politics which suggest that putting a price on carbon may not actually occur or, if it does occur, may be implemented at a meaningless level in small parts of the global economy. Therefore, we’d better be ready with another strategy when these sorts of approaches inevitably fail. ...
The flip side to making carbon pricier is to make carbon-free energy sources relatively cheaper.
And even if these technologies do exist, so do intractable barriers at every level from between different disciplines of science and squabbling government departments on the minute scale to, on the global level, a system of multilateral institutions which is at its lowest ever ebb - not to mention the war on terror which is "a disastrous distraction from real problems".
"It's an American habit," he concludes. "We seem to move from defining an enemy to defining an enemy. The idea of my book is that we all have common interests and common problems, and it's trying to surmount them for future generations."