I would just add that there's the issue of getting the price for carbon right, but underlying this is that substitutes have to be available. I would say, too, that we had a good case study on this when we had that rapid increase in energy prices about a year ago. We saw what kind of impact that had. There weren't any substitutes available, so people cut back. Manufacturing operations shut down and moved elsewhere. Places like China and India subsidize their energy costs, so they didn't suffer the same increase.
That was sort of a good study of what putting on a carbon tax would do. In the short term, it wouldn't really do anything. It wouldn't reduce our consumption of carbon to move to more sustainable options, because they're not available. That's why technology really is the key, I think, to moving away from a carbon-dependent economy.