Who supports a carbon tax?

A piece in the New Yorker makes the case for a tax on carbon emissions.

That's not very surprising. What's more surprising is that, as the article points out, over 100 big corporations — including ExxonMobil and Shell — have expressed support it. In contrast, the White House spokesperson, Jay Carney, recently said: "We would never propose a carbon tax, and have no intention of proposing one."