Fossil Fuel Subsidies

This graph from David Roberts is somewhat misleading (for example, it's hard to tell if magnitude is measured as radius from the origin or total area and I'd like to see a breakdown per BTU or something), but it has a powerful point: We subsidize "dirty energy" more than we subsidize "clean energy" in the aggregate. Why not, before getting into a big brew-ha-ha over cap-and-trade, remove the implicit and explicit subsidies for making the environment worse-off?