Washington is moving to do something that has rarely been attempted: create a market to buy and sell permission slips to, in essence, pollute.
Last week, the U.S. price for high-quality coal was almost $50 a ton. That's about how much premium coal has cost for the past several years, with the exception of a brief, significant run-up in 2008 that was due mostly to global demand pressures from China and India.
Assuming, though, that basic economic conditions are relatively stable in coming years, the effective price of that ton of coal is likely to roughly double within the next decade. That's because of efforts by Congress and the White House to curtail the amount of carbon dioxide and other greenhouse gases released into the atmosphere.