Cap-and-trade rules

California and six other Western states are preparing to launch a dramatic campaign against global warming that will turn pollution into a commodity that can be bought and sold, and create a market for trading hot air. It's an idea that has been tested around the world and can be successful -- but only if it's done right. As the state unveils further details Friday about how the program will be structured, there are two principles that planners should keep at the top of their minds.

October 1, 2008