California, with its long coastline littered with white bags, needs a better approach, one that encourages people to make informed choices between disposable and reusable bags. Here are the options: • A piecemeal, voluntary approach by stores. • A hard-line approach, such as a ban. • A simple, market-based solution: a consumption tax. Ireland has taken this route. Since 2002, consumers who forget to bring a bag are charged a 15-cent tax at checkout. Before the tax, Ireland's 3.9 million people used 1.2 billion bags per year. Now it's 230 million. About $9.6 million was raised from the tax in...