Oregon Public Broadcasting: If you're at the Seattle Mariners season opener Monday you might run into some folks with clipboards, gathering signatures for a newly-announced initiative for 2016 that would tax carbon emissions. The circulation of petitions to put Initiative 732 on the 2016 ballot signals a new strategy that may come into play if Gov. Jay Inslee and fellow Democrats in the Legislature are unable to pass their own carbon cap-and-trade proposal. The Initiative would phase in a $25-per-ton tax on carbon dioxide...