Former Governor Arnold Schwarzenegger signed AB 32, which put California into the cap and trade business. Today for the first time, so called “carbon credits” went on sale to manufacturers, utilities and other polluters, allowing them to continue discharging carbon dioxide into the environment — but for a price. As time goes on, the credits will cost them more, with the goal of reducing emissions back to 1990 levels by the year 2020. Only Europe has a bigger cap and trade program, and California may be out on a limb. At his news conference today, President Obama said he wants a green economy to fight against climate change, but that other priorities are paramount.