Since 2011, California has used a greenhouse gas cap-and-trade market as one of its programs aimed at reducing carbon emissions over time.
Since 2011, California has used a greenhouse gas cap-and-trade market as one of its programs aimed at reducing carbon emissions over time. David McNew Getty Images file
Since 2011, California has used a greenhouse gas cap-and-trade market as one of its programs aimed at reducing carbon emissions over time. David McNew Getty Images file