The researchers then ran the model for over 1,000 different locations across the United States. The results showed a kilogram of dried cannabis would have the smallest climate effect in Long Beach, Calif., thanks to its mild climate and low-carbon energy grid. The same kilogram would be most intensive in Kaneohe Bay, Hawaii. The median impact was about equal to the total greenhouse gas emission of a 9,000-mile road trip in a standard passenger car.
Colorado’s status as a cannabis pioneer doesn’t mean it’s ideal for indoor cultivation, either. The wild temperature swings of the Mountain West mean indoor operations need more energy for heating and air conditioning. Combined with an electricity grid heavy on fossil fuels, the researchers found growing indoor cannabis in Colorado creates almost 50 percent more emissions than an equivalent facility in southern California.