Study: Pot Growers Adding to Global Warming

Legal indoor growers of medical marijuana in the U.S. will use $5 billion worth of energy -- or 1 percent of the nation’s electricity supply -- and produce 17 million metric tons of carbon dioxide this year, according to a study by analyst Evan Mills of Lawrence Berkeley National Laboratory.

The 400,000 legal growers in California use around 3 percent of that state’s electricity. Electricity use in the major pot-producing area of Humboldt County soared 50 percent per person after medical marijuana was legalized in 1996.

Mills equates the full-year energy usage by growers to that of a million typical California homes or a million typical vehicles.