It goes by many names: cannabis, marijuana, pot, chronic, grass, reefer, shwag, Mary Jane. Whatever the name, the trend is clear: the weed is legal but the herb ain't green. Nearly half of all U.S. states have enacted-or have pending-legislation to legalize, decriminalize, or in some way permit the use and cultivation of marijuana. As a result, marijuana has become a significant topic of conversation in the U.S.-especially in the areas of social policy and criminal law. One conversation yet to reach fruition, however, is the industry's projected impacts on energy demand and the climate. As the industry grows, so will its negative externalities. Indoor cannabis cultivation is one of the most energy-intensive industries in the U.S., requiring electricity to power lamps, to maintain consistent temperature and humidity levels, and to power fans for ventilation, among other things. This energy consumption, unless otherwise mitigated, results in significant greenhouse gas emissions. This article explores the opportunities that legalization brings in addressing the negative impacts on energy usage and the climate. It concludes that simply incorporating the marijuana industry into the existing energy regulatory framework will do little to address its negative impacts. It recommends that state and local policymakers take advantage of the opportunity to consider climate risks and energy usage before issuing business licenses for indoor marijuana cultivators.