With Californians welcoming 2018, January 1 marked an important day for state government as a flurry of previously passed bills will finally be enacted as official laws. Among them is the legalization of recreational marijuana.
Previously allowed only for its medical use, California presents one of the biggest markets in America for the psychoactive drug. Rooted in controversy since being nationally proscribed in the 1970s, marijuana’s implications have been explored in countless regards including its effects on pregnancy and health conditions like cancer and depression. Not particularly new, but alarming, is the environmental angle on the drug—marijuana’s impact on climate change.
Evan Mills, a senior scientist at UC Berkeley, led a study in 2011, analyzing the carbon footprint of the cannabis cultivation scene. Since a vast majority of grow operations take place in private indoor facilities, growers are tasked with creating a synthetic environment, one that would be able to imitate the light, ventilation, and water conditions cannabis would naturally experience if grown outside. As a result, high energy initiatives follow in tow.
As Mills penned in a 2016 opinion piece, “Legislators and energy agencies have largely turned a blind eye to the carbon footprint of indoor cultivation.”
When examining the long and complex process of marijuana cultivation, look no further than Colorado. Profiting off a three-year-old cannabis industry with 675 dispensaries located throughout the state, Coloradans were the first Americans to delve into the legal marijuana trade. Inside countless warehouse-sized facilities, rooms filled with hundreds of cannabis plants are grown. Again, since these grow operations take place indoors, production requires everything from air conditioning and ventilation to lighting and water handling.
Mills’ 2011 study concluded that for each kilogram of cannabis grown indoors, 4600 kilograms of carbon dioxide is emitted into the atmosphere, which is also the equivalent emission of 3 million average U.S. cars. The total accounts for the carbon footprint of ventilated light fixtures, lamps, lamp rails, dehumidifiers, ozone generators, and water purifiers, to name a few.
Altogether, growers manifest a synthetic environment by maintaining tropical-weather temperatures while providing excessive lighting and hydration for the plants. Altogether, the 2011 cannabis industry expended a 6-billion-dollar energy bill per year, which is, according to Mills, the equivalent to “twice the energy bill of all domestic pharmaceutical production.
“One joint [smoked] creates 10 pounds of carbon dioxide pollution. That’s as much as driving a Prius 22 miles or running a 100-watt light bulb for 75 hours.”
Note this was all taken into account prior to recreational legalization in any U.S. state, including Colorado, and the more recent decriminalization of the drug in Alaska, California, Maine, Massachusetts, Nevada, Oregon and Washington.

Marijuana cultivation room. Courtesy: Ryan Van Lenning. License: https://goo.gl/H3M9QH
Lacking a serious auditing system, environmental implications of mass marijuana production go unaddressed. With lights blaring at cannabis plants inside factories nonstop, the regulation of lighting methods presents an energy saving potential.
LED lighting, known for low energy outlay in comparison with other alternatives, including incandescent, sodium-vapor and fluorescent, has already been experimented with and used; growers unfortunately revealed them to be less effective, as marijuana plants take longer to grow under LED fixtures; if used, the same energy as any other alternative light source is expended due to the extended time necessary to grow the same quantity of plants.
While environmentalists are only left with mouths agape when addressing this renewed issue, more and more states will push for legalization in the coming years.
Since possession and sale of marijuana has gradually become a lesser punishable offense over the years, decriminalization and widespread legalization is inevitable. The method by which growers and consumers find ways to curtail the energy intensive marijuana cultivation process will be the necessary solution to a beckoning issue.