Recent research reveals that the rapid expansion of the legal marijuana industry has led to significant increases in greenhouse gas emissions, currently equating to the emissions of roughly 10 million cars.
Evan Mills, a Northern California-based researcher, published his findings in the journal One Earth, highlighting the considerable environmental impact of cannabis cultivation, particularly indoor grows.
The report notes cannabis cultivation is now one of the most energy-intensive agricultural activities, surpassing energy consumption by the pharmaceutical, beverage, and tobacco industries. Mills identifies indoor growing as the primary driver, accounting for about 90% of cannabis-related emissions, largely due to artificial lighting and environmental controls.
Shifting cultivation practices from indoor to outdoor methods could drastically reduce environmental impacts, potentially cutting emissions by as much as 76%. While federal legalization alone would only modestly reduce emissions (about 8%), targeted policy changes—such as incentivizing outdoor cultivation, home-growing, greenhouse use, and energy-efficient growing methods—could significantly lower the cannabis industry’s carbon footprint.
However, the study also warns of scenarios that could further increase emissions, including greater reliance on indoor grows and expanded home delivery services.
Current cannabis production trends remain concerning, particularly with large-scale indoor cultivation concentrated in urban areas, which exacerbates existing environmental burdens.
The report urges greater transparency and consumer education regarding cannabis’s environmental impacts, noting that such information is widely available for other consumer products but largely absent in the cannabis market.
Some states, like Colorado and California, have started initiatives to reduce environmental impacts through sustainability programs and funding for eco-friendly cultivation practices, but broader nationwide efforts remain necessary to address the industry’s growing emissions effectively.
