Insatiable Demand for Cannabis Has Created a Massive Carbon Footprint – And Other Environmental Harms!

Colorado State University researchers provide the most detailed accounting to date of the industry’s greenhouse gas emissions.    



The life cycle greenhouse gas emissions from indoor cannabis cultivation modeled across the U.S. Credit: Hailey Summers/Colorado State University

It’s no secret that the United States’ $13 billion cannabis industry is big business. Less obvious to many is the environmental toll this booming business is taking, in the form of greenhouse gas emissions from commercial, mostly indoor production.

A new study by Colorado State University researchers provides the most detailed accounting to date of the industry’s carbon footprint, a sum around which there is only limited understanding. What is clear, though, is that consumer demand for cannabis is insatiable and shows no signs of stopping as more states sign on to legalization.

The study, published in Nature Sustainability, was led by graduate student Hailey Summers, whose advisor, Jason Quinn, is an associate professor in the Department of Mechanical Engineering. Summers, Quinn and Evan Sproul, a research scientist in mechanical engineering, performed a life-cycle assessment of indoor cannabis operations across the U.S., analyzing the energy and materials required to grow the product, and tallying corresponding greenhouse gas emissions.

They found that greenhouse gas emissions from cannabis production are largely attributed to electricity production and natural gas consumption from indoor environmental controls, high-intensity grow lights, and supplies of carbon dioxide for accelerated plant growth.

“We knew the emissions were going to be large, but because they hadn’t been fully quantified previously, we identified this as a big research opportunity space,” Summers said. “We just wanted to run with it.”

The CSU group’s efforts update previous work by Lawrence Berkeley National Laboratory researchers, which quantified small-scale grow operations in California and predated the cascade of state-by-state legalization since Colorado was first to legalize in 2012. To date, 36 states have legalized medical use of cannabis, and 15 have legalized recreational use.

Mapping variable emissions

Their research shows that U.S. indoor cannabis cultivation results in life-cycle greenhouse gas emissions of between 2,283 and 5,184 kilograms of carbon dioxide per kilogram of dried flower. Compare that to emissions from electricity use in outdoor and greenhouse cannabis growth, which is 22.7 and 326.6 kilograms of carbon dioxide, respectively, according to the New Frontier Data 2018 Cannabis Energy Report. Those outdoor and greenhouse numbers only consider electricity, while the CSU researchers’ estimate is more comprehensive, but the comparison still highlights the enormously larger footprint of indoor grow operations.

The researchers were surprised to find that heating, ventilation and air conditioning systems held the largest energy demand, with numbers fluctuating depending on the local climate — whether in Florida, which requires excessive dehumidifying, or Colorado, where heating is more important.

The high energy consumption of cannabis is due in part to how the product is regulated, Quinn said. In Colorado, many grow operations are required to be in close proximity to retail storefronts, and this has caused an explosion of energy-hungry indoor warehouses in urban areas like Denver. According to a report from the Denver Department of Public Health and Environment, electricity use from cannabis cultivation and other products grew from 1% to 4% of Denver’s total electricity consumption between 2013 and 2018.

For complete article Insatiable Demand for Cannabis Has Created a Massive Carbon Footprint (


Colorado's legal cannabis farms emit more carbon than its coal mines.

Legal cannabis production in Colorado emits more greenhouse gases than the state’s coal mining industry, researchers analysing the sector’s energy use have found.

Hailey Summers and her colleagues at Colorado State University have quantified and analysed the greenhouse gas emissions produced by cannabis growers.

They found that emissions varied widely by state, from 2.3 to 5.2 tonnes of carbon dioxide equivalent (CO2e) per kilogram of dried flower produced.

In Colorado, the emissions add up to around 2.6 megatonnes of CO2e, which is more than that from the state’s coal mining at 1.8 megatonnes of CO2e.

“The emissions that come from growing 1 ounce, depending on where it’s grown in the US, is about the same as burning 7 to 16 gallons of gasoline,” says Summers For complete article go to New Scientist 2021


Of course, we haven’t even touched on, let alone measured, the impact of the exponentially burgeoning illegal grows, and their contribution to this environmental disaster – including depleting of natural resources at accelerated rate; diminishing water security; potential for growing threat to food security – But the following will give you a little snapshot of what that is beginning to look like…


 IndoorGrow              OutdoorGrowDump


  • To kill bugs, growers soak the plants in chemicals, pesticides, herbicides, and fertilizers. The toxic carcinogens are ingested by the consumer or run off directly into scarce water supplies.  (Robert Corey)  
  • Fertilizers with high nitrates are of particular concern as nitrate loading contributes to cyanobacteria which kill fish and animals.
  • The pesticides and poisons used to grow marijuana are leeching into the soil and in turn the watersheds that serve literally millions of people, including the central valley and San Francisco Bay Area. The State Water Resource Board has indicated they don’t test for these toxins, and don’t have adequate resources to expand their operations.
  • Marijuana plants consume 6 to 9 gallons of water per day during the 5-month growing season. There are over 50,000 outdoor cultivation sites, with growers depleting streams and water tables. The average number of plants grown at each site is not determined, but taking a range of 100 to 1,000 plants, the water consumption would range from 4.5 to 45 billion gallons a year. California is already in drought conditions while the illicit marijuana industry is sucking the state dry.


If that’s not enough, what about….


Animals and habitat:  video link  

  • Marijuana cultivation in California and other states has caused great harm to our wildlife, including endangered species such as the Spotted Owl, Pacific Fisher and Humboldt Marten and potentially irreparable damage to salmon and steelhead populations. 
  • Use of the banned pesticide Carbofuran, so toxic that 1/8th of a teaspoon can kill a 300 lb. bear, has been found at 70% of the grow sites not licensed by the state. 
  • Diversions of streams for marijuana cultivation effectively dewaters all downstream habitat displacing or killing any water dependent species downstream.


  • Insecticides, fertilizers, etc. not intended for food crops are often used during the growing process. These impurities are found and accumulated in marijuana products. Thousands (if not millions) of marijuana users are poisoning themselves unknowingly. 
  • Research from February 2017 revealed that 93% of marijuana produced in California was laden with dangerous pesticides, yet neither the state nor federal government acted to stop the distribution. This is a threat to health and safety of Americans throughout the US as, according to State and marijuana industry sources, California supplies 60 to 70% of the entire US black market.
  • Marijuana (the plant, including hemp) is a bio-accumulator.  (It was even used to attempt to clean up the Chernobyl site.) It accumulates heavy metals, poisons, and contaminates (even radioactivity) from the soil and concentrates those poisonous components and elements. 
  • Particle concentrations from dabbing and vaporizing cannabis can create levels of indoor air pollution similar to those seen in extreme air pollution events like wildfires and severe industrial pollution. Exposure at these concentrations can cause cardiovascular and respiratory disease.
  • Marijuana corporations have been caught using the notorious Eagle-20 Fungicide on their marijuana plants. Eagle-20 is designed only for outdoor ornamental plants, i.e. outside flowers that you only look at, not plants consumed by humans, and definitely not for indoor enclosed environments. Eagle-20 contains myclobutanil, a chemical which, when heated, turns into hydrogen cyanide, a lethal gas. The effects of this gas are even more pronounced when it is concentrated and stuck into artificial plastic vape pens for heating, which are easier to carry and harder to detect, thus have become the preferred method of consumption for teens, along with glass “dab rigs” that resemble crack pipes.
  • All Marijuana Users Should Be Tested for Heavy Metal Toxicity


*(source: AALM: Not Green)

Environmentalism and Drug use are not just incompatible, they are an oxymoron – Yet that is the kicker – Under the influence of psychotropic toxins, and the ‘Stoner Logic’ that ensues, one can convince oneself that ‘everything is fine, and my Weed use really isn’t hurting too much.’

Make it a Happy Earth Day 2021 and Stop the Pot!

For more go to Cultivating Disaster  and


Dalgarno Institute