Growing cannabis plants can have a significant impact on climate change. Specifically, growing cannabis indoors. As more and more states legalize cannabis, the demand for the beloved green is increasing. The demand is being satisfied via indoor growing operations. This goes for both medical and recreational marijuana. A new study done by the University of Colorado suggests that certain parts of the country are responsible for more emissions than others. It presents the issue of the environmental consequences of growing cannabis and climate change. 

It’s been nearly a decade since Colorado legalized marijuana. It’s still primarily grown indoors. Growing pot indoors requires a lot of energy. Several factors, like temperature and light control, contribute to this. Specific to Colorado, early regulations could be partly to blame for indoor production. Early regulations required cannabis production to be out of view from the public. This slanted the table to indoor growing. 

This also goes for other states that may not experience the desired weather for cultivating marijuana. A specific study illustrated how impactful growing cannabis indoors can be on climate change. 

Colorado University Study on Cannabis and Climate Change 

Ph.D student Hailey M. Summers led a study into the effects of cannabis cultivation indoors on climate change. In the study, they analyzed the energy and materials required to grow cannabis indoors. They also analyzed and quantified the corresponding greenhouse gas emissions. The study was performed across the United States. Additionally, they took into consideration the geographic variations in meteorological and electrical grid emissions data. In other words, they looked at the necessary energy usage based on each state.  

This study took absolutely everything into consideration. For example, if fertilizer is needed and used in the cultivation of marijuana, that would also be analyzed. Including the greenhouse gas emissions, it took to make the fertilizer. What they found was astonishing and surprising. 

The environmental impact of indoor cannabis production depends on the location of the facility. In Colorado, the greenhouse gas emissions released in indoor cannabis production surpassed those in other sectors. For example, it releases more emissions compared to coal mining. This was a huge surprise seeing as the coal sector releases a steady amount. 

Again, there are several factors that contribute to this high result. 


Facilities need a lot of energy in order to maintain a comfortable environment for the plants. They need appropriate light in order to have the plant grow. These lights may be running for hours non-stop. When you have large facilities blasting bright lights, it may get hot there. Also, you need air conditioners or heaters, again depending on the location, to maintain proper temperatures. 

Carbon Dioxide 

A large contributor to facilities’ greenhouse gas emissions is the usage of carbon dioxide. Producers pump carbon dioxide inside in order to increase plant growth. Adding carbon dioxide increases the rate of photosynthesis. This is to get the plants to grow faster and bigger. This also means it produces flower a lot faster too. Producers will release bottled carbon dioxide. Or, they’ll burn natural gas on-site to basically get carbon dioxide in the room. Other indoor cropping systems do this too, but not most. It’s because it’s a commodity that just isn’t as valuable economically. 

Just the carbon dioxide accounts for between 11 and 25 percent of the total emissions. This goes for all the locations across the U.S. in the study. It can be up to a quarter of total emissions in any one location. It’s also important to keep in mind that this is a conservative estimate. The study accounted for the emissions associated with the bottled CO2. As well as the transport and usage of that CO2 in the building. It didn’t account for the possible CO2 escaping through ventilation systems. Possibly because it wasn’t absorbed by the plants. 

Federal Legalization 

Due to the lack of federal legalization, each state must produce its own marijuana. You can’t grow in one state and cross state lines and sell in another. This forces certain states with unfavorable weather to cultivate indoors in a controlled setting. 

For example, California has lots of solar power. Therefore, our grid is pretty clean in comparison to states like Texas or Colorado. Those states depend on a lot of coal and natural gas. 

Federal legalization could allow for central locations for marijuana production. It would most likely be U.S. states with clean grids or weather that don’t need to be modified. Then, it would just be transported across the U.S. This is similar to the system of edible crops.