In brief
As the cannabis industry expands, its environmental footprint grows. Indoor cultivation consumes large amounts of energy and water, releases odorous gases, and generates waste. Federal prohibition in the United States has blocked most research on these impacts and prevented the development of mitigation strategies. State regulators and companies are beginning to fill the data gaps, but more research is needed.
Thirsty crops
Cannabis uses far less water than many other top agricultural commodities in California. According to data from New Frontier Data, water use for cannabis production is measured in billions of litres and is minimal compared with orchards, rice, vegetables, pastureland, wheat, and corn.
Despite low overall water use, the industry’s rapid growth means water demand will rise. New Frontier Data projects an 86 % increase in legal cannabis water use by 2025 relative to 2020 levels, although most of this increase will stem from the illicit market.
Zapping energy gluttony
Indoor cannabis cultivation is energy‑intensive, especially when plants are grown in retrofitted warehouses or large‑scale greenhouses. Most legal states do not impose specific energy standards on growers, though Illinois and Massachusetts do.
Switching to light‑emitting diode (LED) lighting can cut electricity use, but the transition is not always straightforward. Facilities that rely on heat from high‑pressure sodium lamps may need costly upgrades to heating and ventilation systems if they replace those lamps with LEDs. Federal prohibition also bars cannabis businesses from claiming tax credits for energy‑efficient upgrades.
The Sustainable Cannabis Coalition supported a Dartmouth College study that metered energy use at indoor facilities in Massachusetts and Maryland. Preliminary findings indicate that these sites consume two to three times the energy needed for optimal production. Researchers hope the work will inform standardised metering practices that allow meaningful comparisons across the industry.
Conserving water
Moving cultivation outdoors would lower energy use, but it is not always viable in drought‑prone western states. Outdoor cannabis production does occur primarily in the western United States, where water supplies are limited.
Many growers have abandoned reverse‑osmosis water treatment after finding that regular tap water works adequately for their crops, cutting wastewater generation. Others are adopting drip‑irrigation systems with real‑time moisture sensors and producing fertilizers in‑house to avoid the high water content of commercial products. Substrates such as coconut coir improve water retention, aeration, and drainage, further reducing irrigation needs.
Cleaning the air
Cannabis cultivation releases volatile organic compounds (VOCs), notably terpenes, which can react with nitrogen oxides to form ground‑level ozone. However, studies in Denver showed that terpene emissions from cannabis contribute at most a 0.009 % increase in the city’s ozone level—far below regulatory thresholds.
The characteristic skunky odor is not caused by terpenes but by organosulfur thiols such as 3‑methyl‑2‑butene‑1‑thiol. Odor‑mitigation technologies, including carbon scrubbers and dry vapor‑phase systems, are being deployed to capture and neutralise these compounds before they escape greenhouse vents.
Recycling waste
Both plant material and consumer packaging generate waste streams that are expanding with the market. Some states, including Colorado, have relaxed rules to allow composting of low‑THC cannabis waste (stems, root balls) without the previous 50:50 mixing requirement. Other states are considering similar changes.
Packaging waste remains a challenge. Regulations aimed at keeping cannabis away from children often require excess cardboard and plastic. Colorado now permits dispensaries to collect packaging for recycling and reuse, and some operators run loyalty‑program incentives for customers who return clean containers. Michigan and a few other states are evaluating whether to allow similar collection programs.
Vape cartridges and batteries present another recycling gap. As the vape segment grows, these items could become a significant source of waste unless collection and refurbishment systems are established.
Source: Here
