It's the law, mister. A long-standing form of greenwashing is to take credit for simply following mandatory environmental laws and regulations. One company opened their first ESG report by saying that they have received "zero fines or sanctions" environmental infractions (Khiron Life Sciences 2021). In a more subtle example, as some states move to effectively require LED lighting at indoor-cannabis sites, the addition of this technology will no longer be a measure over and above standard practice.

Going solar (or not)? The energy intensity of cannabis operations is so high that covering the roof in solar panels only makes a small dent in the carbon footprint.  This is not always clear from the photo-ops and suggestion that a company has "gone solar".  In some cases the reporting is honest, as in a 126,000 square foot facility in Canada, which, after completely covering its roof with solar panels, deferred 8% of its electricity needs. Even a very small grow facility (17,000 square feet) in a low-humidity ideal Southern California desert solar location claims to meet only 25-35% of its needs (Daniels 2019; Matich 2023). A larger facility would require access to proportionately more undeveloped land area to achieve this.  Oddly, the facility placed the solar panels only over parking areas, and not over its rooftop areas.

Polluting packaging. Packaging is just the tip of the iceberg, but some products asserting their greenness are nonetheless unsustainably packaged. Conversely, unsustainably produced products packaged sustainably also don't pass muster. According to one source, single-use cannabis product packaging resulted in one-billion pieces of plastic trash in 2020 (Olson 2021), bound for landfill, oceans, and roadsides.  This is over and above the substantial amount of plastic used in the cultivation process (Mills and Zeramby 2021).  As noted by MJ Brand Insights (Olson 2021), "[D]isposable vape products are roundly known as the industry’s least sustainable product. Plastic, metal and glass are fused together to develop vape cartridges and they’re impossible to recycle in the US. Americans also can’t recycle the disposable batteries manufactured in single-use cartridges."

When light is only light green. As noted by Jackson (2019) a simple example of greenwashing would occur when a grower claims to cultivate with LED lighting when it really uses such lighting only for clones or the vegetative phase—not the entire growth cycle. The flower phase is particularly energy intensive.  In another example, the statement "LEDs convert electrons to photons, using roughly 90% less energy than incandescent bulbs and about 50% less than compact fluorescent bulbs" appeared in a recent industry magazine (Robertson 2024).  While true in an abstact sense, neither incandescent lights nor CFLs are used in any meaningful way in cannabis cultivation. Indeed, incandescent lights were effectively outlawed a year before the article's publication.  While LEDs nominally draw abut 40% less power than the conventiona high-intensity discharge lighting used in cannabis grows  (e.g. 600 watts vs. 1000 watts), studies measuring the energy use per unit of THC yield (Leichliter et al 2018) show far smaller savings (6% and 22% in two trials) and an increase of 10% in a third trial.

Leaking carbon.  It is common to hear the claim that cannabis (or any plant) stores carbon and thus can be "carbon-negative" by removing carbon from the atmosphere. This claim is made in the first Sustainability Report report by a Canadian-Columbian cannabis producer (Khiron 2020). Unfortunately, while plants do absorb carbon as they grow, it is promptly re-released upon combustion.  Non-saleable crop residues also release their carbon as they decompose. In any case, the carbon embodied in the energy and other inputs (growing media, injected CO2, etc.) is far in excess of that absorbed by the plants as they grow.

Carbon, smoke, and mirrors. A high-profile 1-million-square-foot greenhouse project being completed in Canada is stated to be "net carbon neutral."  This eye-catching claim becomes mind-numbing when one reads that it has its own power plant powered by natural gas (which definitely releases CO2 -- plenty of it -- when burned).  Digging further, one learns that they're implementing a strategy that is indeed highly efficient, taking the waste heat from the power plant and using it for space- and water-conditioning, but natural gas is still burned.  This could indeed reduce greenhouse gases compared to buying power on the grid, unless the grid is run on lower carbon (nuclear or renewables) power plants.  The facility also intends to capture the CO2 from the power plant and inject it into the greenhouses to accelerate plant growth.  While this does eliminate a marginal amount of energy otherwise used to produce bottled industrial CO2 gas, all of this CO2 still ultimately ends up in the atmosphere, initially, as it leaks or is exhausted from the building, and then, ultimately when the carbon-containing cannabis is processed, burned (consumed) and the residues are destroyed or decompose.

It's all (not) in a name.  Mary Jane has pointed out other cannabis business and product names give mis-impressions about their actual green-ness.  In one example, the web page and an upbeat  news release from a cannabis producer called Solar Cannabis Co. (also known as Solar Therapeutics), suggested that the company may be meeting all of its energy needs with the sun despite being an indoor cultivator.  The company website gives this same impression, although this does not seem to be the case. Although the company has implemented many energy-efficiency strategies, the "wall-to-wall" array on the roof and adjacent ground-based array offer 0.7 megawatts of peak output,  generating  10% of the facilities energy needs. To make up the balance, the company uses an on-site, 5-megawatt "microgrid", fueled with natural gas, which they note could power about 5,000 homes.  This modest solar contribution is despite the fact that substantial energy efficiency measures with perhaps 40% savings have been implemented at the site.

Co-generation ain't No-generation. One way to get higher efficiencies with on-site gas power plants is to employ "co-generation", wherein the (significant) excess heat/steam can be used to offset conventional heat production. This is common in industry more broadly, but in cannabis there is negligible process heat need. One possibility may be the use of absorption chillers, where waste heat is used to drive air-conditioning.  Solar Cannabis Co. notes its "energy indepencence", the gas powering its cogen system certainly comes from far away via pipeline.  Also of note is that this site received a $1 million rebate from the local power provider -- National Grid -- for LED lighting (and other energy-efficiency measures), yet utilities normally do not award rebates to customers who produce their own power, as such incentives are ultimately paid by other customers through rates.

Tenuous terroir.  As is routinely noted for wine production, cannabis growers often highlight the terroir – the complete natural environment in which the product is produced, including factors such as the soil, topography, and climate – as a key factor differentiating their product. Indoor cultivation is routinely done without sunlight or soil, and thus such an argument would be spurious.

Rope or dope? Medical and recreational cannabis is often mistakenly attributed (e.g., Zaytsev 2018) to confer the benefits of industrial hemp (which provides a superior and environmentally more benign source of food, fiber, and oil than conventional  crops). However, cannabis grown for recreational or medical purposes is not used in this fashion. 

Hydro headache.  Cultivating cannabis in areas based on hydro power is often touted as an environmentally benign alternative to carbon-based power. However, attention has recently been given to the likely linkages between hydroelectric power production, reduced salmon populations, and starvation issues facing salmon-eating killer whales (orcas) in the Pacific Northwest (Mapes 2018; University of Massachusetts 2017). Hydroelectric power also results in substantially more water evaporation than other forms of electricity production.

Corporate responsibility down the drain.  In an effort to verify green claims by Colorado's largest cannabis producer (600 employees working at two large cultivation sites producing 30,000 pounds of flower annually, and 20 dispensaries), social science researchers conducted an in-depth review of their "corporate social responsibility" statements (Otanez and Vergara 2021). Sadly, they discovered that the company employees have filed dozens of workplace safety complaints and had instructed employees to dump over 100 gallons of hazardous chemical (Rinzate) down the drain so as to avoid mandatory disposal procedures. The company was also using unauthorized chemicals to control mildew. The researchers found that the company offered a reward to employees for thwarting OSHA inspections.

Weed or water? Conventional wisdom is that less direct irrigation water is needed for indoor cultivation, thanks to reduced evaporation, and irrigation efficiencies may be improving with industrialized processes. However—and of particular relevance to the many drought-stricken parts of the country—the massive amounts of water steadily evaporated from dams and power-plant cooling towers while producing the electricity destined for indoor cultivation facilities vastly exceeds the direct irrigation water needed to grow outdoors. Based on the rules-of-thumb of one gallon of water per plant per day, and the water intensity of average U.S. electricity production at the electricity intensities of Mills (2012) and seven liters of cooling water per kilowatt-hour (per Torcellini et al., 2003), indoor cultivation indirectly consumes about 18-times as much water (~1300 gallons per plant) as the amount used for direct irrigation. Amounts will vary locally depending on practices and electric generation mix in the grid. Ironically, the most water-intensive mode of electricity production is otherwise environmentally lower-impact hydroelectric power. Meanwhile, the greenhouse-gas emissions associated with the electricity used to power indoor grows are fueling future droughts. The demands on wastewater treatment plants (and their energy use) must also be considered.

Skunky air. Several studies have noted that the skunky-smelling terpenes and other volatile organic compounds (VOCs) emitted by cannabis plants can be unhealthy at high concentrations (Wartenberg et al., 2021).  This is a consideration not only for cannabis workers, but also surrounding communities which can experience VOC pollution levels at or above regulated safety standards.  This has been observed particularly in the Denver, Colorado area where the combination of hundreds of producers are concentrated in an area with high population and inversion layers that trap air over the city for prolonged periods. Jackson (2019) warns of a quite literal example of greenwashing:  odor-masking agents that emit strong-smelling VOCs (e.g., pine) to mask the smell from actual unhealthful VOCs (terpenes) produced in the grow, instead of a carbon-filtration system that actually captures VOCs.

CBD (Chemicals Barely Disclosed).  One group has discovered a large number of undisclosed chemicals on consumer CBD products.  Provenance and extraction process can be one of the sources.

Bewildered budtenders.  Even in a hip and progressive city like Portland, Oregon, poor environmental information is being dispensed along with cannabis products.  Of the budtenders interviewed at half of the city's dispensaries, only one in five gave accurate information on social and environmental issues (Bennett 2021).  Ten percent of the dispensaries claimed that all cannabis is organic, while, of course, only cannabis cultivated with organic soils or fertilizers qualifies.

Sin-vestment or green investment?  Greenwashing is not only important to tree-huggers. In recent years, the firms representing trillions of dollars of value have achieved recognition as "ESG" companies, i.e., deemed by independent raters to have top-shelf environment, social, and governance practices (Townsend 2020).  Many investors have followed suit, selecting these companies for their portfolios.  However, some observers almost reflexively give cannabis high marks on the ESG scale (Hoban 2021), even characterizing it as the “perfect social-impact investment” (Zaytsev 2018), while others are more cautious (Hale 2019). For example, Otanez (2022) and Bennett (2022) outline concerns about labor practices and workplace safety. Recommendations in the investor media seem piecemeal, e.g., one selecting a major fertilizer company because the product is used in hydroponic cultivation operations (no evidence of environmental benefits) and involvement in exoneration of cannabis prisoners, the latter of which is certainly an ESG-aligned activity but not clearly sufficient to deem a company to be solidly governed by ESG principles (Jagielski 2021). In other cases, only one or two narrow reasons are given, such as emphasis on recycled packaging, support of telework, or purchase of carbon offsets.  According to one source, the majority of institutional investors are on the fence as to whether to anoint cannabis stocks as ESG-worthy, with some seeing “red flags” (sometimes classified with “sin stocks” along with alcohol and tobacco) but also noting energy and water as considerations, and acknowledging the preferability of outdoor cultivation (Ferriera 2020).  One contrarian entity has actually launched an “Anti-ESG” fund that focuses on betting, alcohol, cannabis, and selected pharmaceuticals/biotech Kapul 2021). 

Offsets, Schmoffsets.  While not unique to the cannabis industry, reliance on "get-out-of-jail-free" carbon offsets has taken hold among growers.  Investigative reporters have generated many reports about how offsets rarely work as intended, and often have the effect of providing "perverse incentives" to polluters to maintain the status quo.  Various regulators have allowed cannabis growers to purchase such offsets instead of generating renewable power on-site.

Above the law.  Some property owners and legal cultivators claiming greenness have been cited for running roughshod over safety and air-quality laws.  In a notable example, residents and in East Oakland California were up in arms about a 400,000-square-foot pair of buildings running continuously for nearly two years on up to 11 megawatts of non-permitted diesel generators (Brekke 2022a-b). That's enough to power nearly 9,000 average all-electric California homes. The operation continued despite multiple citations and notices of ordinance violations to the owner/landlord and other interventions by local authorities and regulators.  One cultivator tenant has stated that the energy powering their part of the facility is renewable, while acknowledging in other venues that the fuel is diesel (which has more than four-times the carbon intensity -- emissions per kilowatt hour -- of the California grid). That producer also markets its products as environmentally sensitive, using proceeds to protect monarch butterflies.  Meanwhile, the property owner claimed that a renewable energy power plant using cow methane had been installed, but reporters found that only diesel generators were in operation. Further complicating the situation, the site is in a low-income part of the city with a severe preexisting overburden of environmental problems--including eroded air quality. This differentially exposes nearby residents and children while at school to pollutants from the generators, including hazardous particulate matter. Pollution in that neighborhood, known as Melrose, is designated as the worst of all 113 census tracts in the city, with a "Pollution Burden" rating of 100 on a scale of 0 to 100 (City of Oakland 2022).  In contrast, the relatively wealthy district of Maxwell Park -- only 1.4 miles away -- has a rating of 6.2.  Cannabis real estate arrangements are complex and vary widely.  As with any non-owner-occupied building, owners, management companies, and occupants share in various was in the decision-making that shapes energy use and energy-related pollution.

* Note: the linked video (produced and hosted by the grower's lighting product manufacturer) was published online approximately 3 months after the occupant began using diesel generators.  It is conceivable that the video was actually produced when the site was previously on grid power, which may indeed have been sourced as "green" through the local utility provider.  In any case, the video was not removed or revised once the generators went into use.

References

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