carbon footprint

The Gargantuan Carbon Footprint of Corporate Cannabis

The huge carbon output of modern cannabis production is no secret. According to Colorado’s Department of Public Health and Environment, 1.3 percent of the state’s total annual carbon emissions stem solely from cannabis. A rigorously researched and widely publicized 2021 article in Nature Sustainability found that indoor production, the dominant form in many areas, generates “2,283 to 5,184 kg CO2-equivalent per kg of dried flower.” This staggering carbon output comes mostly from the voracious energy demands of indoor cultivation. Rather than relying on the sun for photosynthesis, artificial illumination is necessary; rather than relying on the wind for ventilation, industrial-scale fans must be used. Dehumidification is also needed, as is cooling during warm periods. In Southern California’s scorching Coachella Valley, the state’s emerging center of corporate cultivation, air-conditioning expenditures can be astronomical. Here even the local water supply requires energy-intensive purification. And, as if to add insult to injury, carbon dioxide is intentionally released into growing facilities to enhance production, some of which inevitably escapes into the atmosphere.

Bizarrely, large cannabis corporations and their cheerleaders sometimes brag about their energy use. Consider, for example, this 2016 article from the Coachella Valley Weekly entitled, “Canndescent: Setting the Bar for Cannabis Cultivation in Desert Hot Springs”:

Impressive at every turn, Sedlin gave a tour describing how the Canndescent facility intends to grow, clone and package premium weed.

He proudly, and probably with more detailed information than necessary, showed how the plants require the perfect temperature, water and light for maximum growth.

The facility is equipped with a 160-ton air conditioner. DHS [Desert Hot Springs] water, known for its award-winning minerals and taste, is not however good for cannabis, so Canndesecent has to use a reverse osmosis system with a 5,000 gallon water backup supply. Plant fertilization is electronically distributed. A shiny outdoor tank containing 1,000 gallons of liquid CO2 pumps the right mixture into sealed rooms producing the ideal growing environment. …

Canndescents’ grow rooms look like something on a Mars’ space station. Everything appears sterile, bright, well-organized and utilizes every inch of space with custom, stainless steel, movable grow beds. Hi-tech monitors are taking constant readings of the air quality. Fans insure the air is moving evenly.

When confronted with this outsized carbon footprint, indoor cannabis apologists typically point to their solar cells, arguing that they are doing their part to reduce their impact. This is simple greenwashing. Solar cells provide “clean” energy only in a relative sense, insofar as they substitute for fossil fuels. If they are used instead to replace sunlight, they are anything but green. Few indoor facilities, moreover, have enough solar cells and battery banks to provide all their energy needs.

In California, indoor cultivation accounts for only around thirty percent of cannabis production, less than in most states with a legal market. But outdoor growing, known in the business as “full sun,” accounts for an even lower share (see the graph posted below). Most California cannabis is grown in greenhouses under “mixed light” conditions. Here most of the energy needed for photosynthesis does come from the sun, but supplementary artificial lighting is used as well. Power-hungry ventilation is also necessary, as are other energy expenditures unknown in outdoor growing. In the final tally, mixed light is far less carbon intensive than indoor cultivation – but far more carbon intensive than outdoor growing.

There are several reasons why indoor and greenhouse production predominate. Outside of California and a few neighboring areas that have a Mediterranean climate, high-quality cannabis cannot be easily grown in the open air. Low humidity is necessary during the crucial late summer and early fall flowering period; otherwise, the flowers will be attacked by mold. Dry weather through September and October, however, is uncommon over most of the country. As federal anti-cannabis laws prevent interstate commerce, each state must produce its own crop, requiring in most cases enclosed growing environments and extensive dehumidification. Under a rational, environmentally sound cannabis regime, most production would take place in California and neighboring states; a state like New York would no more use massive, artificially illuminated buildings for cannabis production than it would for lemons or artichokes.

The triumph of high-carbon cannabis in California stems from both market pressure and government policies. When large-scale corporate cannabis began to flood the market a few years ago, artisanal cultivators came under increasing stress. To remain competitive, many took up mixed-light production themselves, as it allows multiple harvests per year and thus helped maintain profits as the wholesale price started to drop. More insidious are the pressures imposed by consumers in the retail marketplace. Most self-styled connoisseurs prefer indoor flowers, as they tend to be more uniform, visually appealing, and potent than those grown in the sun. As a result, indoor growers enjoy a pronounced price advantage, easily making up for their additional energy costs. The root problem here is the adolescent nature of the core cannabis market, where raw potency reigns supreme, while social, environmental, and cultural considerations, as well as flavor, are usually ignored. If alcohol operated under the same market constraints, fine wine and artisanal beer would be marginalized long ago by 190-proof Everclear.

But the more fundamental reason for the collapse of low-carbon cannabis in California is government policies that discourage and sometimes even prevent full-sun cultivation, while favoring indoor and mixed-light production. Many of these policies are covert, as they are ostensibly aimed at other issues. Some, however, are straightforward. As a recent MJBizDaily article notes:

Onerous regulations or outright bans on outdoor cultivation sites by many California counties also have made it harder for outdoor grow operations to expand their footprints.

Of the 26 counties in the state that have issued cultivation licenses to date, 14 haven’t awarded any to outdoor growers.

To say that California’s  cannabis policies are hypocritical is an understatement of the first order, as will be explored in the final post in this series. But first we need to consider one more issue: the carbon footprint of full-sun cultivation. Although very low by comparative measures, it is not negligible. Some growers, however, do everything they can to minimize their emissions, and a few might even achieve carbon neutrality and perhaps even negativity. Yet for all their efforts, they receive little if any credit, whether in the market, from regulators, or from environmental organizations.

Unnecessary Environmental Destruction from Marijuana Cultivation in the United States

cannabis legal status mapOver the past several years, the campaign for marijuana legalization has surged ahead in the United States. Colorado and Washington have voted for full legalization, and a number of other states now allow the consumption of medical cannabis. Yet the U.S. federal government still regards the substance as a “Schedule 1” drug, more dangerous and less useful than cocaine or methamphetamine. The position of cannabis in American society is a deeply charged issue undergoing a sea change in the court of public opinion.

drug harm graphMarijuana legalization advocates make strong claims. By most objective measurements, cannabis is less harmful than alcohol from both a social and a medical perspective. But those who favor legalization would be advised not to overstate their case. As is true in regard to any substance, marijuana generates problems. Perhaps its most severe drawback is environmental damage, an inconvenient truth that is usually overlooked by legalization supporters. Consider, for example, the graph on the left, recently posted by the renowned blogger Andrew Sullivan. Sullivan is a proponent not only of marijuana legalization but also of its judicious use, as reflected in his book, The Cannabis Closet. Although I am persuaded by most of Sullivan’s arguments, I think that he erred in posting this graph, which purports to show the extent of damages imparted by various drugs. Are we really expected to believe that alcohol is more harmful that heroin, cocaine, or methamphetamine? It would seem that the purpose is to shock rather than inform.

Although I am tempted to break down the graph and criticize its various components, I will confine my attention to one feature: the environmental damage of cannabis production. According to the figure, such costs are almost negligible, as can be seen in the inset illustration (which I have modified to highlight cannabis). In reality, the environmental damage imposed by marijuana growing is massive.

The most extreme form of environmental degradation associated with the cannabis industry stems from indoor cultivation. Growing indoors requires not merely intensely bright lights, but also extensive ventilation and dehumidification systems. The result is a gargantuan carbon footprint. According to a well-researched 2012 report:

The analysis performed in this study finds that indoor Cannabis production results in energy expenditures of $6 billion each year–6-times that of the entire U.S. pharmaceutical industry–with electricity use equivalent to that of 2 million average U.S. homes. This corresponds to 1% of national electricity consumption or 2% of that in households. The yearly greenhouse-gas pollution (carbon dioxide, CO2 ) from the electricity plus associated transportation fuels equals that of 3 million cars. Energy costs constitute a quarter of wholesale value.

Colossal energy use is not the only environmental drawback of indoor marijuana cultivation. Plants in such artificial environments are susceptible to a variety of pests and pathogens, often requiring heavy doses of biocides. Spider mites are a particular problem for cannabis producers. In order to prevent mold infestations, growers maintain low humidity levels, favoring mite proliferation. And as noted by the Wikipedia, “[their] accelerated reproductive rate allows spider mite populations to adapt quickly to resist pesticides, so chemical control methods can become somewhat ineffectual when the same pesticide is used over a prolonged period.”

Growing sun-loving plants in buildings under artificial suns is the height of environmental and economic lunacy. Outdoors, the major inputs—light and air—are free. Why then do people pay vast amounts of money to grow cannabis indoors, regardless of the huge environmental toll and the major financial costs? The reasons are varied. Outdoor cultivation is climatically impossible or unfeasible over much of the country. Everywhere, the risk of detection is much reduced for indoor operations. Indoor crops can also be gathered year-round, whereas outdoor harvests are an annual event. But the bigger spur for artificially grown cannabis appears to be consumer demand. As noted in a Huffington Post article “indoor growers … produce the best-looking buds, which command the highest prices and win the top prizes in competitions.” In California’s legal (or quasi-legal) medical marijuana dispensaries, artificially grown cannabis enjoys a major price advantage, due largely to the more uniformly high quality of the product.

Journalists have been noting the environmental harm of indoor marijuana cultivation for some time. Unfortunately, few people seem to care. In 2011, the San Francisco Bay Guardian reported that environmental concerns were leading some consumers to favor outdoor marijuana, but any such changes have not yet been reflected in market prices. In the cannabis industry, as in the oil industry, ecological damage does not seem to be much of an issue.

dead fisher marijuanaBut even if indoor cultivation were to come to an end, the environmental harm of cannabis cultivation would not thereby disappear. Outdoor growing usually relies on heavy applications of chemical fertilizers, which can easily pollute waterways if not done correctly. Total water use is pronounced as well, which is an issue in the dry-summer cultivation areas of California. The most serious eco-threat, however, is posed by the rodenticides used to combat wood rats. These poisons endanger not merely rodents, but also the carnivores that prey upon them. In far northwestern California, the fisher (Martes pennanti)—rare to begin with—has been put in serious jeopardy by backwoods cultivators.

Cannabis can be raised in an environmentally responsible manner, as it often is by individual growers. Healthy outdoor plants suffer little damage from insects and other invertebrates. Mammals seldom eat the leaves, and wood-rat gnawing causes only minor damage in most areas. The highest yields, moreover, are obtained by those who avoid chemicals in favor of compost, manure, and biochar (buried charcoal). The liberal use of biochar, moreover, can actually generate a negative carbon footprint, as it involves sequestering carbon in the soil. Biochar is also one of the best long-term agricultural investments imaginable; the tierra preta soils of the Amazon, made by indigenous peoples before 1500, have maintained their fertility for centuries in an environment otherwise characterized by impoverished soils that cannot retain nutrients.

Cannabis production by stateGiven these advantages, why is organic cannabis cultivation in general, and the use of biochar more specifically, not more widespread? One crucial issue, which holds for organic farming the world over, is the amount of labor required, which is considerable. But equally important is the lack of consumer demand. In the cannabis market, relatively few buyers consider environmental costs, focusing instead on quality and appearance. And even those who do care about ecological consequences are thwarted by the impossibility of certifying sustainable production. Perhaps carbon-negative biochar-produced cannabis could command a price premium in some markets, but consumers have no way to know if such methods were actually used.

California top cash cropsThis situation is more than a little hypocritical. Both legalization advocates and the environmental community simply give a pass to some of the most environmentally destructive agricultural practices found on Earth. Pot consumers themselves tacitly support hyper-destructive “farming” by their eagerness to pay a premium for indoor product. Yet these same groups tend toward green politics, and many of their members are unforgiving when it comes to “non-sustainable” practices used by other farmers. Self-interest usually generates some level of moral blindness, but here it seems to be particularly pronounced.

California Precipitation Emerald Triangle MapIf cannabis cultivation in the United States were to move in an environmentally benign direction, California’s leading position would be greatly enhanced. California is unquestionably the top marijuana producer in the U.S., and the crop is without doubt the state’s most valuable. In his masterful 2010 Field Guide to California Agriculture, geographer Paul F. Starrs estimated the value of the California cannabis harvest at between $19 and $40 billion: if the former figure is correct, the crop is worth roughly half the value of all other agricultural products in the state; if the latter figure is accurate, then its value exceeds that of everything else combined. Due to climate, top-quality outdoor cannabis is difficult or impossible to produce in other states. Low humidity is required during the long maturation period in September and October; otherwise, mold infestations can rage out of control. Owing to its Mediterranean climate, California has favorable conditions, although in the prime growing counties of the Emerald Triangle, located in the wettest part of the state, mold is still the growers’ bane. As a result, cultivators welcome the Diablo Winds, warm dry easterlies that periodically blow in the autumn months. As is always the case, geography matters.

(Note: much of the information in this post was derived from interviews with cannabis growers, persons who understandably prefer to remain anonymous.)