Over the past decade, we have witnessed a huge increase in the legalisation of both medicinal and recreational cannabis cultivation and consumption across the world. Cannabis is legal for adult use in twelve states across the US and both Uruguay and Canada have legalised weed nationwide. Medicinal cannabis is legal in thirty-six countries.
Due to decades of prohibition, there has been little investigation into the environmental impact of cannabis cultivation. With cannabis riding the wave of legalisation and climate change becoming an increasingly hot topic, researchers and experts are noting the urgent need to grasp the impact cannabis may have on our environment. In turn, this research will help shape agricultural and policy guidelines.
The growing of cannabis plants itself is not detrimental to the environment, but the use of pesticides and chemicals required for cannabinoid extraction are, and the amount of water needed to feed the plants is considerable. Growing cannabis also takes up valuable land and is an energy-intensive business: one study estimated that California’s cannabis industry accounted for 3 per cent of the state’s electricity usage! With its need for artificial lighting, water and land, cannabis growing can actually leave a pretty large environmental footprint. There are various ways to cultivate cannabis – in indoor growing facilities, outdoors and in a laboratory. These productions will impact the environment in different ways – whilst indoor and mixed-light grows will need high external inputs such as electrical energy and fertiliser, outdoor grows can disrupt the local ecosystems. Although cannabis is a natural plant, it requires a lot of power to grow on a large scale making its environmental consequences anything but green.
The billion-dollar cannabis industry is highly energy-intensive. Indoor grows often demands heating, ventilation, 24-hour lighting and air conditioning, making cannabis one of America’s most energy-intensive industries. The legal cannabis providers mainly grow indoors in order to be able to control the environment. Illegal grows tend to be indoors also – for the obvious reasons of operating without detection.
The massive electricity consumption that is essential for large productions produces tons of greenhouse gas emissions every year. Two years after Colorado legalized recreational cannabis, the grow facilities in Denver consumed more than 2% of the city’s electricity usage.
Since grows have, for decades, been done illegally, there has been a serious lack of research undertaken to build an understanding of the amount of energy use connected with indoor cannabis cultivation. With little data surrounding energy use at indoor grows, there is not a lot of management and enforcement that puts pressure on the industry to keep a check on its environmental consequences and carbon footprint.
Whilst there is very limited understanding of the overall carbon impact of the cannabis industry, new studies are being undertaken as the urgency to make the world a greener habitat increases. In March this year, researchers at Colorado State University published a detailed account of the cannabis industry’s carbon footprint, results taken from the assessment of indoor cannabis operations across the U.S. Energy consumption was analysed and used to calculate total greenhouse gas emissions, the report concluding that greenhouse gas emissions from cannabis production can, in a large part, be 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.’
Cannabis is a thirsty plant! Its need for gallons of water during the growing season has caused mounting concern over the impact of cannabis farms on water resources. As many farms are located in rural landscapes without access to municipal water supplies, cultivators have had to rely on sources such as springs and streams. Taking water directly from these sources can be hugely detrimental to wildlife.
As well as the source of water in production being problematic, the amount of water needed to grow plants is a serious issue. It’s been reported that it takes roughly 450 gallons (1,710 litres) to cultivate a single cannabis plant to harvest indoors. This number doubles for outdoor production. The large scale cultivation of illegal and legal cannabis will certainly result in water depletion. With projections that by 2035 some 40 per cent of the world population will live in areas facing water scarcity, it is absolutely necessary that the industry faces stricter regulations and look to implement sustainable water use in production. There are various ways this can be achieved – the use of recycled water and metering water delivery systems are two examples.
Pollution and wildlife
Growers in the illegal cannabis trade repeatedly choose remote, public lands as a base to run operations from. Illegal cannabis farms have been revealed and shown to break up forested areas and landscapes. Fragmenting national landscape encroaches on sensitive habitats, disrupting delicate wildlife habitats, and therefore, threatening our ecosystem.
With a lack of red tape, illegal cannabis farms have been found to introduce both banned pesticides and fertilisers into farms. Excessive use of these toxic chemicals has catastrophic consequences for local wildlife and water supplies. An example of the damage that can be caused can be seen in the case study of an illegal growing site in California’s Shasta-Trinity National Forest that was discovered in 2019. Law enforcement agents and ecologists detected evidence of deadly toxicants – Bromethalin, a rat poison, and carbofuran, an insecticide that is banned by the Environmental Protection Agency – at the site. The results of these toxicants can move through the food chain and damage multiple species.
The loss of landrace strains and traditional production methods
Cannabis is a big business – the growing legal market alone is expected to reach $84 billion by 2028. With value comes competition! Nowadays, growers want to get the highest possible yield and a plant with strong potency. This has led to a rise in hybrid strains, created by major producers, who have pushed out traditional varieties in countries such as Morocco. Imported hybrids can make growers more profit but this comes at the cost of the environment. In Morocco’s Rif Mountains, hashish has been grown by locals for generations but they have witnessed an influx of hybrids being planted, sometimes and the enforcement of big cannabis producers. Whilst hybrids are designed to produce high yields, the strains call for substantial fertilisation, damaging to the soil and wildlife, and uses much more water than is typically used in the cultivation of hashish in the area.
Although cannabis can be credited with having various properties and uses that can have positive environmental impacts – hemp can be used as an alternative to various environmentally destructive substances – the now-massive industrial cannabis market with its commercial-scale cultivation is having a negative impact on the environment. With the industry ever-growing and legalisation sweeping across the world, the environmental implications of growing cannabis will need to be addressed.
Much of the conversation surrounding cannabis is focused on criminalization and public health. It is vital that the carbon footprint associated with producing cannabis also makes its way into political discussions and eventually policies.