What is the Environmental Impact of Commercial Cannabis?

11th February 2020

Humans have been cultivating the numerous varieties of Cannabis plant for thousands of years – and the plant is thought to have grown naturally in the wild for much longer before that. From sativa to indica, the plant has been used for everything from paper and clothing to nutrition and medicine, and everything in between. Cannabis has also been credited with having various properties and uses that can have positive environmental impacts.

But as the plant was driven underground and growers turned to secretive and clandestine methods of production, the ways in which this plant was grown became increasingly questionable. Now that jurisdictions are once again opening the door to legal cultivation of Cannabis (including industrial hemp), what is the environmental impact of the new industry?

The Environmental Benefits of Cannabis

Hemp Clothing

The Cannabis plant is thought to have been cultivated by humans for around 10,000 years. One of the earliest uses of the plant was the utilisation of its fibres for clothing. In China, where the plant likely originated, hemp fabric is still widely used for the production of army uniforms. Hemp fibres can be used as a more environmentally-friendly alternative to cotton, which requires much larger amounts of water and pesticides throughout the growing process.

Hemp Paper

The use of hemp for the development of paper dates back to around 200 B.C. (when the earliest discovered example the material dates from). It is believed that over a 20-year cycle, an acre of hemp plants could produce the equivalent amount of paper as 4-10 acres of trees. The plants also grow much faster and require less processing (meaning fewer chemicals are used). In addition, paper made from hemp can be recycled more times than wood paper.

Ecological Benefits

Cannabis plants have also been found to have the ability to improve soil health. Roots from the plants can effectively reduce concentrations of toxic chemicals and metals in the soil. Hemp was even planted to aid with the clean up of the nuclear spillage at Chernobyl.

They also have deep-rooted systems which maximise the area of soil that can effectively be treated by the crop. These roots can also add stability to the land, preventing soil erosion caused by rainfall, land movement, and excessive farming.

The Environmental Benefits of Hemp: Hemp Fuel
A drill extracting oil

The Downsides

Although Cannabis crops can offer a huge array of environmental benefits when cultivated in a responsible and sensitive way, practises often adopted in the illicit industry usually do more harm than good. The prohibition of (high-THC) Cannabis pushed growers underground. This has meant that crops are usually hidden – often indoors.

Energy Usage

When a crop is cultivated indoors, it requires a much higher energy input. Plants need high-intensity lighting, as they are not exposed to sunlight. In addition, ventilation systems, dehumidifiers, and heaters are also used.

These operations are powered by electricity. which remains largely sourced from fossil fuels. In 2018, around 50% of the UK’s electricity, and 64% of electricity in the USA, was sourced from fossil fuels. Illicit operations may even use petrol or diesel generators in an attempt to remain undetected.

cannabis plant under high-intensity lights
Cannabis plant under high-intensity lighting

Water Usage

Although Cannabis crops can be relatively water-efficient – particularly when compared to the likes of cotton and almonds – an outdoor commercial operation can use a massive amount of water. One plant can use up to 6 gallons of water per day. According to grist.org, that’s up to a billion litres of water per square mile of crop, over a growing season.

When compared with almonds – it reportedly takes 3.2 gallons of water to produce a single almond – this might not seem too bad. However, with Cannabis farms popping up at the current pace, it is sure to have an impact, particularly in US states like California which experience regular draughts.

Other Implications

As stated previously, Cannabis crops have some natural defenses which can sometimes minimise the need for pesticides and fertilisers. However, when the scale of production is maximised, cultivators will implement these measures in order to safeguard their crops. The increased use of pesticides and fertilisers can contribute to the destabilisation of surrounding ecosystems.

Moving Forwards

Despite being easy for agricultural operations of any scale to impact the environment, there are options that can begin to minimise this impact.

Indoor operations can take steps to minimise waste through the collection and reuse of water, soil, and other natural ingredients. Outdoor operations remain the most energy-efficient and environmentally-friendly (depending on pesticides and fertilisers used).

However, many Cannabis farmers in many jurisdictions may face significant barriers when attempting to start an outdoor growing operation. Thanks to many years of Cannabis prohibition, most governments (particularly in the UK, and the USA) require that Cannabis (including industrial hemp) is grown out of sight of the public. Unfortunately, this often means indoors.

Perhaps in the future, when legal Cannabis becomes truly mainstream, farmers and producers will have more options when attempting to create a more sustainable industry.


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