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Cannabis legalisation could raise £1.5 billion for the UK economy, according to a recent report from the charity Transform. But aside from this plant’s economic benefits, cannabis also has many ecological advantages.
My research into the potential role of cannabis in shaping a fairer and healthier world never fails to excite me. Cannabis flowers became legally allowed as a medicine in the UK in 2018, but its origins as a medicinal herb in Britain dates back to at least Anglo-Saxon times. Its popularity is evident in the many place names scattered across the country, from Hemel Hempstead in Hertfordshire to Littlehempston in Devon.
Hemp is a colloquial term for the cannabis plant, Cannabis sativa. Hemp often refers to strains of cannabis that have had its main psychoactive chemical, tetrahydrocannabinol (THC), bred out of the female flowers.
Due to the negative associations cannabis has picked up over the past 50 years of prohibition, hemp farmers have distanced themselves from using the term cannabis. In the UK, this association has resulted in strict conditions for growing hemp creating a barrier for farmers.
In recent years, cannabidiol (CBD), the main non psychoactive chemical found in female cannabis flowers, has become popular as a wellness product. CBD is abundant in low-THC hemp flowers, so it’s easy for the lines between hemp and cannabis to become blurred.
It’s all cannabis. This plant has some incredible environmental benefits, from improving soil health to storing carbon. Here are five ways that cannabis plants can contribute to a greener planet:
1. Productive harvests
Hemp stems have a woody core, known as shivs, that can be mixed with lime to make hempcrete, a carbon-neutral alternative to concrete. Concrete production is one of the major sources of global greenhouse gas emissions. Hempcrete could be used to build eco-friendly social housing across the UK.
Hemp seeds are a nutritious food source, high in protein and omega-3. With the UK’s food system in crisis, hemp seeds and the oil they produce could be a more widespread sustainable homegrown food source if hemp could be grown on an industrial scale.
But industrial monocultures of crops are harmful to biodiversity. One alternative is agroecology – working with nature to prioritise biodiversity through small-scale farming.
Hemp is ideally suited to agroecology, but it’s not an easy crop to grow in the UK because licensing laws make it very difficult for hemp farmers to tap into a global market worth billions.
Farmers at one community farm, Hempen in Oxfordshire, sowed their first hemp crop over an area of 30 acres. In 2019, Hempen were forced to destroy their CBD harvest as their licence wasn’t renewed.
In California, THC strains are allowed. One farming community started producing its own CBD-based medicines on just one acre of land. Others use the plant in other interesting ways, from rehabilitating formally incarcerated people to off-grid market gardens.
2. Healthy soils
Soil is essential for growing 98.8% of our food. Yet, it is often contaminated with toxic chemicals from industrial processes or the legacies of war.
A process known as phytoremediation cleans the soil of these toxic contaminants. Hemp’s deep roots have a high tolerance for absorbing dangerous heavy metals. It is also a great break crop – this is a way for farmers to rotate the types of crops they grow to keep the soil healthy.
Read more: Hemp is more sustainable than timber – here’s how it could transform low-carbon construction
3. Plastic alternatives
Plastic is poisoning our bodies and our planet. Recent reports suggest that the human brain may contain enough microplastics to make a spoon.
Bioplastics made from hemp are biodegradable, composting down into organic matter leaving no microplastics. Hemp bioplastics are already being used by a number of commercial companies from building cars to packaging.
Bioplastics do not offer a complete solution, but with the right infrastructure they could help reduce the need to derive more plastics from fossil fuels.
4. Carbon storage
Trees and other plants remove carbon dioxide from the air through the process of photosynthesis. Hemp is great at this, storing twice as much carbon dioxide than trees.
Hemp is easy to grow without synthetic chemical inputs. It requires virtually no pesticides and reaches maturity much more quickly than trees. Once it absorbs the carbon, it’s easily stored in hempcrete blocks that can be used in construction.
5. Energy storage
It’s very difficult to store excess energy from renewable sources for use at a later date when the sun might not be shining or the wind isn’t blowing. Big batteries are one solution but these require mining precious metals.
Another solution are supercapacitors – mega-efficient energy storage solutions that can be as small as a coin. Graphene, a flat material stronger than steel, is an essential element in the production of supercapacitors but it’s expensive and energy-intensive to make.
The whole stem biomass (unused plant waste) from cannabis could provide a low-cost way to make graphene. Research shows that supercapacitors using hemp-based graphene perform much more efficiently than current commercial models.
Hemp has many other known uses, from textiles to paper. The UK could lead the way in hemp innovation. The previous UK government did announce some minor changes to hemp licensing. Now, further changes to legislation could help farmers to harness the potential of this wondercrop in the fight against climate change.
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Julyan Levy is affiliated with The Green Party of England and Wales.
