Hemp: The Environmental Benefits

The Environmental Benefits of Hemp

Industrial hemp, (low-THC hemp) has numerous properties which make it environmentally beneficial and sustainable. Hemp products can be recycled, reused and are 100% biodegradable. Hemp crops contribute to minimizing the effects of global warming via greenhouse gases through the removal of significant amounts of carbon dioxide from the atmosphere. This is especially true if the end products are locked up in permanent applications like building materials as opposed to recycling the carbon by applications such as compost. The utilisation of hemp in bio-fibre processing has significant environmental benefits, bio-products made of hemp can produce environmentally friendly products that are easily recycled in compost or in landfills. Most hemp-derived products are non-toxic, biodegradable, and renewable. Hemp, in its various forms, is being used more and more to replace traditional products in the manufacturing world.

Carbon Sequestration

Carbon Sequestration is the long-term removal and storage of various forms of carbon from the atmosphere. This includes the greenhouse gas, carbon dioxide (CO2). Carbon sequestration mitigates and/or defers the effects greenhouse gas emissions have in accelerating global warming and dangerous climate change. High biomass crops such as hemp are associated with the ability to sequester high amounts of carbon through photosynthesis, storing it in the body and roots of a plant and transferring some into the soil.

Hemp biomass is approximately 40% carbon, so carbon sequestered in the fibre during the growth of the plant is captured during processing and the sequestered carbon tied-up in manufactured bio-fibre products. Carbon sequestering also occurs in the roots; root biomass is equivalent to approximately 20% of the above ground biomass and a growing plant with high levels of carbon sequestration will have significantly increased root biomass compared to its lesser sequestering crop counterparts.

Carbon uptake by hemp can be measured by examining the carbon content of the molecules that make up the fibres of the plants stem. The carbon locking organic compounds that hemp primarily consists of are:

Cellulose: 70% of stem dry weight and 45% carbon content
Hemicellulose: 22% of stem dry weight and 48% carbon content
Lingin: 6% stem dry weight and 40% carbon content

It follows that every tonne of hemp stems cultivated contains 0.445 tonnes of carbon that was removed from the atmosphere.

Hemp vs Other crops

Hemp can be compared to a commercial crop such as wheat, which on average will produce 300kg of straw per hectare per year and 60kg of residue in the roots. A hemp crop producing 1.2 tonnes of fibre per hectare would produce 240kg of roots per hectare. In summary converting from crop farming wheat to crop farming hemp yields a net benefit of 180kg more carbon removed from the atmosphere per hectare grown. The environmental impact of even a single hectare converted to hemp is significant.

Hemp has a short growing season, 4-5 months on average, so it is also possible to grow the crop twice per year. A dual-season crop such as hemp therefore has double the opportunity to carbon sequester per annum than a single-season crop such as wheat.

A Carbon Farming study by James Vosper goes further and concludes that scientific investigation indicates hemp definitively sequesters more CO2 per hectare than any other forest or commercial crop, this makes it the ideal carbon sink. To consider hemp in a carbon cycle- we can imagine that CO2 emissions associated with hemp manufacturing and cropping processes can be permanently bonded within a fibre that can be used for textiles, building materials and numerous other applications.

Soil Enrichment

Hemp is a robust, competitive plant that will out compete weeds. The plant’s rapid canopy growth enables it to act as a natural weed suppressant by blocking out light and preventing weed growth underneath. In most cases this makes hemp farming possible without the use of herbicides. Hemp is also naturally insect resistant, there are few known hemp pests and thus crops can be grown successfully in the absence of pesticides (organic, inorganic, or otherwise). This is a clean air benefit that reduces pesticide load on the environment and will also factor in reducing overall CO2 emissions. The minimal to non-existent use of pesticides and herbicides renders hemp a long-term proponent of the health and vitality of agricultural lands.

Hemp has a large tap root that is capable of penetrating deep into the soil profile to pick up required water and nutrients for plant development. Hemp is therefore able to recover nutrients that might otherwise be leached below the root zone and enter the groundwater. In addition, the deep roots open the soil structure and enhance the tilth of the soil for future crops. Hemp has also been determined to be a suitable plant for “bioremediation” or “phytoremediation”; a process used to treat contaminated media, including water, soil and subsurface material, by altering environmental conditions to stimulate growth of microorganisms and degrade the target pollutants. Hemp was used in bioremediation at Chernobyl in an effort to remove radioactive pollutants deposited from the 1986 nuclear disaster. Rolling Stone's 2018 article is an informative read on Colorado State University graduate student, Gavin Stonehouse and his experiments with hemp and bioremediation.

Water

There is anecdotal evidence that hemp production offers less impact to the water reserves compared to alternative crops. J.Avernik’s 2015 study shows that the water footprint in cotton textile manufacturing is three times more impactful than the water footprint of hemp textile manufacturing. Further to this the production areas of cotton are often in scarce water regions in the world. Hemp is a well-known drought resistant crop and is mainly grown in parts of the world where there is little water or a regularity of water-scarce events, and production is less impactful on valuable water reserves.

Summary

The industrial, medicinal, and commercial properties of hemp have been known to mankind for a very long time, but its benefits to the environment are only just starting to be realized in recent years. With the timetable for better environmental practice and increased sustainability efforts accelerating, more industries are looking for quick sustainable solutions and many are turning to hemp for the answer.