Carbon sequestration 

Organic carbon sequestration is the transfer of CO₂ from the atmosphere through plants or plant residues into the organic matter of the soil (humus). Hemp plants operate as carbon sequesters by absorbing carbon dioxide from the atmosphere during photosynthesis, thereby reducing climate change by storing that carbon in plant biomass or in the soil (Ahmed et al., 2022). The rapid growth and high yields of hemp make it a good candidate for carbon sequestration.

Mechanisms of Carbon Sequestration in Hemp

The carbon fixed by hemp plants during growth can be sequestered in the ground, primarily through the plant parts that lie beneath the ground or by mechanically plowing residues of the plant into the soil. Additionally, producing Biochar from hemp waste material offers another method of carbon sequestration. Biochar is produced by heating plant material in an oxygen-deficient atmosphere and can be incorporated into the soil, which sequesters carbon and improves soil health (Malabadi et al., 2023).

Hemp-Derived Products and Carbon Storage

The storage of carbon in the form of biomass primarily works through hemp-derived products. For example, hempcrete—a sustainable building material composed of hemp fibres and lime—can retain carbon in buildings throughout their lifespan, supporting carbon sequestration initiatives (Jami et al., 2019; Yadav & Saini, 2022). Other examples include hemp wool, hemp fibre insulation panels, and plastic composites.

End-of-Life Considerations and Circular Economy

After their use phase, hemp products must be disposed of. Due to their biogenic nature, some of these products are naturally and fully biodegradable. Others, especially composites mixed with petrochemicals, are more difficult to dispose of or recycle. In such cases, energetic use through incineration may be the most suitable option. Although some of the sequestered carbon will eventually be reemitted into the atmosphere through incineration or composting, this carbon should not be equated to CO₂ emissions from petrol-based products. The emissions from biobased products were originally fixed from the atmosphere during photosynthesis and do not originate from fossil sources. Additionally, the emitted carbon can again be sequestered from the atmosphere by cultivating new hemp or other crops, resulting in a net-zero carbon pollution and a complete carbon cycle. The diverse product range and the quick growth of hemp make it an optimal candidate for a circular economy. By incorporating hemp into various products and practices, we can enhance carbon sequestration efforts and contribute to sustainable development.