LET’S GROW CANNABIS!

Climate change is probably not your first though when cannabis is mentioned. Better known as hemp by naturalists and farmers, this plant – Cannabis sativa – despite its drug-related reputation has another side in its use agriculturally, for fibre and oilseed. But even that is not what I want to write about here. 

Cannabis sativa is termed an archaeophyte by botanists, defined as “a plant which is mainly associated with human activity, for example as a weed of cultivated ground, but which has existed in Britain since before 1500 at least and may even be native”. Growing it for fibre has recently been revived and commercial varieties for such purpose do not have the narcotic content for drug use, although the species is still classified as a controlled drub. It is found growing wild in much of the British Isles, often on tips and in urban areas as an escape from bird seed.

Recently, though, hemp has entered the carbon capture domain as a potential weapon in the increasingly desperate battle against global warming It grows very quickly to a large size (c. 2.5m tall but more for commercial varieties which are reported to be able to reach 4m in 100 days.) and able to capture 8–22t ha^-1 (up to 22 tonnes per hectare) of CO₂ per year. This is more than woodland and the bonus is that the fibres of the hemp plant can lock up the carbon permanently because they can be used for purposes such as insulation, textiles and as a replacement for plastics[1] [2].

So why are we not seeing huge plantations of hemp rather than the paltry 800ha currently grown? The answer is partly because the Home Office, not known for its ability to keep up to date, still has to issue a licence for growing it because of the cannabis drug connection, even though that does not apply in these circumstances. One can only hope, I fear forlornly but you never know, that unlike COP27, they wake up to the unprecedented urgency of halting and reversing climate change and promote the planting of the 80,000ha of hemp recommended by the University of York. This is not to say we should not also be planting woodland which has added ecological benefits. We need both and, as stock farming for meat reduces, as it must, and our food supply begins to lean more towards micro-organism farming which uses far less land[3], there will be plenty of land for both trees and Cannabis sativa

Except for a few dangerously potty climate change deniers, a faction sadly but not uncommonly found amongst far right political groups, Brexiters and their ilk, most people know global warming is dangerously real and see its effects only too clearly. There is no time to lose.

Betts Ecology do not manage farmland and we don’t have land where we can grow hemp, but we do strongly support initiatives to reverse climate change and we establish richly biodiverse habitats and plant many trees which help to soak up carbon.

 © Betts Ecology

[1] Plester, J. in The Guardian, 24 November 2022.

[2] Pervaiz, M. and Mohini, M.S. (2003). Carbon storage potential in natural fiber composites. Resources, Conservation and Recycling, 39 (4), 325–340. https://doi.org/10.1016/S0921-3449(02)00173-8.

[3] Campaigners at COP27 said that enough protein to feed the whole world could be produced on an area of land smaller than London.