From hemp-based plastics or building materials to using the plant as a source of renewable energy, there is a lot of buzz about how “cannabis can save the world.” While this statement is a bit hyperbolic, two features of the plant’s biology have been getting increased attention for their potential environmental benefits–phytoremediation and carbon capture.
What is Phytoremediation?
In environmental science, the term “bioremediation” refers to using living organisms to break down pollutants and revitalize ecosystems. More specifically, “phytoremediation” is a type of bioremediation where plants are the organism doing the decontamination, usually of soil and water. As it turns out, cannabis is a very effective phytoremediator.
In fact, the tendency for cannabis to pull contaminants from its growth media is precisely the reason testing regulations in almost every legal market require flower be tested for heavy metals prior to processing or sale. If soil, water, or nutrient mixes contain trace amounts of substances like lead, mercury, cadmium, or other toxins, then it is likely that those contaminants will accumulate in the leaves and buds of the plant.
While this is an issue that can adversely affect cannabis grown for consumption, it has the potential to be a beneficial application for industrial hemp. The crop could be planted in fields contaminated by the byproducts of industrial processes like coal mining or steel manufacturing in order to restore the land and make it safe for other uses. It was even planted near the Chernobyl nuclear plant that exploded in 1986 in order to investigate the potential for mitigating the radioactivity of the soil and groundwater. Researchers did see some evidence of reactive elements being absorbed, but not enough on its own to restore the land.
What’s more, in situations less severe than Chernobyl, the crop can likely be safely harvested and used to produce non-consumable durable goods, which are an eco-friendly alternative to plastics or other materials. In this way, land can be reclaimed while also generating revenue more sustainably, which means undoing past damage and reducing future environmental impact all at once.
Does Cannabis Capture Carbon?
Carbon capture or carbon sequestration has been identified as one of the most important actions needed to curb the effects of climate change. These terms refer to the natural process of removing carbon dioxide (CO2) from the atmosphere and trapping it in vegetation, soil, oceans, or icecaps. Because humans have accelerated the rate at which CO2 is being generated, we need to find ways to deliberately stimulate more carbon sequestration. That’s where cannabis comes in.
Cannabis, specifically industrial hemp, has been found to absorb more CO2 per hectare than any other commercial crop. This means that planting more hemp crops is an effective way to create “carbon sinks” or natural systems that absorb and store CO2. However, a critical piece is keeping that carbon trapped, which means if the hemp is harvested, it needs to be used rather than burned or allowed to simply decompose.
Luckily, we are constantly finding new ways to turn cannabis (hemp) biomass into usable goods. Lime hemp concrete (LHC), for example, has the potential to become a widely used carbon-negative building material, meaning it takes less carbon to generate than it actively keeps trapped after it’s used.
Like many other declarations about cannabis or hemp, there is still a lot of study needed to truly understand how it can best be employed to fight climate change. The encouraging potential for phytoremediation and carbon capture should, at the very least, inspire us to start putting these processes to the test. If the dire predictions from climate scientists we read in the news are any indication, we’ve got nothing to lose and no time to waste.