Is Cannabis plant answer to fight against climate change?

In all the debates about how to stop climate change, hemp is hardly mentioned at all. Better known as cannabis, modern varieties of hemp are too weak to be used as narcotics but are extremely efficient at absorbing and sequestering carbon.

A team of scientists studying carbon storage, says that cannabis could be the missing player in the fight against climate change. How? Well, hemp absorbs carbon dioxide from the atmosphere more than twice as efficiently as trees.

Unless you're an advocate of a particular type of green, it's unlikely you've considered hemp as the answer to combating climate change.

But according to new research that suggests the fast-growing plant is twice as effective as trees at absorbing and sequestering carbon, this could be the case.

Numerous studies have found hemp to be one of the best carbon dioxide converters, even more, effective than trees, says Darshil Shah of Cambridge University's Center for Natural Materials Innovation, who led the study.

"Offering incredible scope for growing a better future, industrial hemp absorbs 8-15 tons of CO2 per hectare (3-6 tons per acre) of cultivation." Considering cotton alone, which accounts for 43% of all fibres used for clothing and textiles worldwide, hemp can bring huge benefits due to the vast difference in the water needed to grow hemp compared to cotton.

Although the United States only accounts for about five per cent of the world's population, it is responsible for 28 per cent of the world's carbon emissions. “Broadly speaking, if produced 50 million acres of hemp, we would be sequestering a couple hundred million tons of carbon per year on that acreage,” said Ben Dobson, founder and president of Hudson Carbon.

Fastest growing plant in the world

Another advantage of hemp is that it is one of the fastest-growing plants in the world, reaching four meters in height in just 100 days.

Cannabis plants not only purify the air of polluting gases but can also absorb carcinogenic heavy metals such as mercury, lead or cadmium from the soil. These elements are suitable for crops intended for food, but they are very dangerous for people who consume these plants.

In addition, it produces fewer emissions than conventional crops, more usable fibre per hectare than forestry, and, after permanently storing CO2 in its fibres, it can be used for numerous commodities, including textiles, medicines, and as insulation for buildings or concrete.

“Hemp is a fantastic crop that allows us to tackle a multitude of artificial environmental problems—air, soil, and water, for example—while productively providing us with food, medicine, and materials,” says Tommy Corbyn, co-founder of the  National Hemp Service.

'Now more than ever we need to take immediate action to address climate change, and stimulate our job market and the economy. An increase in hemp cultivation is one way that we can address all of those things at once.”

Explaining how the plant has the potential to help solve a wide variety of problems, he adds that in addition to absorbing carbon, hemp regenerates the soil in which it grows, cleansing it of heavy metals and toxins left over from other crops.

Cannabis and atmospheric CO₂

Interest has been shown in the ability of cannabis, and many other plant species, to increase their growth rate and nutrient use in CO₂-enriched environments. In a study published in 2011, atmospheric CO₂ concentrations of 700 ppm were shown to significantly increase net photosynthesis and water use efficiency in four high-yielding cannabis varieties, compared to ambient concentrations of 390 ppm. On the other hand, concentrations of 545 ppm had negligible effects.

However, atmospheric CO₂ concentrations have not yet reached the magic figure of 700 ppm, which will allow cannabis to grow more efficiently. According to estimates, this point will be reached around 2100 at the current rate of emissions. So we still have over eighty years to try other strategies that potentially keep concentrations lower.

These strategies include the replanting of a wide variety of plant species that are currently threatened or subject to fragmented habitats. If launched now, reforestation plans that include even relatively slow-growing species would still have a measurable impact 80 years from now. If successful, these strategies will disprove the need to grow cannabis in abundance as a carbon sink.

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