Replacing Cotton with Industrial Hemp Could Reduce Demand for World’s ‘Dirtiest Crop’

Substantially replacing cotton with industrial hemp is one of the 20 carbon reduction options that Drawdown lists as Coming Attractions—strategies that weren’t ready for prime time when the book was published, but looked like promising approaches through mid-century.

“The dirtiest crop in the world with respect to chemical inputs,” cotton production is also a climate-wrecker, Drawdown writes, accounting for nearly 1% of global greenhouse gas emissions. A typical white cotton shirt producing 80 pounds (36.4 kilograms) of CO2 “from field to customer”.

Enter hemp, a crop with minimal need for fossil fuel inputs, due to natural pest resistance combined with a growth rate so rapid that it acts as its own herbicide, crowding out the weeds. Hemp also offers a higher yield than cotton, producing “between 800 and 2,400 pounds per acre” of its valuable inner stalks, called “bast”. Those fibres can be woven into paper and textiles of all kinds, from garments and rope to canvas and carpets.

Much of the rest of the plant, called “hurd”, can be used for building materials like insulation and fibreboard, and in stucco.

Drawdown cautions that hemp is not without its problems, needing “quite a bit of water” and deep, rich soils. It is also a bit delicate, which means that “if you harvest hemp with a combine for efficiency, you will damage the bast fibres.” It’s also still illegal to harvest industrial hemp in a number of American states, thanks to the U.S. Drug Enforcement Agency’s determination to uphold a 1938 prohibition against cultivation.

The other drawback is the cost of the product. “As useful as the bast may be,” writes Drawdown, “the cost of hemp fibre is close to six times that of wood pulp.”

But with China urging its own farmers to make the switch from cotton to hemp, the price may drop, which would be a very good thing. If hemp became cost-competitive, “it could certain replace half of the cotton in the world for everyday garments such as jeans, jackets, canvas shoes, [and] caps, and that would have a significant impact on carbon emissions,” Drawdown notes.