The production and use of cannabis for medical or recreational reasons is now legal in several US states, which has led to a booming industry.
Hailey Summers and her colleagues at Colorado State University have quantified and analysed the greenhouse gas emissions produced by cannabis growers.
They found that emissions varied widely by state, from 2.3 to 5.2 tonnes of carbon dioxide equivalent (CO2e) per kilogram of dried flower produced.
In Colorado, the emissions add up to around 2.6 megatonnes of CO2e, which is more than that from the state’s coal mining at 1.8 megatonnes of CO2e.
“The emissions that come from growing 1 ounce, depending on where it’s grown in the US, is about the same as burning 7 to 16 gallons of gasoline,” says Summers.
Most US cannabis is grown indoors, as some states don’t allow outdoor growing and the crops are also at risk of theft. This means that the majority of cannabis production emissions come from climate-control systems and high-powered lights that take the place of the sun.
READ MORE: https://www.newscientist.com/article/2270366-colorados-legal-cannabis-farms-emit-more-carbon-than-its-coal-mines/#ixzz6oepDryEg