Is Legal Cannabis Bad For The Environment?

Glenwood Springs, Colorado, USA - January 6, 2016: A woman and her dog stroll past the tell-tale green crosses on a storefront in downtown Glenwood Springs that identifies it as a legal drug shop.

There’s a Catch-22 to legal cannabis. There are few studies on its effects on public and environmental health, but these studies do not exist because the subject has long been illegal.

It’s not easy to study what you cannot acquire. Have some states have jumped headfirst into legal cannabis without fully understanding the effects on its citizens and environment?

In the meantime, with the influx of pro-cannabis laws, researchers from the University of North Carolina at Chapel Hill and Lancaster University in the U.K. have requested finances from the U.S. federal government to fund the gathering of data from legal cultivation farms and marijuana facilities.

Studies on this data will help minimize the impact of the pot industry on the environment and overall public health, according to an article on

Researchers pointed out in their request that “cannabis is an especially needy crop requiring high temperatures (25-30 °C for indoor operations), strong light, highly fertile soil and large volumes of water – around twice that of wine grapes. In addition, the authors state that the few available studies of marijuana cultivation have uncovered potentially significant environmental impacts due to excessive water and energy demands and local contamination of water, air, and soil.

For example, a study of illegal outdoor grow operations in northern California found that rates of water extraction from streams threatened aquatic ecosystems. High levels of growth nutrients, as well as pesticides, herbicides and fungicides, also found their way back into the local environment, further damaging aquatic wildlife.

Controlling the indoor growing environment requires considerable energy with power requirements estimated to be similar to that of Google’s massive data centres. No significant data has been collected on the air pollution impacts on worker’s public health inside these growing facilities or the degradation of outdoor air quality due to emissions produced by the industrial scale production of marijuana.”

However, researchers were quick to remind federal decision-makers that much of the data gathered on the impact of marijuana has come from the long-existing black market — not from legal operations.