Environmentalists and industry experts are expressing concerns that mass cannabis production is far from green.

Werner Antweiler, for example, is an economics professor at the University of British Columbia’s Sauder School of Business who studies the environmental costs of pot production.

“Growing cannabis is very energy intensive,” he told CTV News.

To better cultivate cannabis indoors, licensed producers often use high-intensity lamps that consume a great deal of electricity. In addition to lighting, fans, air conditioners and dehumidifiers are also commonly used. Although data in Canada is limited, a 2012 U.S. study found that cannabis production was responsible for three per cent of California’s total electricity use, which is the equivalent energy consumption of about one million homes.

“For every kilogram of cannabis that’s produced, we generate about 4.6 tonnes of carbon dioxide,” Antweiler added.

Besides electricity, cannabis production also consumes a great deal of water. A single plant, experts say, can consume up to 23 litres per day.

To reduce their ecological footprint, licensed producer Alexander Close is using greenhouses and collecting rainwater at the SunLab cannabis cultivation facility in Maple Ridge, B.C.

“Every drop of water at SunLab is collected,” Close told CTV News from inside a sprawling greenhouse. “So we capture that rainwater and we use that as our irrigation.”

Growing inside a greenhouse, Close added, can reduce electricity usage by up to 90 per cent.

“What we care about is sustainability,” Close said. “And we thing that that’s very important for this whole industry.”

When it comes to incentives such as green tax credits, however, there is not a lot available for cannabis producers like Close.

Barinder Rasode is the founder of NICHE Canada, a not-for-profit dedicated to researching cannabis production and use in Canada.

“(The) government should be mindful of the environmental impacts of all of these large facilities that are going to be relying on our natural resources,” Rasode said in a recent interview.

Rasode believes that the federal government could do more to ensure that the cannabis industry is eco-friendly. Until then, like other industries, licensed pot producers still must follow established federal environmental laws.

With a report from CTV National News B.C. Bureau Chief Melanie Nagy