BERKELEY, Calif. — As marijuana laws liberalize across the country, much attention will need to be given to the impact that large-scale production could have on the environment, a pair of university scientists assert.
Existing cannabis grow sites pose a high risk of ecological consequences because they potentially use large amounts of water and are near the habitat for threatened species, researchers Van Butsic and Jacob Brenner observe.
While new laws put in place in California to regulate medicinal pot production are “a pretty good start,” enforcement “is going to be a huge issue” if voters approve an anticipated November ballot measure to legalize recreational use, said Butsic, a University of California Cooperative Extension specialist.
“Really for things to change, it’s going to take some grower buy-in where they see the advantages of operating in a way that’s environmentally sustainable,” Butsic told the Capital Press.
He and Brenner, an environmental studies and science professor at Ithaca College in New York, used fine-grained imagery from Google Earth to identify 4,428 grow sites in 60 watersheds, most of which were on steep slopes far from developed roads.
The study focused on the “emerald triangle” in Northern California’s Humboldt, Mendocino and Trinity counties, which some believe is the top cannabis-producing region in the nation, and results were published this spring in the journal Environmental Research Letters.
The scientists observed that most cannabis grow sites are very small and have gone undetected when researchers used automated remote sensing techniques, which are often used to detect larger environmental changes such as deforestation, a UC news release explained.
Many of these sites use lots of water and pose a risk to steelhead trout and Chinook salmon, both of which are listed as threatened under the federal Endangered Species Act and are vulnerable to the low water flows, soil erosion and chemical contamination that can result from nearby agriculture, the researchers observed.
“We’re still not seeing cannabis produced on prime agricultural land,” Butsic said. “It’s produced on lower-quality agricultural lands or lands that are not agricultural at all.”
New state laws require municipalities to develop land-use ordinances for cannabis production, force growers to obtain permits for water diversions and require a system to be set up to track cannabis from when it is first planted until it reaches consumers.
Gov. Jerry Brown’s budget this year included a $2 million boost for the state Department of Food and Agriculture’s medical marijuana program, under which it licenses and regulates grow sites.
But the researchers say regulation could be a constant challenge because it will rely on monitoring techniques that are just now emerging as well as voluntary registration from producers.
Liberalization of marijuana laws could eventually prompt growers to move their operations out of the woods and into areas where cannabis would be easier to produce in an environmentally sustainable way, Butsic said.
However, “there’s just a tremendous amount of uncertainty in what will happen on the production side if recreational or national liberalization happens,” he said. “I don’t think anybody really knows.”