It’s Time To Make Marijuana Green Again

Legalization must reduce the carbon footprint of cannabis.

A dangerous disconnect between drug policy and environmental policy has reared its head amid America’s marijuana legalization process.  Legislators and energy agencies have largely turned a blind eye to the carbon footprint of indoor cultivation, which already belches out greenhouse-gas emissions equal to that from 3 million cars in America.  The problem has been well documented in the academic literature since 2012.

In the latest chapter of this saga, nine legalization initiatives will be on ballots across the country this November.  These and earlier policy efforts are failing to address the energy-intensive practice’s enormous carbon footprint.  The sad irony is that legalization is probably the only avenue for solving the problem, if only policymakers would confront it.

Reliance on indoor cultivation is not a green policy

The dirty little secret of the marijuana industry is that embedded in each average indoor-grown plant is the energy equivalent of 70 gallons of oil.

How can this be? It starts with windowless marijuana factory farms constantly battling local weather conditions to maintain round-the-clock tropical temperatures and pump out acres of electric light brighter than the summer sun, day or night. Running the equipment needed to create these artificial environments requires as much energy as a similarly sized data center.

As a result, the industry was racking up a whopping energy bill of $6 billion each year across the country back in 2011 (there has been no subsequent update). That’s twice the energy bill of all domestic pharmaceutical production. One joint creates 10 pounds of carbon dioxide pollution. That’s as much as driving a Prius 22 miles or running a 100-watt light bulb for 75 hours. The mind boggles.

It was once tempting to assume that legalization would intrinsically solve these problems, with advocates blaming prohibition for growers hiding indoors. But, that was before Walmart-sized multi-megawatt grow factories started sprouting up in states allowing the practice. Perversely, some localities have even banned outdoor cultivation as part and parcel of their legalization process.  This is presumably done with security in mind. Yet, if the giant internationally sanctioned opium poppy plantations for pain-management drugs can be secured outdoors, surely marijuana farms can as well.

Lamp efficiency can’t compete with sunlight in energy — or water — savings

Back indoors, sleek images of energy-saving LED lights and greenhouses look “green” and otherwise guilt-relieving, but the devil is in the details. Peer-reviewed research suggests that marijuana grown under LEDs may actually take longer to mature and have lower yield, thus saving little if any energy. In most climates, even greenhouses use supplemental light, heating, and cooling, so that’s not a panacea either.  Either way, no one seems to want to ask the question of whether it’s worth it to have “better weed” (or medicine) on the backs of polar bears.

Adding insult to injury—and of particular relevance to the many drought-stricken parts of the country—the massive amounts of water steadily evaporated from dams and cooling towers while producing the electricity destined for indoor cultivation facilities vastly exceeds the water needed to grow outdoors.  And the greenhouse-gas emissions caused by indoor grows are only fueling future droughts.

Marketing practices drive consumers to favor high-polluting production methods

Sadly, growers have shown little interest in voluntarily managing their carbon or water footprints. Most dispensaries tout indoor-grown marijuana, and most consumers are trained to favor it, or are unaware of the distinction. There is as yet no product labeling to help consumers vote with their wallets or their conscience.

Indoor cultivation has its defenders and red-herring mongers.  Some point to Hummers, hamburgers, or other ostensibly worse climate offenders. In the more desperate moments, glossy industry trade rags have pushed distractions in the form of debunked coal-industry statistics overestimating energy use in unrelated sectors to divert attention from the true burning problem.

Ignoring the issue has not worked to reduce the carbon footprint

While the nation has achieved hard-earned progress towards climate change solutions, state and federal policymakers have made little or no effort to scrutinize the role of indoor marijuana operations. Thanks to this inattention, these growers are enjoying a climate-change double standard as they are passed over by a host of policies and programs successfully improving energy efficiency and deploying renewable energy into virtually every other segment of the economy.  For marijuana, there is no appropriate LEED rating, no ENERGY STAR label, no energy use transparency.

Nowhere are these oversights more conspicuous than in California, where policymakers have rightfully endeavored to mitigate outdoor environmental damages from deforestation and water pollution while turning a blind eye to the arguably even greater environmental consequences of the prodigious amounts of energy required for indoor cultivation.  The California Lieutenant Governor’s recent 120-page “BlueRibbon” report on the subject doesn’t once mention energy considerations.

Regulations should favor sunlight grown cannabis, greenhouse or outdoors

Fortunately, there are bold yet well-proven ways forward, including those that go beyond garden-variety energy efficiency improvements.  A requirement for indoor cultivation should be that facilities be highly energy efficient with all power generated on-site using renewable energy sources. This “Net Zero” approach is already a goal that the federal government and many states are applying to ordinary types of facilities. Even highly energy-intensive tech companies such as Apple, Facebook, and Google are voluntarily showing us that this is possible in hyper-scale data centers. Time-proven tools like building energy codes and product labeling, together with utility programs familiar to every other energy-using segment of the economy can help achieve this. Better yet, marijuana can be grown securely and sustainably outdoors.

As more states rush to legalization — and perhaps even some day the feds — drug policy and environmental policy must be harmonized. Until then, some of the nation’s hard-earned progress towards climate change solutions is on the chopping block as regulators continue to ignore this industry’s mushrooming carbon footprint. Those citing climate pollution as a reason not to legalize are missing the point: legalization is necessary — but not sufficient — for addressing the problem.

Yet, done poorly, legalization will just make the problem worse.