Cannabis is changing. Today’s marijuana is more potent than ever and there remain many questions about its benefits and risks. We still can’t meaningfully regulate driving while high. And growing cannabis – legally and not – has a staggering environmental footprint.
In The weed of the future, the final episode of our special three-part podcast series on the science of cannabis, Christie Taylor steps back to examine how cannabis fits into our society, both now and in the future, and how scientists may be able to breed cannabis with less of a tiny molecule that is responsible for the distinctive but controversial skunky odour.
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But first, a visit to a mysterious lab where chemicals from cannabis are being made without a single plant involved…
You can find episodes 1 and 2 in the żěè¶ĚĘÓƵ Podcasts feed on you favourite podcast app or on our podcast page.
Transcript
Christie Taylor: Picture an office building. Just a regular, anonymous, old office building. Cubicles, conference rooms, coffee pods. There’s flat, nondescript light from fluorescent bulbs overhead. But if you go through one door in particular, there’s suddenly something else going on here.
James Dinneen: Then you go into the laboratory and it smells kind of like a brewery with a hint of banana. And there is this loud buzzing sound from the air pump.
Christie Taylor: That’s James Dinneen, who recently got to tour the fun part of this not-so-standard office building. Think of a classic biotech laboratory. Shelves of glass beakers, a few white-coated workers pipetting clear liquids into trays. All very stereotypical.
The science of cannabis
As the use of marijuana and its compounds rises around the world, żěè¶ĚĘÓƵ explores the latest research on the medical potential of cannabis, how it is grown and its environmental impact, the way cannabis affects our bodies and minds and what the marijuana of the future will look like.
James Dinneen: And on the shelves along the wall, there are these glass vessels full of several litres of a churning golden liquid. And each of these vessels is hooked up to a bundle of tubes and wires that control the flow of air and nutrients to the mix.
Christie Taylor: For all that this smells like a beer brewery, and looks like a science lab though, this is actually a top-secret facility for cannabis production.
James Dinneen: In order to see it, I agreed not to use the name of the facility or say where it was located. They were pretty secretive.
Christie Taylor: There wasn’t a single pot plant in sight. No dirt, nary a grow light. But it might just be the future of how you get your cannabis.
I’m Christie Taylor for żěè¶ĚĘÓƵ. In this special series on cannabis, we have been following the story of this plant through human history. We’ve visited the stoned brain and the mysterious, ancient endocannabinoid system. But today, we’re looking at the future. What’s next as popular embrace of pot increases?
We’ve talked about one big problem with cannabis, which is the sheer lack of research compared to other intoxicating substances, even as its relationship to one of our most ancient brain and body systems becomes more clear. But if popularity continues to grow, there are some troubling sticking points in the way pot relates, not just to our bodies, but to society and the environment as well. This is all part of a massive months-long reporting project by the żěè¶ĚĘÓƵ team. You can read more about this series at newscientist.com/cannabis. But, for now, this is it, our finale in this special podcast series. And we’re going to talk about why the weed of today is not like the weed of yesterday. And it’s also not like the weed of the future either. And, yes, it involves a visit to a secret cannabis facility.
Weed is already way stronger than it was in the hippie era of the 1960s and 70s. The potency monitoring programme at the University of Mississippi has found that, in the US at least, the average amount of tetrahydrocannabinol, or THC, in weed has gone up tenfold in the last 50 years. That trend holds in the UK, the Netherlands, France, Denmark and New Zealand, where average THC concentrations increased by a third of a percent each year from 1970 to 2017. Why is this? One is just that breeders are simply better at selecting for plants with higher amounts of THC. We’re doing what agriculture has always done.
But another is the growing popularity of seedless cannabis called sinsemilla. These are unpollinated female plants and their buds and flowers are a treasure trove of THC-rich resin. Sinsemilla can contain twice as much THC as the conventional variety and, while seedless cannabis was a small fraction of US samples in the early 1990s, it made up nearly half of samples by 2008 and it has remained neck and neck with less potent strains since then. And there’s one last, more mundane, reason for the rising potency of pot, and it’s how we consume it. Dried flower, aka smoking, remains the most popular way of imbibing. But edibles, vapes, even under-the-tongue tinctures, are growing in popularity. And a vape cartridge is much easier to cram full of THC. Some concentrates have THC levels of up to 90 per cent.
We’ve talked before about how people perceive cannabis as harmless. More and more people do as time passes. But that perception is not entirely correct. High concentrations of THC, in particular, can raise your risk of nausea, vomiting, the oh-so-stereotypical stoner paranoia and even abnormal heart rhythms. Chronic consumption of high amounts has been linked with a rare but growing condition called cannabinoid hyperemesis syndrome and children who encounter edibles and mistake them for candy are particularly at risk of these side effects. So in one way, at least, the future of weed is one of higher highs and more THC.
And then there’s driving cars. In the United States, most states prohibit doing so while, quote, “under the influence of marijuana”. A few have a strict zero-tolerance prohibition against driving with any detectable THC in your blood and several US states and other countries, including the UK, have a legal blood limit that they test against if they suspect a driver of impairment. That number is usually between 1 and 5 nanograms per millilitre of blood.
Karmela Padavic-Callaghan: Research on how cannabis affects driving shows that people have worse control over their vehicles and slower reaction times. And, to make the matter worse, people will often consume cannabis with alcohol and that’s a very risky combination.
Christie Taylor: That’s Karmela Padavic-Callaghan, a reporter for żěè¶ĚĘÓƵ who’s been looking into cannabis and driving.
Karmela Padavic-Callaghan: In the US, the percentage of motor vehicle fatalities caused by cannabis more than doubled between 2000 and 2018, rising to one in five or, basically, 20 per cent. And an international group that focuses on drugs and traffic safety noted in their report that using cannabis increases a driver’s chance of crashing by 30 to 40 per cent.
Christie Taylor: But even with those well-known risks, how do you actually assess whether someone who has consumed cannabis is safe to drive? It turns out it’s not that easy. There’s no one number that applies to everyone’s experience of pot.
Karmela Padavic-Callaghan: The amount of THC in your blood may actually say very little about whether you’re too impaired to drive or not, especially if you use cannabis frequently and have developed a high tolerance. For example, in one study, frequent users did end up having higher blood THC, and even used more cannabis when researchers gave them a fixed amount of time to smoke. But then the group of people in the study who were less frequent users, who actually had lower THC levels in their blood, ended up being more impaired and doing worse on a driving simulator.
Christie Taylor: Okay, so, what about at least checking someone’s breath for recent consumption, the gold standard of drunk-driving enforcement? Unfortunately, the chemistry of THC molecules makes them harder to pick out than the ethanol molecules that alcohol breathalyser tests look for. There are companies working on saliva tests that can detect THC, and their models sort of look like those at-home COVID tests. But even those companies say there’s no definitive answer yet on how detected THC levels correspond to driving impairment.
So this leaves the well-known phenomenon of the field sobriety test where law enforcement officers ask drivers to step out of their vehicles, walk in a straight line and perform other feats of coordination.
Karmela Padavic-Callaghan: Field sobriety tests are brief snapshots of someone’s state and may not be predictive of how well the person will actually drive. In some studies, people who have not consumed intoxicating substances were still marked as impaired by these tests, which means that law enforcement could potentially penalise drivers who are actually at completely normal capacity.
Christie Taylor: So, if more people are going to consume cannabis legally, how can the law and technology work together to keep people safe as they work, drive and perform other activities that it’s really best to do sober? Keeping people from driving while impaired is a genuine societal need, but if we’re to have laws that meaningfully regulate how people behave, we’re going to need to know how they actually behave. Remember how last episode we talked about the desperate need for more research? This is very much another one of those places.
But here’s one of the biggest problems the popularity of cannabis may require us to solve: it’s the environment, especially water and electricity, the uses of which are sky-high for cannabis, even in places where the plant is not legal. A study back in 2012 found that indoor cannabis growers may consume as much as 1 per cent of the electricity in the United States. And that was before the plant was legal recreationally in a single US state. Outdoor growing, especially by unlicensed growers, comes with risks for wildlife and humans. There’s the use of water and electricity but also strong pesticides that may threaten local wildlife. Pot plants can also compete with local vegetation for space and sunlight. Remember it’s called weed for a reason. Here’s Jeremy Hsu, who looked into how cannabis is touching on climate and beyond.
Jeremy Hsu: That 2012 study, for example, with the big 1 per cent number, it also calculated that 1 kilogram of pot grown indoors would generate 4600 kilograms of carbon dioxide. And the entire industry was producing the same carbon emissions as driving 3 million cars for a year.
Christie Taylor: So why is the environmental footprint of cannabis so huge? It’s another consequence of years of prohibition. When growers universally had to hide their tracks, it led cultivation to rely on energy-intensive practices, like indoor farms with inefficient, power-sucking artificial grow lights. Or outdoor farms hidden on public lands like national parks, in direct competition with rare or threatened species. And there was no incentive, until recently, to research sustainable growing practices for either outdoor or indoor operations.
Jeremy Hsu: A more recent study from 2021 found that areas with the worst climates for cannabis were also where growing it had the biggest environmental impact. In the US, that’s the Midwest and the Mountain West. A tougher climate means more need for artificial lights, ventilation, air conditioning and other pampering for the plants. And more energy consumption at the end of the day.
Christie Taylor: But it definitely doesn’t have to be this way. For example, cannabis doesn’t necessarily need a huge footprint to thrive. In California, cannabis is one of the top five cash crops and the state grows an estimated 500 plus metric tonnes legally per year, but only on one-hundredth of 1 per cent of the total agricultural land. And a cannabis plant needs no more water than a tomato. Some of the solution comes back to more research.
Jeremy Hsu: Pot’s history of prohibition means, in some ways, farmers just don’t know the best agricultural practices for its cultivation. And even the researchers who are looking at, for example, pesticides can’t bring cannabis samples from their study sites back to the lab. At least, not yet.
Christie Taylor: Before 2012, when Colorado and Washington state legalised recreational cannabis, the literature of research on cannabis growing practices and environmental footprint was sparse. The research that has come in the years since is still mostly limited to the United States, where cannabis is grown in highly controlled environments in indoor greenhouses. But that still leaves big global gaps. For example, African countries produce about 25 per cent of the world’s commercially grown cannabis. But instead of greenhouses, these plants often grow in outdoor, open-air farms or out in the wild. And how do those farms impact local wildlife? You’re already tired of me saying that more research is needed.
Jeremy Hsu: Some researchers I spoke to are resting their hopes on wider legalisation. So, if recreational weed becomes more widely allowed, the research into energy efficiency and environmentally friendly growing practices can follow more easily. And it would make it easier for government entities to incentivise responsible growing practices and thereby reduce the cost burden of more sustainable outdoor growing operations.
Christie Taylor: Growing weed is legal now in places where it wasn’t before. But there’s a problem with that. The smell. The technical term for the characteristic whiff of strong cannabis is skunky. And it’s a reason communities may be less than happy to host a large growing operation nearby. A quick search of the news serves up headline after headline about communities that are demanding growers do more to control odours. And researchers have been working to isolate what it is that makes weed smell so singular.
And it turns out that chemicals that are present in very, very small amounts may be playing the biggest role in whether our pot smells skunky. These are thiols, volatile sulphur-containing compounds with a molecule attached that is the essence of skunk. This molecule is responsible for when beer gets skunky and, maybe least surprising of all, it’s the same molecule behind the smell of actual skunks when they release musks from their undertail glands.
This compound drifts off from a cannabis plant into the air as it grows. But it actually increases as the plant reaches its final flowering stages. Which is also when the plant is the most potent, has the most cannabinoids. Hence the association that skunky pot is also strong pot. As they say, knowing is half the battle. And knowing the molecular make-up of the skunky smell may make it easier to change in the future. We may be able to selectively breed lower-skunk cannabis or even tweak other odours to bring them to the front. There are other volatile compounds that can actually create a more tropical smell profile, for example. Or even savoury garlic-like notes. Smell, it turns out, is just one of many canvasses that growers could manipulate in the name of a better product that also happens to get along with the neighbours.
But there’s an even bigger development that could touch on all the many things I’ve talked about and it could allow us to customise our relationship with cannabis even further than just breeding out bad smells. Let’s go back to James Dinneen and his mysterious cannabis facility. The golden liquid, the odd smells, the high-tech equipment.
James Dinneen: Since at least 2017, biologists have been able to make cannabinoids without the cannabis plant, using bioengineered yeast and other microbes. Instead of growing cannabis plants, you can make THC, CBD and other valuable cannabinoids in the lab, essentially through fermentation. Just add sugar.
Christie Taylor: In this lab, James is seeing this biosynthetic cannabis in action. Those vats of golden liquid are bioreactors and inside each is a modified version of the same yeast used to make beer. But instead of converting sugar to alcohol, they’re using sugars to make cannabinoids like THC or even rarer cannabinoids that the cannabis plant doesn’t even make. This process was first demonstrated by a researcher named Jay Keasling, whose University of California team modified the yeast, Saccharomyces cerevisiae, with the necessary enzymes to make THC, CBD and other cannabinoids.
James Dinneen: It’s pretty complicated but they basically added a number of different genes to the yeast that enable it to make different enzymes and each of these catalyses a series of steps that enabled the yeast to make cannabigerolic acid, or CBGA. And this molecule is sometimes called the mother of all cannabinoids because it is the precursor molecule for most of the other ones, like THC, CBD, CBN, CBDTHZV and the whole alphabet soup of cannabinoids.
Christie Taylor: Keasling and his team first produced yeast that made a precursor to CBGA. Modifying this yeast produced a second strain that could produce CBGA all by itself. And then even further modifying the yeast yielded a strain that produced the enzymes needed to transform CBGA into THCA and CBDA. Which, don’t worry too much about keeping track, but both of those are easily converted into the THC and CBD you know and love.
James Dinneen: By feeding the yeast different types of fatty acid, Keasling’s team also made cannabinoids that don’t occur anywhere in nature. Chemicals no cannabis plant contains but, you know, which may prove useful to us in some way someday.
Christie Taylor: This new ability to make cannabinoids with microbes spurred a slew of companies to try this approach. Some start-ups, seeing the wave of legalisations across the US and the globe, set out to compete with conventional growers. It’s just another way to make CBD for the booming CBD seltzer industry. But others were focused on other goals. Once company was trying to synthesise CBG, a molecule that’s not involved in the high but seems promising in treating inflammatory and neurological conditions.
Another company set out to synthesise a variety of rare cannabinoids. These are ones the plant produces in vanishingly low concentrations. But they may turn out to have medical applications. And this is, actually, the key argument for going the microbial route because producing large quantities of these rare cannabinoids using plants is really, really expensive.
So, for about two years, a Canadian company named Cronos sold the first, and still only, synthetic cannabinoid product. A popular gummy called Spinach FEELZ Chill Bliss. It included a plant-derived THC but also CBG from yeast. And, perhaps the best news, Cronos says it was able to do this while generating 99 per cent fewer greenhouse gas emissions than it takes to grow and process the same cannabis in an indoor growing facility. So, what’s next? Where can I get these environmentally friendly, yeast-assisted, cannabis gummies?
James Dinneen: Well, the business of biosynthetic cannabis is not going as well as many had hoped. It hasn’t really taken off. One company leader told me everybody’s dead, so it sounds pretty bad. Even though some start-ups sold products at a profit, the covid-19 pandemic and ensuing financial crisis put a damper on what was really a nascent industry.
Christie Taylor: Now, that doesn’t mean that we’re done with having microbes make cannabinoids. It’s those rare cannabinoids that may actually still be the most valuable product of this fermentation breakthrough. For example, one research team has found that two rare cannabinoids when combined with CBD have slowed the progression of leukaemia, at least in mice. And other early clinical research has found rare cannabinoids that may have the potential to treat other cancers. As well as conditions such as inflammation, pain and neurodegeneration.
James Dinneen: Even if microbial cannabinoids haven’t yet found their niche, researchers I spoke with said there are good reasons to pursue it. A big one is the ability to make large and ultra-pure quantities of the rare cannabinoids. Those are really difficult to make with plants, and expensive. And having access to this huge variety of rare cannabinoids would be really valuable for researchers trying to study their potential applications. Another reason is the much lower environmental footprint of microbial cannabinoids. They use less water, less land, less pesticides.
Christie Taylor: So, according to one industry insider, even with the current slump in fermentation businesses, within a few decades, we could still see 80 per cent of our cannabinoids made by microbes, even if recreational users remain dedicated to the plant itself.
James Dinneen: One CEO I spoke with didn’t see microbial cannabinoids replacing all cannabis, but he did think it could be useful for industries trying to use lots of cannabinoids like beverages, pet food or even animal feed.
Christie Taylor: We’re already using synthetic chemistry to generate cannabinoids in the lab. Take the less-potent delta-8 THC that you can get even in states with no legal recreational cannabis. And while the wave of legalisation has also created a wave of people growing cannabis indoors and outdoors, the economics of this newly legal substance are still settling into something like an equilibrium. Microbial fermentation offers a way to meet demand without as much energy, water or land use. There’s no skunk smell when all you’re doing is growing yeast that belch out CBD. And if we want to understand the medical benefits and risks of cannabis consumption in the long run, including when someone is behind the wheel of a car, we need lots and lots and lots of pure, research-grade cannabinoids.
I am not here to say that yeast-based cannabinoids are going to solve every single problem that pot has presented. That includes social justice. Who is benefiting, and who is not, from sanctioned sales of weed? In the United States, the criminal justice system has disproportionately targeted people of colour for carrying small amounts of pot. Will the same people be left out of the economic boom for growers and dispensaries, and even laboratories? That’s not a question science can answer. Only people and their governments. And then there’s just how recent all of this is.
Remember, the current wave of legal recreational cannabis only began in 2012. Even as I’ve been recording and scripting these episodes, another US state has legalised recreational marijuana, new research has come out on the genetic component of cannabis use disorderĚýand we’ve discovered two 17th-century skeletons in Italy with traces of cannabis in their bones. But we are at a point in our relationship with this plant where we can examine it with the same tools of chemistry and medicine that we’ve used to create life-changing treatments from other gifts of the natural world. And that is exciting. Ěý
Just as the endocannabinoid system has taught us so much already about where feelings of euphoria are generated, what could come next in our understanding of memory? Of inflammation? Or of pain? This is an area of great change. And the best I can tell you from here is to keep following our reporting, all over at newscientist.com/cannabis.
Thank you so much to Alexis Wnuk, Jeremy Hsu, James Dinneen and Karmela Padavic-Callaghan for helping me report and write this episode. Thanks also to Timothy Revell for editing. New York Studio production is by Hugo Fonseca Suarez and Diego Sanchez. And our audio and sound design is by Ollie Guillou. I’m Christie Taylor, bye for now.
