Here’s what we know about lab-grown meat and climate change

MIT Technology Review Explains: Let our writers untangle the complex, messy world of technology to help you understand what's coming next. You can read more here.

Soon, the menu in your favorite burger joint could include not only options made with meat, mushrooms, and black beans but also patties packed with lab-grown animal cells.

Not only did the US just approve the sale of cultivated meat for the first time, but the industry, made up of over 150 companies, is raising billions of dollars to bring products to restaurants and grocery stores.

In theory, that should be a big win for the climate.

One of the major drivers for businesses focusing on cultivated (or lab-grown, or cultured) meat is its potential for cleaning up the climate impact of our current food system. Greenhouse-gas emissions from the animals we eat (mostly cows) account for nearly 15% of the global total, a fraction that's expected to increase in the coming decades.

But whether cultivated meat is better for the environment is still not entirely clear.

That's because there are still many unknowns around how production will work at commercial scales. Many of the startups are just now planning the move from research labs to bigger facilities to start producing food that real, paying customers will finally get to eat.

Exactly how this shift happens will not only determine whether these new food options will be cheap enough to make it into people's carts. It may also decide whether cultivated meat can ever deliver on its big climate promises.

Moo-ve over, cows

Raising livestock, especially beef, is infamously emissions intensive. Feeding animals on farms requires a lot of land and energy, both of which can produce carbon dioxide emissions. In addition, cows (along with some other livestock, like sheep) produce large amounts of methane during digestion. If you add it all up and take a global average, one kilogram of beef can account for emissions roughly equivalent to 100 kilograms of carbon dioxide. (Exact estimates can vary depending on where cows are raised, what they're fed, and how farms are run.)

At a cellular level, cultivated meat is made from basically the same ingredients as the meat we eat today. By taking a sample of tissue from a young animal or fertilized egg, isolating the cells, and growing them in a reactor, scientists can make animal-derived meat without the constraints of feeding and raising animals for slaughter.

The USDA just gave two California-based companies, Eat Just and Upside Foods, the green light to produce and sell their cultivated chicken products. This makes the US the second country to allow sales of meat grown in labs, after Singapore.

Cultivated meat will still produce emissions, since energy is required to run the reactors that house the cells as they grow. In the US and most places around the world today, that will likely involve fossil fuels. Renewables could eventually be available widely and consistently enough to power facilities producing cultivated meat. However, even in this case, the reactors, pipes, and all other necessary equipment for production facilities often have associated emissions that are tough to eliminate entirely. In addition, animal cells need to be fed and cared for, and the supply chain involved in that also comes with emissions attached.

And the emissions from cultivated meat might be significant. Some of the early work in the field has relied on materials and techniques borrowed from the biopharmaceutical industry, where companies sometimes grow cells in order to produce drugs. It's a painstaking and tightly regulated process involving high-purity ingredients, expensive reactors, and a whole lot of energy, says Edward Spang, an associate professor of food science and technology at the University of California, Davis.

Spang and his team set out to estimate the climate impacts of cultivated meat assuming current production techniques. To quantify the potential climate benefits, the researchers examined the total environmental impacts of both animal agriculture and cultivated meat in an analysis known as a life-cycle assessment. This type of analysis adds up all the energy, water, and materials needed to make a product, putting everything in terms of equivalent carbon dioxide emissions.

In a recent preprint study that hasn't yet been peer-reviewed, Spang estimated the total global-warming potential of cultivated meat in several scenarios based on assumptions about the current state of the industry.

The scenarios were divided into two categories. The first set assumed that cultivated meat would be produced with processes and materials similar to those used in the biopharmaceutical industry-specifically including an energy-intensive purification step to remove contaminants. The other scenarios assumed that cultivated meat production wouldn't require ultra-high-purity ingredients and would instead rely on inputs like those used in the food industry today, meaning lower energy requirements and emissions.

The two sets of results have very different climate outcomes. A food-grade process results in the equivalent of 10 to 75 kilograms of carbon dioxide emissions-lower than the global average emissions from beef and in line with production in some countries today. But in the biopharmaceutical-like process, cultivated meat leads to significantly more emissions than beef production today: between 250 and 1,000 kilograms of carbon dioxide equivalent for every kilogram of beef, depending on the specific scenario.

Where's the beef?

Spang's preprint, which appeared in April, sparked splashy news headlines about the potential for sky-high emissions. The study also drew quick criticism from some in the industry, including a widely circulated open letter questioning its assumptions.

Experts particularly took issue with the assumption that materials used in producing cultivated meat would need to use pharmaceutical-grade ingredients and go through intense purification steps to remove contaminants called endotoxins. Endotoxins are pieces of the outer membranes of some bacteria, and they're shed as the microbes grow and when they die. Removing them is often necessary in biopharmaceutical processes, since even very small quantities can harm the growth of some cell types and provoke immune responses.

The process that removes those contaminants is the major contributor to the high emissions seen in one group of the preprint's scenarios. However, that purification step won't be necessary in commercial production of cultivated meat, says Elliot Swartz, a principal scientist at the industry group Good Food Institute and one of the authors of the open letter. Different cell types are affected by endotoxins differently, and the ones that will be used for cultivated meat should be able to tolerate higher levels, meaning less purification is needed, Swartz says.

The study's results do differ from those of many previous analyses in the field, which generally found that cultivated meat would reduce emissions compared with conventional beef production. Most of those studies assume that producers of cultivated meat will be able to avoid the energy-intensive methods described in the preprint, and will instead scale up to large commercial facilities and progress toward using more widely available, food-grade ingredients.

Experience will provide a better picture of the industry's potential climate impact, says Pelle Sinke, a researcher at CE Delft, an independent research firm and consultancy focusing on energy and the environment. In all innovative technologies, there's an enormous learning curve," Sinke says. I'm not sure we should worry that much that [cultivated meat] will add an enormous burden to the climate globally."

In an analysis published in January 2023, he and his team set out to estimate emissions associated with cultivated meat in 2030, assuming that the production process can use food-grade ingredients and will reach commercial scale sometime in the next decade. That study put the potential climate impact at between three and 14 kilograms of carbon dioxide per kilogram of cultivated meat.

Where the total emissions from cultivated meat production will fall in this range depends largely on where the energy comes from to run the bioreactors: if it comes from the electrical grid, which will still rely partly on fossil fuels, the carbon impact will be much higher than it will be if renewables are used to power the facility. It also depends on what ingredients are in the media used to grow the cells.

In any case, Sinke's study found that total emissions would be significantly lower than emissions from beef production, which his study estimated as equivalent to 35 kilograms of carbon dioxide in an optimized system in western Europe. (Chicken and pork came in at roughly three and five kilograms of carbon dioxide, respectively.)

Sinke's analysis is far from the first to estimate that cultivated meat could have a smaller climate impact than conventional agriculture. An early analysis in the field, published in 2011, estimated that cultivated meat production would reduce greenhouse-gas emissions by between 78% and 96% compared with meat production in Europe, assuming production took place at commercial scale.

Cultivated meat could eventually have major climate benefits, says Hanna Tuomisto, an associate professor at the University of Helsinki and the lead author of the 2011 study. Tuomisto recently published another study that also found potential climate benefits for cultivated meat. However, she adds, the industry's true climate impacts are yet to be determined. There are many, many open questions still, because not very many companies have built anything at larger scale," Tuomisto says.

Till the cows come home

Scaling up to make cultivated meat in larger production facilities is an ongoing process.

Upside Foods, one of the two companies that received the recent USDA nod, currently runs a pilot facility with a maximum capacity of about 400,000 pounds (180,000 kilograms) per year, though its current production capability is closer to 50,000 pounds. The company's first commercial facility, which it's currently in the process of designing, will be much larger, with a capacity of millions of pounds per year.

In all innovative technologies, there's an enormous learning curve."

Pelle Sinke

According to internal estimates, Upside's products should take less water and land to produce than conventional meat, said Eric Schulze, the company's VP of global scientific and regulatory affairs, in an email. However, he added, we will need to be producing at a larger scale to truly measure and start to see the impact that we want to have."

Eat Just is currently operating a demonstration plant in the US and constructing one in Singapore. Those facilities include reactors with capacities of 3,500 and 6,000 liters, respectively. Eventually, the company plans to produce millions of pounds of meat each year in a future commercial facility containing 10 reactors with a capacity of 250,000 liters each.

There are already plenty of reasons to be hopeful" about the climate impacts of cultivated meat, said Andrew Noyes, VP of communications at Eat Just, in an email. However, achieving those goals is dependent on several factors tied to the optimization and scale-up of our production process, as well as the design of future large-scale manufacturing facilities."

Even though recent regulatory approvals have been celebrated as a milestone for the cultivated meat industry, these products won't be in your burger joint anytime soon. To cut their production costs, companies still need to build those larger facilities and get them running smoothly.

Part of that growth will mean turning away from the more expensive equipment and ingredients the industry has borrowed from other businesses, says Jess Krieger, founder and CEO of Ohayo Valley, a cultivated meat company: This is not how we're going to be doing it in the future." The factors that led to Spang's worst-case emissions scenario, like intensive purification, expensive reactors, and pharmaceutical-grade media, aren't necessary for production, she says.

It is true that early-stage companies still often use pharmaceutical-grade ingredients, says Elliot Swartz of the Good Food Institute. However, there are already cheaper, food-grade options available on the market. Both Eat Just and Upside Foods say they plan to use these nonpharmaceutical ingredients in their eventual commercial operations.

Energy-intensive methods aren't just unsustainable for the planet, says Sinke, the researcher with CE Delft. Many processes that lean on biopharmaceutical techniques won't be used in industry not just because they'd produce high emissions, he says, but because nobody can afford them."

For his part, Spang agrees that economics will likely keep cultivated meat from following the type of production path that would lead to extreme climate impacts. If it requires pharmaceutical inputs, I don't think there will be much of an industry," he says. It will be too expensive; I just don't think that's a viable pathway."

But for him, there are still many open questions to answer, and plans to execute, before the industry can start taking credit as a climate solution. The leap from lab-scale science to cost-effective climate impact-there's a substantial amount of distance there, in my opinion," Spang says.

It's still possible for cultivated meat to become a major positive for the climate, especially as renewables like wind and solar become more widely available. An industry where cells can be grown efficiently in massive reactors while being fed widely available ingredients, in a process all powered by renewable electricity, could be a significant way to help clean up our food system.

But the facilities that would make that possible are mostly still in the planning phases-and it's not yet clear which path cultivated meat might take to reach our plates.