Cellular agriculture: a climate solution?

1. What is cellular agriculture and what is cultivated meat?

Cellular agriculture is biotechnology that enables us to make animal products from cell lines grown in bioreactors, rather than from animals.

Cultivated meat (or in-vitro meat, lab-grown meat, cell-based meat, cultured meat, clean meat, etc. – no lack of terminologies there!) is the end-product of the proliferation of stem cells or undifferentiated muscle cells (myoblasts), cultured in a medium rich in oxygen, nutrients (amino acids, carbohydrates, vitamins, minerals) and growth factors. The growth factors are then removed from the culture medium to trigger cell differentiation into myotubes (muscle fibers), and also into other types of cells, precursors of minor muscle components (fat, blood vessels, connective tissue). A biomaterial acting as a “scaffold” is often needed to support the cells during differentiation so that they form a muscle tissue whose structure is similar to conventional meat.

2. What is currently happening in the cellular agriculture ecosystem?

Startup creation around cultivated meat has been accelerating since 2015

Since the first “synthetic beef patty” developed in 2013 by Professor Mark Post from Maastricht University, startups that develop cultivated meat have multiplied. In 2015, Mark Post founded Mosa Meat in the Netherlands, followed by SuperMeat in Israel, Upside Foods (formerly Memphis Meat) in the United States, and Integriculture in Japan. Aleph Farms (Israel), Higher Steaks (USA), and Eat Just (USA) began in-vitro meat development in 2017. About 40 startups worldwide are now involved in the development of lab-grown meat alternatives.

How close are those startups to market launch?

In Singapore, the SFA (Singapore Food Agency) authorized in December 2020 the sales of chicken nuggets produced by Californian startup Eat Just. These nuggets are now available at Singaporean restaurant 1880, but are still far from being on the shelves of supermarkets. Eat Just’s bioreactors are only at a pilot stage (1200 liters): not enough to supply the volumes needed to target mass food retail.

Several players are currently building semi-industrial-scale facilities, seeking to market their first series of products in 2022 or 2023 in countries where the regulations will allow it. After Singapore, the United States and Israel are the two countries most likely to favorably change this regulatory framework.

To consider large-scale marketing, several technological barriers are yet to be overcome:

• Creating an affordable culture medium adapted to each type of cell
• Optimizing the design and performance of bioreactors
• Improving biomaterials and support structures to create meat pieces with the desired thickness.

Finally, consumer perception, although studies indicate that it is rather favorable to cultivated meat, is likely to significantly vary among countries and targeted consumer groups. To make cell-based meat a common dish in our daily meals and to overcome the reluctance of the broader market, manufacturers still have some work ahead of them.

In summary, despite the announced imminent product launches, our shelves will not be flooded with lab-grown meat for, at least, several more years.

3. The climate issue in cellular agriculture: a point of controversy

Environmental benefits are a core aspect of the value proposition of start-ups that develop cultivated meat. On an industrial scale, cultivated meat production would require less agricultural land, would use less water, and would represent less greenhouse gas emissions than conventional livestock farming.

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Less agricultural land

The issue of agricultural land is not highly debated. In their 2015 study, Mattick et al. estimate that the production of one kilogram of cultivated meat requires 5.5 m2 of agricultural land, compared to 92 m2 for conventional beef produced in feedlots, i.e. a 94% reduction in favor of in-vitro meat. However, from the 2.5 billion hectares of agricultural land currently used for livestock and feed production worldwide, 1.3 billion hectares are non-arable land, which therefore cannot be reallocated to growing crops for human consumption.

Less water

The water issue is also quite clear. The production of in-vitro meat requires only 367 to 521 liters of water per kilogram of meat, compared to 550 to 700 liters for conventional beef meat. According to promoters of cellular agriculture, the gap could be even greater. Some sources indicate that up to 15,000 liters of freshwater would be needed to produce 1 kilogram of beef meat, meaning a difference of about 97% in favor of cultivated meat. Nevertheless, this last figure should be interpreted carefully, as it includes rainwater absorbed by grasslands and pastures, which would therefore be used by plants even without livestock.

Less greenhouse gas emissions?

It is mainly about climate impact that opinions diverge concerning cellular agriculture and cultivated meat.

It is recognized that livestock farming significantly contributes to global warming, with 14.5% of global greenhouse gas emissions. A significant part of which is methane, emitted by ruminants (cattle, sheep, goats, etc.) through enteric fermentation. Despite the efforts that the livestock sector can make to cut its emissions, the release of methane, inherent to animals’ biology, is partly incompressible. Livestock therefore undeniably has a significant impact on the climate.

However, producing cultivated meat requires a lot of energy, notably because of the bioreactor’ heating to 37°C (the temperature which is required for cell culture), and its cooling system which aims to avoid the formation of hot spots (cell multiplication indeed releases metabolic heat which can, paradoxically, harm their development). Energy is also required to stir and aerate the reactor throughout the cell culture cycles (~30 days) to clean and sterilize the facilities at the end of each production batch.

In 2021, the Danish agency CE Delft published a prospective life cycle assessment of cultivated meat. Although GAIA and the Good Food Institute – two promoters of cellular agriculture – are the sponsors of that study, the assessment methodology seems to be truly objective and independent. The data was indeed provided directly by the actual players from various stages of the cell-based meat value chain (manufacturers of cultivated meat, suppliers of the growth medium, equipment manufacturers, engineering companies), without being shared with the sponsors. In this 50-page report, the authors show that, compared to conventional beef meat, cultivated meat represents a 55% reduction in GHG emissions, or even a 92% reduction if the energy used to operate the bioreactors comes from renewable sources.

However, several limitations about those findings should be highlighted:

1. The above-mentioned decrease in GHG emissions only applies to cultivated meat when compared to meat from beef cattle. If dairy cattle is the reference for conventional meat use, the difference remains significant, but drops down to respectively 22% (vs 55%) with a standard energy mix and to 86% (vs 92%) with renewable energies. If pork or chicken meat is the reference, the carbon footprint of cultivated meat is higher, unless the energy used for the production of the latter is from renewable sources.
2. The study compares cellular agriculture and conventional meat in a 2030 projection. It takes into account the potential progress of the livestock sector, which by 2030 will probably have taken action to reduce its carbon footprint. But it also uses several assumptions about what the cultivated meat production process will look like at an industrial scale, although manufacturers are still far from having reached that stage. For instance, calculating the emissions of the growth medium (that represents a large part of lab-grown meat’s overall carbon footprint) comes with a lot of uncertainties, since we do not know yet what types of growth factors cellular agriculture will use at industrial scale, nor how those media will be produced.
3. The CE Delft study does not make any reference to a landmark publication published in 2019 by two Oxford University scientists (Lynch and Pierrehumbert, 2019). This publication, using long-term climate modelling, highlights the drawbacks of a prospective analysis that would be based on GWP₁₀₀ (Global Warming Potential) only, while this is precisely the indicator used by CE Delft. The GWP₁₀₀ is the ratio between the energy reflected towards the surface over 100 years by 1 kg of gas released into the atmosphere, and the energy that would be reflected by 1 kg of CO2 emitted at the same time. Hence, CO2’s GWP₁₀₀ equals 1, whereas it equals 28 for methane. As livestock farming emits a lot of methane, whereas cellular agriculture mainly involves CO2 emissions, a GWP₁₀₀-only analysis therefore leads to a very negative balance for livestock farming. However, methane remains in the atmosphere for only 12 years, whereas CO2 persists and involves cumulative effects that GWP100 cannot model over long periods of time (>100 years). Lynch and Pierrehumbert thus demonstrate that the climate benefit of in-vitro meat seems much less clear-cut than it appears at first sight. They indicate that the relative impact of the 2 systems will depend on the level of decarbonization that our energy mix can reach in the decades to come.

The source of the energy used by cellular agriculture is, therefore, in all likelihood, the key to predicting cultivated meat’s environmental footprint. Should the International Energy Agency’s projections for 2030 (12) become reality, we can reasonably assume that cultured meat will deliver a real climate benefit over – at least – conventional beef meat. But perhaps, livestock farming will surprise us. Technological innovations might indeed reshuffle the cards. For instance, enzymatic inhibitors of enteric fermentation that can be incorporated into feed are currently being studied and could help reduce cattle’s methane emissions.

On the other hand, the comparative assessment of cultivated and conventional meat must also address the positive externalities of livestock farming, which is an important component of our landscapes, ecosystems, and rural economy – especially in Europe. Those two systems will undoubtedly coexist for many years before a “winner” emerges. Which one will prevail, in the end? What a difficult equation to solve. But we can hope that the competition will be virtuous. Livestock farming must reinvent itself to move towards carbon neutrality; as for cellular agriculture, there is still work ahead to deliver its environmental promises.

About the author, 

Thibault, Senior Consultant in Alcimed’s Agrifood team in France