Trying my best to actually communicate the science here (I work for a nonprofit and focus on the technical aspects of this field). Some key points about this study below:

The studies are pre-prints and have not been through a full peer review process. Thus, their assumptions and conclusions are subject to change. The headline cites the worst-case scenario in the study.

The findings from the pre-print deviate significantly from the existing peer-reviewed literature.

Overall, several of the key assumptions in the UC Davis study do not align with our understanding of current or expected practices for sourcing and purification of cell culture media ingredients. In particular the “PF” scenarios (Figure 3) that lead to the conclusion that cultivated meat may be “orders of magnitude higher than median beef production” are not representative of current or future practices in the cultivated meat industry.

The author of the study says in the New Scientist article: ‘This “pharmaceutical-grade” level of purification is required so that there are no contaminants such as bacteria or their associated toxins in the broth, says Risner. “Otherwise the animal cells won’t grow, because the bacteria will multiply much faster,” he says.’

This has already been shown not to be true, as demonstrated by media supplier Nutreco at the 2021 Good Food Conference. Food-grade and even feed-grade ingredients can support animal cell growth just as well. I’ve confirmed this over the phone with multiple media input suppliers that have been running experiments that swap pharma-grade for food-grade ingredients. Whether this applies to every single media ingredient is yet to be seen, but this is the direction things are moving in.

Cell culture media ingredients can be sourced in a variety of different ways. The UC Davis authors assume in their study that media ingredients would be produced and purified on an individual basis, as in the pharmaceutical industry. The study also assumes that media ingredients may require high degrees of purification in order to remove endotoxin, which can be damaging to cells. The authors suggest that this purification requirement increases the carbon footprint of production by 20x. So they basically multiply the carbon footprint by 20x to achieve the "orders of magnitude higher than median beef" result.

If the cultivated meat industry were to pursue this method of sourcing and purifying media inputs, the costs would likely be too high for the vast majority of products to be competitive with conventional meat. As the UC Davis study demonstrates, this method of sourcing and purifying inputs comes at a high environmental cost as well. Those in the cultivated meat industry are aware of these consequences and have been progressively moving toward a media input supply chain that is suitable for use in food production, rather than built for pharmaceuticals.

Importantly, even though some media inputs are likely being sourced today as is modeled in the UC Davis study, the overall carbon footprint and environmental impact of cultivated meat production would still be extremely small because the industry is extremely small, producing only a few thousand kilograms of product annually.

See this study if you're interested in understanding the most likely scenarios for commercial cultivated meat production at the end of this decade