I suspect that cell-based meat research and development could be the most important strategy to protect animal rights and improve animal welfare (with a possible exception of research in welfare biology to improve wild animal welfare), and could strongly reduce climate change.
This post describes my very rough back-of-the-envelope Fermi-estimate calculation of the cost-effectiveness of cell-based meat R&D, and compares it with traditional animal rights and vegan advocacy campaigns. I only estimate the orders of magnitude, in powers of ten. The results are presented in the table here.
The three measures that I calculated, are:
· The number of vertebrate animal saved per euro, which includes all fish, birds and mammals that are no longer killed by humans for food (i.e. excluding invertebrates and animals not directly killed by humans).
· The number of vertebrate land animals spared per euro, which includes all farm animals that are no longer bred in captivity.
· Ton CO2e emissions avoided, which includes all anthropogenic greenhouse gases that are no longer emitted, measured in CO2-equivalents (excluding the carbon capture and storage capacity of reforested farmland).
Cell-based meat R&D calculation
There are 10^11 vertebrate land animals used (i.e. bred and killed) per year by humans. Assume that this number is constant until cell-based meat enters the market. The number of vertebrate animals directly killed by humans for food is an order of magnitude higher: 10^12. The human population counts 10^10 humans, also assumed to be constant, which means an average human uses 10 vertebrate land animals per year and kills 100 vertebrate animals per year. Hence, eating vegan for one year spares 10 animals and also saves 10^0=1 ton CO2-equivalent greenhouse gas emissions.
Global funding for cell-based meat is 10^8 euro per year. This corresponds with 10^2 cell-based meat companies and research units at universities, employing on average 10 employees per organization and 10^5 euro per employee per year.
Assume in the business as usual scenario (where you do not contribute) the same amount of money is funded (by other people) every year until cell-based meat becomes cost-competitive with animal-based meat on the market. In other words, if 108 euro were not invested in cell-based meat this year, the arrival of cell-based meat on the market would be delayed by one year. If 1 euro were invested this year, the arrival on the market will be advanced with 10^-8 year.
Also, assume that the probability that cell-based meat will eliminate animal-based meat and animal farming, is 1/10 (or cell-based meat is guaranteed to take 10% of the meat market in the future). This is probably a low estimate.
The above estimates measure the scale (10^11 animals used per year), the solvability (1/10 probability of eliminating animal farming) and neglectedness (10^-8 years faster elimination per extra euro funding). Now the number of animals spared per extra euro donated to cell-based meat R&D can be calculated as the product of scale, solvability and neglectedness: 10^11x10^-1x10^-8=10^2. This means one euro extra funding spares 100 vertebrate land animals. Including captured and aquaculture fish (also fish used for fish meal for farm animals), the number becomes an order 10 higher: 1000 vertebrate animals saved per euro.
As sparing 1 farm animal corresponds with reducing 0,1 ton CO2e, this one euro funding also means a reduction of 10 ton CO2e, the same order of magnitude as the emission by an average human in one year. Used as carbon offsetting, cell-based meat R&D has a price around 0,1 euro per ton CO2e averted. This is much lower than most other carbon offsetting mechanisms.
The above is a low estimate of the impact of cell-based meat R&D. A higher estimate can be obtained as follows. Suppose it takes 10^2 years of research at 10^8 euro of funding per year before cell-based meat becomes competitive with animal-based meat. Suppose 90% of the funding are investments that will eventually be payed back by consumers who buy cell-based meat. The remaining 10% has no return on investment and hence counts as real costs. Hence, the amount of funding costs is 10^7 euro per year. Suppose without cell-based meat, humans will use farm animals for another 10.000 years at 1011 animals per year. The probability that cell-based meat will eliminate animal farming is again 10^-1. In this scenario, contributing 1 euro of funding has an impact of 10^4 years times 10^11 animals per year times 10^-1 probability divided by 10^2 years times 10^7 euro per year, which equals 10^5 vertebrate land animals spared per euro. This sparing of farm animals is again accompanied by avoided greenhouse gas emissions, but most of those avoided emissions would have happened in the far future. Considering only the short term emission reduction for a time period of 10 years, this again comes down to a carbon offsetting price of around 0,1 euro per ton CO2e averted.
Note that the neglectedness is important. Consider for example investments in plant-based meat, which is an order of magnitude larger than investments in cell-based meat, i.e. 10 times less neglected. Suppose plant-based meat also has a probability of 10% of eliminating the animal-meat market (or reducing animal farming by 10%). Then the effectiveness of investments in plant-based meat is an order of magnitude lower than the investments in cell-based meat. Of course, both plant-based and cell-based meat can mutually reinforce each other (i.e. they can be complementary instead substitutable strategies).
Vegan advocacy campaigns calculations
The above impact estimates of cell-based meat R&D can be compared to other measures to reduce animal farming.
Animal Charity Evaluators estimates a cost-effectiveness of around 10 farm animals spared per euro donated to its top recommended charities. This is an order 10 lower than cell-based meat R&D.
Vegan outreach leafletting has an estimated impact of 1 animal spared per euro. I did a personal leafletting study (at the Belgian animal rights organization Bite Back) whereby the leaflets included a survey that asks questions about the reduced consumption of animal products due to the leaflet. Based only on the responses of non-vegans who answered that they reduced their animal product consumption, it requires roughly 1000 leaflets for one equivalent conversion to veganism. This was measured in vegan-equivalents, i.e. in terms of the equivalent reduction of the number of animals used. For example, two meat-eaters who reduce their consumption by 50% count as one vegan. Assume that a respondent remains vegan or sticks to his reduced animal product consumption for 10 years. One vegan-equivalent spares around 10 farm animals per year and one leaflet costs 0,1 euro. That means a cost-effectiveness of 1 spared animal per euro (i.e 10 animals per vegan year times 10 years divided by 1000 leaflets times 0,1 euro per leaflet). This is in the same order of magnitude of other cost-effectiveness estimates of leafletting.
Vegan education (giving presentations about veganism) also has a cost-effectiveness of 1 spared farm animal per euro: 10 participants of a lecture times 1% probability of a participant becoming vegan (based on a small personal study that surveys high school students who participated my vegan education lectures) times 10 years of remaining vegan times 10 animals spared per vegan year divided by 10 euro costs per lecture (if I were to be paid an hourly wage of 10 euro).
We can also estimate the overall cost-effectiveness of animal advocacy campaigns. The US population has an order of magnitude 10^8 people. Suppose meat consumption is decreased by 10% due to people becoming reducetarians, vegetarians or vegans. Suppose 10% of this reduction is due to animal advocacy campaigning. Then the number of US vegan-equivalents for animal welfare reasons is 10^6. The two largest animal advocacy organizations (HSUS and Peta) have a yearly budget of 10^8 euro. If their campaigns caused the reduction in meat consumption, we get a cost-effectiveness of 0,1 farm animals spared per euro donated to those animal charities (10^6 vegans times 10 animals spared per vegan per year divided by 10^8 euro funding per year). This means cell-based meat R&D is about 1000 times more effective than average animal advocacy.
Cell-based meat research and development is roughly 10 times more cost-effective than top recommended effective altruist animal charities and 1000 times more cost-effective than average animal advocacy and vegan campaigning. One euro finding for cell-based meat R&D could spare the lives of 100 farm animals, save the lives of 1000 vertebrate animals and avoid 10 ton CO2-equivalent emissions. That makes cell-based meat R&D probably the most effective measure to reduce anthropogenic animal suffering and greenhouse gas emissions.
You can support cell-based meat R&D by donating to New Harvest.
In your model, cell-based meat replaces animal-based meat in 100 years, thus each euro invested now will mean a reduction of 10 ton of CO2e in 100 years. I'd argue that one ton of CO2 now is worth way more than one ton of CO2 in 100 years.
How much more? One way to compare the two would be to imagine what would happen if, instead of spending your one euro now, you were to save it, and spend it in 100 years. With an annual interest rate of 5%, you would get 130 euros in 100 years, which you could then spend on the best carbon offsetting mechanism at the time.
My point is, in term of CO2 averted, it's probably more effective to save money and spend it in the future than to fund cell-based meat R&D
PS : To be fair, it's way better if many are willing to fund cell-based meat R&D too. If the funding goes from 10^8 up to 10^9, we only have to wait for ten years for the cell-based meat, and therefore the saving strategy isn't as good anymore.
I partially agree. In my second, high estimate model, cell-based meat arrives in 100 years. However, it more likely arrives sooner, e.g. in 2030. From then on, carbon offsetting starts to count. I agree that we should discount future emission reductions, due to the urgency of the climate problem and the possibility of early threshold values in the climate system being passed. But 10 years is not so long.
Thanks for sharing this! I had considered attempting some sort of back of the envelope calculation like this myself so I'm glad to see your effort.
I also found it interesting to see some of your guesses/assumptions, like "Suppose without cell-based meat, humans will use farm animals for another 10.000 years at 10^11 animals per year." I think that, if a more rigorous cost-effectiveness analysis was attempted, it would be good to survey experts on their intuitions on some big questions like that.
This sort of modelling is definitely not my forte, so apologies if I'm misunderstanding. Am I right in saying that the model currently assumes *no* diminishing returns? I.e. that the 100 millionth dollar donating to cultivated meat R&D is equal to the 1st dollar? I think that the value of additional contributions on the margin is the important (and difficult) thing to estimate.
I'm not sure that ACE's CEAs should really be compared to your CEA. The methodologies are very different. E.g. ACE's CEAs exclude any uncertain, medium-term effects, whereas your CEA is essentially entirely based on those sorts of medium-term effects (I say medium-term to distinguish effects on farmed animals in the next few centuries from effects on other future sentient beings such as artificial sentience).
A couple of lower importance comments, for the main thrust of your post:
ACE's meta-analysis provides less reason for optimism than the study you refer to.
I think that this misses most of the impact of most animal advocacy campaigning. I don't see the main effect of animal advocacy campaigning as being to cause diet change in the short-term. Apart from the indirect positive effects for future sentient beings such as artificial sentience (which could apply similarly to cultured meat R&D success and animal advocacy success), I see the main effects as being:
about the 10.000 years assumption: that is only used to calculate a high estimate of clean meat R&D. I'm not so worried if that is an overstimate.
My calculation assumes indeed no diminishing returns for clean meat R&D. I don't expect diminishing returns in the short run, when so much need to be researched. In my model, the decreasing neglectedness accounts for diminishing returns. When funding and investments by others increses to 1 billion dollars, the cost-effectiveness decreases with a factor 10. Anyway, the point is that clean meat R&D is a good opportunity in the short run, for the next 10 or 20 years.
ACE's CEA methodology is different indeed, but Im not convinced that it is really incomparable to mine. A basic assumption is that ACE's top charities who are not involved in clean meat (i.e. the charities except Good Food Institute), are not capable of eliminating animal farming before clean meat can.
The CEA of leafleting could be an overestimate indeed. The study that I did, was not randomized controlled.
About missing the impact of animal advocacy: I'm sceptical about the possibility of attitudinal change: just like the expectations of leafleting were too high (not strong evidence of behavioral change), the expectations about other animal rights advocacy could be too high as well. The case for clean meat is different: in the past we already have striking examples of animals being replaced by more than 90% within 50 years due to new technologies (e.g. horses -> cars, whale oil -> kerosene, messenger pigeons -> telephone/telegraph, sheep wool -> synthetic fibers, animal insulin -> human recombinant DNA insulin, rabbit skin tests for cosmetics -> human skin tissueand perhaps now movie animals -> CGI animals). These transitions were independent from animal rights campaigning.
I do see much room left for attitudinal change, in particular moral circle expansion (see e.g. https://stijnbruers.wordpress.com/2020/03/17/consider-remarkable-animal-capabilities-to-expand-the-moral-circle/), but perhaps after 10 or 20 years, when clean meat is already well on track and lost its opportunity for more funding (and returns diminished). Also, once people automatically decrease their animal meat consumption, they suffer less from cognitive dissonance, which means attitudinal change might become easier.
I'm skeptical about the welfare reforms strategy. For me to be indifferent between the current welfare reforms and an X% reduction of animal farming, I think X is very low, probably lower than 10%. For example cage free eggs: I don't believe that, if all battery cages were abolished and chickens had free range, that count for more than a 10% improvement in welfare, and probably a 0% in animal rights. Given moral uncertainty, I put some probability on a rights-based ethic where animals should not be used as merely a means. Also, some of the future possible welfare reforms could be so difficult, that clean meat (or animal-free eggs) will arrive sooner, making the welfare reforms campaigns obsolete. Also, welfare campaigns are also much less neglected than clean meat R&D.
This is all fascinating, thanks.
I'm curious about folks' thinking on plant-based meat. GFI's scientific grants program has put $7m+ into plant-based and cultivated (aka cell-based) meat research over the past two years, and our science team is equally bullish on plant-based v. cultivated.
In short, we think it's likely that plant-based will get to the Holy Grail (products that taste the same or better and cost the same or less, which is the only way the products compete for the consumer dollar of the vast majority of consumers) at least as quickly as cultivated. So we think open access R&D into plant-based is as important as open access R&D into cultivated.
I'm very curious about others' thoughts on these assumptions.
To see the projects GFI has funded so far (with dedicated funding from a limited number of philanthropists), the scientific team that makes the decisions, and our funding philosophy, check out gfi.org/researchgrants. Two of our grantees published peer reviewed journal articles just last month, and another had an article in the trade association magazine Cereal Foods World.
Thanks so much to everyone who is focused on making the most effective funding decisions possible.
Hi. I think there is an error in the part your analysis dealing with the cost of developing cell-based meat.
If i understood correctly, we are operating under the simplifying assumption where developing cost-competitive cell-based meat has some up front cost C and then yields U utility every year, forever, starting once that up front cost is paid. If we're choosing between a bunch of interventions that work the same way, then we should first fund whichever intervention has the highest return on investment, which would be U/C.
In comparing two different interventions that achieve an equally good outcome, we should fund whichever has the lower cost. I don't think we can get away with not making an actual estimate of the cost required to accomplish the goal. Under the reasoning used in your analysis, where the current level of funding is used as the cost to advance progress by one year, we would instead end up choosing to fund whichever intervention has the lowest current level of funding, even if completing it would cost more than an alternative intervention.
In the scenario where the level of funding F is the same every year, if you make a one time donation x, the outcome gets closer by xF years, therefore you've produced U⋅xF utility.
The main assumption behind this result is that some utility U in the future is worth as much as some utility U right now. Therefore, when judging which of two projects is the best, since C only affects how long it will take to complete each project, it doesn't matter. The only quantities that matter are U of course, and the funding F.
What if you want to take into account the fact that no, some utility in the future is worth less than some utility right now, therefore completing quick projects first is better?
Warning : this part will involve math
One common way to do that is to assume that the utility decreases over time in a geometrical manner : 1 utility unit in 1 year is equivalent to τ utility units now, 1 unit in two years is equal to τ2 utility units now, with τ slightly smaller than 1. For example, if τ is equal to 0.99, then one utility point in one century is worth about one third of one now, and the closer τ is to 1, the more you adopt a longtermist point of view.
Ok so now we can compute the total utility of a project with cost C, annual funding F, and per year utility U :
Now, making a one-time donation x, is the same as decreasing the total cost C by x, thus the utility gain of this donation will be :
So we have three factors : U, of course, xF, which is how many years of funding you'll provide with your donation, and τCF which represents how much this future utility is worth, compared to utility right now. Once again, if you think that utility in the future is equal to utility now, which means τ=1, you get gain=U⋅xF, which is the original formula in the post. C matters only if utility in the future is not equal to utility in the present.
Now, we can re-write this formula with your notion of return on investment :
With this version, we see three factors influencing the gains : x, the bigger your donation, the better, UC, the bigger the return on investment, the better, and finally CFτCF, which is a function of CF, the number of remaining years. This function is convex, it starts at 0, reaches a maximum, and its limit is 0 again when CF approches infinity.
#TODO : include a graph of this function, once I figure out how to do that
With this model, when CF is too small, it means that the project will soon be funded with or without you, thus you shouldn't invest in it. On the other extreme, if CF is too big, the benefits will take place too far in the future, and because utility points lose value when too far in the future, you shouldn't invest in it either. In the middle are the best projects.
Anyway, the main point is : the cost C matters only if you think that utility right now is worth more than utility in the future, otherwise only the funding F matters
In your equation where future benefits are discounted, using the derivative makes sense if your donation is small relative to the total cost of the project. I was doing the opposite and assuming that we pay for the whole thing. Given that the estimated cost is in the billions of dollars and a lot of that funding is from people we can't coordinate with, your assumption seems closer to reality than mine.
Without discounting, things are less straightforward and i've got a messy page of math/notes right now that i'll try to turn into something post-able this weekend. But basically when i wrote that we should first fund whichever option has higher U/C, i had forgotten the assumptions that that result was based on. U/C is the right metric if there is no outside funding and you have a constant income per year. The way you're approaching the problem is as if we have a limited budget to use today and no income and each project has a constant, positive amount of outside funding per year. I wrote out a bunch of equations under those assumptions and am convinced that, given two projects, we should choose whichever has higher U/F. At least the way i derived them, these metrics come from calculations that work around the whole infinite utility thing by looking at the difference in the finite amounts of utility that we miss out on (relative to having both projects done at time zero) depending on which of two projects we fund first, so this stuff does not generally result in "utility per dollar" numbers that can be compared to other cost-effectiveness estimates where everything is nice and finite.
If there's no outside funding and your money is limited, some projects will never be completed, which causes infinity-related issues that break everything. With finite utilities, i think that's just a knapsack problem.
I have not yet figured out a solution for the case where we have an annual income, there is outside funding, and no discounting, but that's the plan.
Following up on this, i did work out a solution for the case where we have an annual income, there is outside funding, there's no discounting, and there's a consumption option where instead of funding a project we can just collect K utils per dollar. The work behind this is a mess, partly because the equations get long and partly because it was mostly just me doing the same thing repeatedly for slightly different situations until i stopped being confused. Since either declining to show my work or putting 14 kilobytes of garbage in a forum comment would both be bad, here it is in a pastebin link: https://pastebin.com/raw/PnDZ2rTZ
The result is if there are two projects, X and Y, and our income I is such that we can't affect which of two projects gets done first, that is, if C_X / F_X < C_Y / (F_Y + I), then project X will always be finished before project Y and there's nothing we can do about it, then we should fund whichever project has higher U/F. But if we are able to affect which project gets done first, we should fund whichever has higher (U - K*F) / C.
And after thinking about it more and writing more equations, i think U/F really does give us a direct comparison of project-like interventions (utility over time forever once it's fully funded) to consumption-like interventions (utility per dollar). And it gives us a direct comparison of project-like interventions if we can spend money to complete a project in zero time. And it gives us a direct comparison of project-like interventions in the case where making/spending money takes time, but that time doesn't matter because we can't change the order in which things get done. The case where it does not work is when we have an annual income as opposed to a one-shot budget and we're comparing two project-like interventions and the one that we fund first is the one that gets done first.
I think what makes the result for the case where we have an income and can determine which intervention gets done first so qualitatively different from the case where have a stack of cash and can choose between two projects to knock out is that we have to take into account how much choosing to fund the first project delays our ability to fund the second project. And that delay is proportional to C. (Everything here is assuming no diminishing returns to rate of funding, so it's always best to concentrate funding on one project to knock it out as soon as possible and never makes sense to split funding between projects and get neither one done.)
Thanks! I assumed indeed a zero discount rate, because I believe the disutility of farm animal suffering in the future counts the same as the disutility today. Perhaps one could use a very small discount rate, to account for a human extinction probability, but then again, when humans are extinct, there will be no more farm animal suffering. I guess a higher discount rate matters when utility measures greenhouse gas emisions saved. Reducing 1 ton CO2 now is more important than 1 ton later (because in the future the carbon absorption capacity by forests, oceans and carbon capture and storage technologies will be bigger). However, I think cell-based meat will enter the market within 10 years, so I don't expect C/F to be very big.
Thanks for your response!
This makes cell-based meat R&D actually less effective : without discount gain=x⋅UC⋅CF
In term of farm animal suffering, you estimation is U=0.1⋅1011, and C = 1010 . So for each euro invested, you'll avoid the suffering of CF farm animals. The smaller the time we have to wait before cell-based meat enters the market, the less we should donate.
(This is basically because if cell-based meat enters the market in 10 years, instead of 100, its neglectedness is 10 times smaller, therefore your donation is ten times less effective)
It actually depends on why you think it will be 10 years instead of 100 : if you think it's because funding will be bigger, then the neglectedness is smaller. If, instead, you think that's because the cost is smaller (C = 109), then, as previously stated, it doesn't impact the effectiveness of the donation
Sorry, I'm not following. The gain is independent of C, and hence (at given U and F) independent of the expected time period. Assume x is such that cell-based meat enters the market 1 year sooner (i.e. x=F). Accelerating cell-based meat with one year is equally good (spares U=0,1.10^11 animals), whether it is a reduction from 10 to 9 years or 100 to 99 years. Only if C/F would be smaller than a year, accelerating with 1 year would not work.
I totally agree with you, the gain is independent of C.
In your original post, you give a scenario where the cell-based meat enters the market in 100 years, while you seem to believe that an actual estimate would rather be ten years or less. I wondered if this was because you overestimated C, or underestimated F (both affect the timeline, but only F affects the gain)
I now understand that you overestimated C, so this doesn't affect your prediction about the gain
Thanks for clarifying!
The basic (in my opinion realisitic) assumption is that other people invest in cell-based meat R&D anyway, and that in the business-as-usual scenario (where you do not fund anything) no other strategy (technology, intervention, vegan outreach campaign,...) will be able (even with more funding) to abolish animal farming before cell-based meat enters the market at competitive prices. Suppose cell-based meat arrives within a few decades and eliminates animal farming in say 50 years, whereas another, next best strategy would eliminate animal farming in 100 years. Suppose that this other strategy was less costly, for example requiring only 10 million euro funding per year over a period of 100 years to abolish animal farming, whereas cell-based meat would require 100 million euro funding over 50 years. And suppose that other strategy was more neglected, for example receiving only 10 million euro funding per year, compared to 100 million for cell-based meat. Even then, extra funding for that other strategy would not be effective when it is impossible to speed it up such that it will eliminate animal farming within 50 years. When that other strategy takes more than 50 years anyway, it will become obsolete anyway in the business-as-usual scenario where cell-based meat arrives earlier and eliminates animal farming earlier. A global coordination such that all cell-based meat funding goes to that other, less costly strategy, is not effective (not so feasible). Hence, the most effective thing to do for us, is to accelerate that cell-based meat research, such that it enters the market one year earlier. That saves an extra year of animal suffering and greenhouse gas emissions. If other strategies received more funding, there is a likelihood that they make cell-based meat obsolete, and this consideration is included in the 10% probability of cell-based meat eliminating animal farming.
Gotcha. I was thinking about a much simpler situation where we're comparing two interventions to accomplish equally valuable goals, rather than two interventions to accomplish the same goal, where finishing one makes the other obsolete. I was also assuming that we are able to coordinate on what to fund. But in the situation you described, it makes sense to fund the cheaper intervention only if we can put together enough money for it to overtake the one that's already being funded, like 555,555,555 euros in your example. But that number is assuming we can just linearly spend money to make stuff happen sooner.
If your belief that
is true, then it makes sense that people funding other strategies to abolish animal farming should coordinate to instead fund cell based meat. (Unless those other strategies also produce a significant amount of utility in the short term that falls short of abolition.) I don't know nearly enough about this stuff to evaluate your claim that cell based meat will probably be the thing that ends animal farming, but it seems like something that's important if it's true, and i think you should post your reasons for believing this as a new top level forum post.
Thanks for sharing your computation. This highly resonates with a (very rough) back of the envelope estimate I ran for the cost-effectiveness of the Good Food Institute, the guesstimate model is here https://www.getguesstimate.com/models/16617. The result (which shouldn't be taken to literally) is $1.4 per ton CO2e (and $0.05-$5.42 for 90% CI).
I can give more details on how my model works, but very roughly I try to estimate the amount of CO2e saved by clean meat in general, and then try to estimate how much earlier will that happen because of GFI. Again, this is very rough, and I'd love any input, or comparison to other models.
I'm surprised by the level of agreement between our assumptions. In your model, 200 M$ funding is required to advance clean meat with 0,7 years, whereas I assumed 100M$ and 1 year. You assume a lower greenhouse gas saving: 50% of the current 7,8 Gton CO2 emissions, whereas I assumed an increase in meat consumption in businass as usual scenario, and a reduction of 1 ton CO2 per vegan year, that means a reduction of around 10 Gton (assuming 10B people), but you assumed a 25% probability of success, whereas I assumed 10%. But with more lognormal error distributions, you arrive at higher $/ton estimates. Here's my guesstimate
I too was surprised when I first read your post. I find it reassuring that our estimates are not far from each other, although the models are essentially different. I suppose we both neglect some aspects of the problem, although both models are somewhat conservative.
I agree that it is probably the case that cell-based meat is very cost-effective at greenhouse gas reduction, and I would love to more sophisticated models than ours.
I really appreciate this work, but wonder about the magnitude of the uncertainty in your analysis. Would it be possible for you to convert your calculation into a Guesstimate sheet?
I quickly made a guesstimate: https://www.getguesstimate.com/models/16723 (you can also compare it with shaybenmoshe's guesstimate below)