Denkenberger🔸
Bio
Participation4
Dr. David Denkenberger co-founded and is a director at the Alliance to Feed the Earth in Disasters (ALLFED.info) and donates half his income to it. He received his B.S. from Penn State in Engineering Science, his masters from Princeton in Mechanical and Aerospace Engineering, and his Ph.D. from the University of Colorado at Boulder in the Building Systems Program. His dissertation was on an expanded microchannel heat exchanger, which he patented. He is an associate professor at the University of Canterbury in mechanical engineering. He received the National Merit Scholarship, the Barry Goldwater Scholarship, the National Science Foundation Graduate Research Fellowship, is a Penn State distinguished alumnus, and is a registered professional engineer. He has authored or co-authored 156 publications (>5600 citations, >60,000 downloads, h-index = 38, most prolific author in the existential/global catastrophic risk field), including the book Feeding Everyone no Matter What: Managing Food Security after Global Catastrophe. His food work has been featured in over 25 countries, over 300 articles, including Science, Vox, Business Insider, Wikipedia, Deutchlandfunk (German Public Radio online), Discovery Channel Online News, Gizmodo, Phys.org, and Science Daily. He has given interviews on 80,000 Hours podcast (here and here) and Estonian Public Radio, Radio New Zealand, WGBH Radio, Boston, and WCAI Radio on Cape Cod, USA. He has given over 80 external presentations, including ones on food at Harvard University, MIT, Princeton University, University of Cambridge, University of Oxford, Cornell University, University of California Los Angeles, Lawrence Berkeley National Lab, Sandia National Labs, Los Alamos National Lab, Imperial College, Australian National University, and University College London.
How others can help me
Referring potential volunteers, workers, board members and donors to ALLFED.
How I can help others
Being effective in academia, balancing direct work and earning to give, time management.
Posts 38
Comments788
Let's break this into two questions:
1. After a few years of ASI, will the ASI be able to stop or reverse aging?
2. After a few years of ASI, will hardly anyone die of aging related diseases?
Let's tackle number one first. It's true the ASI would not be able to do long term human trials the regular way. However, I think it could learn a lot from the data from running trillions of lab-on-a-chip experiments. I think it could develop nano bots that could remove cancer cells and repair aging related damage. And it could get quick feedback by making C. elegans, etc immortal. It might also be able to simulate biology from first principles in order to run the equivalent of decades long human trials. Â
I also think it could develop noninvasive (or at least non-destructive) scanning techniques that would allow someone's consciousness to be simulated. And even if that doesn't count, it might even be able to build up a new biological human that has equivalent consciousness to the original (which still may not count depending on one's values). There are likely many other routes to quick longevity that I can't think of but an ASI could.
As for the second question, would people allow the, e.g., repair nano bots into their bodies? One subquestion is whether countries would allow it. Based on current laws, probably not, though it's possible they would change quickly due to ASI (and people could go into international waters). Another subquestion is if it is legal, would people do it? Obviously some people would not, but if the alternative is a soon death, I think many people would.
Some people are concerned about AI x-risk, and they have P(doom)s in the 5–25% range. I don't get that. I can't pass an Ideological Turing Test for someone who sees all these problems, but still expects us to avert extinction with >75% probability. I don't understand what would lead one to believe that this is what things look like when we're on track to solving a problem.
P(doom) does not necessarily equal extinction. Paul Christiano had (in 2023) P(AI takeover) at 22%, and P(most humans die from takeover) = 11% (but then other ways of most people dying). But he has much lower probabilities of extinction due to pseudo pico kindness, acausal trade, etc.
Microalgae is fairly expensive, so I think macroalgae is more promising - most of it is low protein, but there are high protein varieties. Leaf protein concentrate (e.g. Leaft) seems promising as well.
Plant-based meat prices per pound are based on frozen and refrigerated plant-based meat subcategories from SPINS year ending 12/1/24. Animal-based meat prices per pound are based on data for fresh meat subcategories from the Circana year ending Dec. 2024.
Fresh meat typically costs more, and it seems like this includes whole muscle meat, so I think if you do a fair comparison, PBM is more like double the cost of ground beef.
I just have info from AI:
| Era | % Plant Calories | Notes |
|---|---|---|
| 1920s (early kibble) | 10–30% | Mostly horse meat + grains; Purina starts ~1926 |
| 1950s–1970s | 40–60% | Corn/soy fillers rise for cost, extrusion tech |
| 1980s–2000s | 50–70% | Grain-heavy economy formulas dominant ​ |
| 2010s–2026 | 60–80% | 52% of US pet foods use plant proteins by 2024; "grain-free" niche lowers some to 40% ​ |
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I haven’t dug into the surveys that Knight cites but I’m super skeptical. I know vegans who don’t have vegan pets, and I know how hard it is to make people go vegan. There are big barriers to getting humans to transition to alternative proteins at scale, and that’s only more true for companion animals.
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I'm skeptical as well, but in some ways, the barriers for pets going vegan are lower:
- Taste is less of an issue for pets.
- Time cost is much lower for pets because you can just pick out one food and buy it every time.
- For people concerned about social interactions involving veganism, you don't have to tell anyone that your pet is vegan.
- It may be easier to mitigate the health issues of being vegan for pets: For methane single cell protein (SCP) fed to salmon, just a little compared to fully vegan (soy) diet showed a big improvement in gut health. I'd be most confident that this would port to other obligate carnivores like cats, but I could see it being beneficial for dogs as well. Methane SCP is not yet approved for human food, but they are targeting pet food.
In the last few decades, dog food has become more plant based because plants are cheaper (and they figured out how to make it appealing to dogs and not offensive to people). If methane SCP can become cheaper than animal byproducts, you could have a healthy cheaper product with lower environmental impact that probably wouldn't taste as good, but I think many non-vegans would go for.
An option to circumvent current laws would be the person dying, and then being fixed by the tech and revived. This could be thought of as like "fast cryonics."