Dr. David Denkenberger received his B.S. from Penn State in Engineering Science, his M.S.E. 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 his patented expanded microchannel heat exchanger. He is an assistant professor at University of Alaska Fairbanks in mechanical engineering. He co-founded and directs the ALLiance to Feed the Earth in Disasters ( and donates half his income to it. 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 95 publications (over 1500 citations, h-index = 18), 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 200 articles, including Science, Wikipedia, Discovery Channel Online News, Gizmodo,, and Science Daily. He has given interviews on 80,000 Hours podcast and Estonian Public Radio, WGBH Radio, Boston, and WCAI Radio on Cape Cod, USA. He has given over 90 technical presentations, including ones on food at Princeton University, Lawrence Berkeley National Lab, Sandia National Lab, Los Alamos National Lab, Cornell University, Imperial College, University College London, University of Cambridge, and University of Oxford.

Denkenberger's Comments

Has anyone done an analysis on the importance, tractability, and neglectedness of keeping human-digestible calories in the ocean in case we need it after some global catastrophe?

Thanks for your interest—all of ALLFED's published research is here. But what is not yet published is that it is looking like the ocean fertilization effect will not be as strong as we had originally estimated. However, there are ~10 billion tons of deeper water fish (200 to 1000 m down), though they would be expensive to harvest. We think producing seaweed would be low cost and feed many people.

AI Impacts: Historic trends in technological progress

This is fascinating work! Small comment: you mentioned that the practical lens concentration limit is about 50% of the intensity at the surface of the sun and that we likely achieved that 1000 years ago. But then you say that magnesium combustion reaches 3370 Kelvin. Since the sun is about 5800 Kelvin and the total radiation goes with the fourth power of the absolute temperature, that would mean magnesium would only be 1/9 the intensity of the sun. So that would mean that magnesium combustion would not have surpassed a good magnifying glass.

Update on civilizational collapse research

Thanks for writing this up. I would love to see more detail in general, but in particular on this point:

The highest leverage point for intervention in a potential post-collapse environment would be at the state level. Individuals, even wealthy individuals, lack the infrastructure and human resources at the scale necessary to rebuild effectively. There are some decent mitigations possible in the space of information archival, such as seed banks and internet archives, but these are far less likely to have long term impacts compared to state efforts.

So you're assuming that the states still function after the collapse? What do you think they would do and what would you like them to do differently? What do you think about interventions post catastrophe to reduce the likelihood of collapse? For instance, there is the idea of a backup shortwave radio system that I mentioned in our joint salon that would not require a state.
Why is the Internet archive (I assume printed out) not important, because there would already be enough information preserved in books? I don't think that would apply so much in the case of seeds because we might not be able to continue growing the high-yielding varieties that are dependent on fertilizer and pesticides.

Clean cookstoves may be competitive with GiveWell-recommended charities

I think this is important to investigate given the high mortality. I noticed that you ignored the savings in fuel. My understanding was that this could be quite significant and the stoves could pay for themselves either in saved fuel cost or saved opportunity cost of time from gathering the fuel. If this were true, you might be able to argue that the life savings and climate benefit came at zero cost. You would still have the issue that people are not willing to pay for them, perhaps because they have a high discount rate. Loans might ameliorate this.

Update on civilizational collapse research
I think most nuclear winter scenarios also have less than a 90% food reduction impact

The Open Philanthropy funded nuclear winter project will soon have an estimate of global agricultural impact, but I think without relocation of crops, 90% production loss is plausible. How that translates into mortality is complicated. It may be possible to relocate crops towards the equator, but the likelihood of that happening would depend on preparation ahead of time for coordination, etc. On the positive side, we have some food storage, which has the potential to take ~10% of the population through a nuclear winter with complete agricultural collapse if perfectly protected. However, on the other extreme, if food were distributed equally, then perhaps a 70% food supply reduction would mean everyone starves. The reality is likely to be between these extremes of perfect protection and equal distribution. Of course the situation changes dramatically if we can produce alternative foods.

Four components of strategy research

Thanks for mentioning ALLFED! As we note in the model you link to, a more updated model is here.

Cotton‐Barratt, Daniel & Sandberg, 'Defence in Depth Against Human Extinction'

I heartily agree-I've been saying for years that response and resilience are neglected in the X risk/GCR community relative to prevention.

Concerning the Recent 2019-Novel Coronavirus Outbreak

Have you looked at how long pandemics have lasted in the past? I think it's a lot longer than five weeks.

Doing good is as good as it ever was

I agree that absolute impact is the better way of looking at this. You talk about the original pitch of EA of donating 10% of your salary and saving quite a few lives. But now that same person can donate the same amount of money to the long-term future and potentially save orders of magnitude more lives in expectation. So I think EA has gotten more exciting. I could see if someone has inflexible career capital in the global poverty or animal space and little ability to donate and became convinced of the value and tractability of the long-term future, that this could decrease one's relative impact. But I think this is less common than the case of being able to pivot (at least somewhat) towards higher impact. So I think a change in enthusiasm is more related to general trends with age and movements, rather than a change in perception of relative impact.

Financial Planning Advice for Charitable Giving

Welcome to the EA Forum! Kudos to you for your generosity! You’ve probably already joined Giving What We Can, but you may also be interested in Bolder Giving (giving high percentages, but not focused on effective giving).

Since you can deduct state taxes and interest on a mortgage, I would guess you are already exceeding the $14,000 standard deduction. So then I think it would be important to donate every year to make sure you are saving taxes on the money you make in the top bracket. Here is a post that might be helpful. There are also quite a few posts (e.g. this recent one) on investing with an EA mindset.

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