Dr. David Denkenberger 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 his patented expanded microchannel heat exchanger. He is an assistant professor at University of Alaska Fairbanks in joint in mechanical engineering and Alaska Center for Energy and Power. 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 104 publications (>2000 citations, >50,000 downloads, h-index = 23, third 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 200 articles, including Science, Vox, Business Insider, Wikipedia, Deutchlandfunk (German Public Radio online), 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 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, and University College London.


Some quick notes on "effective altruism"

Though I was surprised when I read the results of the first EA survey because I was expecting the majority of non-student EAs would donate 10% of their pretax income, I don't think that saying that EA donations are extremely low is quite fair. The mean donation of EAs in the 2019 survey was 7.5%. The mean donation of Americans of pretax income is about 3.6%. However, with a significant number of EAs outside of the US giving less, the fact that many EAs are students, and the since I think that the EA mean is by person rather than weighted by donation (as the US average number is), I would guess EAs donate about 3-5 times as much as the same demographic that is not an EA. I do think that we could do better, and a lot of good could come from more donations.

Why I find longtermism hard, and what keeps me motivated

Nice piece! Though this does not work for all longtermist interventions, some find it motivating that AGI safety, alternative foods, and interventions for losing electricity/industry (and probably other interventions) likely save lives in the present generation more cost-effectively than GiveWell top charities. This book argues that doing more to mitigate catastrophes can be justified by concerns of the present generation.

Big List of Cause Candidates

Congratulations on winning the comment award! I definitely agree we should broaden the scenarios at which we look. You can see some work on the long term future impact of lesser catastrophes here and here.

  • Solar storm disruption

Yes, and other catastrophes that could disrupt electricity/industry, such as high-altitude detonation of a nuclear weapon causing an electromagnetic pulse, coordinated cyber attack on electricity (perhaps narrow AI enabled), or an extreme pandemic causing the desertion of critical jobs may be important to work on.

  • CO2 emissions from fossil fuels and other climate change rendering the atmosphere unbreathable (this would be a good old fashioned X-risk, but seems like one that no-one has discussed - in Toby's book he details some extreme scenarios where a lot of CO2 could be released that wouldn't necessarily cause human extinction by global warming, but that some of my back-of-the-envelope maths based on his figures seemed consistent with this scenario)
  • CO2 emissions from fossil fuels and other climate change substantially reducing IQs

Even 7000 ppm (0.7%) CO2 only has mild effects, and this is much higher than is plausible for Earth's atmosphere in the next few centuries.

  • Various 'normal' concerns: antibiotic resistant bacteria; peak oil; peak phosphorus;

It is possible that overreaction to these could cause large enough increases in prices to make poor of the world significantly worse off, which could cause political instability and eventually lead to something like nuclear war. But I think it is much lower probability than those that could directly reduce food supply abruptly by order of magnitude 10%.

  • substantial agricultural collapse; moderate climate change;

I think the moderate climate change, perhaps 2°C over a century, is difficult to find a direct route to a collapse. However, it would make a 10% food production shortfall from extreme weather more likely. And there are many other catastrophes that could plausibly produce a 10% food production shortfall, such as:

1 Abrupt climate change (10 C loss over a continent in a decade, which has happened before)

2 Extreme climate change that is slow (~10 C over a century)

3 Volcanic eruption like Tambora (which caused the year without a summer in 1816: famine in Europe)

4 Super weed that out-competes crops, if a coordinated attack

5 Super crop disease, if a coordinated attack

6 Super crop pest (animal), if a coordinated attack

7 Losing beneficial bacteria abruptly

8 Abrupt loss of bees

9 gamma ray burst, which could disrupt the ozone layer

  • major wars;

This could be a 10% infrastructure destruction, so I think it could destabilize. Disruption of the Internet for an extended period globally could also cut off a lot of essential services.

  • reverse Flynn effect;

Even if the Flynn effect has stalled in developed countries (has it?), I still think globally over this century we are going to have a massive positive Flynn effect as education levels rise.

Other concerns that I don't know of, or that no-one has yet thought of

Agreed, which is a reason that resilience and response are also important.

How does Amazon deforestation actually work? It's not about soy.

succeeded by land speculators and poor ranchers from other regions, attracted by low-price lands; they’ll put down the remaining forest to raise cattle and subsistence agriculture – with productivity decreasing each year, until they exhaust soil nutrients. 

Indeed, swidden (slash and burn) agriculture was common historically (including in Europe and the southern United States). However, now that we can replace nutrients with artificial fertilizers, it seems like that would be more profitable. Do you have data on what fraction of the land is just abandoned?

Things I recommend you buy and use.

Nice list! How many times can you wear a pair of the silicone earplugs?

Money Can't (Easily) Buy Talent

I agree with Peter - ALLFED has been training up volunteers and we could bring on a lot more talent full-time (both our volunteers and from the general EA pool) if we had more money.

Actually possible: thoughts on Utopia

Nice post - I think it is good to reflect on what we might achieve, rather than only focusing on reducing X risk.

But unlike Heaven, Utopia, if something like it ends up getting built, will be a specific, concrete, physical world, with attendant frictions and problems, idiosyncrasies and contingencies; its own ways of distributing resources, resolving/preventing conflicts, and so on; and ultimately, with fundamental limitations on what can be done.

I’m not sure how feasible these are, but would personal universes address some of these issues?

Notes: Stubble Burning in India

Although stubble burning is an effective way to deal with crop residue in the short term, the practice is pretty bad for the soil.

For one, you lose the nitrogen in the residue to the air through burning. With all the cattle in India, I would think you could just feed the residue to them, and this says it could make up about 50% of their diet. And you might be able to grab some human edible calories first through the leaf protein concentrate process. There is also cellulosic ethanol or cellulosic sugar, though those are likely not economical now.

International Cooperation Against Existential Risks: Insights from International Relations Theory

I agree that IR is important for EA. I would be particularly interested to hear your opinion on collapse of civilization scenarios here.

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