What to eat during impact winter?

A number of possible global catastrophic risks seem like they would do their worst damage by disrupting food production. Some examples include nuclear winter, asteroid impacts, and supervolcanoes. In addition to directly laying waste to significant areas, such events would cast ash, dust, or other materials into the atmosphere. Temperatures would fall and solar radiation for primary producers would be reduced, causing agricultural failures and wreaking havoc on wilderness ecologies. It seems clear that feasible events of this sort could cost hundreds of millions or even billions of lives. But would even extreme events actually bring about would they cause human extinction or constitute an existential risk?

There are several sources of evidence we can bring to bear on the question. We can apply the "outside view" and consider the species, including hominids and primates, that have survived past volcanic and asteroid impacts. We can examine current supplies of food sources that could provide for humans during a period of impaired solar radiation. And we can look at past and present social behavior that bears on the distribution of food and recovery from period of severe famine. In the aggregate, it seems to me that humanity would survive one of these severe food disruptions, despite terrible quantities of death and misery.

This post will take a first-pass look at existing food sources that could be drawn upon during a "year without the Sun," or something close to it.

Economic growth: more costly disasters, better prevention

If you read lists of the most costly earthquakes, hurricanes, and other natural disasters, you will find that they they tend to be quite recent, with damages increasing over time. But earthquake costs have not been rising because of some geological phenomenon, i.e. earthquakes getting more frequent or higher on the Richter scale. Rather, populations and economies have been growing, so that there are more valuable things for earthquakes to destroy. This dynamic offers a powerful defense against global catastrophic risks that can be addressed by interventions with particular fixed or falling costs.

Philosophers vs economists on discounting

Temporal discounting is not about time
Economists doing cost-benefit analysis normally make use of temporal discounting, i.e. benefits further in the future count for less than those nearer to the present. In part this is done to reflect the availability of positive investment returns, but normally analysis also include an additional element of pure temporal preference.

Say that I set up a sealed habitat for some plants and cute bunny rabbits. The rabbits are placed in suspended animation, and the habitat is rocketed out of the Solar System by an automated spacecraft which will never return to interact with our world again. At a predesignated time, the rabbits will be revived and go on to live happy lives in the sealed habitat for a time and then die. With significant pure temporal preference this spacecraft is much more valuable if it is set to revive the isolated rabbits after 5 years rather than 50.

Indeed, economists typically make use of constant exponential discounting, e.g. reducing the valuation of benefits by 3% per year. At a 3% annual discount rate the value of future benefits will be cut by more than half every 23 years. After 230 years a good would be valued at less than a thousandth of an immediate counterpart.   But to most people the change in activation time does not make such an overwhelming difference. Further, constant exponential discounting makes strong distinctions between different far-future periods: benefits received in 1 million years are still more than a thousand times as valuable as benefits received in 1,000,230 years.

But real humans mostly don't care about such distinctions. A difference of a few centuries added onto a  million years is a negligible change in time: in either case they lie far beyond the current era and the proportional change is small. Favoring the earlier time for a thousandfold reduction in the goods achieved seems absurd in that context. Humans may be impatient within our own lives, care more about our children than distant descendants, and so forth, but the constant exponential discounting framework just doesn't make sense of our attitudes towards the further future.

Because of cases like this philosophers tend to reject the idea of pure temporal preference for social cost-benefit analysis, e.g. with respect to climate change, and often critique economists for persisting in making use of it. But economists are not fools, and the reasons why so many continue to do so are worth thinking about.

Utilitarianism, contractualism, and self-sacrifice

[This post is a response to cousin_it's request for counterarguments to utilitarianism.]

Saving the drowning child is not a self-sacrifice
Suppose that you live in a developed country, and earn a high income even by developed country standards. One day you are walking home from a business meeting in your best suit, worth some $1,000, and see a small child drowning in a muddy (and foul-smelling) pond off the road. No one else is around, but you could save the child, at the cost of hopelessly ruining the suit. Most people intuit that in such a case one should save the child, despite the cost of a $1,000 suit.

The utilitarian philosophers Peter Singer has often argued that since we should make a financial sacrifice for the drowning child, we should do the same to save the lives of children in poor countries, e.g. by donating to the most cost-effective public health charities identified by GiveWell. Others would generalize to saving future generations, saying that if we can reduce existential risk and avert astronomical waste to in expectation save trillions of happy lives, then that is even better than saving one life today.

However, the drowning child case is problematic as a justification for self-sacrifice in other contexts: it probably doesn't involve any self-sacrifice at all, but rather an expected selfish gain.

Moderation

For the record, this is a personal blog and I may arbitrarily moderate comments at any time in the name of epistemic norms, civility, or capricious whim.

Are pain and pleasure equally energy-efficient?

Aggregative hedonistic utilitarians are often concerned with the expected value of pleasure minus pain going forward. For instance, they may wonder how to value the expected Astronomical Waste if humanity were rendered extinct by a sudden asteroid impact.

One important consideration is that it appears that biological life as we know it generates pain or pleasure at a very low density relative to long-term technological possibilities. As Nick Bostrom's astronomical waste paper notes, the energy output of the Sun is a number of orders of magnitude higher than the energy that goes into life on Earth, and even higher than the energy going to power animal nervous systems. Further, ultra-efficient computing substrates could run emulations of animal nervous systems at much lower cost in energy.

For particular accounts of the normative importance of pain and pleasure, one could further streamline conscious software programs to have just the right features to maximize pain or pleasure produced by a given lump of mature computing hardware ("computronium").

Call computronium optimized to produce maximum pleasure per unit of energy "hedonium," and that optimized to produce maximum pain per unit of energy "dolorium," as in "hedonistic" and "dolorous." Civilizations that colonized the galaxy and expended a nontrivial portion of their resources on the production of hedonium or dolorium would have immense impact on the hedonistic utilitarian calculus. Human and other animal life on Earth (or any terraformed planets) would be negligible in the calculation of the total. Even computronium optimized for other tasks would seem to be orders of magnitude less important.

So hedonistic utilitarians could approximate the net pleasure generated in our galaxy by colonization as the expected production of hedonium, multiplied by the "hedons per joule" or "hedons per computation" of hedonium (call this H), minus the expected production of dolorium, multiplied by "dolors per joule" or "dolors per computation" (call this D).

By symmetry, my default expectation would be that H=D. Insofar as pain and pleasure involve accessibility to conscious reflection, connections to decision-making and memory, these pose like demands for both pain and pleasure. Evolutionary arguments about the distribution of pain and pleasure in the lives of animals, e.g. that in the lifecycle of some organism there are more things that it is important to avoid than to approach, are irrelevant to hedonium and dolorium. Pleasure (or pain) is set to maximum, not allocated to solve a control problem for a reproduction machine.

This is important to remember since our intuitions and experience may mislead us about the intensity of pain and pleasure which are possible. In humans, the pleasure of orgasm may be less than the pain of deadly injury, since death is a much larger loss of reproductive success than a single sex act is a gain. But there is nothing problematic about the idea of much more intense pleasures, such that their combination with great pains would be satisfying on balance.

So the situation would look good for hedonistic utilitarians of this sort: all that is needed is a moderately higher (absolute as well as relative) expected quantity of hedonium than dolorium. Even quite weak benevolence, or the personal hedonism of some agents transforming into or forking off hedonium could suffice for this purpose.

Now, the "measurement" of pain and pleasure brings in definitional and normative premises. Some may say they care more about pleasure than pain or vice versa, while others build into their "unit" of pain or pleasure a moral weighting in various tradeoffs. However, if we make use of data such as the judgments and actions of agents in choice problems, quantity of neuron-equivalents involved, and so forth, the symmetry does seem to hold. I would distinguish traditional and negative-biased hedonistic utilitarians in terms of the tradeoffs they would make between the production of hedonium and dolorium.