by Brian Tomasik
First written: 23 Feb. 2016; last update: 16 Dec. 2016

Summary

This page summarizes cost-effectiveness estimates for various ways to reduce insect suffering. The numbers are crude and could be off by a few orders of magnitude, and the sign of the intervention (whether it's net good or net bad) is not always clear either.

Intervention Rough expected insect-years of suffering prevented per US$ Is the intervention acceptable to most people? Source
Buy beef directly from Brazil ~106 no this section
Lobby to eliminate human-biting mosquitoes 106? yes number in this section plus number in this section; I reduced the number by a little bit because the calculation is pretty uncertain
Promote energy efficiency / nuclear fusion -6.2 * 105 to 6.6 * 105 (very unclear if good or bad, but stakes are high) yes if reducing climate change turns out to be good; no otherwise bottom of this section
Cover rainforest land 3 * 105 no this section
Donate to Against Malaria Foundation 1.4 * 104, sign is very unclear yes this piece
Campaign against use of silk 104 yes this section
Promote gravel lawns 103 yes if targeted towards people who maintain their lawns end of this section
Oppose (aerobic) composting 5 * 101 maybe not, but possibly yes for people whose landfills or water-treatment facilities do methane capture, and Bokashi composting might reduce both greenhouse-gas emissions and suffering. below

Xysticus-sp-krabbenspinneThe top cost-effectiveness numbers here are quite impressive, even relative to the short-term impacts of helping poor humans or farm animals. An insect-year of suffering is equivalent to the pain of dying for on the order of ~10 adult insects, so the numbers in the above table can be multiplied by ~10 to give "adult-insect experiences of death prevented per $".

A human has ~106 times more neurons than an small insect. Even if you only give an insect 10-6 times the moral weight of a human, 105 insect years (containing the equivalent of ~106 adult-insect deaths) would be approximately equivalent to one human death. So dividing the cost-effectiveness numbers in the above table by 105 represents the equivalent number of painful human death experiences prevented per dollar.

Quick-and-dirty calculation for malaria prevention

This discussion has moved to "Does the Against Malaria Foundation Reduce Invertebrate Suffering?".

Quick-and-dirty calculation for opposing composting

Composting food waste probably creates more bug suffering than throwing food away in sealed containers or shredding it in the sink. One could potentially encourage people who compost their food to stop doing so. Such a campaign seems unlikely to be highly effective, because most people who go through the effort to compost already are probably eco-conscious and so wouldn't be open to changing their minds. But maybe a few people on the fence could be dissuaded. And perhaps if community-wide composting programs also create significant bug suffering (do they? or is that kind of decomposition mostly anaerobic?), those people who only participate in such programs because they're low-effort might be open to persuasion.

Suppose people created an anti-composting campaign. Ignoring startup costs, suppose that a ballpark estimate of the marginal cost to dissuade one person from composting for ~5 years would be $1000. If N is the number of insect-years of suffering created by a person composting for one year, this campaign would prevent 5 * N / 1000 insect-years per dollar.a

What's N? I have a friend who unfortunately maintains a compost bin, and anecdotally, I would guess the bin contains ~hundreds of red-wiggler worms at any given time. The table from The Nature and Properties of Soils that's shown in this section estimates 30-300 earthworms per square meter of typical soil. This table also shows that earthworm biomass dominates total animal biomass in the soil, so I'll focus on earthworms and then adjust their numbers based on their size relative to the size of a typical bug.

A compost bin has much more juicy food to be eaten than does a typical patch of soil, so the density of earthworms (and other bugs) per square meter of a compost worm bin is probably higher than the 30-300 reported in the table. On the other hand, a small home composting bin is probably less than one square meter in size. Hence, I'll fall back on my eyeballed estimate based on my friend's worm bin and assume that a typical worm bin with an amount of food waste generated by a single person has, say, ~200 red-wiggler worms in it at any given time. However, worms are considerably bigger than the typical bug, so I think these worms should count as more than 200 typical bugs.

This source reports that a nightcrawler has a wet mass of 1.21 g, but I think nightcrawlers are typically bigger than red wigglers. This source reports that red wigglers "average about 1.5 gram per worm". That source also reports that mature red wigglers average 3-5 inches in length. Say it's 4 inches, or 10 cm. If the worm is a perfect cylinder with radius of, say, 0.2 cm, its volume would be pi * (0.2 cm)2 * (10 cm) = 1.3 cm3, which is 1.3 g assuming a worm has the density of water. To be conservative, I'll say a typical red wiggler is 1 g. Given that a typical bug in general is ~3 mg, a typical red wiggler would matter ~300 times more than a typical bug if we weigh directly by size, or ~20 times more if we weigh by sqrt of size. Assuming a red wiggler matters, say, ~50 times more than a typical bug, the number of equivalent bugs per worm bin would be about (~200 red wigglers) * (~50 bug-equivalents per red wiggler) = 104 equivalent bugs, i.e., 104 insect-years per year. Conveniently, this is also the estimate we'd use if we ignored the size of each bug and just took the midpoint (on a log scale) of the 103 to 105 bugs per square meter reported as "Other fauna" in the table in this section.

Taking N = 104, we have a cost-effectiveness of 5 * N / 1000 = 50 insect-years per dollar.

Unfortunately, there's some chance that an anti-composting campaign would backfire. Composting has a halo around it in many people's eyes, so even discussing composting might cause more people to become interested in it than to shy away from it. This is a significant concern to explore before undertaking an anti-compost campaign.

Maybe efforts to discourage composting would be most successful in places where landfills or water-treatment plants have methane-capture technology, since in those cases, there's an argument to be made that composting is actually worse for the environment, since home composting just releases greenhouse gases to the air, while methane-capture systems generate human-useable energy in the process of releasing emissions.b This book explains:

One of the dirty little secrets in the composting world is that traditional composting methods inherently generate greenhouse gasses (GHG). This is never mentioned in traditional composting circles, but is actually a pretty big problem. Methane, carbon dioxide, and nitrous oxide are all by-products of the traditional composting process, and all three are greenhouse gasses.

[...] The average home composter isn’t harvesting the methane so the gas goes into the atmosphere.

That book is about Bokashi composting and claims that it generates fewer greenhouse-gas emissions than regular composting. Bokashi composting is also anaerobic, which means less bug suffering. So if the Bokashi claims are true, this could be a win-win for both bug-suffering reduction and environmentalists.

TODO: Extend this analysis and cost-effectiveness calculation to industrial-scale composting operations. This video suggests that in large-scale composting, the compost pile can warm to 131 to 160°F, which I assume is too hot for invertebrate animals?? (Presumably there are still invertebrates on the surface of the pile??)

Sample government policies

Following are a few policies that would probably reduce invertebrate suffering. I haven't done full cost-effectiveness estimates and so can't rank them. All of these proposals might possibly be politically feasible.

Policy Why it probably benefits insects Non-insect arguments for it
Increase logging on federal lands See this section. See this page.
Reduce funding for soil and land conservation Erosion reduces land fertility and hence long-run plant growth. Protecting wetlands and grasslands preserves productive ecosystems. Cutting this funding would save the government money.
Subsidize gravel lawns See this piece. Gravel lawns save water (which is especially appealing in dry states like California) and obviate pesticides / fertilizers.
Encourage solar farms to be built over grassland Reduces plant growth where the solar panels are built Provides green electricity
Reduce or at least don't increase federally protected lands Resource extraction and economic activity in wilderness areas usually reduce plant populations. Create jobs, reduce government bureaucracy
Oppose rewilding projects that would increase the primary productivity of land More productivity generally means more insects. Rewilding costs money.
Reduce eutrophication of lakes and reservoirs, making them more oligotrophic Eutrophic lakes generally seem to support more zooplankton, although this topic is complex. Most people oppose eutrophication for a variety of water-quality reasons.
Support garbage incineration Burning garbage prevents bugs from eating the organic matter it contains. Incineration probably reduces greenhouse-gas emissions compared with landfilling. Other environmental pros and cons are debated.

Footnotes

  1. This calculation ignores a potential increase in bacteria suffering during anaerobic decomposition in landfills or wastewater, but assuming we care less about bacteria per unit of metabolism than about bugs, this consideration shouldn't change the order of magnitude of my calculation.

    Moreover: "the anaerobic respiration pathways release less net energy than the aerobic approach". In fact, aerobic respiration generates ~29-30 ATP molecules per glucose molecule, while anaerobic respiration generates 2 ATP molecules per glucose molecule, which makes aerobic respiration ~15 times more efficient. That's a huge difference in the amount of energy extracted. So even if one cared slightly more about bacteria than about larger animals, anaerobic respiration done by bacteria might still entail less suffering than aerobic respiration done by bacteria and larger critters. Of course, I wonder if the end products of anaerobic respiration, such as ethanol, can themselves be used to power other microorganisms? Also, "some anaerobic organisms, such as methanogens are able to continue with anaerobic respiration, yielding more ATP" than just 2 per glucose molecule.

    My calculation also ignores climate-change effects and other variables that differ between home composting vs. alternate methods of food-waste disposal. While the signs of these impacts are very unclear, these impacts might be fairly important.  (back)

  2. This comment disputes this idea, however:

    From a strictly greenhouse gas metric (which is not the only thing to pay attention to, there is also nutrient cycling, energy use to transport garbage, [...] etc ad nauseam), it would only even begin to make sense where you are sure your landfill has methane-capture technology, and the author seems to be assuming that methane-capture technology is 100% efficient, which it isn't. Estimates range from between 0-70% efficiency, and because methane is ~30 times more potent a greenhouse gas than carbon dioxide, disposing of organic waste into even the best methane-capture landfills (anaerobic, methane producing) contributes more towards global warming than composting (aerobic, carbon dioxide producing) them would.

    Of course, that analysis assumes that compost produces only CO2 emissions, not methane.  (back)