Thanks for the post. I learnt about the size of the plastic pollution problem for animals.
I can’t entirely agree with the framing of the article. 1M seabirds dying per year from plastic is not “small”. It makes me think that this is not a big problem, and I shouldn’t worry at all about it.
I would frame it as “1M seabirds die every year from plastic pollution, so it’s a big problem (malaria kills 0.5M people per year), but it’s still 1 million times less than 1T fish slaughtered per year.”
In my mind, the meaning of words such as “small” and “large” is always context-dependent. In this case, I think it is fair to say that the impact, measured as the number of deaths, from marine plastic pollution on seabirds and marine animals is small in comparison with the impact of catching fish.
In order to make comparisons between species, I think it is worth having in mind the number of neurons (a proxy for sentience) respecting each death toll.
Geometric mean of the neurons for “Harp seal” and “Killer whale”, which are the species in this list with the least and most neurons that are marine mammals.
Seabirds: 606 M.
Geometric mean of the neurons for “Mallard” and “Mute swan”, which are the animals in this list with the least and most neurons that look somewhat similar to seabirds.
I appreciate your quantitative thinking. But I believe it’s unfair to say that a fish is 10,000X worth less than a human because a fish has fewer neurons. What if suffering has a minimum threshold of neurons and then declining marginal suffering after that? We don’t know (as you point out in your last paragraph).
“Not everything that can be counted counts and not everything that counts can be counted.” —Einstein
Thanks for the post. I learnt about the size of the plastic pollution problem for animals.
I can’t entirely agree with the framing of the article. 1M seabirds dying per year from plastic is not “small”. It makes me think that this is not a big problem, and I shouldn’t worry at all about it.
I would frame it as “1M seabirds die every year from plastic pollution, so it’s a big problem (malaria kills 0.5M people per year), but it’s still 1 million times less than 1T fish slaughtered per year.”
Great to know that you found it useful!
In my mind, the meaning of words such as “small” and “large” is always context-dependent. In this case, I think it is fair to say that the impact, measured as the number of deaths, from marine plastic pollution on seabirds and marine animals is small in comparison with the impact of catching fish.
In order to make comparisons between species, I think it is worth having in mind the number of neurons (a proxy for sentience) respecting each death toll.
Estimates for the number of neurons:
Humans: 86 G (see this).
Marine mammals: 7.10 G.
Geometric mean of the neurons for “Harp seal” and “Killer whale”, which are the species in this list with the least and most neurons that are marine mammals.
Seabirds: 606 M.
Geometric mean of the neurons for “Mallard” and “Mute swan”, which are the animals in this list with the least and most neurons that look somewhat similar to seabirds.
Fish: 10 M (see “Adult zebrafish” in this list).
Number of neurons respecting each death toll:
Malaria: 627 k * 86 G = 53.9 P.
Marine mammals: 100 k * 7.10 G = 0.710 P.
Seabirds: 1 M * 606 M = 0.606 P.
Fish: 1.62 T * 10 M = 16.2 kP.
Consequently, the number of neurons regarding:
Marine mammals and seabirds is similar.
Malaria is ~ 2 orders of magnitude larger than that of marine mammals / seabirds.
Fish is ~ 2.5 orders of magnitude larger than that of malaria.
From the above, it naively seems that:
The death toll of marine mammals / seabirds caused by marine plastic pollution is small relative to the death toll caused by malaria.
The death toll caused by malaria is small relative to the death toll concerning wild fish catch.
However, this is not by all means a definite analysis:
It is unclear whether sentience should be measured as a linear function of the number of neurons (see section “Brain size” of this page).
Even for the same level of sentience, the intensity of the death could vary.
There are other effects which are not captured by the number of deaths.
I didn’t know fish had 10M neurons. Thanks!
I appreciate your quantitative thinking. But I believe it’s unfair to say that a fish is 10,000X worth less than a human because a fish has fewer neurons. What if suffering has a minimum threshold of neurons and then declining marginal suffering after that? We don’t know (as you point out in your last paragraph).
“Not everything that can be counted counts and not everything that counts can be counted.”
—Einstein
Yes, I agree, there is lots of uncertainty! Moreover:
In addition to the importance of the death toll, one has to take into account its neglectedness and tractability.
Longterm effects should also be assessed, as they can concern most the expected impact of averting deaths (e.g. via expansion of the moral circle).