I think net change in forest area is a major driver for the impact of humans on terrestrial arthropods.
Is that just a guess, or has someone said that explicitly? I also get the vague impression that forests have higher productivity than grasslands/etc, but that’s not obvious, and I’d be curious to see more investigation of whether/when forests do have higher productivity. (This includes both primary productivity and productivity in terms of invertebrate life.)
It is a guess informed by you (great!) analysis here, where you assumed the median density of arthropods in rainforests to be 1.53 (= 2.3/1.5) times that in Cerrado, although with high uncertainty as you noticed. However, I did not mean that increasing forest area would necessarily lead to more arthropods. I just meant that the change in forest area due to human activities could be the main factor for the net change in the total welfare of arthropods. I am uncertain about the sign of the correlation because I am not only uncertain about which biomes have greater density of arthropods, but also about the sign of the welfare of arthropods.
I have also illustrated here that the change in forest area might be the driver for the nearterm cost-effectiveness of GiveWell’s top charities.
Thanks. :) I’m uncertain how accurate or robust the 2.3/1.5 comparison was, but you’re right to cite that. And you’re right that human land-use changes (including changes to forest area) likely have big effects of some kind on total arthropod welfare.
also about the sign of the welfare of arthropods
Makes sense. I have almost no uncertainty about that because I measure welfare in a suffering-focused way, according to which extreme pain is vastly more important than positive experiences. I suspect that a lot of variation in opinions on this question come down to how suffering-focused or happiness-focused one’s values are, rather than empirical disagreements, though it’s also true that we lack a lot of empirical information about how invertebrates perceive and value various good and bad events.
It seems that most people agree that factory-farmed pigs and battery-cage hens have net negative welfare, so I guess there could be some possible empirical information that would persuade most people to take one or the other side of the issue. However, there’s disagreement about whether, e.g., factory-farmed beef and dairy cows have net negative or positive welfare. That seems to mostly be a difference in moral values.
Is that just a guess, or has someone said that explicitly? I also get the vague impression that forests have higher productivity than grasslands/etc, but that’s not obvious, and I’d be curious to see more investigation of whether/when forests do have higher productivity. (This includes both primary productivity and productivity in terms of invertebrate life.)
Thanks for commenting, Brian!
It is a guess informed by you (great!) analysis here, where you assumed the median density of arthropods in rainforests to be 1.53 (= 2.3/1.5) times that in Cerrado, although with high uncertainty as you noticed. However, I did not mean that increasing forest area would necessarily lead to more arthropods. I just meant that the change in forest area due to human activities could be the main factor for the net change in the total welfare of arthropods. I am uncertain about the sign of the correlation because I am not only uncertain about which biomes have greater density of arthropods, but also about the sign of the welfare of arthropods.
I have also illustrated here that the change in forest area might be the driver for the nearterm cost-effectiveness of GiveWell’s top charities.
Thanks. :) I’m uncertain how accurate or robust the 2.3/1.5 comparison was, but you’re right to cite that. And you’re right that human land-use changes (including changes to forest area) likely have big effects of some kind on total arthropod welfare.
Makes sense. I have almost no uncertainty about that because I measure welfare in a suffering-focused way, according to which extreme pain is vastly more important than positive experiences. I suspect that a lot of variation in opinions on this question come down to how suffering-focused or happiness-focused one’s values are, rather than empirical disagreements, though it’s also true that we lack a lot of empirical information about how invertebrates perceive and value various good and bad events.
It seems that most people agree that factory-farmed pigs and battery-cage hens have net negative welfare, so I guess there could be some possible empirical information that would persuade most people to take one or the other side of the issue. However, there’s disagreement about whether, e.g., factory-farmed beef and dairy cows have net negative or positive welfare. That seems to mostly be a difference in moral values.