it seems like it would be a bit too convenient if a comprehensive cost benefit analysis came out with the answer ‘become a vegetarian’
Convenient for people who are vegetarians on other grounds, perhaps; not so much for me.
In any event, I don’t think anyone was suggesting that vegetarianism is the single best way to reduce your carbon footprint. (The specific suggestion being made was presumably that becoming vegetarian was likely to be more effective than buying an equivalent tonnage of offsets. I think this was true when I became vegetarian, but perhaps the certification mechanisms for offsets have now improved enough that the real issue is cost.)
Whether vegetarianism could be the single best way for any given individual to reduce their carbon footprint will depend heavily on: (a) what margin you’re working at (e.g. if you already don’t drive or fly much, but eat a lot of red meat and dairy then it’s more likely to have a large percentage impact); and (b) the relative value you place on the activities that you could scale back on (which will also vary from person to person).
To get somewhat more precise, the paper I linked to in my previous comment concludes:
a person consuming a mixed diet with the mean American caloric content and composition causes the emissions of 1485 kg CO2-equivalent above the emissions associated with consuming the same number of calories, but from plant sources. Far from trivial, nationally this difference amounts to over 6% of the total U.S. greenhouse gas emissions.
Individual mileage will vary of course. Because my carbon footprint was already pretty low (around 1⁄4 to 1⁄3 of the US average), I estimated the reductions I could achieve by eliminating meat and dairy at somewhere around 20%. (Which pretty much did make it the best single option I had.)
FWIW, I’m a little unsure about the value of buying local for a couple of reasons.
Variation in production efficiency can swamp transport costs. The classic example here is that it’s apparently more energy efficient to ship lamb from New Zealand than to produce it in the UK. (Though much of this apparently comes down to coal vs. hydro electricity generation, and won’t apply to all forms of production.) More broadly, I worry that increasing demand for local products because they are local could incentivise inefficient production.
Large supermarket chains actually have pretty efficient distribution systems, and, as I understand it, most of the emissions from food transport tend to enter at the point-of-sale to front-door stage anyway.
(Not convinced it’s bad, either. Just unsure about the size of the benefits.)
FWIW, I’m a little unsure about the value of buying local for a couple of reasons.
I’m not particularly advocating buying local as a better option, it was just an example of the kinds of factors that one might need to consider.
I tend to think that if there is a significant negative externality to carbon emissions that is not currently reflected in prices, the optimal solution would be to impose some kind of carbon tax to reflect that hidden cost. This would avoid the need for individuals to try and make complex cost benefit calculations for themselves on optimal carbon reducing choices.
I don’t think it’s very likely that it is politically feasible to implement such a tax though so if I considered the issue important I might attempt to make lifestyle choices that reduced my own personal impact. Under those circumstances I’d want to make choices efficiently. It’s not clear to me that vegetarianism would be the best choice but since I don’t consider reducing my own carbon footprint a priority I haven’t done a lot of research on the issue.
It’s not clear to me that vegetarianism would be the best choice
Given that vegetarianism doesn’t exclude other strategies for emissions reduction, I’m unclear why you think it’s relevant whether or not it’s the single best strategy. Surely all that’s required is that it have a net positive effect?
Surely all that’s required is that it have a net positive effect?
Net positive taking into account all of the personal costs, yes. It’s not enough that it merely reduces emissions, it needs to reduce emissions more effectively than other equally costly options. I get the sense that we’re largely in agreement there though.
My original question was an attempt to ascertain whether the reduction in greenhouse gas emissions was truly your primary reason for choosing vegetarianism (with the choice made by weighing up the costs and benefits of various ways of reducing emissions) or whether it was a convenient ‘added benefit’ given a choice that was made partly or wholly for other reasons. The (seemingly) more common animal welfare justification for vegetarianism seems more directly linked to the particular decision to not eat meat than does a carbon emissions argument.
it needs to reduce emissions more effectively than other equally costly options.
Perhaps I’m misunderstanding, but this still seems inaccurate to me. If there is a more effective yet equally costly option O, but the total benefit of O+Vegetarian is still greater than the total cost of O+Vegetarian, then Vegetarian is still worth it (as is O). Your framing seems to deny this.
My original question was an attempt to ascertain whether the reduction in greenhouse gas emissions was truly your primary reason for choosing vegetarianism
Yes. It was, and is. I guess there’s an added benefit in terms of cost, but given that I don’t care about the animals themselves, I really don’t have any other reasons for it.
The (seemingly) more common animal welfare justification for vegetarianism seems more directly linked to the particular decision to not eat meat than does a carbon emissions argument.
Sure. But it would hard to get a more direct link than the animal welfare argument, so that’s not saying much. Something in the order of 20% of global GHG emissions can be attributed to livestock, so it’s not like the link between meat and emissions is weak.
I guess the complication is that there’s a reasonable amount of variation in emissions depending on what meat you’re talking about. Ruminants (cows, sheep) are especially bad (because of the methane), as is dairy (for the same reason). Farmed and deep sea fish are pretty bad too, but other fish are probably OK. Chicken (and especially eggs) aren’t so bad either (and are probably better the worse you treat the chickens).
Ultimately, I figured that it would be easier (and therefore more effective) to have a clear no meat rule than to try to make too many case-by-case calls that I might then be tempted to weasel out of. Nonetheless, in an effort to become slightly more consistent, I’ve made a deal with myself that I can start eating (OK) fish again if/when I manage to completely ditch the dairy (given that the latter is almost certainly worse from a GHG perspective). Haven’t quite managed it yet though.
If there is a more effective yet equally costly option O, but the total benefit of O+Vegetarian is still greater than the total cost of O+Vegetarian, then Vegetarian is still worth it (as is O).
You’ve got to consider opportunity cost and marginal utility. If you valued reducing carbon emissions above all else then your best course of action would probably be suicide. Assuming some upper limit on the cost you’re willing to pay to reduce carbon emissions, your best strategy is to choose the option that provides the greatest reduction for the least personal cost. If given your preferences and available options, buying some carbon offsets is your most cost effective option and becoming vegetarian is your second most cost effective option, it does not follow that you should do both.
While the benefits can be seen as fixed for the purposes of your decision (since whatever you do will have such little impact that you can sum them without worrying about diminishing marginal utility) the costs cannot, if they are significant relative to your total resources. This is more easily seen when you’re talking about choices that can directly be represented with money but is still true when the costs are not purely financial. Assuming the costs can simply be summed you would have to conclude that you should spend all your money on carbon offsets if you thought it was wise to spend any of your money on them (since if the benefit of O is greater than the cost of O then the benefit of 100xO should be greater than the cost of 100xO).
I’m sorry, but this argument seems rather confused to me.
Assuming some upper limit on the cost you’re willing to pay to reduce carbon emissions, your best strategy is to choose the option that provides the greatest reduction for the least personal cost.
No, it’s to choose the best n options, up to the point at which you reach your cost limit. Depending on the limit, and the options you face, n could be 0, or 20, or 100; but there’s no particular reason to think it should be 1.
Of course, assuming a fixed upper bound on willingness to sacrifice runs counter to the idea that the sacrifices you’re willing to bear should depend on the benefits obtained. There are two alternative perspectives you could take here:
From the perspective of what’s best for human welfare generally (which was the basis of my original claim) you simply shouldn’t have such a limit. If the net effect of an option (taking into account opportunity costs) is positive, you should just do it (This applies even if the option is suicide, though the opportunity cost of suicide is probably quite high compared with other ways of promoting human welfare.)
From the perspective of an imperfect altruist, a better way to think about it is in terms of the marginal rate of substitution that you’re willing to accept between your own welfare and others’. This will presumably increase as your own welfare decreases (and is probably the real reason we wouldn’t commit suicide to reduce emissions, even if the benefits to others did outweigh the personal and opportunity costs).
You’ve got to consider opportunity cost and marginal utility.
Agreed. The thing is, the opportunity cost of becoming vegetarian isn’t like the opportunity cost of $5. If I spend $5 on carbon offsets, that’s $5 I can’t spend on something else. If I become vegetarian, I haven’t really used up a resource that I could have done something else with; in fact I’ve probably saved money (maybe I’ve used up a bit of willpower in the process, I’m gonna say the effect is minimal). The opportunity cost of vegetarianism is my direct loss of utility minus whatever utility I can get from the money I’ve saved.
Assuming the costs can simply be summed
They can be, if you denominate them in human welfare. They clearly can’t if you denominate them in dollars, but I never claimed they could be, and my argument doesn’t rest on it.
No, it’s to choose the best n options, up to the point at which you reach your cost limit. Depending on the limit, and the options you face, n could be 0, or 20, or 100; but there’s no particular reason to think it should be 1.
I guess I wasn’t sufficiently clear there. My point is that you need to do a cost-benefit analysis, pick your best choice and then do a new cost-benefit analysis rather than just follow through with your 2nd and 3rd best choice from your original analysis. You can’t assume that your 2nd best choice becomes your new best choice after taking your best choice.
If you’re hungry and you decide your first choice is to buy a mars bar and your second choice a snickers and you buy and eat the mars bar you can’t assume that your next action should be to buy and eat the snickers—the situation has changed and you need to re-evaluate.
Of course, assuming a fixed upper bound on willingness to sacrifice runs counter to the idea that the sacrifices you’re willing to bear should depend on the benefits obtained.
Not a fixed upper bound, just a limit. Anyone who cares about reducing their carbon footprint will reach a point where they are not currently willing to make any further sacrifices for a further carbon emissions reduction because to do so would conflict with their other goals. What I’m saying is that each choice you make changes the calculation a little when considering future choices.
The thing is, the opportunity cost of becoming vegetarian isn’t like the opportunity cost of $5.
Not exactly no. The thing is that one might be willing to pay more than one currently does to continue eating meat. If the cost of meat doubled for example I would not reduce my consumption by 50%, I’d cut back elsewhere. I choose to spend a certain amount of money on meat because it represents better value than my next best opportunity. The reason I currently spend money on meat is that I value the meat more than the money (or other alternate uses of the money). You have to take that into account when considering the opportunity cost of becoming vegetarian.
Assuming the costs can simply be summed
They can be, if you denominate them in human welfare.
No, the benefits can be denominated in (general) human welfare. The costs are denominated in your own personal welfare. Money can serve as a convenient proxy for that to aid in calculation but I’m not sure you can give any direct measure, the best you can do may be a preference ordering.
I think we’re pretty much in agreement. Any remaining differences are either trivial, semantic, or (at the risk of angering the Aumann Gods) “things reasonable people can disagree about”.
I think we’re pretty much in agreement. Any remaining differences we have seem either trivial, semantic, or (at the risk of angering the Aumann-gods) things reasonable people can disagree about.
it needs to reduce emissions more effectively than other equally costly options.
Perhaps I’m misunderstanding, but this still seems inaccurate to me. If there is a more effective yet equally costly option O, but the total benefit of O+Vegetarian is still greater than the total cost of O+Vegetarian, then Vegetarian is still worth it (as is O).
My original question was an attempt to ascertain whether the reduction in greenhouse gas emissions was truly your primary reason for choosing vegetarianism
Yes. It was, and is. I guess there’s an added benefit in terms of cost, but given that I don’t care about the animals themselves I really don’t have any other reason for it.
The (seemingly) more common animal welfare justification for vegetarianism seems more directly linked to the particular decision to not eat meat than does a carbon emissions argument.
Sure. But it would hard to get a more direct link than the animal welfare argument, so that’s not saying much. Something in the order of 20% of global GHG emissions can be attributed to livestock, so it’s not like the link is weak, but there’s a sense in which your scepticism is probably justified. There’s actually a lot of variation in emissions depending on what meat you’re talking about. Ruminants (cows, sheep) are especially bad (because of the methane emissions), as is dairy (for the same reason). Farmed and deep sea fish are pretty bad too, but other fish are probably OK. Chicken (and especially eggs) are actually reasonably energy efficient (and probably more so the worse you treat the chickens).
The only real reason I gave up chicken was because I figured I would be less tempted overall if I made a clean break with meat altogether. I’ve also made a deal with myself that I can start eating (good) fish again if/when I manage to completely ditch the dairy. So there are points where my dietary restrictions don’t entirely mesh with my reasons, based on the fact that I’m imperfect, and that as a result I would probably be doing worse if I aimed explicitly for consistency.
Convenient for people who are vegetarians on other grounds, perhaps; not so much for me.
In any event, I don’t think anyone was suggesting that vegetarianism is the single best way to reduce your carbon footprint. (The specific suggestion being made was presumably that becoming vegetarian was likely to be more effective than buying an equivalent tonnage of offsets. I think this was true when I became vegetarian, but perhaps the certification mechanisms for offsets have now improved enough that the real issue is cost.)
Whether vegetarianism could be the single best way for any given individual to reduce their carbon footprint will depend heavily on: (a) what margin you’re working at (e.g. if you already don’t drive or fly much, but eat a lot of red meat and dairy then it’s more likely to have a large percentage impact); and (b) the relative value you place on the activities that you could scale back on (which will also vary from person to person).
To get somewhat more precise, the paper I linked to in my previous comment concludes:
Individual mileage will vary of course. Because my carbon footprint was already pretty low (around 1⁄4 to 1⁄3 of the US average), I estimated the reductions I could achieve by eliminating meat and dairy at somewhere around 20%. (Which pretty much did make it the best single option I had.)
FWIW, I’m a little unsure about the value of buying local for a couple of reasons.
Variation in production efficiency can swamp transport costs. The classic example here is that it’s apparently more energy efficient to ship lamb from New Zealand than to produce it in the UK. (Though much of this apparently comes down to coal vs. hydro electricity generation, and won’t apply to all forms of production.) More broadly, I worry that increasing demand for local products because they are local could incentivise inefficient production.
Large supermarket chains actually have pretty efficient distribution systems, and, as I understand it, most of the emissions from food transport tend to enter at the point-of-sale to front-door stage anyway.
(Not convinced it’s bad, either. Just unsure about the size of the benefits.)
I’m not particularly advocating buying local as a better option, it was just an example of the kinds of factors that one might need to consider.
I tend to think that if there is a significant negative externality to carbon emissions that is not currently reflected in prices, the optimal solution would be to impose some kind of carbon tax to reflect that hidden cost. This would avoid the need for individuals to try and make complex cost benefit calculations for themselves on optimal carbon reducing choices.
I don’t think it’s very likely that it is politically feasible to implement such a tax though so if I considered the issue important I might attempt to make lifestyle choices that reduced my own personal impact. Under those circumstances I’d want to make choices efficiently. It’s not clear to me that vegetarianism would be the best choice but since I don’t consider reducing my own carbon footprint a priority I haven’t done a lot of research on the issue.
Given that vegetarianism doesn’t exclude other strategies for emissions reduction, I’m unclear why you think it’s relevant whether or not it’s the single best strategy. Surely all that’s required is that it have a net positive effect?
Net positive taking into account all of the personal costs, yes. It’s not enough that it merely reduces emissions, it needs to reduce emissions more effectively than other equally costly options. I get the sense that we’re largely in agreement there though.
My original question was an attempt to ascertain whether the reduction in greenhouse gas emissions was truly your primary reason for choosing vegetarianism (with the choice made by weighing up the costs and benefits of various ways of reducing emissions) or whether it was a convenient ‘added benefit’ given a choice that was made partly or wholly for other reasons. The (seemingly) more common animal welfare justification for vegetarianism seems more directly linked to the particular decision to not eat meat than does a carbon emissions argument.
Perhaps I’m misunderstanding, but this still seems inaccurate to me. If there is a more effective yet equally costly option O, but the total benefit of O+Vegetarian is still greater than the total cost of O+Vegetarian, then Vegetarian is still worth it (as is O). Your framing seems to deny this.
Yes. It was, and is. I guess there’s an added benefit in terms of cost, but given that I don’t care about the animals themselves, I really don’t have any other reasons for it.
Sure. But it would hard to get a more direct link than the animal welfare argument, so that’s not saying much. Something in the order of 20% of global GHG emissions can be attributed to livestock, so it’s not like the link between meat and emissions is weak.
I guess the complication is that there’s a reasonable amount of variation in emissions depending on what meat you’re talking about. Ruminants (cows, sheep) are especially bad (because of the methane), as is dairy (for the same reason). Farmed and deep sea fish are pretty bad too, but other fish are probably OK. Chicken (and especially eggs) aren’t so bad either (and are probably better the worse you treat the chickens).
Ultimately, I figured that it would be easier (and therefore more effective) to have a clear no meat rule than to try to make too many case-by-case calls that I might then be tempted to weasel out of. Nonetheless, in an effort to become slightly more consistent, I’ve made a deal with myself that I can start eating (OK) fish again if/when I manage to completely ditch the dairy (given that the latter is almost certainly worse from a GHG perspective). Haven’t quite managed it yet though.
You’ve got to consider opportunity cost and marginal utility. If you valued reducing carbon emissions above all else then your best course of action would probably be suicide. Assuming some upper limit on the cost you’re willing to pay to reduce carbon emissions, your best strategy is to choose the option that provides the greatest reduction for the least personal cost. If given your preferences and available options, buying some carbon offsets is your most cost effective option and becoming vegetarian is your second most cost effective option, it does not follow that you should do both.
While the benefits can be seen as fixed for the purposes of your decision (since whatever you do will have such little impact that you can sum them without worrying about diminishing marginal utility) the costs cannot, if they are significant relative to your total resources. This is more easily seen when you’re talking about choices that can directly be represented with money but is still true when the costs are not purely financial. Assuming the costs can simply be summed you would have to conclude that you should spend all your money on carbon offsets if you thought it was wise to spend any of your money on them (since if the benefit of O is greater than the cost of O then the benefit of 100xO should be greater than the cost of 100xO).
I’m sorry, but this argument seems rather confused to me.
No, it’s to choose the best n options, up to the point at which you reach your cost limit. Depending on the limit, and the options you face, n could be 0, or 20, or 100; but there’s no particular reason to think it should be 1.
Of course, assuming a fixed upper bound on willingness to sacrifice runs counter to the idea that the sacrifices you’re willing to bear should depend on the benefits obtained. There are two alternative perspectives you could take here:
From the perspective of what’s best for human welfare generally (which was the basis of my original claim) you simply shouldn’t have such a limit. If the net effect of an option (taking into account opportunity costs) is positive, you should just do it (This applies even if the option is suicide, though the opportunity cost of suicide is probably quite high compared with other ways of promoting human welfare.)
From the perspective of an imperfect altruist, a better way to think about it is in terms of the marginal rate of substitution that you’re willing to accept between your own welfare and others’. This will presumably increase as your own welfare decreases (and is probably the real reason we wouldn’t commit suicide to reduce emissions, even if the benefits to others did outweigh the personal and opportunity costs).
Agreed. The thing is, the opportunity cost of becoming vegetarian isn’t like the opportunity cost of $5. If I spend $5 on carbon offsets, that’s $5 I can’t spend on something else. If I become vegetarian, I haven’t really used up a resource that I could have done something else with; in fact I’ve probably saved money (maybe I’ve used up a bit of willpower in the process, I’m gonna say the effect is minimal). The opportunity cost of vegetarianism is my direct loss of utility minus whatever utility I can get from the money I’ve saved.
They can be, if you denominate them in human welfare. They clearly can’t if you denominate them in dollars, but I never claimed they could be, and my argument doesn’t rest on it.
I guess I wasn’t sufficiently clear there. My point is that you need to do a cost-benefit analysis, pick your best choice and then do a new cost-benefit analysis rather than just follow through with your 2nd and 3rd best choice from your original analysis. You can’t assume that your 2nd best choice becomes your new best choice after taking your best choice.
If you’re hungry and you decide your first choice is to buy a mars bar and your second choice a snickers and you buy and eat the mars bar you can’t assume that your next action should be to buy and eat the snickers—the situation has changed and you need to re-evaluate.
Not a fixed upper bound, just a limit. Anyone who cares about reducing their carbon footprint will reach a point where they are not currently willing to make any further sacrifices for a further carbon emissions reduction because to do so would conflict with their other goals. What I’m saying is that each choice you make changes the calculation a little when considering future choices.
Not exactly no. The thing is that one might be willing to pay more than one currently does to continue eating meat. If the cost of meat doubled for example I would not reduce my consumption by 50%, I’d cut back elsewhere. I choose to spend a certain amount of money on meat because it represents better value than my next best opportunity. The reason I currently spend money on meat is that I value the meat more than the money (or other alternate uses of the money). You have to take that into account when considering the opportunity cost of becoming vegetarian.
No, the benefits can be denominated in (general) human welfare. The costs are denominated in your own personal welfare. Money can serve as a convenient proxy for that to aid in calculation but I’m not sure you can give any direct measure, the best you can do may be a preference ordering.
I think we’re pretty much in agreement. Any remaining differences are either trivial, semantic, or (at the risk of angering the Aumann Gods) “things reasonable people can disagree about”.
I think we’re pretty much in agreement. Any remaining differences we have seem either trivial, semantic, or (at the risk of angering the Aumann-gods) things reasonable people can disagree about.
Perhaps I’m misunderstanding, but this still seems inaccurate to me. If there is a more effective yet equally costly option O, but the total benefit of O+Vegetarian is still greater than the total cost of O+Vegetarian, then Vegetarian is still worth it (as is O).
Yes. It was, and is. I guess there’s an added benefit in terms of cost, but given that I don’t care about the animals themselves I really don’t have any other reason for it.
Sure. But it would hard to get a more direct link than the animal welfare argument, so that’s not saying much. Something in the order of 20% of global GHG emissions can be attributed to livestock, so it’s not like the link is weak, but there’s a sense in which your scepticism is probably justified. There’s actually a lot of variation in emissions depending on what meat you’re talking about. Ruminants (cows, sheep) are especially bad (because of the methane emissions), as is dairy (for the same reason). Farmed and deep sea fish are pretty bad too, but other fish are probably OK. Chicken (and especially eggs) are actually reasonably energy efficient (and probably more so the worse you treat the chickens).
The only real reason I gave up chicken was because I figured I would be less tempted overall if I made a clean break with meat altogether. I’ve also made a deal with myself that I can start eating (good) fish again if/when I manage to completely ditch the dairy. So there are points where my dietary restrictions don’t entirely mesh with my reasons, based on the fact that I’m imperfect, and that as a result I would probably be doing worse if I aimed explicitly for consistency.