Fly less, give more

Russ Poldrack writes that he will be flying less:

I travel a lot – I have almost 1.3 million lifetime miles on United Airlines, and in the last few years have regularly flown over 100,000 miles per year. This travel has definitely helped advance my scientific career, and has been in many ways deeply fulfilling and enlightening. However, the toll has been weighing on me and Miles’ article really pushed me over the edge towards action. I used the carbon footprint calculator to compute the environmental impact of my flights just for the first half of 2019, and it was mind-boggling: more than 23 tons of CO2. For comparison, my entire household’s yearly carbon footprint (estimated using is just over 10 tons!

For these reasons, I am committing to eliminate (to the greatest degree possible) academic air travel for the foreseeable future. That means no air travel for talks, conferences, or meetings — instead participating by telepresence whenever possible.

I’m sympathetic to the sentiment, and have considered reducing my own travel on a couple of occasions. So far, I’ve decided not to. It’s not that I disagree with Russ’s reasoning; I’m very much on board with the motivation for cutting travel, and I think we should all try to do our part to try and help avert, or at least mitigate, the looming climate crisis. The question for me is how to best go about that. While I haven’t entirely ruled out cutting down on flying in future, it’s not something I’m terribly eager to do. Travel is one of the most rewarding and fulfilling parts of my job, and I’m loathe to stop flying unless there are no other ways to achieve the same or better outcomes.

Fortunately, there are other things one can do to try to keep the planet nice and habitable for all of us. For my part, I’ve decided that, rather than cutting back on travel, I’m going to give some money to charity. And in the next ~4,000 words, I’m going to try to convince you to consider doing the same (at least the giving to charity part; I’m not going to try to argue you out of not flying).

Now, I know what you’re thinking at this point. You’re probably thinking, what does he mean, ‘charity’? Is he talking about carbon offsets? He’s talking about carbon offsets, isn’t he! This dude is about to write a 4,000-word essay telling me I should buy carbon offsets! Like I don’t already know they’re a gigantic scam. No thanks.

Congratulations, my friend—you’re right. I do mean carbon offsets.

Well, kind of.

What I’ll really try to convince you is that, while carbon offsets are actually a perfectly reasonable thing for a person to purchase, the idea of "offsetting" one’s lifestyle choices is probably not the most helpful way to think about the more general fight against climate change. But carbon offsets as they’re usually described—i.e., as promissory notes you can purchase from organizations that claim to suck up a certain amount of carbon out of the atmosphere by planting trees or engaging in other similarly hippie activities—are a good place to start, because pretty much everyone’s heard of them. So let me start by rebutting what I see as the two (or really three) most common arguments against offsets, and in the process, it’ll hopefully become clear why offsets are a bit of a red herring that’s best understood as just a special case of a much more general principle. The general principle being, if you want to save yourself a bunch of reading, do a little bit of research, and then give as much as you comfortably can.

Offsets as indulgences

Carbon offsets are frequently criticized on the grounds that they’re either (a) ineffective, or (b) morally questionable—amounting to a form of modern day indulgence. I can’t claim any particular expertise in either climate science or catholicism, but I can say that nothing I’ve read has convinced me of either argument.

Let’s take the indulgence argument first. Superficially, it may seem like carbon offsets are just a way for well-off people to buy their way out of their sins and into heaven (or across the Atlantic—whichever comes first). But, as David Roberts observed in an older Grist piece, there are some fairly important differences between the two things that make the analogy… not such a great one:

If there really were such a thing as sin, and there was a finite amount of it in the world, and it was the aggregate amount of sin that mattered rather than any individual’s contribution, and indulgences really did reduce aggregate sin, then indulgences would have been a perfectly sensible idea.

Roberts’s point is that when someone opts to buy carbon offsets before they get on a plane, the world still benefits from any resulting reduction in carbon release—it’s not like the money simply vanishes into the church’s coffers, never to be seen again, while the newly guilt-relieved traveler gets to go on their merry way. Maybe it feels like people are just taking the easy way out, but so what? There are plenty of other situations in which people opt to give someone else money in order to save themselves some time and effort—or for some other arbitrarily unsavory reason—and we don’t get all moralistic and say y’know, it’s not real parenting if you pay for a babysitter to watch your kids while you’re out, or how dare you donate money to cancer charities just so people see you as a good person. We all have imperfect motives for doing many of the things we do, but if your moral orientation is even slightly utilitarian, you should be able to decouple the motive for performing an action from the anticipated consequences of that action.

As a prominent example, none of us know what thought process went through Bill and Melinda Gates’s heads in the lead-up to their decision to donate the vast majority of their wealth to the Gates Foundation. But suppose it was something like "we want the world to remember us as good people" rather than "we want the world to be a better place", would anyone seriously argue that the Gateses shouldn’t have donated their wealth?

You can certainly argue that it’s better to do the right thing for the right reason than the right thing for the wrong reason, but to the extent that one views climate change as a battle for the survival of humanity (or some large subset of it), it seems pretty counterproductive to only admit soldiers into one’s army if they appear to have completely altruistic motives for taking up arms.

The argument from uncertainty

Then there’s the criticism that carbon offsets are ineffective. I think there are actually two variants of this argument—one from uncertainty, and one from inefficacy. The argument from uncertainty is that there’s just too much uncertainty associated with offset programs. That is, many people are understandably worried that when they donate their money to tree planting or cookstove-purchasing programs, they can’t know for sure that their investment will actually lead to a reduction in global carbon emissions, whereas when they reduce their air travel, they at least know that they’ve saved at least one ticket’s worth of emissions.

Now, it’s obviously true that offsets can be ineffective—if you give a charity some money to reduce carbon, and that charity proceeds to blow all your money on advertising, squirrels it away in an executive’s offshore account, or plants a bunch of trees that barely suck up any carbon, then sure, you have a problem. But the fact that it’s possible to waste money giving to a particular cause doesn’t mean it’s inevitable. If it did, nobody would ever donate money to any charity, because huge inefficiences are rampant. Similarly, there would be no basis for funding clean energy subsidies or emission-reducing technologies, seeing as the net long-term benefit of most such investments is virtually impossible to predict at the outset. Requiring certainty, or anything close to it, when seeking to do something good for the world is a solid recipe for doing almost nothing at all. Uncertainty about the consequences of our actions is just a fact of life, and there’s no reason to impose a higher standard here than in other areas.

Conversely, as intuitively appealing as the idea may be, trying to cut carbon by reducing one’s travel is itself very far from a sure thing. It would be nice to think that if the net carbon contribution of a given flight is estimated at X tons of CO2 per person, then the effect of a random person not getting on that flight is to reduce global CO2 levels by roughly X tons. But it doesn’t work quite that way. For one thing, it’s not as if abstaining from air travel instantly decreases the amount of carbon entering the atmosphere. Near term, the plane you would have traveled on is still going to take off, whether you’re on it or not. So if you decide to stay home, your action doesn’t actually benefit the environment in any way until such time as it (in concert with others’ actions) influences the broader air travel industry.

Will your actions eventually have a positive impact on the air travel industry? I don’t know. Probably. It seems reasonable to suppose that if a bunch of academics decide to stop flying, eventually, fewer planes will take off than otherwise would. What’s much less clear, though, is how many fewer. Will the effective CO2 savings be anywhere near the nominal figure that people like to float when estimating the impact of air travel—e.g., roughly 2 tons for a one-way transatlantic flight in economy? This I also don’t know, but it’s plausible to suppose they won’t. The reason is that your purchasing decisions don’t unfold in a vacuum. When an academic decides not to fly, United Airlines doesn’t say, "oh, I guess we have one less customer now." Instead, the airline—or really, its automated pricing system—says "I guess I’ll leave this low fare open a little bit longer". At a certain price point, the lower price will presumably induce someone to fly who otherwise wouldn’t.

Obviously, price elasticity has its limits. it may well be that, in the long term, the airlines can’t compensate for the drop in demand while staying solvent, and academics and other forward-thinking types get to take credit for saving the world. That’s possible. Alternatively, maybe it’s actually quite easy for airlines to create new, less conscientious, air travelers by lowering prices a little bit, and so the only real product of choosing to stay home is that you develop a bad case of FOMO while your friends are all out having fun learning new things at the conference. Which of these scenarios (or anything in between) happen to be true depends on a number of strong assumptions that, in general, I don’t think most academics, or even economists, have a solid grasp on (I certainly don’t pretend to).

To be clear, I’m not suggesting that the net impact of not flying is negative (that would surprise me), or that academics shouldn’t cut their air travel. I’m simply observing that there’s massive uncertainty about the effects of pretty much anything one could do to try fight climate change. This doesn’t mean we should give up and do nothing (if uncertainty about the future was a reason not to do things, most of us would never leave our house in the morning), but it does mean that perhaps naive cause-and-effect intuitions of the if-I-get-on-fewer-planes-the-world-will-have-less-CO2 variety are not the best guide to effective action.

The argument from inefficacy

The other variant of the argument is a bit stronger, and is about inefficacy rather than uncertainty: here, the idea is not just that we can’t be sure that offsetting works; it’s that we actually have positive evidence that offset programs don’t do what they claim. In support of this argument, people like to point to articles like this, or this, or this—all of which make the case that many organizations that nominally offer to take one’s money and use it to pull some carbon out of the environment (or prevent it from being released) are just not cost-effective.

For what it’s worth, I find many of these articles pretty convincing, and, for the sake of argument, I’m happy to take what many of them say about specific mechanisms of putative carbon reduction as gospel truth. The thing is, the conclusion they support is not that trying to reduce carbon through charitable giving doesn’t work; it’s that it’s easy to waste your money by giving to the wrong organization. This doesn’t mean you have to put your pocketbook away and go home; it just means you might have to invest a bit of time researching the options before you can feel comfortable that there’s a reasonable (again, not a certain!) chance that your donation will achieve its intended purpose.

This observation shouldn’t be terribly troubling to most people. Most of us are already willing to spend some time researching options online before we buy, say, a television; there’s no reason why we shouldn’t expect to do the same thing when trying to use our money to help mitigate environmental disaster. Yet, in conversation, when I’ve asked my academic friends who express cynicism about the value of offsets how much time they’ve actually spent researching the issue, the answer is almost invariably "none" or "not much". I think this is a bit of an odd response from smart people with fancy degrees who I know spend much of their waking life thinking deeply about complex issues. Academics, more than most other folks, should be well aware of the dangers of boiling down a big question like "what’s the best way to fight climate change by spending money?" to a simplistic assertion like "nothing; it can’t be done." But the fact that this kind of response is so common does suggest to me that maybe we should be skeptical of the reflexive complaint that charitable giving can’t mitigate carbon emissions.

Crucially, we don’t have to stop at a FUD-like statement like nobody really knows what helps, so in principle, carbon offsets could be just as effective as not flying. No, I think it’s trivial to demonstrate essentially from first principles that there must be many cost-effective ways to offset one’s emissions.

The argument here is simple: much of what governments and NGOs do to fight climate change isn’t about directly changing individual human beings’ consumption behaviors, but about pro-actively implementing policies or introducing technologies that indirectly affect those behaviors, or minimize their impacts. Make a list of broad strategies, and you find things like:

  • Develop, incentivize and deploy clean energy sources.
  • Introduce laws and regulations that encourage carbon emission reduction (e.g., via forest preservation, congestion pricing, consumption taxes, etc.).
  • Offer financial incentives for farmers, loggers, and other traditional industrial sources of carbon to develop alternative income streams.
  • Fund public awareness campaigns to encourage individual lifestyle changes.
  • Fund research into blue-sky technologies that efficiently pull carbon out of the atmosphere and safely sequester it.

You can probably go on like this for a long time.

Now, some of the items on this list may be hard to pursue effectively unless you’re a government. But in most of these cases, there’s already a healthy ecosystem of NGOs working to make the world a better place. And there’s zero reason to think that it’s just flatly impossible for any of these organizations to be more effective than whatever benefit you think the environment derives from people getting on fewer planes.

On the contrary: it requires very little imagination to see how, say, a charity staffed by lawyers who help third-world governments draft and lobby for critical environment laws might have an environmental impact measured in billions of dollars, even if its budget is only in the millions. Or, if science is your thing, to believe that publicly-funded researchers working on clean energy do occasionally succeed at developing technologies that, when deployed at scale, provide societal returns many times the cost of the original research.

Once you frame it this way—and I honestly don’t know how one would argue against this way of looking at things—it seems pretty clear that blanket statements like "carbon offsets don’t work" are kind of dumb—or at least, intellectually lazy. If what you mean by "carbon offsets don’t work" is the much narrower claim that most tree-planting campaigns aren’t cost-effective, then sure, maybe that’s true. My impression is that many environmental economists would be happy to agree with you. But that narrow statement has almost no bearing on the question of whether or not you can cost-effectively offset the emissions you’d produce by flying. If somebody offered you credible evidence that their organization could reduce enough carbon emissions to offset your transatlantic flight for the princely sum of $10, I hope you wouldn’t respond by saying well, I read your brochure, and I buy all the evidence you presented, but it said nothing about trees anywhere, so I’m afraid I’m going to have to reject your offer and stay home.

The fact of the matter is that there are thousands, if not tens of thousands, of non-profit organizations currently working to fight climate change. They’re working on the problem in many different ways: via policy efforts, technology development, reforestation, awareness-raising, and any number of other avenues. Some of these organizations are undoubtedly fraudulent, bad at what they do, or otherwise a waste of your money. But it’s inconceivable to think that there aren’t some charities out there—and probably a large number, in absolute terms—that are very effective at what they do, and certainly far more effective than whatever a very high-flying individual can achieve by staying off the runways and saving a couple dozen tons of CO2 per year. And you don’t even need there to be a large number of such organizations; you just need to find one of them.

Do you really find it so hard to believe that there are such organizations out there? And that there are also quite a few people whose day job is identifying those organizations, precisely so that people like you and I can come along and give them money?

I don’t.

So how should you spend your money?

Supposing you find the above plausible, you might be thinking, okay, fine, maybe offsetting does work, as long as you’re smart about how you do it—now please tell me who to make a check out to so I can keep drinking terrible hotel coffee and going to poster sessions that make me want to claw my eyes out.

Well I hate to disappoint you, but I’m not entirely comfortable telling you what you should do with your money (I mean, if you insist on an answer, I’ll probably tell you to give it to me). What I can do is tell you is what I’ve done with mine.

A few months ago, I set aside an evening and spent a few hours reading up on various climate-focused initiatives, Then I ended up donating money to the Clean Air Task Force and the Coalition for Rainforest Nations. Both of these are policy-focused organizations; they don’t plant tree saplings or buy anyone a clean-burning stove. They fight climate change by attempting to influence policy in ways that promote, respectively, clean air in the United States, and preservation of the world’s rain forests. They are also, not coincidentally, the two organizations strongly recommended by Founders Pledge—an organization dedicated to identifying effective ways for technology founders (but really, pretty much anyone) to spend their money for the benefit of society.

My decision to give to these organizations was motivated largely by this Founders Pledge report, which I think compellingly argues that these organizations likely offer a much better return on one’s investment than most others. The report estimates a cost of $0.02 – $0.72 per ton of CO2 release averted when donating to the Coalition for Rainforest Nations (the cost is somewhat higher for the Clean Air Task Force). For reference, typical estimates suggest that a single one-way economy-class transatlantic plane ticket introduces perhaps 2 – 3 tons of CO2 to the atmosphere. So, even at the conservative end of Founders Pledge’s "realistic" estimate, you’d need to give CfRN only around $2 to offset that cost. Personally, I’m a skeptical kind of person, so I don’t take such estimates at face value. When I see this kind of number, I immediately multiply it by a factor of 10, because I know how the winner’s curse works. In this case, that still leaves you with an estimate of $20/ton—a number I’m perfectly happy with personally, and that seems to me quite manageable for almost anybody who can afford to get on a transatlantic flight in the first place.

Am I sure that my donations to the above organizations will ultimately do the environment some good? No.

Do I feel confident that these are the best charities out there? Of course not. It’s hard to imagine that they could be, given the sheer number of organizations in this space. But again, certainty is a wildly unrealistic desideratum here. What I am satisfied with is that I’ve done my due diligence, and that in my estimation, I’ve identified a plausibly effective mechanism though which I can do a very tiny bit of good for the world (well, two mechanisms—the other one is this blog post I’m writing, which will hopefully convince at least one other person to take similar action).

I’m not suggesting that anyone else has to draw the same conclusions I have, or donate to the same organizations. Your mileage will probably vary. If, after doing some research, you decide that in your estimation, not flying still makes the most sense, great. And if you decide that actually none of this climate stuff is likely to help, and instead, you’re going to give your money to charities that work on AI alignment or malaria, great. But at the very least, I hope it’s clear there’s really no basis for simply dismissing, out of hand, the notion that one can effectively help reduce atmospheric CO2—on a very, very tiny scale, obviously—via financial means, rather than solely through lifestyle changes.

Why stop at offsets?

So far I’ve argued that donating your money to climate-focused organizations (done thoughtfully) is a perfectly acceptable alternative to cutting back on travel, if your goal is to ultimately reduce atmospheric carbon. If you want to calculate the amount of money you’d need to give to the organization of your choice in order to offset the carbon that your travel (or, more generally, lifestyle) introduces every year, and give exactly that much, great.

But I want to go a bit further than that. What I really want to suggest is that if you’re very concerned about the environment, donating your money can actually be a much better thing to do than just minimizing your own footprint.

The major advantage of charitable giving, unlike travel reduction, or really any kind of lifestyle change, is that there’s a much higher ceiling on what you can accomplish. When you try to fight global warming by avoiding travel, the best you can do is eliminate all of your own personal travel. That may not be trivial, and I think it’s certainly worth doing if your perceived alternative is doing nothing at all. Still, there’s always going to be a hard limit on your contribution. It’s not like you can remove arbitrarily large quantities of carbon from the environment by somehow, say, negatively traveling.

By contrast, when you give money, you don’t have to stop at just offsetting your own carbon production; in principle, you can pay to offset other people’s production too. If you have some discretionary income, and believe that climate change really is an existential threat to the human species (or some large subset of it), then on on some level it seems a bit strange to say, "I just want to make sure I personally don’t produce more carbon than the average human being living in my part of the world; beyond that, it’s other people’s problem." If you believe that climate change presents an existential threat to your descendants, or at least to their quality of life, and you can afford to do more than just reduce your own carbon footprint, why not use more of your resources to try and minimize the collective impact of humanity’s past poor environmental decisions? I’m not saying anyone has a moral obligation to do that; I don’t think they do. But it doesn’t seem like a crazy thing to do, if you have some money to spare.

You can still fly less!

Before I go, let me circle around to where I started. I want to emphasize that nothing I’ve said here is intended as criticism of what Russ Poldrack wrote, or of the anti-flying movement more generally. Quite the opposite: I think Russ Poldrack is a goddamn hero (and not just for his position on this issue). If not for Russ’s post, and subsequent discussions on social media, I doubt I would have been sufficiently motivated to put my own money where my mouth is on this issue, let alone to write this post (as an otherwise fairly selfish person, I’m not ashamed to say that I wrote this post in part to force myself to give a serious chunk of cash to charity—public commitment is a powerful thing!). So I’m very much on board with the initiative: other things equal, I think cutting back on one’s air travel is a good thing to do. All I’m saying here is that there are other ways one can do one’s part in the fight against climate change that don’t require giving up air travel—and that, if anything, have the potential to exert far greater (though admittedly still tiny in the grand scheme of things) impact.

It also goes without saying that the two approaches are not mutually exclusive. On the contrary, the best-case scenario is that most people cut their air travel and give money to organizations working to mitigate climate change. But since nobody is perfect, everything is commensurable, and people have different preferences and resource constraints, I take it for granted that most people (me included) aren’t going to do both, and I think that’s okay. It seems perfectly reasonable to me to feel okay about your relationship with the environment so long as you’re doing something. I respect people who opt to do their part by cutting down on their air travel. But I’m not going to feel guilty for continuing to fly around the world fairly regularly, because I think I’m doing my part too.