Carbon Offsets

A friend asks:

A quick question: if somebody wants to donate money to reduce his or her carbon footprint, which org(s) would you recommend that he or she donate to?

Do you have a good answer to this? I don’t want answers that deny the premise. We’re assuming someone wants to donate money to reduce his or her carbon footprint, and choosing an organization based on this. We’re not comparing this against other activities, like cutting personal carbon emissions or voting for politicians who want to cut carbon emissions.

Here’s my best answer so far:

The Gold Standard Foundation is one organization that tackles my friend’s question. See for example:

• Gold Standard, Offset your emissions.

Here they list various ways to offset your carbon emissions, currently with prices between $11 and $18 per tonne.

The Gold Standard Foundation is a non-profit foundation headquartered in Geneva that tries to ensure that carbon credits are real and verifiable and that projects make measurable contributions to sustainable development.

45 Responses to Carbon Offsets

  1. Toby Bartels says:

    Giving What We Can recommends Citizens' Climate Lobby/Education and Cool Earth as cost-effective charities for the cause of climate change; see (and the additional reports on the sidebar to the right). Neither of these is set up to be used as offsets, but GWWC's estimates tell you how much CO₂ emission reduction you can expect per dollar given (and conclude that this is more reduction than you get by explicitly buying offsets). In particular, they calculate that a mere $1.34 to Cool Earth takes out a tonne of CO₂, and that's the conservative estimate.

    • John Baez says:

      I wonder why Giving What We Can says the best charities can offset a tonne of CO2 for $1.34 while the UN-recognized Gold Standard Organization lists prices ten times that! Is someone being overly optimistic, or overly pessimistic?

      • Colin Rust says:

        It’s a good question, John, why such a large disparity? I don’t know. For the Coalition for Rainforest Nations, the Founders Pledge estimates a seemingly crazy low estimate of $0.12 per tonne of CO2e, with a “plausible range” of $0.02 to $0.72.

        My suggestion to your friend would be to donate to one of the climate charities that have been rated most highly, but assume something like the GSO’s rate. So e.g. donate to CfRN, but donate $11 per tonne of CO2e they are seeking to offset.

        • John Baez says:

          I’m worried that the people with seemingly crazy low estimates are doing something wrong: I always worry when someone wants to sell me something for one-hundredth the usual price. But maybe they’re doing something right! It’d be good to dig into these estimates and see how they’re made.

        • Colin Rust says:

          I think part of the difference may be that standard approaches for carbon offsets are looking for relatively sure bets, whereas the Effective Altruism approaches (from Giving What We Can, Founders Pledge, Let’s Fund) are looking to maximize the expected value. So e.g. some of the interventions are to fund research or to try to affect political change, which may well not pan out even if they are high in expected value per charitable dollar. No question the discrepancy of two orders of magnitude is pretty dramatic though!

      • Toby Bartels says:

        For one thing, there’s a note on the GWWC pages that they haven't reevaluated their charity recommendations since 2016 and aren't going to. (They list three other places to get recommendations from in general, but none of those seems to have a category for climate change.) So maybe we've learnt something important in the last three years.

        It also may be that GSF is looking only at charities structured as offsets. In the evaluation of Cool Earth, GWWC notes that offsets cost at best around $10 per tonne of CO₂, so that's not exactly disagreeing with GSF, just saying that offsets aren't the best strategy. Cool Earth doesn't plant trees; it protects existing rainforests. It may be that GWWC is overestimating the impact of this, or it may be that GSF is overlooking this strategy.

    • Colin Rust says:

      I think that’s the right framework: what is the most efficient charity in terms of $ per tonne of CO2 equivalent averted, in expected value? But the GWWC recommendation is (on their own account) out of date; for a critique see here.

      More recently, John Halstead for the Founders Pledge has recommended the Coalition for Rainforest Nations and the Clean Air Task Force; and Let’s Fund recommended a restricted gift to the Clean Energy Innovation program at the Information Technology and Innovation Foundation.

  2. Carsten Führmann says:

    The compensation provider that seems to dominate in Germany is this one: There is German-language magazine called “Stiftung Warentest”, very established for a long time, which provides tests for all kinds of consumer products. Atmosfair say they came top in the 2018 test: (Alas, the issue of the magazine is paywalled with 5.70 Euros) So far, I haven’t done any verification of vetting myself. If I find the time for that, I’ll report here.

  3. Bob says:

    Transmeta claimed they would produce energy-efficient microprocessors. They had a few celebrities onboard and attracted a lot of investors. Then they sold off their intellectual property leaving their original investors holding an empty bag. Green venture capital is being called the new gold. Unless you think that you can survive on a trampoline with Sumo wrestlers, you should probably invest locally.
    So, how does one verify the relevance of a personal carbon footprint contribution in a global context? Will wiggling your pinky affect the center of mass of the whole universe? Greta Thunberg realizes her trans-Atlantic yacht trip is an attempt to leverage a symbolic gesture. She appears to have no illusions that she’s actually registering on any scale that can be verified.
    I’ve inserted dollar-store foam core sheets in my windows to keep down air conditioning costs. But then I realized gallons of hot water are still going down my drains every day. Where are the heat-exchangers on the plumbing? American housing, even with the hermetically-sealed double-paned windows, the siding, the insulation,…is still incredibly energy-inefficient.
    Many green efforts continue to look like the fabled little Dutch boy trying to stop a dam from breaking. The old proverb, “The road to hell is paved with good intentions.”, seems very relevant these days.

  4. MarkR says:

    The way I see it, anything that plants trees must be able to guarantee (i) the new trees are guaranteed to be protected for centuries and (ii) they also guarantee there’s no way other trees could be there at any point in the next centuries. Otherwise you’re not necessarily reducing CO2 on relevant timescales.

    Point (ii) also applies to renewables and energy efficiency where there’re risks of double counting.

    Turning CO2 into stone seems like it’s definitely long term and additional, the only offsets that I’ve been convinced work properly. Unfortunately current prices are almost $900/tonne CO2.

    They say it’ll get cheaper with investment, so buying now will also help others in future. But the same argument goes for buying solar panels or an electric car.

  5. ecoquant says:

    John, I actually answered this for my son, Jeff, who was asked about it while at SNAP a week or so back. Here was my take:

    There are a large number of carbon offsetting programs, and some are much better than others. In our case, we calculate the amount of CO2 needed to be offset using online tools, e.g., per the pattern:


    I calculated to offset each person for a round-trip to Tuxtla (airport code TGZ), with a stop in Mexico City (airport code AZP), and added the radiative forcing component. The emissions for an Economy class round trip per person is 1.23 metric tonnes or 1230 kg CO2. Offsetting 383 kg of CO2 costs US$40. So offsetting 1230 kg costs about US$129.

    I used the facility at to get the pounds of CO2 emitted, with radiative forcing.

    The offset can be done as a one-time contribution here:

    What’s particularly good about doing it that way is that it is has a local/regional effect, and is preferable to offsetting via, say, or is that we know exactly where and how the monies are being used, specifically to buy WRECs. See for more details about that, and
    for even more.

    Justification for this from Erin Taylor of MassEnergy as included below.

    I did this for a friend who was traveling to Tuxtla in Mexico. The point is to buy WREC, which are Wind Renewable Energy Credits, and you can’t get more specific and concrete for offsetting than that. These are generated by production of wind a Massachusetts State program (many states support this, and it was originally a U.S. EPA initiative), and utilities are required by law to purchase a set number of these per year. By buying these back oneself, wind power is being incentivized, and there’s a doubling effect because then the utilities pool of WRECs is smaller than it otherwise would be, so it needs to get them elsewhere.

    There are also SRECs, solar energy credits, which we earn from our PV generation. One SREC is generated per MWh. When we sell these on the open market we earn about $220 apiece, which is what utilities and so on pay. (It’s a trading market so it fluctuates.) WRECs are cheaper.

    Ticking the radiative forcing for flying is important, because CO2 and H2O emissions at jet aircraft altitudes is vastly worse than emitting at sea level.

    Hope this helps.

  6. Kartik says:

    ACM SIGPLAN maintains a list of resources for Carbon Offsets:

    They seem to recommend primarily CoolEffect and atmosfair

  7. Rif A. Saurous says:

    I’m a fan of, and I offset using them.

  8. Toby Bartels says:

    Further, part of the idea of carbon offsets is to pay the real price of your pollution. GWWC is part of the Effective Altruism movement, and that’s all about getting the most good out of your charity money, not about deciding how much to give. So carbon offsets are going to be something that will scale up, so that if the whole world offsets their carbon, then global warming is halted. Whereas once Cool Earth gets enough money to save all of the rain forests, the next best use for any additional money will be something less effective, and the $1.34/tonne price won’t scale. In other words, $11/tonne is the average price to offset carbon, while $1.34/tonne is the marginal price.

    So the Right Thing might be to calculate how much to give using GSF's recommendations but direct the money using GWWC's recommendations. Then you're both paying your fair share and using that share most effectively.

  9. Wolfgang says:

    ” I don’t want answers that deny the premise.”

    Sorry, but that is not the way to solve a problem, if the premise is wrong.

    The question sounds a little like “What diet book should I buy to get slim?” while the only answer can be “eat less”. Carbon offsets are fooling yourself into thinking that you have achieved some CO2 reduction by paying other people to do it for you. It’s outsourcing and diffusing your own responsibility. Sorry, it does not work like that. There is nothing happening physically, if you transfer money between bank accounts. In fact it contributes to energy costs (however small) and increases CO2. That’s capitalistic madness! Free yourself from thoughts that money is the solution, it is part of the problem! Don’t participate in actions which are easy and pretend to solve a problem, but do it the hard way and attack the problem directly. It is all about changing YOUR lifestyle habits, the hardest thing to do for the average human being.

    If one wants to achieve a real change, keep your money, but travel less, consume less, produce less waste, don’t buy an SUV, or plant some tree yourself. The money you keep you can invest in paying fair prices of products, in buying products that will be produced well, and stay with you a long time. They are more expensive on average, but they usually pay off in quality, including better effects on the environment, so that’s where your money should go. Support your local industries, such that they safe money on transport, too. You have much better control on your money spent then, too. Tiny things to do, for sure, but since there is no unique and easy solution the only ones where you know, that they REALLY made a difference.

    • ecoquant says:


      This may be true of some Carbon offsets, and it is true that we need to zero emissions. But, in our case, where we use the offset monies to purchase WRECs, there is a correspondence between fossil fuel generation which is pushed off the grid by an increment of wind power and the dollars.

      Still, offsetting, say, a single person’s plane seat doesn’t do anything for the massive generation of everyone else flying on board. Also, to some degree, those planes fly whether or not they are full, even if airlines are incentivized to fill them. And, you are correct, that the only real way of making an impact on flying is to boycott flying, so there are fewer planes aloft. To some degree a stiff Carbon tax or fee has the same problem. True, there will in principle be fewer people flying because it will be less affordable. But, for some transport, prices are really inelastic, and people will fly because there isn’t any other choice.

      But, particularly with flying, there are no good alternatives on the horizon. There is the Varialift concept which, as long as it is powered by solar PV and electric motors, offers a solution. It could be used for passenger transport. But it is slow. That might, eventually, be suitable for luxury trips.

      In the meantime, there’s no other solution to international meetings apart from rich, digital and video interconnections. And some collaborations simply need to be done in person.

      • “In the meantime, there’s no other solution to international meetings apart from rich, digital and video interconnections.”

        Of course, these have carbon-dioxide emissions associated with them as well, unless the computers involved are running on completely green power.

        People know that cars and factories produce emissions. There is a restaurant chain in Sweden which has the amount of carbon dioxide produced for each item on the menu. Then there is Google’s carbon footprint.

      • Taranga says:

        The UK has a Hybrid Airship Company –
        They are planning to offer 50 ton and bigger in the future and although at the moment they are depending on diesel propellers the future ones could be largely powered from PV and batteries and or renewable H2.
        One great advance over previous Airships is the possibility of needing no ground crew or runway as they’re working on an inflatable hovercraft skirt with the ability to suck the airship to the ground whilst loading and unloading.

        Obviously the top speed of 100 knots and max altitude of 20,000ft means a far more civilised travelling with cabins and wonderful views.

        There is also a solar powered Canadian cargo airship being built for deliveries in South Africa.

    • John Baez says:

      Wolfgang wrote:

      Carbon offsets are fooling yourself into thinking that you have achieved some CO2 reduction by paying other people to do it for you.

      Okay, so you think the term “carbon offset” has self-delusion built in.

      Instead of calling them “carbon offsets”, let’s call them “donations to organizations that work for CO2 reduction”. Here’s my question: suppose one wants to give some money to organizations that work for CO2 reduction. Whom should one give it to?

      I called them “carbon offsets” because if you want to find answers to this question, it helps to look at material on “carbon offsets”.

      • Giampiero Campa says:

        I glanced at the gold standard web site and it’s not too clear to me how the donations are split among all the projects they have. There are some project that do help reducing CO2 but many don’t. For example the “Chlorine dispenser in Uganda” is absolutely great, but it’s not obvious to me how and if it helps recapturing C02 from the atmosphere. Googling for “donate to reforestation project” suggests some options there, of which seems to be the leading one. If one assumes that the objective is strictly to recapture CO2 then reforestation seems to be the best bet to me.

      • Bob says:

        “Here’s my question: suppose one wants to give some money to organizations that work for CO2 reduction. Whom should one give it to?”
        Isn’t spending money the greatest fundamental cause of carbon emissions? Consider how the largest bit-coin mining farms are located next to the largest hydro-electric plants. Every finanical transaction generates a chain reaction of energy use and this seems fundamentally unavoidable. So wouldn’t a global recession benefit the world far more than donating money to any bandaid in an attempt to cure a fundamental cause?
        Perhaps instead, bequest any donations towards opening, enlarging and slowing the Earth’s closed system by supporting future expansion into outer space?
        Or, donating to better education seems less likely to souffle.

  10. James Smith says:

    ACCT are great:

    Lovely people! I heard of them via a personal recommendation.

    After some digging, I found that another organisation with a seemingly similar remit and a much slicker website paid their founder over $600,000 in one year out of donations of less than double that.

    And I’m not sure that certification addresses the issue of proving legitimacy, in fact I’d say that sadly it often contributes to the problem. The Forest Stewardship Council is a perfect example.

    I’d say trust your instincts and use your common sense when confronted with people who want your money and claim to be doing good with it.

    Kind regards,

  11. Isn’t it a bit naive to assume that some donation can completely offset the CO2 emission? Assuming this were true, and seeing that it is only a small fraction of the cost of a flight, say, then a tax of the corresponding amount would solve all problems related to carbon footprint. If it sounds too good to be true, then it probably is.

    • John Baez says:

      Completely offset all carbon emissions? All carbon emissions worldwide? I don’t think anyone is planning to completely solve the problem of carbon emissions through charity. This will require a massive effort involving individual changes in behavior, new technologies, new laws and government policies, adaptation to climate change, etc.

      But I’m not trying to solve the whole problem in this one blog post. I’m just asking: if one wants to give some money to organizations who are helping to reduce CO2 in the atmosphere, which organizations are best—and how good are they? That seems like useful information to have.

      • Yes, I agree; my remark is a bit tangential to your post. What I’m wondering is whether one should have a good conscience if donating somewhere to compensate the CO2 emission of, say, a flight. It could be, of course, that this works, but doesn’t scale. If it did work and did scale, of course, then there is a very simple solution.

        Case in point: Greta Thunberg is sailing across the Atlantic, because sailboats have a smaller carbon footprint than flying. Problem: the sailors are flying back. Solution: the sailors are donating to compensate. Question: why doesn’t Greta just fly and donate to compensate? One reason is that the sailboat gets more media coverage than the flight. On the other hand, if she is OK with the sailors donating to compensate, why not just fly without the sailors and donate herself? (I’m sure that her trip to the USA would still get substantial media coverage.) This is actually something people could do themselves, while for most a sailboat is not an option.

    • ecoquant says:

      Yes, until people start boycotting flights or the cost per flight goes up a lot due to a Carbon price, the total number of flights won’t decrease. On the other hand, marginally increasing the amount of zero Carbon energy generation does help

  12. John Baez says:

    Ritesh Ragavender says:

    Just saw your last post on Azimuth about carbon emissions and wanted to ask what you thought about Project Wren – a new startup out of YC that calculates your carbon footprint and helps you pick a carbon protection project to fund.

    Does anyone have opinions about this?

  13. Just donate to EA in general? says:

    If the goal is not to reduce a personal carbon footprint, but to reduce the world’s carbon footprint, then that implies some amount of indirectness is permitted. It might be that they’d do best to donate to contraceptive funding in SSA, or women’s education, or anti-malarial organizations.

    I am having a hard time thinking about this, because to me it is hard to stop thinking in terms of aggregate utility in general, and instead think specifically in terms of this one specific form of harm. That seems a little bit at odds with the notions of offsets itself.

    Are they okay with a probabilistic reduction in carbon offsets, so long as the expected value of the offset equals the expected carbon they’ve emitted? Or do they need a high degree of certainty and directness to their efforts? My feeling is that the methods involving directness and high certainty will tend to be much less cost-effective.

    • John Baez says:

      I am having a hard time thinking about this, because to me it is hard to stop thinking in terms of aggregate utility in general, and instead think specifically in terms of this one specific form of harm.

      You could think of it as like taking out the trash. When my wife says to take out the trash, I should take out the trash, not buy her flowers—because there really is a reason to take out the trash.

      Here however the trash is CO2, and it quickly spreads worldwide, so any form of reducing it anywhere counts as taking out the trash.

  14. James Smith says:

    I like the dispersed trash analogy.

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