Myles Allen, Oxford Professor of Geosystem Science and Director of the Oxford Net Zero initiative, breaks down what carbon offsets are, and describes several types of offset projects. He also describes the Oxford Principles for Net Zero Aligned Carbon Offsetting, and how those principles aim to reduce the risk and uncertainties associated with the use of offsets by companies, organizations, and countries as they strive to meet their net zero goals.

With carbon offsets, you pay another organization to reduce its greenhouse gas emissions, and you get the credit for that reduction. Carbon offsets tend to be nature-based, like planting trees or wild grasslands, or technology-based, like installing equipment that captures and stores carbon from smokestack emissions.

Offsets have become a hot button topic, with concerns over issues like permanence (a forest can burn down, for example), additionality (whether the reduction would have happened without the purchase of the offset), and greenwashing.

To address these concerns, the interdisciplinary research team that comprise the Oxford Net Zero initiative developed the Oxford Principles for Net Zero Aligned Carbon Offsetting (“Oxford Offsetting Principles”). These four principles describe how organizations can use offsets credibly to support net zero goals. Key among the principles are that organizations should prioritize reducing their own emissions first, and should shift their offset purchasing from projects that reduce emissions to those that remove carbon from the atmosphere.

Myles Allen discusses some of the controversy over carbon offsets and details how the Oxford Offsetting Principles aim to decrease the associated risk as companies and countries try to reach decarbonization goals. He talks about the need for the market to reflect net-zero aligned offsets to ensure permanence of emissions reductions and what that would look like.

Myles also talks about what the University of Oxford is doing to address its own emissions, and shares the advice he gives his students interested in embarking on climate change careers.

Resources

• The Oxford Principles for Net Zero Aligned Carbon Offsetting
• Oxford Net Zero
• University of Oxford Environmental Sustainability Strategy
• Voluntary carbon markets: how they work, how they’re priced and who’s involved (S&P Global Commodity Insights)
• Puro.earth

Guests

Climate Rising Host: Professor Mike Toffel, Faculty Chair, Business & Environment Initiative

Guest: Myles Allen, Professor of Geosystem Science in the School of Geography and the Environment and Department of Physics at the University of Oxford, and he is Director of the Oxford Net Zero initiative

Transcript

Editor’s Note: The following was prepared by a machine algorithm, and may not perfectly reflect the audio file of the interview.

Mike Toffel:
This is Climate Rising, a podcast from Harvard Business School, and I’m your host, Mike Toffel, a professor here at HBS.

Our recent episodes have focused on the decarbonization strategies of companies and industries. We’ve examined products and services that are less carbon intensive, but few of them are actually carbon free. And so to attain their net zero goals after reducing their carbon emissions, many companies then turn to carbon offsets. A carbon offset occurs when one organization pays another to reduce or remove its carbon, and the organization who pays gets the credit for the reduction.

But carbon offsets are tricky--and controversial. And so we’re taking two episodes to discuss carbon offsets–what they are, how they’re used, what’s controversial about them, and what best practices are emerging.

Today, we’ll hear from Myles Allen, a geophysics professor from Oxford. Myles is also Director of the Oxford Net Zero initiative, an interdisciplinary research effort that is providing advice and expertise to organizations, industry leaders, and governments who are trying to meet net zero climate goals. He has also been a lead author on several Intergovernmental Panel on Climate Change—or IPCC—reports.

Most importantly for today’s episode, Myles helped develop the Oxford Principles for Net Zero Aligned Carbon Offsetting, which is often referred to more simply as the Oxford Offsetting Principles. These four principles describe how an organization can use offsets credibly to support its net zero goal. Key among them are that organizations should prioritize reducing their own emissions first, and should shift their offsets from projects that feature emission reduction, toward those feature carbon removal and long-term storage.

Carbon offset projects vary widely, but they all tend to rely on nature-based solutions, such as planting trees, or technology like carbon capture and storage, or CCS.

One reason offsets are controversial is that they allow their buyers to continue emitting greenhouse gasses. Moreover, the reductions they’re paying for might have happened anyway, and the carbon reductions or removals might not be permanent. For example, if you pay an organization to plant trees to absorb carbon, would those trees have been planted anyway? And will those trees always hold their carbon, or might they burn down or be harvested in the future? The Oxford Offsetting Principles are an important effort to help address these concerns.

Today, you’ll hear Myles discuss some of the controversy surrounding carbon offsets, and how the Oxford Principles seek to overcome them by helping organizations adopt a credible offset strategy.

Myles also talks about what the University of Oxford—which has been around nearly 10 centuries—is doing to address its own emissions. And he shares with us the advice he gives his own students who are interested in embarking on climate change careers.

Here’s my interview with Oxford University’s Myles Allen.

Mike Toffel:
Professor Myles Allen, thank you so much for being with us here on Climate Rising. I wonder if we can start by just asking you to introduce yourself in your various roles.

Myles Allen:
Sure. Well, I'm Myles Allen. I'm a physicist, but a professor in the School of Geography and the Environment and Department of Physics here in the University of Oxford, and I'm director of the Oxford Net Zero Initiative, and as of a couple of months ago, I'm also a member of the advisory board of puro.earth. I mention that because it's particularly relevant to the conversation we're having this afternoon.

Mike Toffel:
Great. So can you tell us a bit about the net zero initiative?

Myles Allen:
Well, this is something the University of Oxford decided to do a year and a half ago or so to invest two and a half million of our own money into helping the world get to net zero as best we could. It's focused primarily on policies on the social science around net zero. We recognized that there's a lot being done on the technologies that will be needed to get us there but less progress on how we are going to actually get people to use these technologies. So that's the real focus of Oxford Net Zero.

Mike Toffel:
We've asked you here primarily to learn about the Oxford Principles for Net Zero Aligned Carbon Offsetting, or more simply, the Oxford Offsetting Principles of which you're one of the co-authors. Let's begin by, even before we talk about the principles, just talking about offsets. What's a lay definition of carbon offsets and why are they part of the conversation in the net zero space?

Myles Allen:
Offsets are, in a nutshell, paying someone else to take care of your carbon for you. And on the one hand, if you are a classical economist you'd say that makes total sense. We don't grow our own food, most of us, at least, so why should we necessarily dispose of our own carbon? On the other hand, they've been derided as that's like paying someone else to take care of your sins as they were able to do back in the middle ages. And so offsets raise strong views, and many of those views are quite justified, so we felt it was necessary for us as academics to engage in this space and start to think about what would an effective offsetting market actually look like.

Mike Toffel:
Sounds like there's two types of objections to offsets. One is sort of philosophical, that says even if the instruments were totally credible, there's something illegitimate about paying others to reduce to allow you to continue polluting, and on the other hand, there are sort of institutional concerns, like, are these real? Are they actually doing anything that we think they are doing? Is that a reasonable way to understand it?

Myles Allen:
Absolutely. And of course those two link up. I mean, many of the philosophical objections sort of trickle through into the practical objections to offsetting schemes. But whatever your philosophical view on the legitimacy of taking care of carbon in this way, everybody agrees it's got to work. There's no point whatsoever in an offsetting scheme that doesn't actually result in compensating for the carbon that's emitted. And so, at a minimum, your offsetting schemes have to achieve that. And many at the moment unfortunately don't, so that's why we need to raise the whole standard of the offsetting market. And we are not the only ones to have recognized this at all. There's a big effort to try and clean up this whole market right now.

Mike Toffel:
So these concerns are what led to the creation of these offsetting principles, which seem to me to be establishing sort of a set of best practices, or really even a floor, of what offsets should contain or how your offsetting philosophy should be pursued. Is that about right?

Myles Allen:
That's right. I mean, the long-word title is important. We were asking ourselves, what would it actually mean for an offset market to actually be aligned with net zero? It's quite a specific question we were raising. until recently, until the past couple of years at least, nobody was really talking about getting to net zero at all. It was just all about reducing emissions. But now we've got an additional challenge. How are those markets themselves going to work in a world that's on a transition to a global net zero? Because a lot of the forms of offset available at the moment just no longer make sense when you're in a net zero world. That was our concern.

Mike Toffel:
Interesting. Can you give an example of an offset that had made sense a decade ago that no longer makes sense?

Myles Allen:
Well, I mean, most offsets around at the moment, more than 80% of them at least, you're paying for someone else to avoid emitting. So you're paying to reduce emissions in some way as a way of compensating for your own continued emissions. And, again, when there were no incentives on most people to reduce emissions at all, this made a certain amount of sense for efficiently identifying the cheapest ways of reducing emissions around the world.

The difficulty with this, of course, is that once the whole world has committed to net zero, it no longer really makes sense to pay someone else to reduce their emissions to compensate for the fact you're not reducing your own emissions as fast as you might do otherwise because they're going to have to reduce their emissions to net zero anyway. So it becomes a lot more difficult to argue those kind of avoided emissions offsets are aligned with a transition to a global net zero.

Mike Toffel:
Well, if I understand it correctly, if only a few institutions and organizations are declaring net zero, then they can continue with their positive emissions, pay others to reduce somewhat their emissions, and then it would work for them, but the point that I think you're making is, if the whole world is transitioning to net zero, then actually we need some people to go negative, if anyone is going to stay positive.

Myles Allen:
You could say it would work for them in the sense it would work to perhaps make their consciences feel a bit clearer but it doesn't actually solve the problem. And so what we need is an offset market that actually supports solving the underlying problem which helps stop climate change. And our concern was that it wasn't entirely clear to us that much of the offset market operating at the moment was actually helping to stop climate change at all, because it was allowing companies that could afford to reduce emissions to do something else instead, which wouldn't necessarily support the whole world transitioning to net zero, which is why we emphasized, in the first of the Oxford Offsetting Principles, the first thing you got to do is work out how to cut your own emissions. And only when you've done that and you've really done everything you can should you be out there looking for offsets to offset the remainder.

Mike Toffel:
So we're getting into the principles here. So there's four principles, and let's walk through them one by one, and that was a good segue to the first. The first principle's cut your own emissions then use high quality offsets. But the key there is to prioritize reducing your own emissions first. When you speak to chief sustainability officers or climate folks, that's often the mantra. It's, reduce as much as you can and then offset the rest.

The economist perspective would say, look at the marginal costs of abatement for each project you can do internally. How much would it cost? So first you start with the cheap ones, dollar a ton, and then you find that you've exhausted those and now you're up to two, and five, and 10 and a hundred. And the offset market, even for the most credible offsets, imagine they are at $80 a ton. The economist perspective would say, well, go up to 80 internally and then shift to the offset market to do the rest, but this seems to be suggesting that that's not the right way to think about it.

Myles Allen:
Well, there's a bigger picture than that, which is that there is a co-benefit to those who can afford it, investing in technologies to reduce emissions, technologies which will be needed by everybody else later on. So it does make sense to encourage tech companies and so on who are concerned about addressing their emissions, it makes sense for those companies to invest in solar power. Even if building their own solar power plants is going to cost them more than they could just wandering into the offset market and buying carbon, it's promoting the market for renewable energy. It's increasing that market. It's increasing innovation. And very often these companies actually then start to play a role in that innovation themselves. So that's what we, and many others, feel is important is that those who can afford it needs to put their resources behind promoting the transition.

That said, most offsets, high quality offsets, are available in other parts of the world which might be at earlier stages of the transition. They can also play a role in helping the transition, so investing in practices that are going to last rather than just investing in potentially just temporary carbon storage.

Mike Toffel:
And we'll talk about that, short-lived versus long-lived, which is principle three. We'll get there. So as I understand it, the priority of why you might go above and beyond even the marginal cost of abatement and use that efficiency curve that I described is partly motivated by the opportunity, and perhaps obligation in the view of some, for companies that can afford to to actually invest in their own reductions in part to spur the markets for those reduction technologies, whether it's insulation, or whether it's solar or wind, in order to spark an experience curve or a learning curve to reduce those costs so that others can enjoy them at lower cost down the road.

Myles Allen:
A big part of what's driven down the cost of solar worldwide, for example, has been the energy vendor in Germany. And a lot of people sort of kind of laughed at Germany at the time of going all out on renewables, and saying, "Well, there's much cheaper ways of you reducing emissions. Why are you spending all this on subsidizing renewables?" Well, the net benefit to the world has been probably solar and onshore and offshore wind costs now that are much lower than they would be otherwise, thanks to that enormous investment. That's at a national scale but companies can do the same thing. So that's the sort of example I'm referring to here.

Mike Toffel:
Okay, so the other part of principle one, beyond the idea of focusing on your own emissions first and then transition to high quality offsets, is this idea of what is a high quality offset? And the principle describes a few parameters I wanted to see if you could help us unpack. So three are: non-additionality, reversal, and then creating negative unintended consequences. So these are all things to watch out for. Let's take them one by one. First of all, additionality or non-additionality, can you unpack that for us?

Myles Allen:
Yeah. So non-additionality, it's a terrible jargon word, isn't it? What we mean is that if you are paying, for example, to an afforestation project, so you're paying for somebody to plant trees to take up carbon, you need to assure yourself that those trees are not being planted where you're paying for them to be planted instead of somewhere else. The problem of non-additionality is if you're simply displacing carbon uptake from one place to another, for your offset to be genuinely additional, it's got to either take carbon out of the atmosphere or avoid carbon being put into the atmosphere that would definitely have ended up in the atmosphere otherwise. And it's that sort of what would have happened otherwise that's often a big challenge in offsetting projects, because in many cases, it can be quite difficult to pin down exactly what would have happened in the absence of this project.

This is particularly true, of course, in countries where land is in short supply, and so every allocation of land to offsetting potentially comes at an opportunity cost, increasing the pressure on land elsewhere. So if you conserve or replant a forest in one part of the country, does that simply mean that forest gets cut down somewhere else to satisfy food demand? If it is, then your offsetting project is not really achieving very much at all. That's the non-additionality question.

Mike Toffel:
Let's talk about reversal. What does that mean?

Myles Allen:
Reversal's really simple. It's you plant a tree and then as a result of either poor management or poor governance, maybe you didn't have adequate ownership in place of the land on which the tree is planted, I'm just using the sort of planting a tree as a generic activity here, of course it could be many types of activities, or possibly even as a consequence of climate change itself, that tree is no longer viable in 15 or 20 years time, or is subject to increased fire risk or something and the carbon ends up in the atmosphere. It's this risk of reversal which has to be thought about carefully. And we'll come onto that again when we talk about short-lived versus long-lived storage. But obviously you want to be careful not to invest in offsetting projects where the positive impact of the project could be reversed in relatively short order.

Mike Toffel:
And finally, creating negative unintended consequences. That's another thing we want to avoid. What does that mean?

Myles Allen:
Well, clearly there's a danger in any activity that involves encouraging something to happen or paying for something to happen. Particularly in a poor part of the world, you've got to be really careful because the amount of money being spent on the offsetting project, for example, might be far in excess of the resources available to indigenous people in that region, and you can end up with awful consequences of entire indigenous populations getting displaced in order to make room for an offsetting project that is simply satisfying the consciences of lots of people half a world away. Clearly, we've got to guard against that. And that's a big part of the nature-based solutions standards that people require, is to ensure that this kind of negative consequences for people, indigenous people in particular, and the environment don't happen. So these are sort of minimum standards that any offsetting project has to step up to.

Mike Toffel:
Before we move on to the other principles, which I think of as more straightforward, these three that we just talked about: the non-additionality, reversal, and avoiding negative unintended consequences, are all characteristics, quality attributes in a sense. And the ability to assess the extent to which this has a non-additionality concern, or a reversal concern, or the unintended consequences seems to me like it would really require kind of on-the-ground assessment of the particular project. And so if you're a company who's trying to adhere to these principles, how are these organizations going about verifying whether in fact the projects that they are considering are adhering to these? Are there folks on the ground doing audits? Are there standards that have developed with certifications that are attesting to these characteristics?

Myles Allen:
yes, there are perhaps unfortunately many different standards out there and many different certifiers and so on. It is, I think everybody agrees, a bit of a mess of a market at the moment. We actually think one of the strongest approaches to offsetting is for companies and institutions to take out long-term contracts, where they actually know what's going on and they take out a contract with somebody who they're willing to commit to for the duration. I think universities are particularly well-placed to do this. We have long-term endowments. We make long-term management decisions. I personally feel that universities are much better placed, for example, to take out contracts with individual projects that can last for decades rather than just buying offsets on the open market where you really have much less control of what's going on.

Mike Toffel:
All right. Let's talk about principle two, which is the urge to shift offsets from emission reductions to carbon removal. Can you just give an example of each just so that listeners have a clear understanding of what the difference is between an offset that promotes emission reduction versus carbon removal? To many people those sound like the same thing.

Myles Allen:
So just to take two which are in a sort of similar part. If you pay someone to avoid deforestation or to prevent deforestation of a part of the world that's under threat, that would be an emission reduction offset because you're paying for the avoided emissions of carbon that would otherwise have ended up in the atmosphere if the deforestation had gone ahead. Keeping with the trees, if you conversely pay someone to plant trees in an area that's savannah at the moment or that doesn't have a lot of trees on it right now, then that would be a carbon removal offset, so you're paying them to take carbon out of the atmosphere.

I use this example deliberately because you can immediately see where does emission reduction stop and where does carbon removal begin can be a little bit of a gray area. In fact, one of our concerns was a lot of people sort of read principle two, and said, "That's it. No more emission reduction offsets. Only carbon removal now." Well, we didn't say that. We said shift to carbon removal or recognize the need to shift to carbon removal in your offsetting strategy. Because the point is, we have to stop deforestation, full stop

At the moment the biosphere is a big source of carbon. That has to end if we're going to get to net zero and if we're going to conserve the biosphere anyway. So we can't continue to rely on paying people not to deforest when they have to stop deforestation anyway. So that was really what we wanted to emphasize, was that offsetting strategies have to recognize the need to move from paying people to avoid emissions to actually paying to remove carbon dioxide back out of the atmosphere.

Because in the end, in a net zero world, it won't make sense to pay someone to avoid emissions because that's just sort of passing the buck, because then they'll have to pay somebody else to avoid emissions as well. I mean, it just goes round in circles.

Mike Toffel:
Let’s think beyond forestry about another example of carbon removal. What about farmers who change their practices in ways that increase the carbon in the soil? Their claim is that’s a higher-quality carbon offset because we’re actually taking CO2 from the atmosphere and embedding it in the soil. Is that a carbon removal example?

Myles Allen:
If you could establish that the total amount of carbon in the soil is going up, and going up permanently, not being re-released a few years later as a result of that activity, then sure, that is a carbon removal. And there's a lot of scope for carbon removal in that direction because we've depleted the carbon content of our soils across the world horribly. So yes, putting a lot of that carbon back is definitely a good idea but of course it has to stay there.

The crucial point is that when you burn a fossil fuel, the impact of that oxidation of that fossil fuel is hundreds of thousands of years. It lasts in the active carbon cycle effectively forever. So if you're going to offset that by storing carbon away, you've got to store carbon away for a very long time, if not necessarily forever. Forever's hard to measure. We need to be careful that removals result in removals and very long-term storage.

Mike Toffel:
And what about investments in renewable energy? For example, if you want to offset your scope two emissions, which is the emissions associated with electricity procurement. Not everyone can put solar on their roofs and wind turbines on their property to fully move to renewables, instead some of them are paying for the creation of more wind farms, or more solar, or more tidal, or maybe even more nuclear, other carbon-free sources elsewhere. That sounds to me like an emissions reduction strategy.

Myles Allen:
Those would be emission reduction offsets. Again, we're emphasizing a shift here, but those would be the sorts of examples of offsetting projects that I would imagine us shifting away from quite rapidly, because the world needs to shift to renewable where it can anyway. And indeed, in many cases, renewable energy is already economic relative to fossil, so you're paying to promote a renewable energy project when it's probably going to make money anyway. So that raises serious questions about additionality, to come back to that word, because, perhaps you say that your offsetting is paying for the building of this renewable energy project but perhaps they would have built it next year anyway.

Mike Toffel:
Let's move on to principle three, which is about shifting offsets from short-lived storage toward long-lived storage. Let's start by just an example of each and then talk about the rational

Myles Allen:
Sure. Interestingly actually, this is the principle that for me was most obvious as a physicist and yet seems to be most controversial to people for other reasons. As I emphasized, the impact of burning fossil fuels is permanence, multi-millennial timescale. So if you're going to store carbon to offset the combustion of fossil fuels, you should be storing it away for multi-century timescales at minimum. The difficulty is, of course, if you're storing carbon in the biosphere or pretty much anywhere in the biosphere, the turnover time of forests and of coastal ecosystems and so on is much faster than that. So you've got to address the question of what's going to happen to the carbon in the future. Is it safe where you've put it and have you put structures in place to make sure that it is safe?

We did not say that it was impossible to store carbon permanently in the biosphere but you've got to think about permanence in where you put it. One particularly obvious example, in some offset markets and under some offset standards, you can take credit for planting a tree even though that tree everybody knows is going to be cut down in 30 years time and used potentially in building and whatever it's built from might be knocked down 30 years later after that and then the carbon ends up in the atmosphere in 60 years time. So some standards completely allow that. You can take full credit for planting that tree even though the carbon in the tree is only stored away for, max, 50, 60 years. That's clearly problematic.

A really important point about net zero aligned offsetting is to think about what the world in net zero has to look like. And at a really fundamental level, any carbon dioxide we generate by continued fossil fuel use in that world will have to be compensated for by putting the equivalent amount of carbon dioxide back underground, or turning it back into rock, or some similar storage mechanism that is permanent on multi-century to multi-millennia timescales.

Now, again, we emphasized in this principle, we're going to need that kind of long-lived storage in a net zero world. That doesn't make short-lived storage valueless. And, of course, short-lived storage is generally far, far cheaper than that kind of geological timescale storage that I'm talking about here, but you've got to build the need to transition to durable storage into your offsetting plans.

Mike Toffel:
Now, the need for these long-term storage is based on what you said earlier about fossil fuel emissions taking millennia to ever percolate out of the atmosphere. And so it would seem to me this shift should be done really as soon as possible in the sense of if you have opportunities today, why not emphasize these long-lived storage? Where's the technology on this? What's the cost premium for

Myles Allen:
Well, I mean, the technology is there. It's possible to do this, but it's far more expensive than short-lived biological storage. So if you like, the ideal offset today would be one that both helps nature, helps biodiversity and guarantees long-lived carbon storage at the same time. And that would probably be much cheaper than storing carbon back underground right now. The problem is those opportunities are surprisingly few and far between. We need to find them, we need to use them where they exist, but relying on the biosphere to mop up our fossil carbon emissions isn't a sustainable strategy,

First of all, at the moment, the biosphere is a net carbon source. We have to turn it into a net carbon sink. Everybody agrees on that one, but at the same time we have to recognize that as the world warms, many biospheric sinks are going to turn into sources. Carbon is already being released from our tundra from parts of the world where carbon has been locked up for millennia and is being released just because of global warming itself.

And it's very possible that we will need all of our nature-based climate solutions capability just to keep the carbon content of the biosphere stable by the time we get to mid-century. And if that's the case, we can't afford then to count on the biosphere to compensate for remaining fossil fuel emissions. So we have to be investing now in building up our capability for getting rid of carbon dioxide back underground, which is why I personally would advocate companies that can afford it investing in geological storage today because we're going to need that technology desperately in two or three decades’ time.

Mike Toffel:
And just to clarify the technology carbon sources and carbon sinks. Carbon sources are, where carbon dioxide or other greenhouse gas emissions are coming from, and carbon sinks is where they are going to. Is that right?

Myles Allen:
That's right. Sorry, I slipped into that jargon. So a permanent carbon sink would be, for example, to capture carbon dioxide from the atmosphere, purify it, compress it to a liquid, reinject it back into rocks, into, say, a depleted hydrocarbon reservoir.. That, at the moment is, as I said, right out at one end of offset durability and offset expense as well. These are the most costly forms of offset, but in 30 years time that might well be only approach that actually makes any sense anymore for offsetting continued use of fossil fuels. Particularly when large companies are declaring their offsetting strategies going forward, I think it's very important for them to recognize this.

For example, one of my concerns is that quite a few large fossil fuel companies recently have announced plans to deal with their so-called scope three emissions, that's the emissions associated with the products they sell, that involve in effect very large scale offsetting of the carbon dioxide generated by the products they sell by planting trees. And it's not clear to me that those numbers add up because it's not clear to me that the world will be able to continue to mop up the CO2 generated by fossil fuels by mid-century just by planting trees. The land isn't there, and the world as a whole as it warms will be releasing carbon back into the atmosphere, which we will have to protect and put back through better management of the biosphere itself.

Mike Toffel:
So even if the numbers add up today, the concern is, is that a trajectory that makes sense. And also because of this short-lived contrasting with the long-lived emissions, we have to be worried about the separation of the emissions versus the durability of the solutions.

Myles Allen:
That's right. And coming back to what you were saying about economists sort of liking to sort of pull off the cheap options first. It ignores the fact that there may be benefits to doing something early just so that you've built up experience of doing it. So if we know we are going to need to get rid of CO2 back underground, and it's very hard to see how we can avoid that being a big part of how we deal with the climate problem in 20 or 30 years time, then we need to be investing in the technology to do that right now.

I mean, at the moment we reinject back underground 0.1% of the carbon dioxide generated by our use of fossil fuels. Now, there's a very high chance that in order to achieve a durable net zero world by mid-century, we're going to have to get that number to a 100%. That's one ton of carbon dioxide reinjected into the earth's crust for every ton generated by continued use of fossil fuels by mid-century. And we're not making anywhere close to the kind of progress we need to make in that area to do that. And that's why I think, while there’s obvious benefits to companies investing in nature-based solutions today, we mustn't allow the fact that those nature-based solutions are much, much cheaper than putting carbon dioxide back underground to mean that we ignore the need to put carbon dioxide back underground until the 2030s, 2040s when suddenly we discover we need it desperately and we won't have the experience knowing how to do it at that time.

Mike Toffel:
Let's go to principle four, the final principle, which is to support the development of net zero aligned offsetting. And here some of the language used in the principle includes market signaling, aggregating demand and supply, farming sector specific alliances, and so on. So I wonder if you can talk about the need for principle four, what motivated it, and some of the examples of what it actually encompasses.

Myles Allen:
There's a lot of enthusiasm at the moment through initiatives like the Taskforce on Scaling Voluntary Carbon Markets, which I was involved in advising myself in the build up to COP26, to develop a global liquid offset market to allow companies to trade carbon efficiently and so on. So there are obvious short-term economic benefits to doing that, but the difficulty with that is if you are simply trading carbon in a large liquid market, you get none of the benefits of early adopters actually investing long-term in the projects that are needed to ensure that the carbon they are offsetting is safely put away, and that we learn from these projects to make offsetting more secure in the future. So we certainly would favor those that can, so institutions like universities but also pension funds and many companies. Those that can form long-term agreements to support offset project developers should aim to do so rather than simply buying on open markets.

Mike Toffel:
How do you characterize long-term? Is that a five-year contract, a 30-year contract?

Myles Allen:
Well, the longer, the better. For example, in universities, I'm arguing, I should say this is an ongoing discussion within our university, that we should use some of our extensive landholding, so Oxford University's fortunate we own a lot of land, to store carbon. That's of course the ideal long-term agreement, is that you actually own the carbon you've stored, and then of course you can take responsibility for it and make quite sure that it doesn't end up back in the atmosphere. Not many institutions would have the capability of doing that. And also it's important to stress that I'm not suggesting, and it wouldn't be a good idea, for wealthy Western companies to go out and buy large tracks of the developing world in order to store carbon. That obviously raises all sorts of awkward memories of things that have happened in the past.

We need to support projects by entering into agreements with projects where we're ensuring that the carbon which is being stored is going to stay there ideally for centuries. So you need agreements that ensure that's the case.

Mike Toffel:
So right now a buyer pays a seller to take several actions to reduce or remove carbon, and hopefully in the short-term that happens. And the question is, this is a long-term problem, so what happens in T plus five, or T plus 10, or T plus 30?

Myles Allen:
I can quote an example. I mean, my own College of Linacre in Oxford. When we built a building 20 years ago or so, we sort of netted out the carbon that was required to build the building by paying for a chunk of forest in Indonesia, but sadly, that forest burned down about 20 years later. And that was embarrassing for us but there was no other consequence, whereas in a logical world, if you've generated some carbon, you should be responsible for looking after that carbon for as long as it's affecting the climate, which means effectively forever. So if you decide to store your carbon in one place and it starts to leak out back into the atmosphere, you should be responsible for recapturing it and putting it back somewhere safer.

Mike Toffel:
So it sounds to me like there's three options for ensuring carbon that you think is getting removed or reduced stays that way. One is the seller bears the risk, says, "Well, if this forest burns down, I will make sure to reduce the same amount of carbon elsewhere," or the buyer. Or perhaps there's an insurance product that could come up to sort of address this risk.

Myles Allen:
insurance is starting to be talked about. Should we insure our offset schemes to make sure that something happens if they are reversed? That sounds pretty sensible. The difficulty, of course, is that if offsetting evolves on the scale that people envisage it evolving, and climate change itself is putting some of these offset options at risk by increasing the risk of forest fire, for example, will that really be insurable? Will any insurance company want to take on that sort of global risk? The insurance markets typically work by assuming that risks are different in different places. When you've got a common risk that's happening everywhere, that's where insurers tend to get stuck aiming for the door.

Mike Toffel:
All right. So this has been a terrific review of the four principles. What critiques has Oxford or the co-authors themselves received about these principles?

Myles Allen:
One of the debates that's been going that we feel perhaps this publication has actually partly triggered is this tension between long-term engineered storage and inevitably shorter-term, but not necessarily short-term, storage in the biosphere in nature-based climate solutions. Now, the reason there's a controversy over this is because there are no other benefits to pumping carbon dioxide underground. The only benefit of pumping carbon dioxide underground is it's not in the atmosphere.

However, there are obvious myriad benefits to many nature-based carbon solutions. If you are preserving biodiversity in a region, if you're restoring carbon to soils that have been depleted, if you are protecting nature in a coastal ecosystem. There are so many good reasons to invest in nature, as well as nature's ability to capture carbon. People are concerned that by emphasizing the need for long-term geological timescale storage, we might divert resources away from investing in nature-based solutions.

And this is not a debate between us and other people, it's a debate that's going on within the authors of the Oxford Principles themselves. We continually argue about priorities here and where the balance lies. But I think, at least within Oxford, we all agree, it's one of these things where it's not an either or. You have to do both. And we have to make sure that the current enthusiasm for nature-based climate solutions doesn't mean we ignore the long-term need for geological storage, which is necessarily engineered storage, in the future and that we're going to need to invest now for that geological storage capability to be available when we need it in a couple of decades time.

A great approach might be... In fact we have a paper where we introduce the notion of a proset, progressive offset, where you increase the fraction you store geologically over time, but you ensure that even if 99% of your offsetting today is in nature-based solutions, at least 1% is carbon that's being reinjected back into the earth's crust, because that makes sure that at least somebody somewhere is doing it and learning what the pitfalls are, learning how to do it cheaper, and making sure that the technology's available when we need it.

Mike Toffel:
Let's do the flip side. So we talked about critiques of some of the principles and some of the key trade offs. How do you think about the success of the principles? How will you measure the extent to which this effort that you and your colleagues went through has been successful?

Myles Allen:
Well, a lot of people are thinking about this issue so I feel that they've certainly helped stimulate the debate. And I think they have helped many people recognize the fact that there's no good offsetting strategy for today that doesn't think about tomorrow. Part of your offsetting strategy has to be your trajectory. Maybe people would have worked this out anyway. I mean, of course, eventually every good idea is had by somebody. So who knows, whether it was us or somebody else. I don't know.

But the point is, we're all, I think, getting our minds around the fact that an excellent offsetting market is one which is on a path to durable net zero and supporting the transition to durable net zero. And that's something you can't evaluate by just looking at the transactions that are happening now but you've got to look about what they're doing going forward into the future. And companies that are using offsetting to address their net zero strategies need to talk beyond just offsetting their present day emissions and being able to declare net zero. They need to think about, if they're using short duration offsetting or avoided emission offsets today, if those are the kind of offsets they're relying on, they need to be investing in projects that will mean they'll still be able to pursue their business in 20 or 30 years time. And also, of course, investing in business transformation so that they perhaps won't need to rely on offsetting in 20 or 30 years time.

What we are concerned about is the availability of a huge liquid offset market might allow some of the most progressive companies in the world on this issue to simply tick a box and say, "Yes, we've reached net zero so we don't have to think about this anymore." If nothing else, we hope the Oxford Principles have emphasized to people, just because you've got to net zero today, it doesn't mean you're done. You've got to think about where you're going in the future and where the whole offset market is going in the future to make sure it's aligned with net zero.

Mike Toffel:
To some extent this reminds me of the beginnings of organic, where lots of people were saying, "Oh, this is all natural, this is organic," before there was a credible standard that people believed in and that was certifiable, either by governments or private sector, to say, "Actually, no, this is organic, and this is not organic." It seems to me like we are in that space right now where people are calling a lot of different things offsets, some credible, some not credible, and that we really need some credible body to come in and say either this is an offset or this is not an offset. Or they grade them like, like they do fruits, vegetables, and other agricultural products to say, this is a grade A offset, this is a grade B offset, and so on. Are you seeing progress in either of these directions?

Myles Allen:
Well, lots of people are stepping up to do that. I think what we need is not so much grading as assessments of reliability and durability. Everybody wants their offset to be a gold standard. Who would want the brass standard offset? Actually we've got to be much more quantitative than that. It's how many years has this carbon been put away for, what's the risk of it being re-released to the atmosphere, and have you taken that into account in your offsetting strategy? So have you put in place a strategy to put the carbon back if it gets re-released or, how have you dealt with that contingency? Those are the kind of decisions we need people to be thinking about today.

Despite having spent a lot of time thinking about these kind of global certification standards over the past year, I'm less convinced that we're collectively ready for them. I'm more convinced that companies that are engaged in this space just need to be getting out there and identifying projects that can ensure that they know where their carbon's going. I think we're still at that stage that the best approaches to offsets are ones where you haven't just bought a high standard offset but you actually know physically where your carbon has gone.

Mike Toffel:
And you are involved yourself in an organization called puro.earth. Could you talk about that effort?

Myles Allen:
Yes. So puro.earth, which is actually now jointly owned by Nasdaq, is trying to build a global market in high quality offsets by recognizing the fact that many companies don't have the capacity to do this kind of engagement in very long-term, or they don't want to invest management time in going out and poking peat bogs somewhere to see whether the carbon's leaking out so they need a company to do that for them. And I've agreed, I think possibly this is partly as a result of the Oxford Offsetting Principles, to advise puro.earth in this enterprise. I should stress, it's a contingent agreement. They themselves recognize their business model is itself an experiment. I think Nasdaq recognized this as well. But it's a needed experiment. It's one which we need to make work. So I'm happy to support that at the moment.

Mike Toffel:
So what's the business model? They are providing on the ground assessments of offset projects?

Myles Allen:
They are identifying the projects but also providing a web-based marketplace where people who pay to have carbon put away know where it's gone so you can see what's been done with your carbon. And it's all transparent in the sense that, if a company, like a tech company, for example, buys an offsetting contract with pure.earth, then a member of the public can, in principle, at some point in the future will be able to go to a website and see what happened to that carbon. Their business model, and I think it's sensible, is that transparency is all in this. If the company itself doesn't have time to go and check where their carbon has gone, you can rest assured some activists will go and check for them, and if it's all leaking back out in the atmosphere then you'll be able to go tell them, and that'll raise the standard of these offsetting practices around the world. That's the basic idea. But clearly it's a relatively new initiative, and it's evolving and it'll be very interesting to see how it progresses.

Mike Toffel:
So it sounds like transparency and traceability coming to the offsets market through this organization.

Myles Allen:
That's actually what it's all about. It's all about transparency. It's a Finnish-run organization, and the Finns are very big on everything out in the open. They're also big on tech as well so they want it to be out in the open on the internet. So that's the principles that they're working by.

Mike Toffel:
Let's shift and talk about Oxford University. They are one of many universities and other types of organizations that have declared their own carbon targets. Can you say what are their targets and how much have they embraced these principles developed by their own team of faculty?

Myles Allen:
So Oxford's declared for net zero by 2035, and of course, many people will immediately react with an intake of breath saying, "What? Only 2035? My university's declared for next zero by 2023 or something." And the reason we're aiming for 2035 is because we want to be at net zero, not just for the emissions associated with our own estate, and not just relying on offset markets to offset remaining emissions, but we want to be at net zero for all of the activities that are caused by Oxford University, including by the way, the carbon that's generated by us inviting students from all over the world to come to us to attend our courses. I mean, that's will be, if we get on with reducing our in-house emissions as we plan to, relatively soon that will be the bulk of our carbon footprint.

And we want to remain a global university. We want to remain somewhere where people will want to come to to study and to research and so on and our own faculty and our own students will need to be able to travel around the world. So we will need to address the carbon associated with that travel, and at the moment there isn't an immediate solution into it. I think everybody needs to recognize that. And that's why we've set a later date which will cover all of the emissions associated with our activities because we didn't see much point in an early date that only covers some of your emissions. And by the way, as well as aiming for net zero by 2035, we're also aiming for net biodiversity gain by that stage as well.

Mike Toffel:
Interesting. So this is scope one, the onsite emissions, scope two, the emissions associated with purchased electricity, and at least the travel component of scope three. Is that right?

Myles Allen:
Yes. The division on scope one, scope two, scope three emissions, I personally don't think works very well for universities. I think you need to look at our business practices and what we do and what emissions they cause.

Unquestionably, our business practices result in travel-related emissions, and we need to address that. So one very practical thing, of course we can do to reduce those emissions, we need to be careful in the way we think as we design courses and as we design accommodation arrangements for students and so on that we're not forcing people to make multiple flights in a year just to attend our courses. We need to think about that in the way we design our offerings going forward.

We also need to think about incentives for faculty and for students to make sure that people aren't sort of stuck in an arms race where they feel they have to go to multiple international conferences every year in order just to sort of stay in the job market. We've all learned through COVID that it's possible to hold conferences without people flying around the world, but we've also learned that to some extent that sucks. We like going to places. We like meeting people. We like in-person physical conferences, but I do feel we can't go back to where we were before, where conference travel in particular, was on this, apparently, inexorable, exponential increase within academia that just simply wasn't sustainable and was no way compatible with a transition to net zero. So that's something that we need you to think about.

I hope all universities are really thinking about this one.

Mike Toffel:
Yeah. Interesting. Okay. So final question, if I may. Some of our listeners are considering dedicating their careers to working somewhere in the business and environment space. You being at the school of geography and the environment must come across students all the time asking for career advice, what are the promising opportunities. You bring a scientific lens, a social science lens, and now, increasingly, a business opportunistic lens to the problem. What is the type of advice that you find to be giving to students or maybe perhaps alumni or others you come across who are seeking to enter this space?

Myles Allen:
Well, certainly for students, I advise them to think about what the world will look like in 20 years time when they are at the peak of their careers, where do they want to be, and which business do they want to be in at that time, and compare that to the size of businesses around today, which are the ones that'll need to grow a hundred fold, which are the ones that will need to shrink a hundred fold. And maybe it's a good idea to join the growing one rather than the shrinking one. One area which is clearly going to have to grow is long-term geological carbon dioxide disposal. We're going to have to get rid of a lot of carbon dioxide and we're going to have to get rid of it permanently. So if students have an option of getting involved in that business, I would say, "Grasp it with both hands."

Mike Toffel:
Terrific. Well, Professor Myles Allen, thank you so much for being with us here today on Climate Rising. We really appreciate your time.

Myles Allen:
Thank you very much. Well, thank you for inviting me.

Mike Toffel:
That was Myles Allen, a geophysics professor at Oxford and Director of the Oxford Net Zero Initiative.

In the next episode, we’ll turn attention to our own backyard as we look at what Harvard University is doing to address not only its carbon emissions, but also the health impacts of its use of fossil fuel.