Welcome, everyone to 100 Climate Conversations. Thank you for joining us. I’d like to acknowledge the Traditional Custodians of the land, the Gadigal people of the Eora Nation. We respect their Elders, past, present and future and recognise their continuous connection to Country. This is number 81 of 100 conversations happening every Friday. The series presents 100 visionary Australians that are taking positive action to respond to the most critical issue of our time climate change. We’re recording today live in the Boiler Hall of the Powerhouse Museum. Before it was home to the museum, it was the Ultimo Power Station. Built in 1899, it supplied coal-powered electricity to Sydney’s tram system in the 1960s. In the context of this architectural artefact we shift our focus forward to the innovations of the net zero revolution. I’m Craig Reucassel from docos like War on Waste and Fight for Planet A. Dr Kerryn Brent is a researcher and senior lecturer at the Adelaide Law School at the University of Adelaide. Kerryn researches in the fields of international and environmental law examining how legal systems can facilitate effective responses to climate change. Her research primarily focuses on the governance of emerging climate intervention technologies. We ae so thrilled to have her join us today. Please join me in welcoming Kerryn. So, Kerryn, in high school, you were on your way to becoming a pilot, why did you pivot from law? And then when did climate change become part of that?

It’s a funny story. So, as part of Year 11 and 12, I took aviation studies, and I got my private licence and my dream was to become a pilot. And this was around about the time that Ansett had collapsed. So, I wasn’t sure what a career might look like. And also, there’s a big jump between getting your private licence and then taking those steps and becoming qualified to fly for Qantas or something like that. And so, I thought, ‘Okay, I’m going to need some cash behind me if I ever want to get there. What will I study? What will I do as an interim career? I’ll study law, I’ll give that a go.’ And that plan of becoming a pilot ends up getting moved to the back burner because I started studying law and I loved it. I loved the way that it trains you to think and the different perspective that it gives you on the world. And instead of gravitating towards, you know, tax law, commercial law, I fell in love with international law and also developed an interest in environmental law. So, I did my undergraduate, started practising, so practicing with my dad. It was nepotism, the best kind. At the same time started doing some casual research and teaching and realised that that’s what I wanted to do. I wanted to do my Ph.D. with a guy called Jeff McGee. And Jeff said, ‘Hey, look, you’re looking for a topic in international environmental law have a think about this thing called geo engineering’. Tell me what your thoughts are. Go away and have a read. So, I went away, did some reading, and the more I read about it, the more I had pretty big questions come to mind. The first was oh my God, why? Why are people suggesting that we intervene in the climate? And then the next questions were, surely our legal systems have something to say about this. Are people even allowed to do this under international law? Under domestic law? What rules are there to make sure something doesn’t go wrong? And I guess I’ve been asking those questions ever since.

Yes, I mean, it is quite high stakes stuff. So, let’s actually let’s start with can you tell us about climate interventions sometimes called geoengineering? What is it? And what are some of the examples of climate intervention? You know, I guess from the smaller end up to the end where you were going, oh, no, what is this?

So, climate intervention describes, I guess, two broad categories of proposals to address climate change. The first category is called carbon dioxide removal or CDR for short. And, these are proposals to draw carbon directly — carbon dioxide — directly from the atmosphere and store it in land or ocean-based sinks to address climate change. So, that’s one category. I like to think of it as cleaning up our mess, that category. The other category is called solar radiation management or solar geoengineering. And these are proposals to reflect a percentage of incoming sunlight or solar radiation energy to have a direct cooling effect either at a regional or a global scale. And within those two categories, there are a whole range of proposals and ideas.

Yes, okay. We’ll go deeper into those as we get into this — you know, some kind of evil figure holding up a mirror, the top of the atmosphere. That’s the kind of thing, I imagine. But is this stuff necessary? I mean, the obvious thing is to say, well, why don’t we just stop using fossil fuels? Why don’t we just do that instead? Is this kind of climate intervention necessary to maintain temperatures, you know, around 1.5–2 degrees?

Let’s start with CDR, carbon dioxide removal first. And is carbon dioxide removal necessary? The science is telling us, yes. We have left it too late to just rely on conventional climate change mitigation. Let’s stop polluting at source. The science is now suggesting that if we want to meet those Paris Agreement targets, if we want to achieve net zero emissions, then carbon dioxide removal is now a necessary tool to achieve that. No one’s saying that it’s the only thing we should be doing by the way.

They’re still saying you need to stop digging out fossil fuels.

Yes, 100%. Yes, a rapid and significant mitigation is necessary. Conventional adaptation strategies also necessary. But this is another essential tool now to achieve those targets. And the question, I guess, is then, not so much is it necessary? We are now seeing it integrated into IPCC, Intergovernmental Panel on Climate Change models, they now include carbon dioxide removal under their definition of mitigation. So, in a decade this has moved as a fringe geoengineering idea to now being part of mainstream climate change, science and policy. So, that’s carbon dioxide removal. SRM, is solar radiation management necessary? That’s a different answer to that question.

We might– we’ll get more deeply into that later. Are there types of climate intervention technology that are in use in the world already?

So, if we talk about carbon dioxide removal, yes, there’s nature-based solutions that are being–

Tree planting.

Tree planting. So yes, reforestation, afforestation, in our coastal areas, blue carbon restoring or enhancing coastal ecosystems like mangroves and salt marshes to bolster their capacity to draw carbon down and store it in coastal soils and ecosystems. Another really cool idea is enhancing the capacity of soils through agriculture and land management practices to enhance their capacity to store soil, but also with some really interesting co-benefits as well. Things like improving the quality of the soil by doing that, and also things like increasing resilience to drought. So, there some of the nature based proposals that are already being implemented in Australia and around the world. An example of a solar radiation management technique that’s being developed in Australia for regional application is marine cloud brightening on the Great Barrier Reef. It’s being developed to help the reef, a potential way to help the reef adapt to climate change and become more resilient in the face of climate change. So, this involves spraying minor salt particles from the seawater into low lying clouds over the ocean to make them wider, brighter, reflect more sunlight, and potentially have a cooling effect on the reef as a means of addressing marine heatwaves and the coral bleaching that is threatening the future of the reef. Those proposals are currently being researched and there has been some small-scale field testing, but it’s nowhere near ready for deployment yet as far as I know.

Well, we spoke to Daniel Harrison as part of the 100 Climate Conversation, so you can go back and listen to that if you want to know more about marine cloud brightening. I guess before we get into the legal questions around this, we probably do need to set up the kind of bigger style ideas of solar radiation management. What are the kind of more — you know, that kind of marine cloud brightening is quite local, small area. What are some of the kinds of bigger, more crazy ideas out there in that area?

So, I guess the poster child here is something called stratospheric aerosol injection.

Great name.

The idea is to mimic the climatic effects of a large-scale volcanic eruption by placing particles into the stratosphere. So, we are in the troposphere, which is a layer of the atmosphere with quite a bit of up and downwards movement. The stratosphere is a lot smoother. And scientists have observed from volcanic eruptions like Pinatubo in 1991 that that spewed all this stuff into the stratosphere, that these particles can help cool global temperatures. I think Pinatubo, it was something like half a degree for 12 months or more, which is quite significant. So, the idea is to mimic that effect by placing particles into the stratosphere using maybe a sulphur-based precursor of something else. One point someone said diamond dust. So, that’s one idea. I actually have a Ph.D. student at the moment who is looking at the law and governance of space-based proposals. So, you said putting mirrors in space, there are ideas out there to do that.

Fascinating ideas. And of course, you’re not here as a scientist. You’re here as a lawyer. You are here because the question becomes, how do we regulate this? Like, how do we decide as a country, as a society, as a world, as a global system, whether or not this is a good way forward or not? Like if one country decides we’re going to start spewing particles into the air to try and save ourselves from climate change. Can other parties, can other countries say no? So, I guess let’s go back to that. Where are we in terms of having rules in the global system or domestic system even to actually deal with this? I mean, have the laws even caught up with the fact that this is being discussed?

Short answer, not really. We have bodies of international rules and domestic rules that are relevant to both carbon dioxide removal and solar radiation management. But, I think the key thing to understand is the majority of these rules were not developed with governing these technologies in mind with responding to the particular challenges that they present. So, at an international level, there has been limited action taken for marine based proposals, and that’s through a little-known treaty called the London Protocol. And it was developed to regulate and prohibit the dumping of waste and other matter at sea to prevent harm to the marine environment, to protect the marine environment Through that agreement and that treaty body, states have negotiated the first international law rules for intending to go on marine based carbon dioxide and maybe also some marine based solar radiation management. So, it’s a bit of a milestone. You don’t see those developments happening every day, but there has not been a push by states yet to develop an overarching treaty for solar radiation management. We’re not there yet.

We’re not there. So, there’s kind of a couple of things to touch on. I mean, is the London protocol — I’m thinking back to my international law days — is this actually legally binding yet or is it just the kind of protocol initially?

The protocol itself is a legally binding treaty. It’s a really good question, because as much as these rules have been negotiated, there’s a key step in the international lawmaking process where states have to accept or ratify those rules before they become legally binding and enforceable before they’re an operational part of the international legal system. Those rules for marine geoengineering have been negotiated, but only a small handful of states have accepted them, and so they’re a long way off becoming legally binding and enforceable. There scopes are really limited at present. They have the potential to govern a whole suite of marine based technologies, but the only ones specifically listed and regulated at the moment is something called ocean fertilisation. So, they have potential but are very limited in scope.

And explain how ocean fertilisation works. How is that a mitigation approach?

It’s a category of marine-based carbon dioxide removal, like the name suggests, just when you put poo on to your garden to make things grow, the idea is that there’s parts of the world’s oceans that could be more productive if you add key nutrients to them like iron. The idea is if put iron, maybe iron filings, something like that into parts of the world’s oceans, that can stimulate marine productivity — so, stimulate algae or phytoplankton bloom, this is the building block of the marine food chain — and through photosynthesis, the algae draws carbon dioxide from the atmosphere. And the theory is that marine processes might see some of that stored in the deep ocean and removed from the carbon cycle.

What are the kind of risks? What are the concerns and the risks we’re looking at? Let’s start firstly with carbon dioxide removal. What are the risks that you’re concerned about that you’re thinking, okay, we need to have regulation, we need to have global rules here to deal with this. What are the risks there? I’m not thinking the United Nations is going to say you can’t plant a tree in your backyard. So, what are the ones that there are concerns about the amount of risks?

One of the concerns at an international level is ocean fertilisation. Again, this is speaking as a lawyer and not a scientist. One of the concerns is that if you create a big phytoplankton bloom and you stimulate that productivity in one area, it might draw or rob nutrients from other areas in the ocean. And if that was big enough, maybe that will not just affect the marine environment of the state, the country that decides to use it, it may be its neighbours or maybe high seas areas, areas beyond national jurisdiction. These are what we call transboundary effects. That’s one concern with that proposal. But even some of the nature-based, less alarming proposals, ones with potentially great co-benefits. There are challenges associated with them as well. So, you know, reforestation and afforestation, there’s only so much land available that is suitable to engage in these activities. And so, we also have to be mindful of competing land uses. So, we need land as well to grow food and to preserve biodiversity. And so, that’s another challenge for managing those proposals. And also, a challenge is, okay, if you do this, how do you account for the carbon drawdown? How do you make sure that cradle to grave you’re delivering a net negative emission? And that somewhere in that chain there isn’t an activity, transportation, energy input. That’s actually, I guess, robbing Peter to pay Paul, so to speak.

So, let’s go to solar radiation management then. What are the kind of risks involved there? What are the concerns there that are looking to be regulated? There seems to be potentially more in this case?

Yes. Let’s talk about stratospheric aerosol injection. These proposals have great promise in the sense that they have the potential to rapidly, in a short timeframe, affect temperatures. But there is currently great uncertainty and knowledge gaps around both their actual potential, but also the risks and side effects involved are at the different scales they might be deployed. So, for example, one concern — and this is again from scientists observing what happens after large-scale volcanic eruptions — is that, yes, you might have a cooling effect, but it’s going to affect different parts of the world differently. One concern is that it might affect regional monsoon and rainfall patterns and maybe cause drought in certain areas. So, often when scientists talk about this, they say these technologies could have winners and losers. Some parts of the world might benefit, and some might not.

And what does the IPCC say about solar radiation management? Is there any kind of acknowledgement of it? Encouragement of it?

It’s now and this is a milestone we are now seeing it considered and the science evaluated in, IPCC reports that unlike carbon dioxide removal — where the IPCC says, yep, we’re integrating this in our models, this is necessary, this is a necessary tool, and it’s now we’re lumping it with mitigation — they are not taking that approach to solar radiation management. It is very cautious. There is acknowledgement that, hey, these proposals have potential. They could offset climate change. They should not be the first thing we do. We need to mitigate, we need to adapt. We need to invest and maybe develop more CDR and also acknowledging that the knowledge gaps and that the lack of governance is also, it exacerbates the risk. It exacerbates the challenges. So, a very cautious approach being taken by the IPCC, very cautious approach being taken in other reports, there was a report earlier this year by the United Nations Environment Programme that similarly said, hey, there might be some benefits to doing research and what we should be researching, but no one’s advocating for doing this until we know more and we have robust governance frameworks internationally, but maybe also domestically to govern risk and informed decision-making.

And that’s, I guess where it becomes fascinating, becomes an international law issue, because international law is all about, you know, trying to ensure that one country is not just doing something which is going to disadvantage another. Is there any kind of international law that kind of, I guess, broad scale that kind of talks to that and that kind of informs people on that?

We have some important general rules. One is the obligation not to cause significant transboundary harm to other countries or to common areas like the high seas. It’s often referred to, in short, as the no-harm principle or the no-harm rule. By way of background there are a few different ways rules can be made in international law that are legally binding. This rule is not generated by a treaty. It’s generated by custom. So, consistent state practice and a belief that that practice is required by law. It’s a legally binding rule. It has the same status legally as a rule contained in a treaty. And because it’s custom, it applies to every state. Part of the research I did in my PhD, actually my whole PhD, I should say, asked this question of the no-harm rule and what is its potential to govern solar radiation management and stratospheric aerosol injection? And what does it have to say about the development, including the research and use of these technologies. It’s a general rule. And again, it wasn’t developed to deliberately respond to the particular challenges of these technologies.

It makes me think — put aside solar radiation management first — my first thought is that why are we not taking petrochemical states or trenchers that dig up coal and burn it? Why are they not being taken to the courts to use this very principle by the countries like Vanuatu and Fiji and that kind of thing.

And so, this is the thing about international law, there is the international law rules and then the practice. We don’t have international police system or even a compulsory court system to adjudicate disputes and enforce international law rules. And so, this is one of the limitations that I did come across in my research, is that this rule may have a role to play, and I think it would certainly be an important role that might inform future treaty negotiations. And if you look at most modern environmental agreements, you will see an iteration of the no-harm rule in there somewhere. But in practice, you’re relying on states to consent to have a case heard before an international court or tribunal. And also, the way this rule– what it actually means in practice is a bit unclear. It only applies to harm that meets the threshold level of significant and that’s not objectively defined either. When does something become significant harm? When does that then trigger obligations under this rule? It’s not clear or certain.

Are countries talking about solar radiation management? Are they talking about, you know, this stratospheric aerosol injection and whether or not they think it’s a good idea and whether or not they should try and ban it?

It’s early days again, but I think we might see some interesting developments into the future. And that’s because [early] last year, American private company conducted some experiments in Mexico without the consent of the Mexican authorities. And this has caused a strong reaction from Mexico, understandably. And their government is making moves at a domestic level to ban solar radiation management and also maybe advocating for other states to follow suit. Whether that will translate into any kind of international agreement or negotiation. We will see. But what we are seeing is solar radiation management 10-15 years ago, it was a taboo topic. It wasn’t talked about. We’re now seeing it considered and the research evaluated by the IPCC by the United Nations Environment Programme, by leading national bodies and organisations like the US National Academies of Sciences, Engineering, and Medicine. And so, these bodies aren’t just talking about the science, they are also talking about the importance of governance and it’s concerning that there is this gap. So, they are certainly flagging this for further consideration. These kind of movements might be the starting point of something bigger down the track. And I think it’s important to acknowledge — we just talked about the limitations of the no-harm rule, but — that we shouldn’t be throwing all our eggs in the one basket with international law. I know I love it, but I am the first to acknowledge that it is a slow-moving beast. So, it can take decades for something to go from this stage to a fully formed treaty. Great example, and it’s a huge milestone in international law, is the new agreement for biodiversity beyond national jurisdiction. This is a huge milestone, but it has been more than a decade in the making. The other reason I would say we shouldn’t rely wholly on international law is because international law, by and large, only creates binding rules for states. For countries. It doesn’t create rules that directly apply to scientists, to universities, to private companies. That has to be done at a national level, regardless of what’s in international law or not.

It’s interesting, I mean, you use the example of a private company, an American company in Mexico, it’s doing experiments without the permission of the government there. I mean, that’s kind of a frightening approach. If you just can have private companies, you feel like this is an unregulated space and we can do what we like. When you’re talking about something on the scale that could have a huge impact on the Earth long-term there, I think Australia has recently moved to kind of bringing some laws in this kind of space, haven’t they?

Australia has made the first moves towards accepting those rules I mentioned under the London protocol. They’re not going to apply to stratospheric aerosol injection, but they create a framework for managing the risks to the marine environment from things like ocean fertilisation. And so, recently the Australian Government has proposed a bill to amend a piece of legislation called the Sea Dumping Act to bring it into line with those international law rules. This is also a really interesting development because Australia was a key mover and shaker, a key player in developing those rules — so they were negotiated and finalised in 2013. In the lead up to that, Australia played a really key role. And so, a decade later it’s important to see them making moves towards ratifying these rules. However, there may be some drawbacks towards implementing those rules as they are. The first is that carbon dioxide removal. We are at a point where as much as the science is saying we need to do this, the technology is nowhere near ready to be deployed at the sheer scale that’s needed to make a difference. So, what this does is it makes research and development really important. The London protocol rules are they may permit research for ocean fertilisation and if other technologies are added in the future. They may permit research but research that’s primarily for financial gain or profit is not allowed. And so, as much it is concerning and to think of private companies going out and particularly in the solar geoengineering space, but for carbon dioxide removal, it may be really important to have their input and their support for research and development to realise the benefits of these technologies. And the other concern I have with that particular set of rules is that at an international level, we’re now seeing countries in the London Protocol parties consider adding other technologies to that set of rules, including marine cloud brightening. And I think a key question for Australia is to consider, well, if that happens, what does that mean for the research that’s being done for the Great Barrier Reef?

It’s interesting that, so you’re talking about a kind of difficult balancing act because on one hand you’ve got this example of a commercial company coming in and just doing experiments with no permission. But you’re saying if you go too far the other way and you say, do you have legislation that removes essentially the profit motive and removes any of that ability to make money out of it, you might actually stifle the ability to actually get research into that area.

Not necessarily make money but incentivise research. And I think you’ve touched on a really key challenge here that our legal systems, both at an international and a domestic level, need to grapple with and that’s it, no one’s proposing carbon dioxide removal or solar radiation management in the abstract. It’s being proposed in this bigger context of climate change. The climate crisis, this ticking clock that, you know, we’ve let tick too long now just to rely on mitigation and adaptation alone. And we need to recognise through our laws, through our risk management provisions, through our decision-making frameworks, that yes, these technologies and some of them, certainly more than others, pose significant risks, uncertainties, challenges. But there will be consequences now for inaction, for not pursuing research, for not providing pathways to responsibly and carefully scale up technologies.

You’re a founding member of the Australian Forum for Climate Intervention Governance. What are the aims of the forum?

Okay, so we’re a research group, all with law and government backgrounds, and the reason we formed this group was because there was a lot of research being done about climate intervention, governance at an international level, quite a bit being done in Europe from a European perspective and from a North American perspective. And what we wanted to do is drive the research agenda in Australia and promote research that considers, well, what’s happening here? Our legal system domestically is different from, it’s unique from Europe and North America — particularly our environmental rules. So, what rules in Australia might apply? Where are the gaps? How do we fill those gaps to address governance challenges? We wanted to ask these questions with Australian law in mind. And look, we’re seeing some — aside from that example earlier of the Sea Dumping Act and the bill that’s been put forward — actually seen some really interesting developments governance-wise for the Great Barrier Reef. And so, in 2020, the Great Barrier Reef Marine Park Authority produced a policy on interventions for the reef. And so, by this I don’t just mean marine cloud brightening and cooling and shading, it includes things like coral translocation and crown of thorns starfish control. And so, it’s not with climate intervention or geoengineering in mind. This policy is really interesting because it’s the first I’ve seen that doesn’t just take a myopic focus and individualistic focus to, hey, you want to do some research, what are the risks? Hey, you want to engage in this activity, what are the environmental risks? What do we do about them? This policy acknowledges that broader climate change context and what it means for the reef and that yes, inaction, not doing research and investigating different proposals will have its own consequences and that that must be factored into and in the background of decision-making.

It’s interesting, isn’t it, because you obviously, you’re in a position where you go, we need regulation here. We don’t want to mess this up. We don’t want to choose the solution to be cane toads, and it ends up being a big problem long term. But on the other hand, you also don’t want to kind of prevent change happening. You don’t want to prevent a solution that has great potential at a time where we are, as you say, the clock is absolutely ticking on solutions here. So, that’s a difficult kind of line to balance.

It is difficult. And part of the challenge, as I’ve said, is that with very few exceptions, our laws, our policies have not been developed with these technologies, with these proposals in mind. And so, the first step is to ask that question. What implications do current rules have? What gaps are there? But yes, the big challenge, as I see it for our legal systems is how do we create rules and decision-making frameworks that not only assess the risks of individual activities, but have the capacity to weigh that up against the risks of climate change? And the other thing our laws don’t do a particularly great job of is considering the cumulative impacts of different activities. So, solar radiation management is an example where this is going to be important because you might assess the impacts and risks of an activity happening over here. But what if that activity is happening elsewhere, or in other countries? What does that all add up to? How do we assess that? How do we make decisions in light of that? This is something else, another challenge that our legal systems are going to have to grapple with.

Let me ask you, so what are the key changes to law and policy that you would like to see in the next decade?

I think it’s important to start having conversations at an international level about what law and governance might look like. But in the meantime, we do need to look more closely at our domestic legal systems and what they might do. So, with my colleagues, Jan McDonald, Jeff McGee, Australian Forum for Climate Intervention Governance, we currently have a project funded by the Australian Research Council where we’re asking that question concerning solar radiation management and Australian laws and what might a good governance framework look like in Australia? I think focusing on domestic law is really important to start with. That’s also because that question of scale that you talked about earlier, that maybe really small-scale activities and research don’t always require big international law rules. It may be that governance at national, subnational level can do the job for the time being and lead into those bigger conversations in future about larger-scale experimentation. And certainly, if there’s ever going to be any full-scale deployment.

Please thank Kerryn, ladies and gentlemen, join me in a round of applause. To follow the program online you can subscribe wherever you get your podcasts. And visit the 100 Climate Conversations exhibition or join us for a live recording, go to 100climateconversations.com.

This is a significant new project for the museum and the records of these conversations will form a new climate change archive preserved for future generations in the Powerhouse collection of over 500,000 objects that tell the stories of our time. It is particularly important to First Nations peoples to preserve conversations like this, building on the oral histories and traditions of passing down our knowledges, sciences and innovations which we know allowed our Countries to thrive for tens of thousands of years.