1 Introduction: a Polarising Climate
On the 23rd of February 2023, a group of climate scientists published an open letter calling for “research on reflecting sunlight to reduce the risks of climate change”.1 “Climate change”, the letter opened, “is causing devastating impacts on communities and ecosystems around the world, posing grave threats to public health, economic security, and global stability”. Even more menacingly, “natural systems are approaching thresholds for catastrophic changes with the potential to accelerate climate change and impacts beyond humans’ ability to adapt”. The threat climate change poses to the future is now so severe that even if stringent carbon mitigation measures materialise in the coming years, catastrophic consequences cannot be ruled out, as even “1.5–2°C of warming brings with it significant risks to human, ecological, and global economic systems”. It might cause the crossing “of the threshold of Earth system ‘tipping points’”, leading to irreversible and highly dangerous changes in the planetary system. Given these severe threats, the letter’s authors argue, scientists need to research the potential of solar radiation modification (SRM), a controversial set of potential approaches aiming to increase the reflectivity of the Earth, also known as solar geoengineering. Today, over 110 climate scientists have signed the letter. Implicitly, the letter said: conventional mitigation may now be out of reach, geophysically and/or politically, so it is time to look for more options.
At first glance, such a call for more research is unsurprising and unproblematic. After all, scientific interest in any technology that may alleviate the worst effects of climate change is to be applauded. According to the authors of the letter, SRM holds precisely that promise. It might “slow warming and reduce climate impacts”. Yet, at the same time, this call for SRM research is more than a simple story of scientists responding to an urgent political and climatic need.
The open letter was the latest round in an on-going debate over SRM. Its authors wrote it as an explicit response to a similar letter warning against the normalisation of SRM research published a year earlier. In a perspectives article published in the scientific journal WIRE s Climate Change – “Solar Geoengineering: The Case for a Non-use Agreement” – 16 academics had argued that solar geoengineering presents unacceptable geophysical, ecological, and political risks.2 In the piece, they proposed an international agreement not to use SRM, the restriction of government funding for SRM research, a limitation of SRM support and assessment in the Intergovernmental Panel on Climate Change (IPCC), and a prohibition of patents for SRM technologies. Furthermore, they also sought to limit experimental scientific research, going as far as to call for a ban on outdoor experimentation in countries that would sign the agreement. Instead of viewing solar geoengineering as a necessary complementary approach to climate change, these authors saw even ‘research’ into these technologies as a major risk.
This debate whether SRM ought to be researched more widely – or whether its research ought to be banned or defunded – has raged for nearly two decades, although it has older roots. In recent years, however, simmering tensions within the research field have resurfaced, as increasing fears about anthropogenic climate change are propelling SRM towards the scientific and political mainstream. SRM’s imminent public arrival on the geopolitical agenda raises complex governance questions. This is a technology that purports to have the ability to influence the climate on a global scale, the potential to cool the Earth as a whole. Clearly, such an undertaking would be fraught with political, bio-ecological, and geophysical risks.
This chapter is a case-study of the emerging debate on the proposed Non-use Agreement for Solar Geoengineering (non-use agreement or NUA). I write it not from the perspective of a neutral analyst, but as one who has been intimately involved with the controversy: I was one of the lead authors on the call for a non-use agreement. As such, this chapter is a personal-academic
2 Using Geoengineering to Address Climate Change
To understand the case for (and against) an SRM non-use agreement, it is important to address some technical and practical questions first. In this section, I explain what solar geoengineering is and why it is controversial. To properly appreciate why SRM is controversial, however, we must first turn, briefly, to its history as part of the debate on geoengineering, the idea to use large planetary systems to counteract global warming.
Geoengineering has always been a part of the debate on climate change. Scientific interest in manipulating the climate is at least as old as the scientific recognition of anthropogenic climate change. When climate change first
In 2009, the Royal Society published the first major assessment report on geoengineering. The report defined geoengineering as the “deliberate large-scale intervention in the Earth’s climate system, in order to moderate global warming”.7 This definition included – in principle – “any methods for geoengineering climate” through large-scale interventions in “the working of the Earth’s natural climate system”.8 This meant that, to the authors of the report, geoengineering included two major sets of interventions, ‘carbon dioxide removal’ and ‘solar radiation management’.9 Although both types of technologies were controversial, they aimed to play at different geophysical mechanisms. From
CDR’s status changed after the 2015 Paris Agreement when political dynamics around the newly determined 1.5°C and 2°C goals rendered CDR at scale a political necessity rather than controversial speculation.12 It was no coincidence that critics called the agreement a ‘Trojan horse’ for carbon geoengineering. Since the Paris Agreement, a complex process of ‘political calibration’ between scientific projections, the IPCC, and the United Nations Framework Convention on Climate Change (UNFCCC) has created an image of CDR as an inevitable, feasible, and desirable part of climate governance, despite severe doubts about whether CDR is feasible at the required scale (as even the IPCC itself admits).13 In recent years, net-zero promises that assume
SRM, on the other hand, is, in the words of a climate expert I interviewed for my PhD-thesis, the more ‘brutal form of geoengineering’. Its basic premise is simple: the global average temperature could potentially be lowered by increasing the reflection of sunlight from the atmosphere. By increasing the Earth’s albedo, its reflectiveness, SRM technologies would reduce the energy coming into the climate system, slow the climate warming, and (hopefully) reduce climate impacts. In the scientific literature, many SRM proposals circulate. Some are ‘science-fictionesque’ technofixes that are wholly unachievable in the near term, such as mirrors in space or using Moon dust as a solar shield. Other proposals are mundane and localised – such as brightening urban infrastructures – and would not affect the global climate significantly.15
At least three proposed SRM technologies, however, seem to hold some promise in terms of cooling the Earth: stratospheric aerosol injection (SAI), marine cloud brightening (MCB), and cirrus cloud thinning (CCT). The first, SAI, is the most well-researched. Consequently, it is the most visible and hence the most controversial of the three. SAI would entail injecting aerosol particles in the stratosphere, increasing the scattering of sunlight, sending a part of it back into space. As a technology mimicking the real-world effects of large volcanic eruptions, there is little doubt that SAI could cool the global climate, although serious questions remain about to what degree and at the cost of what side-effects. The second technology, MCB, also focuses on the reflection of incoming solar radiation. By adding sea salt aerosols to low-hanging marine clouds, these clouds could be made to thicken and brighten, enhancing the amount of sunlight they reflect out into space. Although there are a lot
All three of these technologies bring technology-specific risks and benefits. Potentially, if scientific understanding of the effects of these technologies advanced enough and the implementation of such technologies could take place in a carefully considered and coordinated fashion, SRM could significantly reduce the risks that climate change poses. At the same time, they all raise intractable political problems. Who would control such a technology? How could it be governed? How would the scientific expertise and technological capabilities be distributed? What would the effects of SRM be on the climate? Would it lessen or worsen the risks of climate change? All these questions remain open, without a clear answer in sight. For those worried about SRM research, even the ‘prospect’ of SRM might be dangerous, as it may distract from the fundamental and systemic emissions cuts needed in the present.
3 The Case for Caution
I don’t know why anybody should feel obligated to reduce carbon dioxide if there are better ways to do it. When you start making deep cuts, you’re talking about spending some real money and changing the entire economy. I don’t understand why we’re so casual about tinkering with the whole way people live on the Earth, but not tinkering a little further with the way we influence the environment.18
The ‘we should at least do the research’ lobby assumes that, if geoengineering research succeeds and the situation calls for deployment, it
will be done in a way that respects the scientific evidence and protects the interests of the poor and vulnerable. Do we really believe that? The irony is that if we did believe in such a world, there would be no need for research into geoengineering.21
Very similar concerns animate the 2022 call for a non-use agreement on solar geoengineering. According to the authors of the WIRE s article, SRM research may cause more problems than it solves. Not only might SRM bring risks to rainfall patterns, unequal cooling, and other geophysical and bioecological risks, its governance also presents almost unsurmountable problems.22 Because SRM, at a global scale, purports the manipulation of a global climate, it raises all kinds of concerns about who controls the technology, how major powers would negotiate such immense powers, and how disputes about SRM might be resolved. This might mean that solar geoengineering turns out to be ungovernable – or at least ungovernable in a fair and democratic manner. In that light, “proliferating calls for solar geoengineering research and development are cause for alarm, as they risk the normalisation of these technologies as a future policy option”.23 Specifically, the authors worried about the potential of solar geoengineering research to deter decisive mitigation commitments. The long-standing history of climate change denial, the tendency of vested interests to obfuscate and attack climate scientists, and tense climate negotiations all point to a political system that struggles to incorporate systemic change.24 It is, as critics of SRM point out, a political system that tends to look to speculative technological solutions rather than to address the underlying, extractive causes of climate change. In this view, SRM presents an uncertain technofix that will allow vested interests to continue to drag their heels. The prospect of
While we fully support research into SRM approaches, this does not mean we support the use of SRM. Uncertainties about how SRM implementation would play out in the climate system are presently too large to support implementation. Decisions about whether and how SRM might eventually be implemented must be preceded by both:
- –a comprehensive, international assessment of how SRM interventions would affect climate risks regionally and globally.
–cooperative international decision-making on the use of SRM based in the latest science.
From these fundamental agreements, two important implications for SRM governance follow. The first is that, given the political and physical uncertainties, a moratorium on the use of SRM technologies may be necessary, indefinitely or only for a limited time. The second, and most urgent, is the need for real, strict, and robust ‘research’ governance. In the remainder of this chapter, I will address the question of the non-use of these technologies, based on Guggisberg’s typology, and draw out issues surrounding research governance. I review some previous proposals and attempt to formulate what I consider to be a minimum aim for a non-use agreement on SRM. To do so, I start by painting an (imperfect and brief) picture of its current governance landscape.
4 Non-use: De-Jure and De-Facto SRM Governance
In this section, I explore, in brief, existing governance frameworks that relate to SRM. From there, I survey, again briefly, several attempts to come to grips with the prospective governance of SRM, both in terms of research and implementation. However, as the debate around SRM is fast-moving and volatile, not unlike the climate debate, these surveys have an exploratory and introductory character.
4.1 Current SRM Governance
The governance of SRM (non-)use is complex. In the academic debate on SRM, it has become a truism to remark there exists very little de jure governance over SRM research and implementation. In legal terms, only a few treaties and agreements directly pertain to SRM, especially on a global scale. However, as Jesse Reynolds rightfully observes, SRM would not land in a legal and political vacuum.25
Pre-existing legal frameworks affect the playing field of international SRM governance. Legal frameworks, such as the polluter-pays principle and the obligation of prevention of transboundary environmental harms, as well as implicit and explicit norms, such as the precautionary principle, would almost
- –The Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques (ENMOD) bans the hostile use of environmental modification techniques. It was drafted in 1976, entering into force in 1978. Currently most States are party to the convention. Originally put on the international agenda in response to the USA’s illicit and secret use of weather modification techniques in the Vietnam War, ENMOD does not govern the manipulation of the climate ‘for environmental protection’ purposes. It could potentially, however, play a role in alleviating fears over the militarisation and securitisation of these technologies.
- –Both the regimes created under the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention and Protocol) and the Convention on Biological Diversity (CBD) include clauses on ‘geoengineering’, in which they limit the use of spatial-extension resources (especially the oceans) for geoengineering purposes.27 The London Protocol limits any dumping in oceans that is not agreed-upon. It remains an open question whether the London Protocol will hold any specific relevance to solar geoengineering. As to the CBD regime, it expressly prohibits any geoengineering interventions that may put biodiversity at risk.
- –In 2023, Mexico became the first country to announce its intention to prohibit SRM, after the American start-up Make Sunsets, which sells cooling credits through releasing sulphur into the stratosphere, had started to conduct trials from Baja California. Mexico further explicitly stated its intent to investigate the possibility to use the CBD to ban SRM at large. At the
moment, however, this remains an intention, with the exact legal frameworks still to be developed.28
However, it is yet unknown exactly how such existing legislation and international norms would affect SRM governance. The implications of this uncertainty are debated. Reynolds himself argues that it is too early for a rigid framework, as much is still unknown about SRM, a valid point for those seeking to govern the responsible use of SRM (instead of restricting it in the form of non-use). Beyond these examples, which – apart from Mexico’s unilateral decision to ban SRM above its territory – only partially apply to SRM, little explicit forms of governance exist.
Most crucially, the governance of SRM ‘research’ remains an uncertain space. Because such research would present use of spatial extension resources only on a very limited level – its introduction of substances and climate effects being extremely small – the question of research governance on a non-use of resources basis is difficult. This does not mean, however, that SRM research is ungoverned. Here too non-legal norms and conventions play a crucial role. As David Keith’s lament about a ‘geoengineering taboo’ – which resonated with many other researchers – makes clear, implicit norms can also govern research.29 As Ina Möller and Aarti Gupta point out, the governance of SRM does not have to happen in a de jure manner.30 In fact, they argue, the field of SRM research is already governed through de facto governance. Through implicit and explicit norm-setting, as well as the work of ‘defining’ the problem and potential solutions through expert assessments, the field of geoengineering has already established social norms about ‘how to conduct geoengineering research’. Of course, these norms could be flaunted in principle, but, in practice, de facto work to prioritise research and development of SRM. Importantly, de facto governance encompasses more than early attempts to formulate norms and regulation; it also includes implicit rules about priorities and behaviour, mechanisms related to research funding, and the existence of expert communities who determine what is and is not acceptable and high-quality research. Many of the disagreements currently swirling around whether to do
4.2 The Road to Future SRM Governance
There have been various attempts to govern SRM research, ranging from explicit legal framework to norm-setting and codes of conduct. Early in the current debate around geoengineering, in 2009, a group of scholars at Oxford University formulated the so-called ‘Oxford Principles’ for geoengineering. At the time, geoengineering still referred to both CDR and SRM. As a result, the principles lack some specificity. However, they are still widely regarded as one of the most fruitful starting points for thinking about SRM (research) governance. The Oxford Principles suggest five guiding rules for geoengineering governance:
Geoengineering should be ‘regulated as a public good’, meaning that the regulation of geoengineering should be ‘undertaken in the public interest by the appropriate bodies at the State and/or International level’.
Public participation should play a role in public decision-making around geoengineering, meaning that those conducting research should be required to inform and seek prior consent from those affected by research activities.
Geoengineering research should be disclosed and its results should be openly published, meaning that researchers should provide a complete overview of their research plans and all results, also negative ones, should be made publicly available.
There should be an independent assessment of impacts, meaning that a body independent of research should conduct the assessment of what impacts the research may have.
Governance before deployment, meaning that before any decisions are made about the eventual implementation of geoengineering mechanisms, robust governance mechanisms should already be in place.31
The Oxford Principles remain an excellent starting point for responsible research around SRM. However, they are also somewhat insular, providing a
An International Non-use Agreement on Solar Geoengineering could commit signatory countries to five core prohibitions and measures:
The commitment to prohibit their national funding agencies from supporting the development of technologies for solar geoengineering, domestically and through international institutions.
The commitment to ban outdoor experiments of solar geoengineering technologies in areas under their jurisdiction. The commitment to not to grant patent rights for technologies for solar geoengineering, including supporting technologies such as the retrofitting of airplanes for aerosol injections.
The commitment to not deploy technologies for solar geoengineering if developed by third parties.
The commitment to object to future institutionalisation of planetary solar geoengineering as a policy in relevant international institutions, including assessments by the Intergovernmental Panel on Climate Change (IPCC).33
The non-use agreement proved highly divisive and polarising. On Twitter, other academics and researchers accused its authors of going against academic freedom, being anti-democratic, and even anti-Enlightenment. While such accusations seemed to miss the point, our proposal certainly had shortcomings as a concrete governance proposal. The term ‘use’, which clearly connoted the use of SRM as a global technology, was not defined very clearly. Moreover, much of the proposal for a non-use agreement did not address use per se, rather the road to use. Furthermore, the proposal was rigid in its proposals, aiming to restrict a research space by rather heavy-handed measures. Importantly, however, the proposal was meant to incentivise further development of restrictive governance frameworks. This also influenced its definition of use and non-use. Rather than governing the use of a resource, these commitments were intended to restrict the development of (a) technological structures, and (b) interest groups who would push these technologies into central view. Before and since the NUA proposal, alternative research governance frameworks, for example relying on systematic public engagement protocols, have proliferated.34 An already existing debate on SRM governance has intensified. Which of these proposals would be best in our current legal, political, and sociocultural practice is an open question. It is also a deeply
5 Conclusion: Non-use of technology or of Technology?
The debate on the (non-)use of solar geoengineering is unfolding at a high pace. SRM is presently being researched. The National Academy of the Sciences in the United States has already called for more research, as have various other leading institutions. In February 2023, the United Nations Environment Programme (UNEP) also published a report signalling both a knowledge gap on the possible effects of SRM and the riskiness of SRM.35 The call for SRM research fits the scientific and political climate of the early 2020s. So too does the call for a non-use agreement on these technologies. Almost all SRM researchers agree that the ‘use’ of solar geoengineering should be restricted through a moratorium, at least for the time being. On research, the picture is more muddled. Some would seek a ban of development altogether. Some, like me, would accept research, but only within a strict governance framework. Some, like the American National Academy of the Sciences and UNEP, argue for comprehensive research programs, with so-called ‘off-ramps’ in place in case the technologies prove too risky or uncertain.
The political and scientific history of SRM renders the question of the use and non-use of climate manipulation technologies complex. Where in other cases the argument for use or non-use of a resource can be clear – in that it may exhaust the resource or have detrimental effects on the environment – the arguments here are doubled-sided. The use of SRM is imagined to be a precaution or insurance against climatic devastation. At the same time, implementing SRM would also mean increasing the additive use of the lower atmosphere, the stratosphere, or outer space. As a result, debates about SRM non-use for the most part revolve around geopolitical and mitigation consequences of research and potential implementation. This fuels a difficult debate around how to configure a non-use agreement. It also creates difficulties classifying such a potential non-use agreement legally. As Guggisberg points out in chapter 2 of this volume, ‘use’ typically refers to “any activity that targets or otherwise impacts a resource”. She observes that any activity, even benign ones,
SRM complicates this typology, as the ‘non-use’ here is primarily directed at the use and development of a specific technology. Because of the diversity of proposed technologies – some of which in outer space, some in the stratosphere, and some in the lower atmosphere – the spatial-extension upon which these technologies would act are not clearly defined.36 As a result, most proponents of a non-use agreement for SRM prefer to argue for a restriction on the use of a technology – or of forms of environmental management – rather than rooting the legal framework in the notion of spatial resources. In that sense, the debate over SRM non-use has important links with nuclear non-proliferation treaties and the use of genetic modification and nano technologies.37 For the premise of precautionary non-use, as interpreted in this volume, this means that there exist varied ideas about the aims of non-use. In the table below, I give a brief impression of different perspectives on what a non-use agreement ought to achieve, based on the ways in which governance proposals see and frame the risks of solar geoengineering, (a) whether a non-use agreement
The question becomes even more complicated when we consider that the spatial resources would be used for the manipulation of an abstract phenomenon, namely the climate. Unlike most spatial-extension resources, the climate does not have a direct physical presence. Instead, it is a cultural-scientific
Different perspectives on what a non-use agreement ought to achieve
| Aim of SRM non-use measures | Precaution against | Understanding of use | |
|---|---|---|---|
| Proposed Non-use Agreement, Restrictive Research Governance | Prevent implementation of technology, permanent moratorium
Limit normalisation of SRM in climate politics Limit building of constituencies arguing for use |
Precaution against: political consequences, mitigation deterrence, inevitability of implementation of SRM | Use defined as: development of technological capacity, implementation of technology, implementation of spatial-extension use of atmosphere |
| Moratorium on Use, Permissive Research Governance | Prevent (premature) implementation of technology, temporary moratorium with periodic revisions.
Gather further information about the feasibility and risks of technology Limit chance of panicked implementation |
Precaution against: climatic disruption, panicked implementation of SRM | Use defined as: implementation of spatial-extension use of atmosphere, implementation of technology |
Climate Intervention Research Letter, “An open letter regarding research on reflecting sunlight to reduce the risks of climate change” (23 February 2023), available at <https://climate-intervention-research-letter.org/> accessed 21 June 2024.
F. Biermann et al, “Solar Geoengineering: The Case for an International Non‐Use Agreement” (2022) 13(3) Wiley Interdisciplinary Reviews: Climate Change e754. On their website, they invited academics and non-governmental organisations (NGOs) to support these measures. By early 2024, their open letter was signed by over 470 academics, including key IPCC authors and climate scientists.
See the discussion by Guggisberg in chapter 2 of this volume.
C. Marchetti, “On Geoengineering and the CO2 Problem” (1977) 1(1) Climatic Change 59.
D. Keith, A Case for Climate Engineering (MIT Press 2013) 92.
See eg J. R. Fleming, Fixing the Sky: The Checkered History of Weather and Climate Control (Columbia University Press 2010); J. Baskin, Geoengineering, the Anthropocene and the End of Nature (Palgrave Macmillan 2019); J. Oomen, Imagining Climate Engineering: Dreaming of the Designer Climate, Routledge Environmental Humanities (Routledge 2021).
Royal Society, “Geoengineering the Climate: Science, Governance and Uncertainty” (2009) IX, available at <https://royalsociety.org/-/media/policy/publications/2009/8693.pdf> accessed 20 September 2024.
ibid.
Later, geoengineering mostly disappeared from policy discussions. Where the term still appears, it is mostly in relation to SRM, sometimes in a somewhat pejorative sense.
Oomen (n 6).
Although, obviously, CDR too introduces a host of new forms of use of environmental components, such as the storage of CO2 in sub-oceanic rock formations, the introduction of iron filings into the ocean to stimulate algae growth, or the dumping of limestone dust aimed to capture carbon from ambient air.
K. Anderson and G. Peters, “The Trouble with Negative Emissions” (2016) 354 Science 182–183; S. Beck and M. Mahony, “The Politics of Anticipation: The IPCC and the Negative Emissions Technologies Experience” (2018) 1 Global Sustainability e8; S. Beck and J. Oomen, “Imagining the Corridor of Climate Mitigation – What Is at Stake in IPCC’s Politics of Anticipation?” (2021) 123 Environmental Science & Policy 169–178; L. van Beek et al, “Navigating the Political: An Analysis of Political Calibration of Integrated Assessment Modelling in Light of the 1.5°C Goal” (2022) 133 Environmental Science & Policy 193–202.
M. Allen et al (eds), “Global Warming of 1.5°C: An IPCC Special Report on the Impacts of Global Warming of 1.5°C above Pre-Industrial Levels and Related Global Greenhouse Gas Emission Pathways, in the Context of Strengthening the Global Response to the Threat of Climate Change, Sustainable Development, and Efforts to Eradicate Poverty” (2018) IPCC, available at <https://www.ipcc.ch/sr15/> accessed 20 September 2024; IPCC, Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (CUP 2022).
For an older, long profile, see: A. Rathi, “Vicki Hollub Is Showing Big Oil How to Survive Climate Change” (Quartz, 1 July 2019) available at <https://qz.com/1641227/vicki-hollub-is-showing-big-oil-how-to-survive-climate-change> accessed 28 July 2024.
For a good overview of the proposals and its scientific uncertainties, see National Academies of Sciences, Engineering, and Medicine, Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance (National Academies Press 2021); National Research Council, Climate Intervention: Reflecting Sunlight to Cool Earth (National Academies Press 2015).
Importantly, however, there exists serious concern about unequal cooling effects of MCB technologies. As Wan et al show, for example, cooling of the USA could lead to increased heatwaves in Europe. Such effects raise quite serious concerns about the feasibility of MCB technologies, see J. S. Wan et al, “Diminished Efficacy of Regional Marine Cloud Brightening in a Warmer World” (2024) Nature Climate Change 1–7.
For a first-hand account, see S. H. Schneider, Science as a Contact Sport: Inside the Battle to Save the Earth’s Climate (National Geographic Society 2009).
R. Frosch, as cited in J. R. Fleming, Fixing the Sky. The Checkered History of Weather and Climate Control (Columbia University Press 2010) 246.
C. Hamilton, “No, We Should Not Just ‘At Least Do the Research’” (2013) 496 Nature 139.
See A. Ghosh, The Nutmeg’s Curse: Parables for a Planet in Crisis (University of Chicago Press 2021) for reflections the USA’s geopolitical power; J. Schubert, “Science-State Alliances and Climate Engineering: A ‘Longue Durée’ Picture” (2022) 13 WIRE s Climate Change e760 for a history of US interest in solar geoengineering.
Hamilton (n 19).
For an overview of physical risks, see National Academies of Sciences, Engineering, and Medicine, “Reflecting Sunlight” (2021), available at <https://nap.nationalacademies.org/catalog/25762/reflecting-sunlight-recommendations-for-solar-geoengineering-research-and-research-governance> accessed 28 July 2024; P. L. Zarnetske et al, “Potential Ecological Impacts of Climate Intervention by Reflecting Sunlight to Cool Earth” (2021) 118 Proceedings of the National Academy of Sciences e1921854118; M.G. Lawrence et al, “Evaluating Climate Geoengineering Proposals in the Context of the Paris Agreement Temperature Goals” (2018) 9 Nature Communications 3734.
Biermann et al (n 2) 2.
N. Oreskes and E. M. Conway, Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming (1st US ed, Bloomsbury Press 2010); G. Supran and N. Oreskes, “The Forgotten Oil Ads That Told Us Climate Change Was Nothing” (The Guardian, 18 November 2021), available at <https://www.theguardian.com/environment/2021/nov/18/the-forgotten-oil-ads-that-told-us-climate-change-was-nothing> accessed 28 July 2024; M. Mildenberger, Carbon Captured: How Business and Labor Control Climate Politics (MIT Press 2020).
J. L. Reynolds, The Governance of Solar Geoengineering: Managing Climate Change in the Anthropocene (1st ed, CUP 2019) 76.
ibid 198.
About the London Convention/Protocol, see (LC/LP, “Resolution LC-LP.1 (2008) on the Regulation of Ocean Fertilization” (2008) LC/LP.1; LC/LP, “Resolution LC-LP.2(2010) on the Assessment Framework for Scientific Research Involving Ocean Fertilization” (2010) LC/LP2; and LC/LP, “Resolution LP.4(8) on the Amendment to the London Protocol to Regulate the Placement of Matter for Ocean Fertilization and Other Marine Geoengineering Activities” (2013) Resolution LP.4(8). See also the discussion by Harrison in chapter 8 of this volume. About the CBD, see CBD, “Biodiversity and climate change” (2010) COP Decision X/33.
See eg C. Garrison, “Insight: How Two Weather Balloons Led Mexico to Ban Solar Geoengineering” (Reuters, 27 March 2023), available at <https://www.reuters.com/business/environment/how-two-weather-balloons-led-mexico-ban-solar-geoengineering-2023-03-27/> accessed 28 July.
Oomen (n 6); M. G. Lawrence and P. J. Crutzen, “Was Breaking the Taboo on Research on Climate Engineering via Albedo Modification a Moral Hazard, or a Moral Imperative?” (2017) 5 Earth’s Future 136–143.
A. Gupta and I. Möller, “De Facto Governance: How Authoritative Assessments Construct Climate Engineering as an Object of Governance” (2019) 28 Environmental Politics 480–501.
Notably, this already failed in respect to CDR, which has become an embedded assumption of climate politics despite the absence of any good governance mechanisms.
Oomen (n 6) 202.
Biermann et al (n 2) 5.
For example, the National Academy of Sciences proposed a system with ‘offramps’, in case research turn up unexpected physical risks. In several other publications, Buck and Nicholson, and Parsons and others have also introduced new options: H. J. Buck and S. Nicholson, “Solar Geoengineering Research in the Global Public Interest: A Proposal for How to Do It” (2023) 6 One Earth 1652–64; National Academies of Sciences, Engineering, and Medicine (n 22); E. A. Parson et al, “Toward an Evidence‐informed, Responsible, and Inclusive Debate on Solar Geoengineering: A Response to the Proposed Non‐use Agreement” (2024) WIRE s Climate Change e903.
National Academies of Sciences, Engineering, and Medicine (n 22); UNEP, “One Atmosphere: An Independent Expert Review on Solar Radiation Modification Research and Deployment” (2023), available at <https://www.unep.org/resources/report/Solar-Radiation-Modification-research-deployment> accessed 20 September 2024.
Furthermore, the debate about the non-use of SRM typically revolves around the question of intent rather than the use of a specific resource. In the case of SAI, for example, the use of the technology would entail adding sulphur or calcium carbonate to the stratosphere, using the stratosphere as a resource for climate protection. However, it is the intent of climate manipulation (and its possible consequences) rather than the introduction of particles itself that is deemed problematic. Humanity already emits a lot of sulphur into the atmosphere as a side-effect of industrial production, shipping, and aviation – which is not deemed problematic in the same way.
For an in-depth analysis, see A. Gupta et al, “Towards a Non-Use Regime on Solar Geoengineering: Lessons from International Law and Governance” (2024) Transnational Environmental Law 1–32.
See eg O. Corry, Constructing a Global Polity Theory, Discourse and Governance (Palgrave Macmillan 2013); B. Allan, “Producing the Climate: States, Scientists, and the Constitution of Global Governance Objects” (2017) 71 International Organization 131–162; M. Hulme, Why We Disagree about Climate Change: Understanding Controversy, Inaction and Opportunity (CUP 2009).
J. Oomen and M. Meiske, “Proactive and Reactive Geoengineering: Engineering the Climate and the Lithosphere” (2021) WIRE s Climate Change.