It is not an exaggeration to claim that climate change is the defining problem of our age. It is a problem that needs to be managed and, hopefully, solved. Since Crutzen’s (2006) watershed publication, Solar Radiation Management (SRM) — a specific climate engineering (CE) technology — has entered the mainstream parlance in climate politics and several researchers now consider it as one of the options available, alongside mitigation, adaptation, and other CE technologies, to address the climate problem. According to the influential definition offered by Shepherd et al. (2009), climate engineering is the deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change. CE technologies can be distinguished into two types: on the one hand, Negative Emissions Technologies (NETs) remove CO2 from the atmosphere and, thus, work towards the mitigation of the climate; on the other, SRM techniques reflect a part of the incoming sunlight and heat back into space. SRM masks the warming effects of atmospheric concentrations of greenhouse gases (GHG), but does not reduce them and, in this sense, it is similar to an adaptation measure.
The idea of engineering the climate by altering the reflexivity of the earth has a long history (Morton 2015). However, for a long time, it was considered taboo to suggest that it might be a serious strategy to curb rising atmospheric temperatures (Reynolds 2019: 18). Recently, the ever more frequent frame of climate emergency (Lane et al. 2007; Sikka 2013; Hulme 2014) and the realisation that the pace of mitigation does not yet match political goals has brought many scholars to reconsider the balance of risks and benefits between not having this kind of technological asset in our climate solutions portfolio, if we ever need one, and having it, even though it might be dangerous and difficult to manage. Whereas the earlier taboo suggested that the risks of trying to manage SRM might not be worth taking, now the ever-growing production of research dealing with the governance and management of SRM tells its own different story. Nonetheless, concerns over SRM research, governance, deployment, and termination remain and abound.
The Intergovernmental Panel on Climate Change (IPCC) has so far been suspicious of SRM. In the 2018 special report of 1,5°C (IPCC 2018), the IPCC did not include any SRM in the modelled pathways because of ‘large uncertainties and knowledge gaps as well as substantial risks and institutional and social constraints to deployment related to governance, ethics, and impacts on sustainable development’. Things might still change when the other two reports of the sixth cycle come out next year.
And one problem in particular keeps creating a cleavage between researchers supporting SRM and those more sceptical of it: does implementing SRM, and thus lowering atmospheric temperatures to acceptable levels, create a moral hazard such that people and governments will be less likely to pursue ambitious climate mitigation? This is one of those risks mentioned above by the IPCC related to governance, ethics, and impacts on sustainable development. Furthermore, since SRM only masks the warming effects of atmospheric concentrations of GHGs but does not reduce them, once the deployment of SRM is stopped, and if mitigation has been insufficient, atmospheric temperatures would rapidly rebound to the level that they would have reached without deployment. The consequences of this could be disastrous to humans and ecosystems, as they would have little time to adjust and adapt. Once deployed to exert a high degree of cooling — this is an important disclaimer (Reynolds et al. 2016; Parker and Irvine 2018) — to avoid a termination shock, SRM needs to be phased out over a long period and cannot be stopped abruptly. The issue of the possible moral hazard in implementing SRM is, indeed, quite serious.
According to Szerszynski et al. (2013), once SRM is deployed, opting out will be limited by the economic forces interested in the continuation of deployment and likely to be opposed to more ambitious mitigation efforts. To this, Horton et al. (2018) reply that SRM would favour vested interests no more than other forms of climate risk management such as mitigation, adaptation, or negative emissions technologies, all of which are currently considered acceptable. Furthermore, the authors note, the relatively small implementation costs of SRM would limit the potential of the technology to become the preferred option for private economic gain and, consequently, a force capable of shaping policy, as is the case with the fossil fuel industry. While their position is understandable, it is nonetheless important to stress that the costs of operating a technology might not necessarily reflect the possible profit margins of a company, especially if it is perceived as providing an essential good. Those margins, if large enough, might then bring researchers to reconsider the impact of the companies operating SRM technology on the public sphere. Large profits might also be accrued by those companies who researched, developed, and patented the deployment technology as, despite the usual rhetoric of SRM being cheap and potentially deployable unilaterally, the technology to spray large quantities of particles at the altitude of the stratosphere is not quite there yet.
However, as the authors rightly note, the main concern when addressing the possibility that SRM might be co-opted by the economic forces is really that SRM might end up displacing mitigation and, by so doing, locking humanity into continuous deployment in order to avoid a termination problem; that’s the moral hazard problem. The position according to which SRM would displace mitigation comes from the reasonable intuition that policy and economic actors might adopt risk compensating behaviours if SRM becomes available. As noted by Reynolds (2021), risk compensating behaviours are common in public policy and often lead to a net benefit; however, if such behaviour contributes to develop or intensify a termination problem and making opting out more difficult, then it warrants the preoccupation expressed by the critics of SRM, such as Szerszynski et al. (2013), irrespective of the net-benefit accrued in economic terms.
Opinion surveys and behavioural experiments have been conducted to check whether, after learning about SRM, respondents would commit to more or less mitigation. As respondents usually increase their commitment towards climate mitigation, probably because of the sheer undesirability of SRM and/or an availability heuristic dynamic, these studies are used by proponents of SRM to argue against the claim that SRM would displace mitigation (see Reynolds 2019: 37-40). That being said, the context of these studies is rarely representative of how debates unfold in the public sphere where framing and perceived affiliations play a large role.
Sikka (2012) and Huttunen et al. (2015) use discourse analysis to understand how different political groups frame CE and how CE technologies are being constructed and made political. These studies find that some political actors are already trying to force a ‘premature closure of the framing’ (Bellamy et al. 2012) by highlighting certain features of CE. According to Sikka (2012), neoliberal think tanks linked to private corporations tend to discursively position CE as useful to sustained economic growth and in line with neoliberal societal values. Huttunen et al. (2015) similarly found that climate-sceptic think-tanks and lobbyist are active in the pro-CE political arena and ‘have prepared very politically charged reports for national and international audiences’ (2015: 27). They also found that official policy documents in the US and UK tend to present the debate around CE as technical and environmental issues – thus focusing on cost-efficiency and technical feasibility – rather than societal ones which would focus on the ethical implications and the possibility of SRM displacing mitigation. Ott (2018) found that the political economy of the US fits with a political position favourable to SRM deployment. The reply that SRM is not a right-wing corporatist project because right-wing politics often denies climate change instead of trying to solve it (Reynolds et al. 2016), is oblivious to the fact that this discursive pre-positioning of SRM will become useful when the reality of climate change cannot be denied anymore, when the political landscape moves and what is left on the table are only solutions which can be more or less favourable to the powerful economic actors and more or less consistent with the economic status quo.
Both the capture from economic interests and the possibility of emission displacement remain valid concerns when it comes to the issue of opting out of SRM. Strategically linking SRM to mitigation could offer a possible solution to this problem; this means that countries which planned and pursued an ambitious mitigation strategy could use SRM to shave off the peak in temperatures later in the century. But once again, problematic collective dynamics remain: if a country doing its part of the mitigation effort could implement SRM at the scale and level to significantly cool the atmosphere, then we might solve a moral hazard problem in the country implementing SRM but not globally. If, on the other hand, a country doing its part of the mitigation effort implements SRM in a way that it is proportional to its mitigation, then we might not be able to reach a significant cooling of the atmosphere. Another proposal to address the possible termination problem is to have a governance system which kickstart a gradual phaseout of SRM when certain conditions are met, for example, when a percentage of the countries wishes to pull out because of unplanned adverse effects. But while admirable and ingenious in theory, this solution might not work in practice. Time and again international politics has been driven by the interests of the most powerful countries: what would happen if the majority of the countries wanted to pull out of SRM and kickstart the gradual phaseout but not USA and China?
Researchers are pondering these questions and the answers are never straightforward. Sometimes disagreements between groups of researchers go all the way down to what counts as reliable data in an experiment or the appropriate methods to conduct it. Being told about SRM and then being asked, directly or indirectly, whether one supports more or less mitigation is an approach potentially rife with biases. On the other hand, assuming that people will adapt to SRM to the point of prolonging it indefinitely while dismissing the experiments because, no matter how well-designed, they cannot anticipate the larger socio-technical imaginaries into which these technologies will be inscribed, is also a non-starter.
These debates have so far mostly unfolded away from the mainstream media and relegated to seminars, conferences, and scholarly articles; a fuller engagement with the public could potentially offer a third way beyond the dichotomy between biased experiments and the impossibility to even conceive experiments representative enough. That being said, one has the feeling that both proponents and sceptics fear more participation (what if the public likes the idea? What if the public dislikes it?). A lot is at stake: from personal careers to none other than addressing climate change. Of course, when SRM pilot projects have been proposed, local populations have been consulted to give consent to them, but what is needed now is a more open public debate on geoengineering similar to what is currently happening in France about the role of nuclear energy in the decarbonisation path of the country.
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